This guide is to help you build the DOUK KSL-M77 Preamp clone kit.

[Kanders1]

The responsibility is with you to make sure you understand the safety implication of Valve amplifiers. They can kill you!

The modification worked on my amp. If it does not work for you then I am not responsible for any damage you may incur.

If you use this information its at your own risk. It’s a guide. I did a lot of research into building this amp I suggest if you don’t like the suggestions then do your own research and your own modification.

This is a very good sounding Preamp! It’s not by any means the Kondo M77 !! Just Google the real thing and be impressed by just the images! But for around 30k it should sing you to sleep and make your breakfast! Having said that you wont be disappointed with the clone its fun to build and lends itself to modifications and upgrades.

There are some fundamental items you will need to complete this build.

A soldering iron with a flat tip and a pointed tip
Solder
A test meter
Screw drivers
Wire stripper
Heat shrink insulation
Tweezers for SMD components.

Best regards,
Karl Anderson


Building the KSL-M77 Clone from DOUK/NOBSOUND

The build is relatively straight forward, even with very little ‘electronic’ knowledge. Having said that you will need a steady hand for soldering and if the amp does not work when finished you may need a friend who does know their way around a valve or two. The reason being is that at the time of writing this document the schematic that is supplied with the board is not accurate and there are a few values and items missing from it. One thing that you will notice is that there are 9 valves in total on the board but only 7 shown on the schematic. But if you look close you will see one section does show a 1/2 therefore implying the section is copied.

The amp has a great sound! And for the cost it’s hard to better! BUT out of the box build it “Hum’s” like it don’t know the words..!! The good news is that it can be fixed. This is where you need the soldering skills.

The board can be bought in three states, just the board, built with no capacitors and finished. (There are no valves supplied with any build).

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I personally went for the finished board, mainly because its tested and one less issue for me to look into if it does not work. I then upgraded the parts I believe needed changing. The choice is yours..!

You will need a box! And it needs to be big enough to fit the amp board, a good-sized transformer and an extra power rectifying/smoothing board. There are a number of boxes out there just be mind-full that many do not have holes drilled and text on them. Drilling holes not such a big issue but screen-printing text to get the ‘Pro’ look isn’t that easy. Again the choice is yours.

I bought the ‘Kondo KSL-M7 box off E bay purely because it has the right holes and the text is correct for the amp functions. The only issue I found is that the M7 board is smaller than the M77 board and fitting the ‘on off’ and volume pot requires some thought and slight modifications. Also if you want to fit different caps later on as an upgrade the volume pot will limit the physical size of capacitors.

The chassis comes with power inlet (cheap don’t use) on/off switch (again not very nice) Two solid aluminium control knobs. All screws, An LED and a safety cap are supplied. The chassis was very well packaged and comes flat packed overall excellent quality. Very quick delivery too!

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The transformer, I purchased the DOUK 230V one meant for the board. Reasonable price plus it’s got all you need for the amp on it. Again as long as you have the right outputs you can source a transformer of your choice. (Required Outputs are 100W, 250v-0v-250v 12.6v and 6.3v)

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[Kanders1]

The mains filter, I bought a filter/fuse and mains socket combined to replace the cheap supplied one and to keep thing neat. It is very slightly larger so a small modification with a flat file is required.
BULGIN IEC EMI FUSED INLET FILTER PS20/A0320 250V AC 3A RATING POWER ENTRY

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The additional rectifier/regulator Board. (To replace the original on board heater DC supply, this is the primary cause of the HUM)
Supplied by - Jim’s audio (E-bay) LT1963A very low noise 1.2V-20V 1.5A - 6A power supply PCB w/soft starting! This comes as just a board; you will have to build it. Its not hard and you only need one side of the board to supply the clean DC for the valve heaters. The board uses SMD components so a pointed soldering iron, some tweezers and a steady hand is needed. (YouTube training if you have never done it plus you can practice on the spare side of the board. As some of the components come in qty of 10 only).

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I used a Texas Instruments TPS7A4501KTTR IC, REG LDO ADJ 1.5A 5DDPAK regulator chip but the LT1963AEQPBF (PBF - lead free) is available at RS Components. The rest of the items I got from E-bay and Mouser (postage is expensive). Jim’s Audio supplies a parts list.
Note: - The 100uf 50v 1812 SMD cap (C25 C26) is not easy to get. The voltage does not exceed 12v at this point so a 100uf 16v can be used (mouser have AVX 100uf 16v 1812 size) I didn’t use the 2 pin terminal blocks, easier to solder directly onto the board. Also you will need a heat sink for this. I modified a computer processor one to fit but they are easy to find on the web.


Volume control, I used a China 24 step attenuator to start as I wanted the stepped volume control. As it happens it seems very good for the money! My intention was to upgrade it but can’t really fault it. The only issue is fitting it in! They are big fortunately the China copy does not have its resistors soldered the same way as the real thing so you can bend them out away from the valves located in that area. In hindsight the ‘ALPS RK27112 Audio Potentiometer 100k stereo’ would be best for packaging. (Beware of China copies! Info on the web how to tell the difference)

Audio connections and wire, I used silver Phono sockets and RS wire to connect the inputs/outputs. I started with screened wire but found it not so easy to work with around the multiple signal in area of the board and also I think it may also have given me some grounding issues. So twisted single core wire for all the in’s and out’s.

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Building the amp.
I put mine together as is from DOUK using the finished board. Most of the connections are oblivious. And labelled on the board. The AC connection to the board are 6.3v 250v-0-250v 12.6v I soldered them from below purely for neatness. They are labelled on the DOUK transformer but mine had yellow as 250v - 0v but actually was orange.

The new mains filter socket has the safety capacitor already fitted, it is slightly larger than the supplied socked hole but a file is all that’s need to make it fit.

I drilled an earth point for a nice solid ground point to the chassis next to this socket and connected the earth to it and then the earth wire from the transformer. And also an earth for a phono connection, I drilled mine in the middle but its better located near the divide as there is more room for the earth wire to the board and the banana plug socket. (The board earth is located in the centre)

The Transformer is mounted on 10mm acrylic spacers to lift it from the chassis (this was a recommendation from DOUK when I queried the hum from the finished stock unit, not sure if it really made any difference TBH). The transformer is still connected to the chassis via nuts bolts and spring washers. I had to drill new holes for the Transformer fixings.

The main board, its important to get this in the right place if you use the same box as I did as its a tight fit. There are pre drilled threaded holes but these are for the M7 board so no use. Also bear in mind where the chassis feet will go. There are pre drilled holes but even they interfere with some other threaded pre drilled holes.( I ended up moving the feet and using 3M double sided tape for a temporary fix whilst building).
Fit the volume control into the front panel along with the selector switch. The on/off switch was not a nice one supplied so I went for a good old heavy-duty toggle switch; this is a problem though… as the heat sink for the power transistor gets in the way of the switch. I fixed this by removing the end two legs from the heat sink and then slightly bending the next two outwards.

[Kanders1]

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You may also find the hole in the front panel to large for the switch. I turned a small aluminium bush to fix this.

Fit your switch and locate the board into the best place and mark the holes for the fixings. Remember the valves!! They stick up!! So if you have them or just some that fit put them in to check clearances. Mark the hole positions and drill clearance holes for the supplied brass up-stand fixings.

Put the center divide into place and position your transformer as close to the chassis side as possible (put the side on to check before you fix) it needs to go near the front so as to allow room for the LT1963A regulator board you will fit later. Remember the selector switch! it has a ribbon cable connected too so make sure you have it in. Position the transformer and mark the fixing hole positions.

Once you have the locations and all seems to fit okay, you can solder the connections. If you use single core unshielded cable then make sure you twist each pair together. Make sure the phono sockets are tight before you solder. I only connected the Phono stage and CD to start with to test the board.
The volume control is wired as a stereo duel pot. The pin out connections are not labelled on the board.

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The connection nearest the edge of the board is pin 1

There is a balance control but I did not use this.

Connect the transformer to the mains filter and earth tag on the chassis, (the filter does not come with a fuse) the chassis supplied one does..! Make sure you twist the transformer leads together for each set of voltages (reasonably tight twist is best) then solder to the main board. As its AC it does not matter which way round the12.6v and 6.3v supply wires go, but make sure the 250v-0v-250v are correct!

The mains switch, depending on what type you want connect it as required, switch the mains 230v live.
**MAKE SURE YOU HEAT SRINK WRAP THE CONNECTIONS OF THE SWITCH!!**

If you don’t things could get a little hot and sparky!! Including you! If you can see any metal or wire on the switch connections you are asking for trouble. Be warned!!

There is an LED for on off supplied but I used one of the on board ones this is located by the 7805 chip. Either remove and put a 12v LED of your choice or just move it to the front panel. (I would leave this until you have had the board working).

So now you should have all the parts secured and connected. Check over for anything obvious like ins and outs connected the wrong way round and look for anything that may short out like bits of wire or loose solder that’s dropped into the board or even the chassis. Put the 12ay7 valves in. Leave the rectifier valve out that way you don’t get B+ high voltage through the board yet. Switch the selector to CD. If all is good you should see the pre amp valve heaters glow, then turn the selector switch to phono to get the phono stage valves to light up. Check the voltage ‘CAREFULLY’ at the 12.6v test point. Mine read low set to phono and correct set to CD. Don’t worry too much about this at the moment because there is a good chance the amp will hum anyway and you will be replacing the 12.6v supply with a much cleaner and adjustable one.

If all the heaters work switch off and put the rectifier 6X4 valve in. Connect a CD player and try the amp. Mine worked fine first time, as it was a complete tested board. If you have built yours and its not working then good luck with fixing it! ;-)

So if you have a preamp that works and does not HUM Then congratulations!

But if like a few others and myself you do have a hummer then you can fix it. The Hum in mine was two fold. One was with the Preamp volume down power amp volume up which I think was due to an earth loop. I rewired later without screened cable, which I believe was the cause, but can’t verify. And the other HUM was from the heater supply being on the main board, and to close to the audio signal paths. There is a ton of info about this on the web if you are interested.

Teaching the amp to sing and not hum !

The schematic is not so helpful, but its not a million miles away. I printed it out on A3. There is a version that is on a white background most are on a black background that makes it hard to read. I got this from DOUK. I also printed the images of the circuit board, both sides on A3 this is a double sided board so having both sides is important. (Google images)

You need to construct the LT1963A board including a heat sink! And test its supplying 12.6v (its adjustable with the small variable pot that’s on the board) use the 12.6 AC supply from the transformer and measure the output. It should be set to 12.6V DC. Once you are happy its working mount the board behind the transformer. I used the brass up stands again stacked two high to let air get around but you can mount side on its up to you. You will be connecting the output directly to the main board so some long wires required.

Because you now have a new 12.6V smooth ripple free DC supply you don’t need the rectifier or smoothing capacitor on the main board. These components need to be removed. So remove the four diodes and the first 4700uf 25V capacitor after them. The cap is stuck to the board with mastic.

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Connect the new supply to the middle 1000uf 25v capacitor that is located just below the two 5 ohm 5W resistors. MAKE SURE YOU GET THE + and - the correct way round !!! solder to the underside. (See images)

Re assemble the amp and test again without the 6X4 check and adjust the 12.6 voltage when the phono is selected. Replace the 6x4 and play the CD. Hopefully you have a great sound with no hum..!! Well done. If all works well connect the other inputs and tidy up.

If you have Hum still.. Check your “earth’s” you may have an earth loop somewhere.


I have changed the supplied caps with better quality parts, but even so the original amp configuration sounded very good indeed. You may need to stack the caps due to the volume control position.

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[Kanders1]

Here are a couple of images of inside the chassis, any question I will try to help as much as i can.


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Hope this helps someone.. and saves some time in research :) Good luck if you have a go at this project.

Cheers K :cool::cool:

[Bigman80]

Great post.

[walpurgis]

Good stuff!

[Wakefield Turntables]

Surely best post of the year! Well done!!

[Kanders1]

Thanks gents...! 😊

Very kind words..

[Kanders1]

I have just found that you can buy the actual chassis for the M77.. Ive :hmm: ordered one :hmm: Its from China of course and Ive not used this web site before.. so my house could now belong to the peoples republic of China... :help: Ill update post if and when I receive it.

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K :)

[montesquieu]

Anyone else feel a bit uneasy about branded knock-offs like this?

[Clive]

Anyone else feel a bit uneasy about branded knock-offs like this?

I do feel uneasy but this is tempered by the excruciating price of the original in this case. At least it's not going take sales from AN Japan. The board originates from a part of the world with a different attitude to IPR. Morally yes I'm conflicted but I'm interested too...and as has been said a real M77 will no doubt sound different. If I'm going to expend moral outrage I suppose I'll reserve it for climate change, plastic, even Brexit (all conversations have to come back to this nowadays).

I suppose I'm 25% uneasy, 75% interested.

[Bigman80]

Anyone else feel a bit uneasy about branded knock-offs like this?Nope [emoji23][emoji23]

I think for DIY, as long as its stated as a replica, it's ok.

[montesquieu]

Nope [emoji23][emoji23]

I think for DIY, as long as its stated as a replica, it's ok.

Cloning circuits has a long history going back to the dawn of hifi and there certainly seem to be a few versions of the M77 circuit out there and have been for a long time. It's kind of hard to argue that's a big issue especially as it's never going to sound like a Kondo with its hand-rolled capacitors and silver hand-wound transformers. (Hearing the M77 in my setup was a transcendent experience for me and changed my view about preamps fundamentally).

But having built the circuit, why not just put it in a standard case? Why clone the case if it's not the intention to mislead in some way?

In my view it's like fitting Toyota with Ferrari badges and a bodykit. What's wrong with admitting it's a Toyota?

[crimsondonkey]

Great idea for a thread, nice work.

I heard this one a while back - https://audioabattoir.com/t/build-your-own-747/673

Suffice to say it was an uncomfortable couple of hours for the three Kondo M7 owners in the room...

[montesquieu]

Great idea for a thread, nice work.

I heard this one a while back - https://audioabattoir.com/t/build-your-own-747/673

Suffice to say it was an uncomfortable couple of hours for the three Kondo M7 owners in the room...


Never been a fan of the M7. The M77 is in a different league entirely (sonically and indeed in terms of its price!).

[crimsondonkey]

Never been a fan of the M7

Nor me. Its an effects box, which if you like that lovely golden Kondo sheen on all your music , is great - but I don't particularly.

The Nobsound M77 as a number of people noted, was somewhere between the M7 and M77 and erred towards the M77 in terms of character.

[Mr. C]

Agree 100% with the Donkey,

Have both a M7 and M77 neither of them really deliver involving music, a beautiful soundscape polished within an inch or its life indeed yes, musical er...NO

Why not have a spot of DIY if you can match 80% of the performance for 10% price go for it, you will also see many areas of improvement you can perform whilst you are in the build and finial running stage.

But that was the fad a few years ago KONDO, humm these days you can obtain far superior sounding products for less imho

Also good write up on the build, nice to see some one having a go at a project well :)

[Bigman80]

Cloning circuits has a long history going back to the dawn of hifi and there certainly seem to be a few versions of the M77 circuit out there and have been for a long time. It's kind of hard to argue that's a big issue especially as it's never going to sound like a Kondo with its hand-rolled capacitors and silver hand-wound transformers. (Hearing the M77 in my setup was a transcendent experience for me and changed my view about preamps fundamentally).

But having built the circuit, why not just put it in a standard case? Why clone the case if it's not the intention to mislead in some way?

In my view it's like fitting Toyota with Ferrari badges and a bodykit. What's wrong with admitting it's a Toyota?Well, that's kind of my point, Tom. As long as the article is clearly defined as a Knock-off, where's the harm.

I've seen loads of folks buying up the knock-off EAR834 clone boards and telling folks they have an EAR834, when they don't.

To OP is going for the same case as the PCB out of pride in his work most probably rather than to deceive and that's very important in my view of the subject.

He's been up front about it.

[Wakefield Turntables]

Well I own a fairly well sorted EAR 834 clone. I only originally bought the thing for a bit of fun but I went in balls deep and ended up with something that sounds pretty half decent. TBH I wanted a MM phonostage for my then Lenco 75 project which utilised a highly modded Shure M55E cart, overall the EAR sounded very very good. Currently it resides in my Garrard 301 / Valve system. It occasionally gets fired for a but of fun. I won't be selling it but I've no doubt that an original EAR 834 probably sounds miles better. There are umpteen threads comparing some of these clones, some appear to be better than others, I suppose like most things you'll have to do your own research.

[montesquieu]

Well, that's kind of my point, Tom. As long as the article is clearly defined as a Knock-off, where's the harm.

I've seen loads of folks buying up the knock-off EAR834 clone boards and telling folks they have an EAR834, when they don't.

To OP is going for the same case as the PCB out of pride in his work most probably rather than to deceive and that's very important in my view of the subject.

He's been up front about it.

It's still a Toyota with Ferrari badges on.

[Bigman80]

It's still a Toyota with Ferrari badges on.As long as it's "sold" like that, will utter transparency, there's no drama IMO.

[montesquieu]

As long as it's "sold" like that, will utter transparency, there's no drama IMO.

Is that really what you think when you see one in the street?

[Bigman80]

Is that really what you think when you see one in the street?Yes, there's a local guy who managed to convert an old Mazda (I think) into a Ferrari lookalike. Its convincing from a distance but as you get up close, it's obvious a lookalike and when you ask him he absolutely acknowledges that it's a bit of fun and not to be taken seriously.

I think you have to look at this M77 in the same vein. Its a homage to the original, an original so expensive that the only way to even get close to one is to replicate it. Hell, every bloody valve amp out there has topology and a circuit diagram that's been done before. There's nothing new, it's all a recycle and a few tweaks of old technology .

The M77 is an interesting kit and having the matching chassis is a bonus. Why not have some fun and knock up a knock-off!

[montesquieu]

I think you have to look at this M77 in the same vein. Its a homage to the original, an original so expensive that the only way to even get close to one is to replicate it. Hell, every bloody valve amp out there has topology and a circuit diagram that's been done before. There's nothing new, it's all a recycle and a few tweaks of old technology .


That's actually not true in the least there's quite a lot of genuine innovation if you look for it.

[Bigman80]

That's actually not true in the least there's quite a lot of genuine innovation if you look for it.Well, we disagree, not for the first time!

My point is, us mere mortals with low budgets for hifi can't afford "genuine innovation" so what we end up with is recycled, revamped circuits in new chassis with shiny new badges.

You may not agree but take a browse across anything from China with a valve in and I am confident it will be taken from some circuit developed in the 60s. Valab did it with their Valve phonostage, it was a copy of the old Marantz phonostage.

Its very common, Tom but less so in the pool of good you play with.

[Wakefield Turntables]

Guys, have a look at some of the threads about this subject. Some posters have gone to great depths detailing the differences between the original designs and the chi-fi clones. As I stated some clones appear better than others with respects to how faithful they've been in copying the original design.

[Bigman80]

Guys, have a look at some of the threads about this subject. Some posters have gone to great depths detailing the differences between the original designs and the chi-fi clones. As I stated some clones appear better than others with respects to how faithful they've been in copying the original design.Will do, I'm now rather interested in building one [emoji38]

[Firebottle]

Well I own a fairly well sorted EAR 834 clone..... but I've no doubt that an original EAR 834 probably sounds miles better.

The clone you have with the FB modifications is far better than the original EAR 834. I have applied similar modifications to a real 834 and improved it a fair bit.

[Bigman80]

The clone you have with the FB modifications is far better than the original EAR 834. I have applied similar modifications to a real 834 and improved it a fair bit.I have heard both variations of that phonostage, the original and the modded. The modded is far better IMO.

[Primalsea]

For me the issue is people earning money from someone else’s work and IP. Copying something is fine, even copying something for a friend who compensates you for your time. It’s when someone makes a business of it without the original designer’s permission.

[Wakefield Turntables]

The clone you have with the FB modifications is far better than the original EAR 834. I have applied similar modifications to a real 834 and improved it a fair bit.

I was being modest!

[Wakefield Turntables]

For me the issue is people earning money from someone else’s work and IP. Copying something is fine, even copying something for a friend who compensates you for your time. It’s when someone makes a business of it without the original designer’s permission.

TdP put the 834 circuit into the public domain so the 834 can be cloned legally.

[Lawrence001]

I think if a law is being broken then it's wrong as that's why we have the laws to protect us. Having access to global markets via the internet to import stuff from countries who don't subscribe to the same IP protections is as bad as going to your local market and buying a Rolex knock off from a guy with a suitcase.

However, if the circuit is not patented/copyrighted or the differences between them are sufficient to make the copy legal (and as I understand it fairly minor changes are usually enough) then I don't see a problem. If nobody had ever copied Edison's lightbulb and improved it, or Watt's steam engines, where would we be now?

Having made the first point, I would ask how many of us have at least one music file that is not a legitimate copy of an album we have bought? Where do you draw the line?

Sent from my BLN-L21 using Tapatalk

[Bigman80]

I think if a law is being broken then it's wrong as that's why we have the laws to protect us. Having access to global markets via the internet to import stuff from countries who don't subscribe to the same IP protections is as bad as going to your local market and buying a Rolex knock off from a guy with a suitcase.

However, if the circuit is not patented/copyrighted or the differences between them are sufficient to make the copy legal (and as I understand it fairly minor changes are usually enough) then I don't see a problem. If nobody had ever copied Edison's lightbulb and improved it, or Watt's steam engines, where would we be now?

Having made the first point, I would ask how many of us have at least one music file that is not a legitimate copy of an album we have bought? Where do you draw the line?

Sent from my BLN-L21 using TapatalkMy line is dictated by budget. I'm not interested in "fakes" like rolexs etc but a hifi DIY PCB isn't in that category for me. Its an opportunity to build something and if anything, Chi-Fi has demonstrated that they don't bother to really put the effort into most of the clone PCBs to be even nearly accurate.

Layout, track width and thickness would need to be exact and they never are so they can never be real clones.

[User211]

The clone you have with the FB modifications is far better than the original EAR 834. I have applied similar modifications to a real 834 and improved it a fair bit.I doubt that would be hard. I had an 868PL and grew to realise it wasn't that great pretty quickly. Initially I conned myself it was good, though.

Made serious money when I sold it. I got it ridiculously cheaply.

[User211]

The only real concern I would have is if the knock off gets so good it becomes hard to differentiate it from the real thing.

Accuphase anyone?

https://youtu.be/Mn-JTDEk-_g

[oceanobsession]

A big thanks to the op for taking the time to share his knowledge and experience . also worth a look at jims audio which has some fine looking boards and components . phil

[Mr. C]

There is no way you can label a circuit diagram a patent just one change of device and the circuit can be used for a completely different purpose

Main difference between the M7 and M77 apart for a bank balance outlay is the ability to bore the bollocks of a charging Rhino at 60 paces increases Four fold

Think extra polish to a really well wax valeted car

Oddly enough although the Audio Note is not as smooth the musicality is far better, now perhaps a M10 signature clone would be more interesting? Though a three box pre amp does take up the rack space somewhat!

I suspect the gent who started the thread may have heard one of these nice pre amps as one resides also in his home town

[User211]

I just read the Abbatoir thread.

Great to see the boys are still on form. Some class A humour in it.:)

[Barry]

There is no way you can label a circuit diagram a patent just one change of device and the circuit can be used for a completely different purpose

Main difference between the M7 and M77 apart for a bank balance outlay is the ability to bore the bollocks of a charging Rhino at 60 paces increases Four fold

Think extra polish to a really well wax valeted car

Oddly enough although the Audio Note is not as smooth the musicality is far better, now perhaps a M10 signature clone would be more interesting? Though a three box pre amp does take up the rack space somewhat!

I suspect the gent who started the thread may have heard one of these nice pre amps as one resides also in his home town

That is so arcane, I simply don't understand what you are describing. :scratch:

[montesquieu]

Main difference between the M7 and M77 apart for a bank balance outlay is the ability to bore the bollocks of a charging Rhino at 60 paces increases Four fold

Think extra polish to a really well wax valeted car

Touchy. Did a Mr Kondo steal your girlfriend once?

And also utter bollocks.

[montesquieu]

My line is dictated by budget. I'm not interested in "fakes" like rolexs etc but a hifi DIY PCB isn't in that category for me. Its an opportunity to build something and if anything, Chi-Fi has demonstrated that they don't bother to really put the effort into most of the clone PCBs to be even nearly accurate.

Layout, track width and thickness would need to be exact and they never are so they can never be real clones.

It's not the PCB that concerns me (nor, I suspect lawrence) but the notion of putting it in a branded case.

[User211]

Searching for Kondo on Ali Express provides a large number of links to Japanese Anime sex dolls.

Curious.

https://uploads.tapatalk-cdn.com/20190419/0ae8b141fa2166cec7a0054322c0fdf7.jpg

[User211]

It's not the PCB that concerns me (nor, I suspect lawrence) but the notion of putting it in a branded case.Why so offended by it, Tom? There are blatant, branded fakes for all sorts of products. Always has been, always will be.

[montesquieu]

Lol. Well it's a very common surname but perhaps some people are taking the decluttering thing a bit too seriously.

[montesquieu]

Why so offended by it, Tom? There are blatant, branded fakes for all sorts of products. Always has been, always will be.

I'm actually baffled anyone finds this acceptable. So we have a looky-looky man for hifi now?

[User211]

The £13.13 M7.

https://uploads.tapatalk-cdn.com/20190419/a04eaa20f1c43849c66a272a97826d36.jpg

[User211]

I'm actually baffled anyone finds this acceptable. So we have a looky-looky man for hifi now?There's nothing that can be done about it. Apart from eradicating China and perhaps a few other places.

[Lawrence001]

It's not the PCB that concerns me (nor, I suspect lawrence) but the notion of putting it in a branded case.Yes, if the circuit is not patented then I can't see a problem (and without the high end components in it it won't sound the same) but the name Ongaku on the box worries me if there is a copyright on that name on the context of hifi. If there isn't I suppose it's fair game as long as nobody buys it later down the line thinking it's original.

Sent from my BLN-L21 using Tapatalk

[montesquieu]

Yes, if the circuit is not patented then I can't see a problem (and without the high end components in it it won't sound the same) but the name Ongaku on the box worries me if there is a copyright on that name on the context of hifi. If there isn't I suppose it's fair game as long as nobody buys it later down the line thinking it's original.

Sent from my BLN-L21 using Tapatalk

Indeed, a quick search shows the Kondo logo is trademarked in at least the UK and the US. Pretty sure it would be unlawful to make or sell that case in most geographies.

https://trademarks.ipo.gov.uk/ipo-tmcase/page/Results/23/WE00001028334
http://tsdr.uspto.gov/#caseNumber=79078728&caseType=SERIAL_NO&searchType=statusSearch

[walpurgis]

Guess you could always opt for one of the MBL or Krell marked cases from China. ;)

[Mr. C]

Touchy. Did a Mr Kondo steal your girlfriend once?

And also utter bollocks.

Tom

Utter Bollocks eh? I suspect more pretentiousness from yourself


No Kondo-san had no interest in my love life thank you :)

Touchy moi? I suggest you being overly touchy about this matter, Kondo was designed for the more wealthier hifi buffs over 55 who life revolves around low-brow classical, chamber music, female vocals, Sunday afternoon folk music. These listeners who wish to have a grain free wide open window polished to sheen to the listeners truly believe it is one of the pinnacles of sonic reproduction available. Humm pretentious factor 10 Captain.

On this occasion Tom you have managed to exceed your own standards of self-preoccupation no mean feat!

No danger of of fatigue listen to Kondo at all, just shy of directly injecting Mogadon into your eyeballs, only Meridian can be awarded that title.

I suspect your are ruffled by the fact someone would 'dare' copy your pedestal ideology of Kondo, we are not worthy audio, humm get used to it, the Chinese will be gunning for all high end manufacturers very shortly. I would have thought that being able to obtain one of your most desirable audio items for less than 1/25th the price would have been appealing even to a man of your stature in the world audio community :)

Have you lived with one in your system for any length of time to pass your thoughts? Kondo does one thing better than just about any other piece of audio equipment it removes the music and replaces it with a sublime sweetness that washes and brushes up the sound to a superb level without question, Deliver real musical insight I'm afraid not old boy, one must accept the fact that is Kondo's biggest draw back!

Also I would further suggest to fully appreciate Kondo's special sound a full Kondo system would be needed with complimenting speakers.

Audio UK for me if I had to resort to valves would be my weapon of choice, I would be fully satisfied that whenever I listened to my system I could be safe in the knowledge that it would entertain me with music insight for many hours BOREDOM free. The cost is similar but the results are very different.

I have many Japanese friends who's system would cost at least a decent house in middle England, yet their apartments are smaller that my workshop, they also have uber horns and wonderfully build exquisite equipment. yet they listen to Chopin etc at half past whisper O'clock for fear of upsetting the neighbors! for them obtaining the equipment and setting up the system gives them more pleasure than listening to it imho.

Back to the OP, keep up the good work, I will also offer any services free to improve your creation as a gesture of thanks for bringing this to the attention of the forum.

[montesquieu]

Tom

Utter Bollocks eh? I suspect more pretentiousness from yourself


No Kondo-san had no interest in my love life thank you :)

Touchy moi? I suggest you being overly touchy about this matter, Kondo was designed for the more wealthier hifi buffs over 55 who life revolves around low-brow classical, chamber music, female vocals, Sunday afternoon folk music. These listeners who wish to have a grain free wide open window polished to sheen to the listeners truly believe it is one of the pinnacles of sonic reproduction available. Humm pretentious factor 10 Captain.

On this occasion Tom you have managed to exceed your own standards of self-preoccupation no mean feat!

No danger of of fatigue listen to Kondo at all, just shy of directly injecting Mogadon into your eyeballs, only Meridian can be awarded that title.

I suspect your are ruffled by the fact someone would 'dare' copy your pedestal ideology of Kondo, we are not worthy audio, humm get used to it, the Chinese will be gunning for all high end manufacturers very shortly. I would have thought that being able to obtain one of your most desirable audio items for less than 1/25th the price would have been appealing even to a man of your stature in the world audio community :)

Have you lived with one in your system for any length of time to pass your thoughts? Kondo does one thing better than just about any other piece of audio equipment it removes the music and replaces it with a sublime sweetness that washes and brushes up the sound to a superb level without question, Deliver real musical insight I'm afraid not old boy, one must accept the fact that is Kondo's biggest draw back!

Also I would further suggest to fully appreciate Kondo's special sound a full Kondo system would be needed with complimenting speakers.

Audio UK for me if I had to resort to valves would be my weapon of choice, I would be fully satisfied that whenever I listened to my system I could be safe in the knowledge that it would entertain me with music insight for many hours BOREDOM free. The cost is similar but the results are very different.

I have many Japanese friends who's system would cost at least a decent house in middle England, yet their apartments are smaller that my workshop, they also have uber horns and wonderfully build exquisite equipment. yet they listen to Chopin etc at half past whisper O'clock for fear of upsetting the neighbors! for them obtaining the equipment and setting up the system gives them more pleasure than listening to it imho.

Back to the OP, keep up the good work, I will also offer any services free to improve your creation as a gesture of thanks for bringing this to the attention of the forum.

The only Kondo stuff I've owned was a full rig of cabling, an Io-J and accompanying S6c-SUT, owned for several years. In the end I got rid of the Io and SUT because I felt the Miyajima Shilabe I compared it to to, while less perfect perhaps in a hifi sense (indeed it was impossible to fault the Io/S6c in hifi terms) didn't communicate emotion as well as the Miyajima/Hashimoto combination. I own no Kondo kit at the moment so I don't have a dog in this fight, except perhaps to call bullshit on people with an agenda.

I don't rate the M7 particularly but that's party because there's no definitive M7 to rate - there were solid state versions, and even with the valve models there were major variations over time in the circuit. None I've heard have set the heather on fire.

The M77 though is a glorious piece of kit and the very few times I've heard it, once in my own system, it absolutely communicated music. There was no 'silver sheen'. Urban myth that some impecunious (and resentful with it) types are happy to buy into and propagate. It's a fabulously musical bit of kit.

It just seems to me that the (very few) people who might be tempted to criticise the M77 have either not heard it in proper circumstances or (more likely) are practicing some kind of inverted snobbery, ie just because something is close to unaffordable for most mortals means it must be a con job. Well it isn't. And that's why you were taking bollocks.

However I can only speculate as to your motives for talking bollocks - I assume with your position as trade you have heard it, and it's probably not inverted snobbery as you are quite used to dealing in high-end kit (most of it sold to, er, over 55s I'm sure) - so perhaps you have let the cat out of the bag here that your comments have more than a little to do with the fact you flog other, rival, stuff in the same price bracket?

[Mr. C]

Tom

Very rarely do I say these things but just stop being twat for once, reverse snobbery? Now you really are clutching at straws my dear boy

Due to circumstances over the years we ownboth the M7 and M77 both of these pieces )as mentioned in previous post) which I know very well and sheen/polish is very apt, I feel your depiction of natural fluid music maybe somewhat different from others here. You would also need to take into account those models made before Kondo-san death as well, which imho are superior.

Certainly do not have agenda with Kondo, what I do have issue with is way that snobby up their own ass so called music lovers fawn over them to the point of almost being indoctrinated into the cult of naim :mental: Similar to way that Linn 'tune dem' their potential customers.

Kondo deserves it rightful place in the high jewellery section of audio no quibble, one of the best at what it does, but with all forms of music their lies a different tale.



No I was not going to suggest an alternative or even mention any possible counter point, thus your insecurity shows once again.

Perhaps a trip to listen to other forum members systems may somewhat focus your mind from your kink with Kondo.

[crimsondonkey]

Anyway...

There is for some, an appeal in achieving 80-90% of the M77's performance for less than a grand. I think that is who this thread is for.

[walpurgis]

Further discussion with a negative tone will likely result in post deletions. Thanks.

[User211]

Further discussion with a negative tone will likely result in post deletions. Thanks.I think it's just healthy disagreement.

Just sayin'.

Seen far worse and posted worse myself.

[Mr. C]

Anyway...

There is for some, an appeal in achieving 80-90% of the M77's performance for less than a grand. I think that is who this thread is for.

Wayne,


Which is what I mentioned on this thread in previous post!

[crimsondonkey]

Yeah, it was a general purpose comment to get back on track and not aimed at you or anyone else

[User211]

Wayne,


Which is what I mentioned on this thread in previous post!Well in the Abbatoir thread there was a link to a pretty nice looking fully made copy in a decent case.

Shame it's no longer I would have bought it.

[smangus]

Never seen anything Kondo , let alone listened to it, apart from the myth stuff around it , it sounds intriguing.

Starting to sound like marmite kit now though lol

[Mr. C]

Well in the Abbatoir thread there was a link to a pretty nice looking fully made copy in a decent case.

Shame it's no longer I would have bought it.

My point Justin, it may not be exactly 100% however it will be able to make very close for a fraction of the outlay as will many other high end brands.

Good on the OP for making the effort

[montesquieu]

Tom

Very rarely do I say these things but just stop being twat for once, reverse snobbery? Now you really are clutching at straws my dear boy

Due to circumstances over the years we ownboth the M7 and M77 both of these pieces )as mentioned in previous post) which I know very well and sheen/polish is very apt, I feel your depiction of natural fluid music maybe somewhat different from others here. You would also need to take into account those models made before Kondo-san death as well, which imho are superior.

Certainly do not have agenda with Kondo, what I do have issue with is way that snobby up their own ass so called music lovers fawn over them to the point of almost being indoctrinated into the cult of naim :mental: Similar to way that Linn 'tune dem' their potential customers.

Kondo deserves it rightful place in the high jewellery section of audio no quibble, one of the best at what it does, but with all forms of music their lies a different tale.



No I was not going to suggest an alternative or even mention any possible counter point, thus your insecurity shows once again.

Perhaps a trip to listen to other forum members systems may somewhat focus your mind from your kink with Kondo.

Twat? Explain please. I was merely pointing out your opinions come with a big dollop of agenda. Which they most certainly do. (And as you have just confirmed).

Insecurity? Explain please? In what way is it insecure to point out you are merely repeating oft-posted nonsense? Kink with Kondo? I don't own any (though I have in the past and if I wanted some more, I'd buy some). Are you mixing me up with someone else?

Visits to forum members? I do that often though generally based on common musical interest. I seldom go to bakeoffs, mainly because the music that tends to be played is seldom my cup of tea and tells me little I want to know about a system's performance (also fed up with putting on a Bach cantata or Schubert Lieder recording only to clear the room).

I'm somewhat bemused at being offered lectures on musicality from a hifi salesman. How many times have you stood in front of a choir and directed it before an audience, or played the organ on a concert relayed on the BBC, or orchestrated music and then conducted it before a full band? I think I can guess the answer to these.

[User211]

My point Justin, it may not be exactly 100% however it will be able to make very close for a fraction of the outlay as will many other high end brands.

Good on the OP for making the effortYeah good on the OP.

But is it even a major bummer for Kondo? I suspect not. It may be a plus.

Everyone knows an M77 is top notch in one way, shape or form. Those that can afford them won't want the cheapie anyway. Multiple copies simply assert it's a desirable item.

And yes I spent a good few hours with an M77 and Kondo Neiro years ago. I got an idea of what it could do, but it needed better speakers than the owner had at the time to really show itself off.

I have also heard Kondo on Olympians at Munich a few times. Those speakers are good enough. But they are the domain of classical music fans. Not really my bag.

[Marco]

Guys, I won't pretend to have read the whole of this thread, and therefore until I have [which is unlikely, as I have a life], I can't form an informed opinion on who's more 'in the right', or to blame (Tom or Tony), in terms of the dispute that's taken place about Kondo, simply because it's Easter Sunday and I've just finished a long family lunch/do, and have consumed copious quantities of alcohol...

However, what I will say is that when you make things personal and refer to what someone's written as "bollocks", and then that person responds by referring to you as a "twat". it's no wonder that the discussion has degenerated into name-calling, and long since lost any constructive perspective!:doh:

Therefore, in future, play the ball, not the man, stop being so provocative, and debate the SUBJECT, without turning things personal - and that applies to both of you. Cheers!

Marco.

[Mr. C]

Twat? Explain please. I was merely pointing out your opinions come with a big dollop of agenda. Which they most certainly do. (And as you have just confirmed).

Tom

I really must apologies for my late response to your assumptions which you have had the thoughtfulness to post yesterday. You are to be applauded on your outstanding rapier whit coupled with a towering intellect of monumental proportions delivering a crushing response of epic proportions, I doff my hat sir :)

To quote your good shelf 'big dollop of agenda' if your thoughts are in the region of; "Arh he dislikes Kondo with a passion" then you are absolutely and unequivocally 100% incorrect, I do admire its sonic capabilities and the original (Pre Kondo-san death) models build quality was superb without question. Would I wish to actually retail these units, no thank you. However as Justin made the observation and to one I whole heartily agree it is a two trick pony, albeit an exceptional two trick pony! For this sort of outlay one would expect more all round capability with all forms of music.

My ethos is very simple you have to totally understand and believe in the products that you are offer for purchase as well as the fundamentals of room/system interactions of said equipment Simply having them available on the shelf for prospective purchases doesn't fit in well with the purchasers of this style/type of equipment, they need a completely different approach.

Where I do have a 'kink' if you like, is the mythical almost religious status granted to certain brands, not for their performance but for the decades of serial bullshit, zealotry indoctrination that has been subversively and subliminally into the audio buying public, that's my kink if you like Tom



Insecurity? Explain please? In what way is it insecure to point out you are merely repeating oft-posted nonsense? Kink with Kondo? I don't own any (though I have in the past and if I wanted some more, I'd buy some). Are you mixing me up with someone else?

Let us start with the 'oft-posted nonsense?' are you referring to my observations that I feel the M77 is not exalted enough to install one in my own system? or possibly I do not share your passion for said piece of hardware, music reproduction is different for many people and certain sonic traits that will appeal to one or two folks will turn one or two others off completely. That is personal choice and will always be so. I am pretty convinced my personal system would would be a total revulsion to you as it produces music a natural, fluid manner according to the composer/artist or band's recording space.

Would I get upset or flustered? no, as everyone is different and we all have a way we like our music to be produced, no kink there just personal choice. Certainly not mixing you up with any one Tom please be sure of that :). Maybe investing in some Kondo may bring you some solace and peace in the knowledge that you have reached your personal pinnacle of audio reproduction thus elevating your insecurity issues of challenging anyone who speaks out against the temple of Kondo. I could be wrong that is also a possible equation to explore ;)




Visits to forum members? I do that often though generally based on common musical interest. I seldom go to bakeoffs, mainly because the music that tends to be played is seldom my cup of tea and tells me little I want to know about a system's performance (also fed up with putting on a Bach cantata or Schubert Lieder recording only to clear the room).

You did start off so well, then it curtailed downhill after the first four words?, back to Classical music again. So you make a concerted effort to visit those members who have a very similar music preference to your own. I can understand that to a point shared interests, common goals indeed can help. However even visiting members who musical first preference is not classical, a lot can be gained by listening to how other systems cope with big crescendo's (a culminating rock opus approaching its finale can also deliver really good indications on how a system can cope with Rachmaninoff, Stravinsky, Shostakovitch, Wagner, Hayden, Schubert , Liszt, Mendelssohn etc full piece compositions. Similarly a good jazz quartet can deliver intricate, timing cue's and spatial awareness, tonal layering which again can help give greater insight with Classical music, granted it may not float you boat Tom, however music helps the soul and delivers better understanding of how other musical genre's can be improved in the playback quality. Most of the clients I have which they would themselves would describe as classical heads, (some 10000 plus recordings) also listen to other form's of music, maybe for only 10% of the time but they make it their business to understand all forms of music and gain a greater knowledge to help enjoy their main chosen form of music better. There are some rather good systems out there in forum land, do not cut your nose to spite your face, you maybe missing quite a few musical systems.








I'm somewhat bemused at being offered lectures on musicality from a hifi salesman. How many times have you stood in front of a choir and directed it before an audience, or played the organ on a concert relayed on the BBC, or orchestrated music and then conducted it before a full band? I think I can guess the answer to these.

Tom I guess this is what they call the will waving section of the post (insecurity again?):stalks:

Nowhere have I personally given any lecture to you on the musicality of anything, what I have done is made observations based on PERSONAL experience of said products both in various systems (including all Kondo with speakers that could do it justice) and actually owning said piece.

This lowly "Hifi salesman" has never conducted an orchestra, stood in front of a choir and directed them or played the organ for BBC to broadcast the recording in some form or another. You got me fair and square Tom :)

However this owner of two recording studios has recorded over two hundred artists (all forms of music) from intimate club style surroundings, recording studio's, small churches and a medium 2000+ seater venue so I do understand, pretty much most issues from tonal quality, acoustical space, dynamic headroom, compression, latency, recording techniques, the bending of vu meters :lol: etc.

Also having played to just over 4000 people at a few public concerts (in a band) over the years although we were playing not what you consider to be be 'proper music' on the bonus side the crowd did not throw bottles at us :lol:

One of the more enjoyable professions is designing digital electronics both for the audio and pro-audio world, so I do understand the a lot of the playback chain pro's and con's and have a decent inside knowledge of how to extract and deliver a particular sound.

Dealing with the subject of classical musicians, I can cite an example of a well know classical string player who's benchmark is to compare everything against his perspective as a player in that if the immediacy is not up to how he plays his instrument then it is wrong, possible a very skewed view of music reproduction. Still a great player though even if his reproduction style is very naim orientated!

On this occasion we are not going to see eye to eye Tom, so let us agree to disagree :)

[Wakefield Turntables]

Is it me or are the replies here just getting longer, convoluted, and BORING!

[Kanders1]

So Just for update info.. the Correct size case for the clone amp is very good.. things fit better, not cheap but does look the part.

This is a great build and sounds very good indeed.. of course it does depend on whats with it but I have no complaints what so ever for the money and the enjoyment of building it. Highly recommended. it can be modified and tweaked for all those that like to fiddle too :eyebrows:

If anyone needs help or any questions just ask..

Cheers
Karl

[Ned]

Great work Karl !

I am just finishing my build as well and took your advice about using a separate clean 12V power supply as original one makes terrible hum. Guess what ? It's absolutely amazing...! Thanks for sharing your detailed experience. Although I went the whole way from assembling the board myself to building a custom case. I used Mundorf capacitors (the best ones I could afford) and Electro-Harmonix tubes. In my opinion preamp sounds very transparent compared to any other system I've had. I bought a faulty Denon home cinema preamp to use as a case for the preamp in order to 'match' my power amp, which is also modified Denon POA-2200. It makes a wonderful combo.

This post was really about building decent preamp, not arguing about what is Kondo is or who has a more expensive system.

Ned

[Kanders1]

Hi Ned,
Thanks for the post..👍 I’d stopped looking as I was getting fed up with the off track posts.
Your build look bloody marvellous 👍👍👍😊
I’ve tweaked a few more bits to mine since the original build. Main thing I’ve done is gone to 12ax7’s and I’ve just started to add a switchable RIAA filter. As the amp only uses a 47k resistor.. which works well but I’ve got some Jico stylus for my Shure V15VxMR and they just don’t sound as good as the original MR stylus. I have a new one on there and the sound is absolutely amazing but I know it’s not going to last for ever so experimental measures are in order to prepare..
I also just finished a speaker build, using Tannoy 315HD’s.. based on a design by Paul Coupe.. They were a mammoth build but I think that combined with this pre amp takes a lot of beating for the money...!
Well done Ned. 🍻
Cheers Karl


269812698226983

[Ned]

Karl,

Your speakers are fabulous ! Looks like you spent some time on these speakers. Front baffle is superb, real classic. I suspected you were building something else, not just pre-amp. Same with me - I have to build something all the time, there is never enough. I actually first built my speakers and then went to power amp / pre-amp combo. I absolutely accidentally came accross Denon power amp that I repaired and later modified. And only then came up with the idea of building KSL-M 77.
I hope to see more posts soon.

[Kanders1]

Hi Ned,
Impressive build there Ned..! looks very well finished. Well done.
Thank you, they took a lot of hours work.. but the resulting sound is spectacular! unbiased as i am :) My main project is a turntable design Ive been working on, there are some prototype images on my profile.. Ive just moved house so my workshop is not up and running so a hold on all project work atm. looking forward to getting the finished model finalized with some modification like an interchangeable arm board and some isolation feet which im half way through making but on hold due to lack of machines etc... I hope to start making them to sell at some point.

27028

27029

27030

Cheers,
Karl

[Toob-Noob]

Hi Karl,

First, thank you for taking the time to document and post all your hard work with this M77 Pre-amp clone. An impressive outcome.

I'm interested in similar and would also go down the seperate DC heater supply route. I see you plummed for the Jim's Audio low-noise regulated DC supply so I have a couple of queries if you could help me:

- were you able to measure the noise on the DC supply output? I can see no claim or spec. relating to what you might expect and I've found another supply using the same chip claiming <40uV RMS output noise.
- looking at heater spec. for 12AY7 @12.6v (AC or DC) heater draw is 0.15 amps. So, 8 valves = 1.2A. Did you measure/verify this at all? The unit I'm condering is rated up to 1.5A so has 25% headroom which is a good safety factor.
- the Jim's Audio unit has a time delay ramp up. Do you consider this to be a valuable enhancement or not particulalry of use since the B+ is not going to be delayed?

I appreciated I'm firing questions at you but it would be a plasure to share my results back to this thread when I go ahead.

Thanks again.

[Kanders1]

Hi Ron,
Thanks for the kind words, the amp is well worth the time, it does have its issues but once sorted its a great sound.

So first of all let me say I'm no expert.. fortunately i work with one :) my "Valve guru" so when i get stuck he's the spurt !

You questions..
were you able to measure the noise on the DC supply output? - I did not as my man said that this board and the chip were well designed and would be perfect for the job.

heater draw is 0.15 amps. So, 8 valves = 1.2A. Did you measure/verify this at all? - Yes this is okay. and you are correct. The board is actually two independent supplies that you can use if you need more i only built one side and have had no issues. Also with that board you can tune the voltage nicely.

the Jim's Audio unit has a time delay ramp up - I only use the amp for the Phono input so its permanently switched to that, therefore as you say the B+ governs the supply so it has no real affect. (Ive not noticed any issues because of it).

Im in the process of making a little mod to the RIAA, it only uses a 47k resistor and relies on the circuit capacitance. For my current setup this is okay. I am running an SME IVarm with a Shure V15Vx cartridge and the VN5xMR stylus. These are very hard to come by now and very expensive. I bought the JICO versions but they are very "bright and quite harsh at the top end" there are a number of threads on this, so for future proofing I am making this little mod. once I've got it right ill post the mod. Its just a switchable set of combinations of resistors and caps.

Hope this helps..

Good luck with the build !
Cheers
Karl

[Ned]

Hi Karl and everybody,

Happy New Year to you all and I wish you some more new and exciting projects come your way !!!

Just a matter of interest - what's the progress of your turntable and the workshop ? As for myself, I was busy at work recently, but now starting to work on a custom audio rack - commercially available ones are too small for my gear...

Regards,
Ned

[Kanders1]

Hi Ned, happy new year to you to..!
So, currently I’m working on my listing room. It’s gutted at the moment and I’m loving the echo !! Haha !! It won’t be there for long..!
I’m postponing my workshop build until the weather breaks and longer days. So that means the Turntables are also on hold..
Just added an SME IV to my working prototype and also managed to get the Mrs to let me have one in the lounge.. think she was drunk when she gave the go ahead and I had it in there before she sobered up 😈. So at least I have something to listen to until the room is complete.
I’m going to be building a rack as well for the new room so would be interested in what you are doing.
My deck will be mounted directly to an outside wall so as solid as I can get it.
I’m also into building a quadratic defuser which will be in the room. That’s a mammoth job as it measures 1200 x 2500 and weighs a ton !!
Attached pic is of one tile there will be 10 !! 🤪
27171

Cheers
Karl

[Ned]

Karl,

It looks you're going full audiophile scale !!! Listening room, suspended shelf for turntable, difusers... Congrats ! When I own our own place I'll do the same. Just don't underestimate your Mrs ! She's a clever woman if she gave the go ahead. Lucky enough my Mrs likes what I do even though it takes me away for hours. It's a 'transition' period in our life, so I don't own a workshop any more and have to use an old wrecked garage at the house we're renting, but it can't stop me !

By the way, are you filling the inside of difusers with something ? I mean vibration absorbing. A while ago I was looking at different options. There's even decorative wall tiles made of straw... My rack is going to be simple, but solid and something cheap, nothing fancy. The only nice touch will be granite slab that friend made me. Just working on design now. It will take a while, but I'll update as soon as there's some progress.

Regards,
Ned

[walterssong]

Hello Karl,
Thanks for all the info relating to your M77 build it's given me the bug to try one myself! I've been in the process of building my own over the past couple of months and I've hit a stumbling block regarding the transformer wiring and was hoping you may be able to help! Like you I bought the Douk board and the Douk transformer. My problem is I cannot for the life of me work out what wires go where from the transformer to the IEC/PCB. I admit I'm a novice to this (although I did manage to build the EAR 834P from Lenco Heaven!!) I've been searching online the last couple of weeks trying to understand transformer windings but from what I can see the secondary windings won't produce the 240/0/240 required for the PCB. I have attached here a blank diagram showing the IEC/Transformer/PCB, would you have time to draw the wiring connections (Similar to your experience buying the DOUK transformer it doesn't help that the wire colour positioning doesn't quite match the diagram on the case!)? I'd really appreciate it if you could. I've not added the Jims Audio LT1963A as yet as I wanted to see how it sounded without initially. Anyway, thanks again and hope you can help!

Cheers
T

[Barry]

It is difficult to read the lettering, but it looks like the green and yellow pairs together will provide the 240/0/240v you need. You will have to be careful with the phasing however.

[walterssong]

Hello Barry,

Thanks ever so much for getting back to me especially as I noticed this thread is quite old now (a bit like myself!). And thanks too for your advice... could I ask another favour? As I said earlier I'm a beginner when it comes to electronics, if I have pic to follow I'm fine but when I try to understand the theory I fail. I have tried to get my head round reading about transformer windings/in series vs parallel/primary and secondary (and now phasing) etc but I still come away unconvinced I know what I'm doing. Would it be possible for you to have a look at the updated attached pic and judge if what I intend to do is correct? Sorry to ask and obviously I take full responsibility for any wiring I do!!

Cheers
T

[Barry]

The 6.3V and 12.6V connections look to be correct, but I think you have made a mistake with the 250/0/250V connections.

According to the diagram on the transformer, the yellow '250' and the green '0' wires should be connected together and go to the '0' terminal on the PCB. The yellow '0' goes to one of the 250v connections on the PCB and the remaining green '250' will go to the other PCB connection.

But to make sure, I would suggest before you wire up the PCB, connect the leads to a three way 'chocolate terminal block' and using a multimeter set to 1000V AC, measure the voltage across the unpaired yellow and green wires. If all is wired correctly you should get a reading of 500V.

Take care - these voltages are lethal.

[walterssong]

Barry, you are a gentleman and a scholar!!

That's made the order of the wiring very clear. I'll be very careful with the wiring and test as suggested.

Thank you again for taking the time to explain, and thank you to the good folks at AOS who make friendly communities like these happen, it really is appreciated by those less knowledgeable people like myself!

Cheers
T

[Kanders1]

Hi T, sorry for late reply, Mail went to spam..
On my transformer it’s the green 250v green 0v orange 250v the wires do not match the colours on the label. The yellow is not used the orange is 250v

[Kanders1]

Hope this helps…👍
302703027130272

[Kanders1]

T, if you look at the first pages of the build info it tells you about the wire colours. ��

[walterssong]

Hello

Many thanks, Karl, for getting back to me. Much appreciated.

I hate to do this but may I ask for another piece of advice? I've attached here a pic (PIC1.jpg) of the actual transformer I'm using (in principle it's the same as the stock image I used previously). If I wire up as you suggest 250V blue/0V blue/250V black (PIC2.jpg) I get a reading of 263V AC on the blue and 104V on the black. But if I wire up as Barry suggested using all four of the blue and black wires (PIC3.jpeg) I get 263V AC both left and right.

Where I have the problem (well two really!) is that my multimeter AC readings are coming out a bit high overall ... instead of 6.3V I get 7.1V, 12.6V reads 13.5V and 250V reads 263V. Is that normal or should I look into buying a new multimeter?

My main problem is that when wiring up to the PCB using choc terminal blocks to do a quick test prior to soldering a deep hum comes from the PCB mainly at the 6.3V connection area and the zener diodes there get super hot and start to smoke!!! especially the two circled in green on PIC4.jpeg.

Is there something I'm obviously doing wrong that comes to mind or would you suggest I strip the PCB back and re-solder the components to see if that fixes things? I realise it's difficult to diagnose without physically seeing the PCB etc so no worries if you are unable to suggest anything, you guys have already been a great help! And hope you're enjoying the Bank Holiday!

Cheers
T

[Kanders1]

T,
Send me a PM and I’ll give you my contact details..
I would say that the connections in the second picture look correct.

Cheers
Karl