Nelson Pass B1 preamp build

[Bigman80]

Hi all,

After missing out on a Nelson Pass B1 preamp recently, I decided I'd have a look at building one.

A quick chat with Alan alerted me to a B1 buffer being sold by Jazid (James) so I snapped it up.

I've decided to try and reuse the case it's all currently residing in and get a black perspex sheet to replace the Aluminium front.

I settled on an Elma 2 pole selector switch (same as in the Slagle I have just sold) which I felt was as good as it gets really for a selector switch and a Khozmo Stepped attenuator, which again is scant company at the top of the attenuation tree.

2 shaft extension bars will enable mounting of the switches to be as close to the outputs and input as possible so this should keep the signal path extremely short.

The hopes are that we can fit a 3 in 1 out configuration on the already slightly congested back panel. Luckily I have an expert to call on so that should be very beneficial.

Hookup wire is still to be decided but I'd like to try and use the same as the existing wire.

Any suggestions on what it is from the pictures?


https://uploads.tapatalk-cdn.com/20180618/564ffb89bdcaed82b721e812fd187489.jpghttps://uploads.tapatalk-cdn.com/20180618/0b3d8659c13a0454af72431a0e84f91e.jpghttps://uploads.tapatalk-cdn.com/20180618/caf28a9151f12ceb7517a6cc2983804f.jpg

[Bigman80]

Parts ordered

https://khozmo.com/series_khozmo_attenuator.html

https://www.hificollective.co.uk/switches/elma-2-pole-6-way-switch-04-1264.html

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F13 2330744851

http://cpc.farnell.com/rean/nys367-2/phono-socket-chassis-red/dp/AV11155?mckv=sSXueqVYV_dm|pcrid|224645161149|kword ||match||plid||pid|AV11155|&CMP=KNC-GUK-CPC-SHOPPING&gclid=EAIaIQobChMI_LfospTe2wIVlIbVCh0aPArsEAQYAiAB EgK-2fD_BwE

[YNWaN]

Yeah, the hookup wire is solid silver in Teflon from HiFi Collective.

[Bigman80]

Yeah, the hookup wire is solid silver in Teflon from HiFi Collective.Cheers mate,. I'll order a bit.

[Simon_LDT]

I settled on an Elma 2 pole selector switch (same as in the Slagle I have just sold) which I felt was as good as it gets really for a selector switch and a Khozmo Stepped attenuator, which again is scant company at the top of the attenuation tree.



If you wanted to go mad, get a 34 or 46 step Seiden attenuator and stuff it full of Charcroft Z-foils! I believe the Seiden attenuators are the best if there is no budget (I haven't seen anything better).

Here: https://www.hificollective.co.uk/catalog/glasshouse-seiden-stepped-attenuator-step-version-p-7254.html

[Bigman80]

If you wanted to go mad, get a 34 or 46 step Seiden attenuator and stuff it full of Charcroft Z-foils! I believe the Seiden attenuators are the best if there is no budget (I haven't seen anything better).

Here: https://www.hificollective.co.uk/catalog/glasshouse-seiden-stepped-attenuator-step-version-p-7254.htmlHi Simon,

Ha! Yes I did see that yesterday but over £350 on a volume control is outrageous and unfortunately budget has come in to the equation!

I'm happy with the Khozmo

[Simon_LDT]

That's one of the reasons why I went with a standard Series attenuator (Acoustic Dimensions 41 step).

The other thing I did not like about the Shunt type is that if for some reason the contact fails or doesn't click into place right, the volume will not be attenuated at all so speakers will likely be blown (tweeter at least). I know the chances of it happening are very slim but contacts can get dirty after time.

[Bigman80]

My opinion is that the current fad for so-called "shunt" stepped attenuators is based on a fallacy. Here's a quote from the HiFi Collective site:
" ...we are proud to offer a version of the Glasshouse stepped attenuator range in SHUNT format...we are offering a choice of 7 resistor types, though bear in mind you can always buy the all important Series (load) resistors separately..."
How is the series resistor any more of a load than the shunt resistor? Why would one be any more important than the other? Why doesn't it matter that the impedance seen by the source and the output impedance both vary other an extremely wide range?
Absolutely none of it makes sense and makes me doubt the competence of those making and selling them.

My advice is to buy a conventionally configured stepped attenuator.Hi Andrew,

Thanks for the advice,

I have purchased a series type which I understood to be "conventional" ? If it's not then so be bit. I will admit to naivety in regards to how they differ and why one would be better than the other. The advice I was given is that Series presents a constant load.

Either way, it's all about how it sounds SO! how's about this.....

If someone sends me a "conventional" stepped attenuator, I'll do a comparison and write it up.

[Simon_LDT]

Yes, I believe a series type will appear as the same load towards the source, however it does vary it's output (a 10k based attenuator will be 2.5k at worst case (half volume on the dial).

[Bigman80]

Hi Oliver

Yes, what I referred to as a conventional stepped attenuator is, I think, often referred to as a series attenuator. Yes, it presents pretty much a constant load to the source. That would be my choice.Ah, excellent! Looks like the advice was sound. As usual!

I looked at the Shunt type with ZFoil resistors but couldn't justify the spend.

[Yomanze]

Just a little clarification that this is not a Pass B1, it is a DC-coupled version of the B1 with on-board shunt regulators, and is thus better than the Pass B1. :)


Sent from my iPhone using Tapatalk

[Firebottle]

That's why I suggested Oliver snap it up quick ;)

[mikeyb]

I tried a DC B1, kept it a week, and that was only because I worked 3 days that week, otherwise it would have been gone sooner lol

Best of luck with the build, hope it turns out good for you.

Sent from my SM-G950F using Tapatalk

[Bigman80]

Just a little clarification that this is not a Pass B1, it is a DC-coupled version of the B1 with on-board shunt regulators, and is thus better than the Pass B1. :)


Sent from my iPhone using TapatalkAh! Yes that good news lol

[Bigman80]

I tried a DC B1, kept it a week, and that was only because I worked 3 days that week, otherwise it would have been gone sooner lol

Best of luck with the build, hope it turns out good for you.

Sent from my SM-G950F using TapatalkMikey lol, that made me laugh.

What didn't you like about it and what did you use it with?

Hopefully it's a better experience than yours.

[Bigman80]

I would seriously consider re-housing the circuit in a new, bigger box. Having that large mains transformer sitting right next to everything else would concern me. A bigger box would give you more space to work and allow you to get the mains transformer well off to one side.I know Andrew but the cost of buying a new case is out of the question at the minute. I may be able to re-home the transformer into a smaller case and we'll away from the circuit. I'll see how big the transformer is when it arrives and work from there.

After I've had a listen to it, as I don't want to throw good money at a dead duck.

[mikeyb]

Mikey lol, that made me laugh.

What didn't you like about it and what did you use it with?

Hopefully it's a better experience than yours.I'm just very susceptible to an edge on treble and it was the same when I tried the EWA M50 Pre I borrowed from Colin.

Both into my Primaluna Power amp, but don't worry I'm sure you'll like the Pass. It just didn't suit my ears.




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[Bigman80]

Ah, I see. Ok, well I'm not put off by that so that's good. Just looking forward to it arriving and getting started.
I'm just very susceptible to an edge on treble and it was the same when I tried the EWA M50 Pre I borrowed from Colin.

Both into my Primaluna Power amp, but don't worry I'm sure you'll like the Pass. It just didn't suit my ears.




Sent from my SM-G950F using Tapatalk

[337alant]

Oliver
Why would you only choose a 2 way switch ?, get a 6 way and give yourself the option of more inputs if required

Alan

[Firebottle]

2 pole 6 way Alan.

[337alant]

Ah I see, sorry miss read the thread :doh:
excellent switches the Elma, I use them myself
Alan

[Bigman80]

Ah I see, sorry miss read the thread :doh:
excellent switches the Elma, I use them myself
AlanNo worries!

I had one in the Slagle and it was quality so why go anywhere else!

[Jazid]

If I'd kept it I'd have been keen to try upping the bias, but for that you'd want a bigger trafo and heatsinking. I'm pretty sure you have also got a bunch of audio note silver phono sockets on there as well, it's a nicely made bit of kit. And it never hummed at all so the trafo must be well enough shielded.
Wish I could remember which chap sold it to me. Anyone recognise it?

Sent from my BLA-L09 using Tapatalk

[Bigman80]

If I'd kept it I'd have been keen to try upping the bias, but for that you'd want a bigger trafo and heatsinking. I'm pretty sure you have also got a bunch of audio note silver phono sockets on there as well, it's a nicely made bit of kit. And it never hummed at all so the trafo must be well enough shielded.
Wish I could remember which chap sold it to me. Anyone recognise it?

Sent from my BLA-L09 using TapatalkGave it the once over today and there's a quite a lot of "build up" on the sockets and which looks like it's in the sheath of the wires too.There's also some on the RCA sockets. Nothing a good clean won't fix.

I decided to replace them and get some of the best quality copper wire known to man!!!

Upping the bias may be possible BUT as it will require a new TF I leave that for now.

I may end up having to remove the TF to fit everything in so if I do I will go bigger on the TF too.

[Yomanze]

Here's a quote from Nelson Pass himself, taken from his page about the B1:
"The preamp typically draws fewer that 0.02 amps, so current is not much of an issue."
That transformer will deliver 20mA easily. There's no need for anything bigger.

This unit (DCB1) uses shunt regulators, so has much higher current draw. Some people set the bias really high, over an amp, and big heatsinks.

[Bigman80]

Here's a quote from Nelson Pass himself, taken from his page about the B1:
"The preamp typically draws fewer that 0.02 amps, so current is not much of an issue."
That transformer will deliver 20mA easily. There's no need for anything bigger.I read that too. Was just about to look into the merits of upping the bias. Won't bother [emoji23]

[Bigman80]

Why?
This unit (DCB1) uses shunt regulators, so has much higher current draw. Some people set the bias really high, over an amp, and big heatsinks.

[sq225917]

Me neither, but I'd design it so that it offered the ability to shunt as much as the rest of the circuit consumed.

[Yomanze]

Shunt regulators? Does that mean they're like zeners?
Personally, I wouldn't design something that had the regulators drawing more current than the amplifier does.

Yep, similar, except an LED voltage reference is used in place of a zener.

[337alant]

The PFM B4 is a good bootstrap buffer stage as well no gain though
I replaced mine with 2 x Avondale Audio 821A boards (4x gain) and am very happy with it

Alan

[Bigman80]

The PFM B4 is a good bootstrap buffer stage as well no gain though
I replaced mine with 2 x Avondale Audio 821A boards (4x gain) and am very happy with it

AlanReplaced a DCB1?

[Jazid]

Having thought about it again I see that shunt regulation in this case isn't a terrible idea. If the preamp was to drive a 10k load with 1V, it would need to supply 0.1mA. Lets go mad and allow it to supply ten times more, so 1mA. The quiescent current requirement is only 20mA anyway, so a shunt regulator that draws, say, 5mA would do fine. That isn't terribly wasteful, won't require a massive transformer and won't dissipate excessive unused power, so is feasible.
Still, I would probably prefer a series regulator.Just to be clear I wasn't saying anyone should do this, just that I would have if I'd kept it. There's a thread of about a godzillion pages long on DIYAudio about this, and the general take is that the higher the bias the better the DCB1 sounds, this thread including input from' papa' himself.

I don't have a justification for being curious but I do know that what works best in audio on paper doesn't always work best in real life in lugholes. Consequently I would have had a play, not because of a clear technical justification but simply because others found an improvement, I wished to see for myself, and could afford the cost of parts for my own pleasure.

Sent from my BLA-L09 using Tapatalk

[Bigman80]

I'll read the thread lol

[Jazid]

Good man, you won't suffer insomnia for a couple of days [emoji16]

Sent from my BLA-L09 using Tapatalk

[Bigman80]

Good man, you won't suffer insomnia for a couple of days [emoji16]

Sent from my BLA-L09 using Tapatalk[emoji23][emoji23]

[Yomanze]

I'll read the thread lol

Good luck! 60ma is the default, pushing to 200ma seemed to be a stage up. There is a great build guide somewhere will dig it out.

[Bigman80]

Good luck! 60ma is the default, pushing to 200ma seemed to be a stage up. There is a great build guide somewhere will dig it out.Tried last night but there's just way too much to get through.

[Yomanze]

Tried last night but there's just way too much to get through.

Start with this build guide: https://www.audiocircle.com/index.php?topic=85001.0

[Bigman80]

Cheers. I'll have a look through.
Start with this build guide: https://www.audiocircle.com/index.php?topic=85001.0

[337alant]

Replaced a DCB1?

No replaced a PFM B4

Alan

[Bigman80]

Ah I see.
No replaced a PFM B4

Alan

[Bigman80]

Been shopping in the Chinese market and bought one of these.......

http://s.aliexpress.com/ERF7JveM?fromSns=Copy to Clipboard

Unfortunately, the casework i originally got with the board and traffo just isn't big enough.

Extender bars will be used to get the Khozmo attenuator and the Elma switch as close to the RCA sockets as possible, keeping the signal path nice and short.

[337alant]

Been shopping in the Chinese market and bought one of these.......

http://s.aliexpress.com/ERF7JveM?fromSns=Copy to Clipboard

Extender bars will be used to get the Khozmo attenuator and the Elma switch as close to the RCA sockets as possible, keeping the signal path nice and short.

Yes good plan thats how I do it as well :eyebrows:
Its also a big saving in the amount of hook up wire you use going from the front panel to the back

https://farm2.staticflickr.com/1828/28223282037_1e5d034603_c.jpg (https://flic.kr/p/JZZGsZ)IMG_0088 (https://flic.kr/p/JZZGsZ) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr

Alan

[Bigman80]

Yes good plan thats how I do it as well :eyebrows:
Its also a big saving in the amount of hook up wire you use going from the front panel to the back

https://farm2.staticflickr.com/1828/28223282037_1e5d034603_c.jpg (https://flic.kr/p/JZZGsZ)IMG_0088 (https://flic.kr/p/JZZGsZ) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr

AlanWell, if I'm doing things the same you, I must be on the right path.

[Bigman80]

All the parts are here!!!!

Time to start the assembly

In a mock layout, I have settled on this (picture)

Any suggestions?https://uploads.tapatalk-cdn.com/20180704/200a924d5b1542ba543ab7fe6baa6b44.jpghttps://uploads.tapatalk-cdn.com/20180704/3bdad8b33bffa56af21ceaa7c476a0d0.jpghttps://uploads.tapatalk-cdn.com/20180704/4a0cc7e3dbe2fb79122da0637b9498c4.jpg

[Firebottle]

Looks good, keeping all interconnects short :)

[Bigman80]

Looks good, keeping all interconnects short :)Sweet,

How do I wire it all up between the board/attenuator/selector switch?

[Firebottle]

Can't really tell you from that photograph.

[Bigman80]

Any better?https://uploads.tapatalk-cdn.com/20180704/53294e5e195ade96836dda1e637ab2ce.jpghttps://uploads.tapatalk-cdn.com/20180704/51d815cdad8a9285e711e3be1d2da897.jpg

[337alant]

From the back panel each input pair (L & R channel) go directly to the switch, lets say input 1 left channel to the first outer tag pin after the mounting bolt and right channel to the opposite tag, input 2 to the next pair of opposite tags and work you way round with all you inputs.
The R & L switch outputs are the 2 inner tags, run wires from these to the R&L Inputs of the stepped attenuator .
Join all of your input grounds together for each channel with a tinned wire, run a wire to your start earth point and back to the Stepped attenuator grounds

The L&R outputs from the attenuator go to the Pre amp input L&R

I use a start earth point at the output Grd of the power supply caps so you would need 2 grounds from there to the ground on the amp board input

The output from the amp board go to you RCA outs on the back pannel

Note make sure that bolt on the transformer does not touch the top pannel or ou will get a short on your transformer

Hope this helps

https://farm2.staticflickr.com/1790/29220136988_8a40eb2a1c_c.jpg (https://flic.kr/p/Lw5QHj)IMG_0089 (https://flic.kr/p/Lw5QHj) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on Flickr

[Bigman80]

From the back panel each input pair (L & R channel) go directly to the switch, lets say input 1 left channel to the first outer tag pin after the mounting bolt and right channel to the opposite tag, input 2 to the next pair of opposite tags and work you way round with all you inputs.
The R & L switch outputs are the 2 inner tags, run wires from these to the R&L Inputs of the stepped attenuator .
Join all of your input grounds together for each channel with a tinned wire, run a wire to your start earth point and back to the Stepped attenuator grounds

The L&R outputs from the attenuator go to the Pre amp input L&R

I use a start earth point at the output Grd of the power supply caps so you would need 2 grounds from there to the ground on the amp board input

The output from the amp board go to you RCA outs on the back pannel

Note make sure that bolt on the transformer does not touch the top pannel or ou will get a short on your transformer

Hope this helps

https://farm2.staticflickr.com/1790/29220136988_8a40eb2a1c_c.jpg (https://flic.kr/p/Lw5QHj)IMG_0089 (https://flic.kr/p/Lw5QHj) by Alan Towell (https://www.flickr.com/photos/69508926@N05/), on FlickrHi Alan

Thanks for the information. I understand most of that better than expected lol.

One question,

How do I know what channel is what on the attenuator there are no markings at all!!!

[Bigman80]

Oh!! It doesn't matter does it lol, as long as it's R in and R out to the R RCA it'll be right lol.

Can you tell I haven't done it before 🤣

[337alant]

Oh!! It doesn't matter does it lol, as long as it's R in and R out to the R RCA it'll be right lol.

Can you tell I haven't done it before ��

Oliver Yes you got it just keep you lefts and rights in phase all the way through the amp from input to output

Alan

[Bigman80]

Thanks Alan,

I really appreciate your help.
Oliver Yes you got it just keep you lefts and rights in phase all the way through the amp from input to output

Alan

[Bigman80]

Spent a couple of hours on the DCB1 today,

I now have power to the board and switches nicely fitted.

The Khozmo is in place and just need to cut the extender bars to fit. Just measuring up for the Elma selector switch.

I need to buy and fit two more RCA sockets too.

https://uploads.tapatalk-cdn.com/20180705/a9dcdf732428a82c8d3f948201c4998c.jpghttps://uploads.tapatalk-cdn.com/20180705/67bd6aaef37322a22b968b6d585ae2df.jpghttps://uploads.tapatalk-cdn.com/20180705/c2d1ef5c366f26410abba17e0fe6682b.jpghttps://uploads.tapatalk-cdn.com/20180705/39459b4481577076918662f41fc25ee3.jpghttps://uploads.tapatalk-cdn.com/20180705/b950962b4afef1660a065ef7abd04393.jpghttps://uploads.tapatalk-cdn.com/20180705/29de9d263ea3b99e944879b2021f01ae.jpg

[ijrussell]

This is my DCB1 built by a friend for me. I went a bit foo with Khozmo attenuator, Audio Note Tantalum resistors and Mundorf caps but it's defintely worth it!

http://audioabattoir.s3-eu-west-1.amazonaws.com/original/3X/d/c/dcff57b574afdcb1bc5500db3b20b71c890e8bb8.JPG

[The Black Adder]

There is nothing foo in regards to the Khozmo. Had one for years and have always been very nice.

Sent from my 9001X using Tapatalk

[Stryder5]

Won't the knobs stick out a bit.....lol.....sorry



Spent a couple of hours on the DCB1 today,

I now have power to the board and switches nicely fitted.

The Khozmo is in place and just need to cut the extender bars to fit. Just measuring up for the Elma selector switch.

I need to buy and fit two more RCA sockets too.

https://uploads.tapatalk-cdn.com/20180705/a9dcdf732428a82c8d3f948201c4998c.jpghttps://uploads.tapatalk-cdn.com/20180705/67bd6aaef37322a22b968b6d585ae2df.jpghttps://uploads.tapatalk-cdn.com/20180705/c2d1ef5c366f26410abba17e0fe6682b.jpghttps://uploads.tapatalk-cdn.com/20180705/39459b4481577076918662f41fc25ee3.jpghttps://uploads.tapatalk-cdn.com/20180705/b950962b4afef1660a065ef7abd04393.jpghttps://uploads.tapatalk-cdn.com/20180705/29de9d263ea3b99e944879b2021f01ae.jpg

[Bigman80]

Looks very well made.

Somehow, on mine, the predrilled hole isn't central so the volume knob is off centre!!!!

Pants.

[Bigman80]

Won't the knobs stick out a bit.....lol.....sorryLol

[Bigman80]

Fixed the knobs lol

[Bigman80]

More progress.
https://uploads.tapatalk-cdn.com/20180706/b81c6e5c8458eeed61adc8fa94454764.jpg

[WESTLOWER]

More progress.
https://uploads.tapatalk-cdn.com/20180706/b81c6e5c8458eeed61adc8fa94454764.jpg

That big toe nail has seen better days! :eek:

[Bigman80]

That big toe nail has seen better days! :eek:Lol, I know!! It's been dead since I broke the original off at MMA (Mixed martial arts as seen in the UFC)

Nasty injury that, opponent trod on my foot wile my toe was folded under itself. Broke the toe and popped the nail off. It doesnt grow properly now and when I've been swimming it literally just pulls off lol. Makes the kids cringe when I do it [emoji23][emoji23][emoji23]

[WESTLOWER]

Lol, I know!! It's been dead since I broke the original off at MMA (Mixed martial arts as seen in the UFC)

Nasty injury that, opponent trod on my foot wile my toe was folded under itself. Broke the toe and popped the nail off. It doesnt grow properly now and when I've been swimming it literally just pulls off lol. Makes the kids cringe when I do it [emoji23][emoji23][emoji23]

Crumbs! :spew:

[Bigman80]

Lol, I know. The "pop" when my toe broke stopped the fight, the ref wanted to stop the fight, I wouldn't let him. Then he trod on it again and I was finished [emoji23][emoji23] worst way to lose a fight ever [emoji23]
Crumbs! :spew:

[Bigman80]

Well, it's in and yes.......IT WORKS!!!!!!!!

Turned out my UP-OCC was too think to manoeuvre and solder so I nicked the middle out of some RG316 I had lying around. I will swap it for some UP-OCC of suitable guage when time allows.

Big thanks to Alan T & Alan K

First impressions? [emoji16]
https://uploads.tapatalk-cdn.com/20180706/55637e9d2226ec3d72a178d65bdadcb3.jpg

[Jimbo]

Well, it's in and yes.......IT WORKS!!!!!!!!

Turned out my UP-OCC was too think to manoeuvre and solder so I nicked the middle out of some RG316 I had lying around. I will swap it for some UP-OCC of suitable guage when time allows.

Big thanks to Alan T & Alan K

First impressions? [emoji16]https://uploads.tapatalk-cdn.com/20180706/057272676a81f2f7cab9f4d0e9fe076f.jpg

Looking good Oli. What's that other black box underneath it?;)

[Bigman80]

Looking good Oli. What that other black box underneath it?;)Oh. Erm. Nothing?

[Jimbo]

:lol:

[Bigman80]

[emoji38]

[emoji51]

[Bigman80]

So, I've put the lid on and hum has appeared. It's the same on every input so there's a problem somewhere.

Any ideas?

[Bigman80]

It does.
Does the hum go away when the lid is removed?

[YNWaN]

How odd. Is the case and lid made from aluminium or steel?

[Bigman80]

How odd. Is the case and lid made from aluminium or steel?It looks like its steel as a magnet sticks

[walpurgis]

Have you got the case earthed?

[Bigman80]

Yes mate.
Have you got the case earthed?

[walpurgis]

Is the case earth commoned with the in/out socket negs? They may need separating if so.

[Bigman80]

Is the case earth commoned with the in/out socket negs? They may need separating if so.They are not commoned mate. They are earthed to the chassis in a separate location.

Would this matter as the hum goes when the lid goes?

[walpurgis]

What I'm suggesting is that it may (or may not :)) be best if the signal negs are not earth to the case.

[Bigman80]

If they're both connected to the chassis, they're commoned.Ah, so how else do I do it?

[Bigman80]

This is what I'm thinking. How do I get rid of it?
Yes, the 0 volts doesn't have to be connected to mains earth. If it is, there's the chance of creating an earth loop (depending on what other equipment is connected to it).
I prefer to link 0V to the chassis via a 100 ohm resistor.

In this case I don't think the problem is an earth loop. It sounds to me like the case forms a complete loop around the transformer when the case lid is on and it's creating a magnetic pathway.

[walpurgis]

Non-Ferrous lid?

[Bigman80]

Non-Ferrous lid?Not simple enough Geoff lol,

Transformer shield?

[montesquieu]

Non-Ferrous lid?

That's what I was thinking. Nice thick sheet of black perspex. Maybe that's why I'm not an engineer.

[CageyH]

Have you tried it without the transformer shield?

[Bigman80]

Shouldn't be necessary. The world is full of preamps with steel enclosures - they don't all hum. Correct wiring should make it immune to picking up hum. I suspect a large loop somewhere which is acting as an induction loop. Star earthing is all about eliminating loops and is why it's favoured.Tell me more. How would you approach the earthing

[Bigman80]

Have you tried it without the transformer shield?There isn't a shield, Kevin. It's just a potted transformer. The outer casing is plastic

[walpurgis]

Mumetal box? I'm just saying the first things that come to mind. Could all be rubbish (or not).

[Bigman80]

Mumetal box? I'm just saying the first things that come to mind. Could all be rubbish (or not).Well, I used one in the DIY phonostage which has a larger TF and the casework is steel. I didn't get any hum in that case. Might be worth a punt.

[Bigman80]

A punt has been taken. A mumetal shield on route from China.

[walpurgis]

:)

[YNWaN]

Ah, I’m sorry to say but I don’t think that will cure the issue - in fact I suspect the shield will cause exactly the same issue the lid does. I say this because the shield is essentially doing the same as the lid, just from an even more magnetically permeable material.

[Bigman80]

Ah, I’m sorry to say but I don’t think that will cure the issue - in fact I suspect the shield will cause exactly the same issue the lid does. I say this because the shield is essentially doing the same as the lid, just from an even more magnetically permeable material.I suspect you'd be right BUT if it doesn't help, it can be used elsewhere. Not much investment either, £8 lol.

[337alant]

Every system has to have at least 1 point were the chassis earth is connected to the signal ground
Some pre amps have this as an earth lift switch where you can have it connected or not at the flick of a switch
In some source components they have this connection and as long as that is connected to wont get a hum but if you have it in a source component and a pre amp you will get an earth loop and get a hum so you cant have it in 2 components.
None of mine have this connection so I deliberately connected mine in the pre amp and the hum disappears

So from your case earth run a wire to your star earth or signal ground and see if the hum disappears ?

If you buy Mumetal plate and bend it, it may need heat treatment afterwards for maximum permeability

Alan

[Bigman80]

Every system has to have at least 1 point were the chassis earth is connected to the signal ground
Some pre amps have this as an earth lift switch where you can have it connected or not at the flick of a switch
In some source components they have this connection and as long as that is connected to wont get a hum but if you have it in a source component and a pre amp you will get an earth loop and get a hum so you cant have it in 2 components.
None of mine have this connection so I deliberately connected mine in the pre amp and the hum disappears

So from your case earth run a wire to your star earth or signal ground and see if the hum disappears ?

If you buy Mumetal plate and bend it, it may need heat treatment afterwards for maximum permeability

AlanI'll give it a go Alan,

Thanks.

[Bigman80]

A keen eyed watcher (Mr Firebottle) has spotted that both the output and input are sharing the same common which is also connected to the Chassis. I'll cut the wire tomorrow and see if it helps.

Geoff, you also stated this so you might be on to something!

[Bigman80]

This is my DCB1 built by a friend for me. I went a bit foo with Khozmo attenuator, Audio Note Tantalum resistors and Mundorf caps but it's defintely worth it!

http://audioabattoir.s3-eu-west-1.amazonaws.com/original/3X/d/c/dcff57b574afdcb1bc5500db3b20b71c890e8bb8.JPGThat looks fantastic.

So far today, the Khozmo & DCB1 have been a very good listen. I am very happy with it all so far, apart from the hum that has disappeared after unscrewing the lid and just resting it in place.

Not overly happy with the RG316 as it sounds hard at times and a little etched but it's a characteristic of the cable I was aware of. UP-OCC is ordered and should be here next week. I'll rewire the thing when I get a chance.

Also, any of you eagle eye watchers may have noticed that the fuse holder isn't connected. Thats because I didn't have a suitable fuse! One on the way. All will be done next week.

I've given it a thorough workout today with my DIY valve phonostage and a Solid-state phonostage and the results are wonderful with both. Great soundstage, Excellent depth and very revealing. It's a pleasure to listen to.

I really felt like I was taking a risk when I sold the Slagle but it was a blind punt I'm glad I have taken.

The DCB1, a really really good preamp.

[alphaGT]

I’ve got great respect for DIY gear. I’ve been wanting to build my own stereo for years! I’m sure it sounds just that extra bit better when you build it yourself. Nice thread and a great project!

Russell

[Bigman80]

I’ve got great respect for DIY gear. I’ve been wanting to build my own stereo for years! I’m sure it sounds just that extra bit better when you build it yourself. Nice thread and a great project!

RussellThanks Russell, I am sure its impossible to be impartial when listening to it. When you've DIY'd something, it certainly adds a bit of enjoyment. You also get the "I wonder if I change....." Feeling a lot too. Which can be quite distracting.

Overall, I've been very lucky to have Alan's help and the help of AlanT on this one so it's turned out well.

[Wakefield Turntables]

I’ve got great respect for DIY gear. I’ve been wanting to build my own stereo for years! I’m sure it sounds just that extra bit better when you build it yourself. Nice thread and a great project!

Russell

better in most cases. Great thread BTW.

[brian2957]

I’ve got great respect for DIY gear. I’ve been wanting to build my own stereo for years! I’m sure it sounds just that extra bit better when you build it yourself. Nice thread and a great project!

Russell

+1 . Wish I had listened at school :D

[Bigman80]

Thanks Andrew!

Heres a pic of it now hum free (separation of the common earth on in and out puts has done the trick)

Wait, no it's back lol


https://uploads.tapatalk-cdn.com/20180707/bb9a09cdd5d096a1223545548b8e08ac.jpghttps://uploads.tapatalk-cdn.com/20180707/aa216b5d51c23331d4b7257611453a8c.jpg

[brian2957]

Well done mate :D

[walpurgis]

Glad you got it sorted Oliver. What's it sound like?

[Bigman80]

Glad you got it sorted Oliver. What's it sound like?Geoff, the hum returned when I screwed the lid on. Not as bad but it's there. More investigation to do.

Soundwise, i am finding it preferable to the Slagle. As good as the Slagle is, the bass control wasnt really what I was looking for. After having a listen to some very good Solid state stuff, I really wanted to try and improve the bass.

After doing some reading and chatting with Al, we thought about trying a buffer such as the DCB1 in the Slagle. The other issue I had was Volume. My Phonostage has high gain so I couldn't get the volume low enough for evening listening. I decided to just go for an all new (ideas) pre instead.

I was a little hesitant to sell the Slagle but it's the only way I could finance the DCB1.

First impressions are, it was a wise move. There are some caveats, the RG316 isn't a cable I'd pick to wire the DCB1 but I didn't have an alternative. I've found that although it's a very revealing cable, it's a little harsh and etchy. This is apparent in the listening.

Bass control has improved massively and has far more slam. It's no deeper, frequency wise but just under better control now. The soundstage is massive, as it was with the Slagle and in relation to the treble, I can't really tell at the minute because of the cable. Once I've swapped the RG316 for UP-OCC the characteristics will change again so I'm not listening too critically.

I don't feel like I've lost anything by taking the gamble. So that's good news. I also expect it to improve with the new wiring.

[337alant]

Great job BTW Jamie

This Rane article has some interesting reading on grounding schemes :)

http://www.rane.com/note151.html

Alan

[YNWaN]

Oliver, I share your view regarding RG316 - bloody awful stuff for audio use.

[Bigman80]

Oliver, I share your view regarding RG316 - bloody awful stuff for audio use.Seems very harsh to me. I like the insight it gives but I can get that with SPOTFIRE stuff.

Luckily, I have some of my cable of choice on the way. Cannot wait to get it done.

[STD305M]

Hi Oliver

Ive been following this Thread with great interest, as you know I'm in the middle of a DC-B1 turbo build, not easy for me as i have no idea about electronics but I'm learning very quickly.
Fortunately the board has the values of all the components. Iv tried where possible to order the best i can afford ie; vishay dale - Nichicon - Khozmo Series Attenuator Blah Blah Blah !!!
Ive taken advice from yourself and Mr Firebottle ( thank you both ) and done a massive amount of research online.
I will of course be needing a little more help to complete my project but have found working on my preamp very rewarding.
Lets hope it sound as good as it looks.

I cant wait to get it hooked up to my new Firebottle mono's when Alan completes them.

Regards Steve

[Bigman80]

Hi Oliver

Ive been following this Thread with great interest, as you know I'm in the middle of a DC-B1 turbo build, not easy for me as i have no idea about electronics but I'm learning very quickly.
Fortunately the board has the values of all the components. Iv tried where possible to order the best i can afford ie; vishay dale - Nichicon - Khozmo Series Attenuator Blah Blah Blah !!!
Ive taken advice from yourself and Mr Firebottle ( thank you both ) and done a massive amount of research online.
I will of course be needing a little more help to complete my project but have found working on my preamp very rewarding.
Lets hope it sound as good as it looks.

I cant wait to get it hooked up to my new Firebottle mono's when Alan completes them.

Regards SteveHi Steve,.

It's a great preamp in its standard form and as you know, I will be putting a Turbo version together too.

Some folks aren't convinced on the merits of parts such as the Dale and Vishay stuff but I Certainly am. Good move there.

The Khozmo stepped attenuator is a fantastic bit of kit and it's been superb. It did take a number of hours before I felt it relaxed as at first I thought it sounded a bit stiff but I'm happy to report it isn't the case in the long term. Transparent and honest. Can't go wrong.

Looking forward to seeing the finished article mate. Well done for having a bash.

O

Sent from my VKY-L09 using Tapatalk

[Bigman80]

It's been some time since this thread got an update but seeing as it's been a bit of an experimental path, with upgrades and rebuilds done in great haste, I think a return to it and a brief summary of developments will be acceptable!

After building the first itineration of the DCB1, selling it on and rebuilding another DCB1 with a more suitable chassis, it ran at 600mA for some time. This was always going to be a temporary thing as the real goal was to get it up to 1.2A.

Running at 600mA certainly provided more of the best bits this preamp gives by opening up the soundstage and sounding even more transparent than my original one before we upped it's mA's

STD305 (Steve) and I started to discuss what to do next. I wanted 1.2A so that's what we went for.

The 1.2A was less straight forward to build than id have liked. For instance, the reported resistor values were in fact, well short of what was required to get 1.2A running through the board. I had to get some help from Alan, but as usual, he sorted it out.

This build saw Steve and I deviate from the supplied kit in the form of swapping the brand of resistors. We were messaging daily on the status of our builds and looking for exotic parts to stuff the board with. Though the PCB kit is normally supplied with Dale Vishay resistors, We went for Audionote Tantalum resistors instead. I loved them instantly but Steve felt they were a little light on bass. Steve ventured off into ZFoil madness and more, even building an I'll fated dual moni DCB1 with zfoils in, but I kept mine running in. Eventually, they opened up and the bass was no issue. I felt the AN Tantalum were more transparent than the Dales and after some time, Steve came back to the AN, which I believe are still in situ.

Steve and I discussed capacitors to replace the WIMA 0.22UF. At the time, i felt the WIMA were doing just fine but as usual, Steve went bonkers and bought bees wax and paper caps (I think). He really goes all out when he's on to something!

He reported a very noticeable improvement. I remained with the WIMA until this week when I swapped mine out for some Obbligato Gold caps. I wish I'd done it earlier on.

Today, I was absolutely convinced that this IS as good as any preamp I've ever heard. So, what's the best test of a preamp? Remove it and see what happens

I decided to see what effect the DCB1 has on things by removing it from the chain altogether. This was only possible to do now that I have the Raspberry Pi and could control the volume via the Volumio app.

From Pi directly to Krell.

I listened to a fair few tracks and tried to notice whatever I could. Little notes, breaths, fret buzzes. Literally anything that COULD be masked by a lack of transparency.

I put the DCB1 back in and listened again.

Everything I had heard was still there BUT the DCB1 does have an effect but it's not on transparency. It's on the feel of the music. It gives it a bit more drive or potency, if you will. It's not a lot but I was using the pi to send a signal to the Krell via 2m of cable. With the DCB1 in place it felt like it was getting there a little quicker.

Transparency and insight were absolutely unaffected and so too was tone. It was incredibly close to the sound when it wasn't there at all. So close, I'd challenge anyone to blind test it and pick between them.

The other difference I noted was that the soundstage was a bit bigger through the DCB1 but I have no explanation for that at all.

Overall, the DCB1 has been one of the best finds I've had in HiFi. I love mine to bits and now only have one thing left to do with it, and that is fit a power button. That should arrive this week. Pilot hole has already been drilled lol. Then the lid can finally be screwed on and left on.

If you are in the market for a preamp, I absolutely recommend getting a listen to one.






https://uploads.tapatalk-cdn.com/20190323/6b71e30e35ceb13029fa8b44952241b4.jpghttps://uploads.tapatalk-cdn.com/20190323/290dab2ec01ffa69778e4f86dc85a743.jpg

[karma67]

Why was the dual mono dcb1 ‘I’ll faited’?

[Bigman80]

Why was the dual mono dcb1 ‘I’ll faited’?Steve can probably answer that more thoroughly but my understanding was that once he'd built it, under instructions given to him by the creator, the unit had a hum or ground loop or some kind of noise he couldn't get rid of.

I believe he stripped it back to a single PCB and is now using it noise free.

Shame because it would have been epic!

[smangus]

Hi Oliver good to see the amp being improved , what effect did the Obligatos have on the sound?

Cheers Andy

[Bigman80]

Hi Oliver good to see the amp being improved , what effect did the Obligatos have on the sound?

Cheers Andy

Well, It's only my opinion but i feel the soundstage had improved vastly, almost like the odd noise or sound comes at you from an angle you didn't expect or hasn't done before. Transparency has improved. Its removed a thin film from the sound that i didn't realise was there. Bass had better detail, whilst leading edges are clearer which of course means the decay has improved too. I feel closer to the music and like i am able to pick out more. I didn't expect that from changing two capacitors.

[smangus]

Thats interesting, something else to think about lol

Sent from my SM-G950F using Tapatalk

[Bigman80]

Thats interesting, something else to think about lol

Sent from my SM-G950F using TapatalkI know, it's a pain because everything costs.

To be fair, I don't know why I was so surprised. I've experimented with caps in phonostages and found that some were clearly better than others. I didn't expect it though and it's always a nice moment when you make the right choice.

The WIMA are decent caps but I've got Dale resistors, Audio note tantulum resistors, Nichicon gold caps, and SPOTFIRE wire throughout the DCB1 so really, I should've put better caps in from the start. Pleb!

There's about 10-15 hours on the Obbligato and they sounded a little bassey in the early stages but that's evened out already. If they open up further after more hours, I'll be putting some in my Bigbottle phonostage too!

[smangus]

When I bought the board I got 2 , my intention was always tobuse the 1st one as a learning experience (done![emoji846]) and then use the 2nd one for better quality parts etc. So I've got this to look forwards to .

Sent from my SM-G950F using Tapatalk

[STD305M]

Hi Oliver,
Great write up on your progress.
I've got a little respite so have decided to add to the thread.
I've gone through several DCB1 builds including a very expensive dual mono build which was a little disappointing, only because i didn't have the skill to get to the bottom of quite a few issues it had.

I've finally ended up going back to using a single board but stuffed full of boutique parts.
Ive ended up having tried resistors from 6 manufacturers with audionote tantalums. They work really well and beat the Charcrofts by quite some margin.
The buffer caps from Nichicon stayed but the Wima caps which are very good indeed were replaced with Jupier caps, they gave the whole sound a lift.

The only thing i really would recommend is to experiment, I did at a huge cost but worth the effort even though it didn't work as it gave me the chance to see what works best.
I'm also very lucky that when i split the dual mono and rebuilt 2 machines i recouped my costs and 2 people ended up with top quality preamps.

Anyone putting together a dcb1, should budget allow should use tantlum resistors throughout and replace the 2 Wima caps for higher spec caps. Stay with the khozmo, Elma switch and get the best hook up wire you can find, I personally like Oliver's spitfire cable.

Then just sit back and enjoy, very probably, the best preamp I've personally ever heard, knowing you built it yourself

Regards Steve...

[Macca]

I'm also very lucky that when i split the dual mono and rebuilt 2 machines i recouped my costs and 2 people ended up with top quality preamps.

...


I was one of them and am extremely grateful. I don't know how it would perform with other power amps since as it has no gain it might not be compatible with some, but feeding a Krell KSA50S the sound quality is astonishingly good. Not just for the cost which was peanuts but in absolute terms. Even after a couple of months I still can't get over it. Sounds like hype I know but I don't make such comments lightly and if anyone within striking distance of me wants a listen you're welcome to come over and hear for yourself.

[STD305M]

I was one of them and am extremely grateful. I don't know how it would perform with other power amps since as it has no gain it might not be compatible with some, but feeding a Krell KSA50S the sound quality is astonishingly good. Not just for the cost which was peanuts but in absolute terms. Even after a couple of months I still can't get over it. Sounds like hype I know but I don't make such comments lightly and if anyone within striking distance of me wants a listen you're welcome to come over and hear for yourself.

Hi Martin

I would have been up to upgrade yours if it wasn't for the fact I'm looking after my father in law who had a stroke recently.

It also performs extremely good with pretty much any power amps. Have heard it with quite a few!!!
Even the Quads.

I will get some time very soon and will pop over to do the upgrade.
Your dcb1 sounds great but you won't believe what it really is capable of untill you hear it after the upgrade.

F,ing awesome!!!!!

Regards Steve...

[Macca]

Looking forward to that Steve. Actually the only niggle I have with it is the bright blue LED, can we swap that out for an orange one? Got a bit of card covering it over it at the moment!

[STD305M]

Hi Martin
Any colour you want mate also dim it a little

Steve..

[Macca]

:rock:

[Bigman80]

Hi Oliver,
Great write up on your progress.
I've got a little respite so have decided to add to the thread.
I've gone through several DCB1 builds including a very expensive dual mono build which was a little disappointing, only because i didn't have the skill to get to the bottom of quite a few issues it had.

I've finally ended up going back to using a single board but stuffed full of boutique parts.
Ive ended up having tried resistors from 6 manufacturers with audionote tantalums. They work really well and beat the Charcrofts by quite some margin.
The buffer caps from Nichicon stayed but the Wima caps which are very good indeed were replaced with Jupier caps, they gave the whole sound a lift.

The only thing i really would recommend is to experiment, I did at a huge cost but worth the effort even though it didn't work as it gave me the chance to see what works best.
I'm also very lucky that when i split the dual mono and rebuilt 2 machines i recouped my costs and 2 people ended up with top quality preamps.

Anyone putting together a dcb1, should budget allow should use tantlum resistors throughout and replace the 2 Wima caps for higher spec caps. Stay with the khozmo, Elma switch and get the best hook up wire you can find, I personally like Oliver's spitfire cable.

Then just sit back and enjoy, very probably, the best preamp I've personally ever heard, knowing you built it yourself

Regards Steve...I wanted to call the cables the SPITFIRE but the name was already taken!!!

Totally agree about the experimental aspect. I bought some little lugs, it means I can swap resistors out very easily, without taking the board out or even heating the board.

Ironically, I now have no desire to change anything else lol

[STD305M]

Hi Oliver

Not needing to change anything else is a really good place to be.

I'm really happy with my setup but i still feel a speaker change is what i need to realise the full potential of my system.

Steve...

[Bigman80]

Hi Oliver

Not needing to change anything else is a really good place to be.

I'm really happy with my setup but i still feel a speaker change is what i need to realise the full potential of my system.

Steve...The next change for me will be the listening room. To realise the full potential of the system, the room is the biggest issue. I'm not looking to sell anything else UNTILL the room is built. It could take 10 years though lol

[STD305M]

Hi Oliver

I'd be more than happy with your system for the next 10 years mate :) :lol:

[Macca]

The next change for me will be the listening room. To realise the full potential of the system, the room is the biggest issue. I'm not looking to sell anything else UNTILL the room is built. It could take 10 years though lol

Wait till I get the Tannoys & you get the JM Labs in, you might change your mind. Although that could take ten years too...

[Bigman80]

Wait till I get the Tannoys & you get the JM Labs in, you might change your mind. Although that could take ten years too...[emoji23][emoji23][emoji23]

Well, it doesn't mean I'll sell anything. I'd really like to hear the pioneers in a purpose built room. I think they are capable of more. I'm that confident, I'm going to redo the crossovers and put some very nice cabling inside. In a smaller room, the sealed cabs offer a great deal IMO. A purpose built room should allow me to really see what they can do

[Bigman80]

Hi Oliver

I'd be more than happy with your system for the next 10 years mate :) [emoji38][emoji38][emoji38]

Yes I feel it is certainly "up there" in terms of performance.

[oceanobsession]

Have you compared your pre amp to anything else yet . phil.

[Bigman80]

Have you compared your pre amp to anything else yet . phil.Yes,

The Truth
Stereo Coffee
Slagle AVC
Firebottle KIN
Chinese Relay Volume Control
DIY Alps Blue Passive
Goldpoint Passive preamp
Xiang Sheng DAC/Preamp

Plus others.

[oceanobsession]

Well it looks great , the black case looks cool aswell , there seems to be a big following for these kits , am I right in thinking that there is no gain , how much is the basic kit , phil.

[Bigman80]

Well it looks great , the black case looks cool aswell , there seems to be a big following for these kits , am I right in thinking that there is no gain , how much is the basic kit , phil.Its about what you want from it. Big standard, with Alps blue (not recommended by me) would cost £2/300.

Mine, cost £600.

Its about how far you want to push it's ability. Personally, I like to go all out.

[Edward]

Oli, what was your opinion on the LDR Stereo Coffee pre? Did you try it in your system or at Alan's?

I'm using it now and very pleased with it. Really gelled between the Metrum dac and the Radford.

[Bigman80]

Oli, what was your opinion on the LDR Stereo Coffee pre? Did you try it in your system or at Alan's?

I'm using it now and very pleased with it. Really gelled between the Metrum dac and the Radford.Hi Edward, apologies but iv eonly just seen this!

For the cost I thought it was excellent. I did do a bake off report on the comparison we did with my DCB1, so I'll try and post a link to that. My impression was fresh as we'd not long finished.

[JohnG]

I have recently purchased a B1 Buffer and B1 Korg to trial.
Both are assembled but not mounted in a chassis.
I have a DACT Stereo Attenuator that can be used in either build.
The image shows the B1 Buffer circuit.
If it can be identified, is there any improvements that can be made on this, i.e recommended box dimension, exchange components, increase Ma output.
It didn't cost me much, so any brutal opinions, won't be too hurtful.
I am assuming this build is a basic version.


26344

[Firebottle]

That doesn't look much like a B1 buffer to me John.
Can't quite make it out, what is the text on the bottom right of the pcb?

It looks like a 5 input relay switched, remote volume control preamp. Whether it has a B1 buffer stage I couldn't say.

[JohnG]

Hi Alan
The circuit board text states.
Simplistic Pass B1 Buffer, RPRE V2.2, August 2015, Design by Rudi Ratlos.
It is going away for assembly today.
Am I correct to assume, it will not be comparable to the recent designs being created, if the circuit is looking different.

[Bigman80]

Hi John,

This is the PCB I associate with the Korg B1 https://diyaudiostore.com/products/b1-buffer-with-korg-triode-pcb-and-jfets

I don't think it works in the same way as the DCB1 IIRC. I'd have to do some digging.

[Bigman80]

Hi Alan
The circuit board text states.
Simplistic Pass B1 Buffer, RPRE V2.2, August 2015, Design by Rudi Ratlos.
It is going away for assembly today.
Am I correct to assume, it will not be comparable to the recent designs being created, if the circuit is looking different.

Where did you get it, John. I cant even find a thread online for it?

[JohnG]

It came of DIY audio, the seller is still on page two of the sales page, with a few Hypex devices.
Have a look at post history and it is a as placed in May.
The builder is the guy on the circuit board, who has a history of activity on the B1 thread on DIY audio.
It was purchased at under the ad price, as it was a impatient punt from my end, with 2019 being dedicated to investigations of pre amps, that is limping along.

[Batty]

26623

My B1 in build stage, it is the "Ten Years After" Mezmerise verion from DIYAudio.

[Light Dependant Resistor]

It would help IMO to see schematics, to make the thread tangible as to what one version is vs another. :eyebrows:

[ijrussell]

26623

My B1 in build stage, it is the "Ten Years After" Mezmerise verion from DIYAudio.

I have a DCB1 built by a friend (http://teribil-audio.com/2018/06/dcb1-preamplifier/) with the same board. If you want to get better sound from it, upgrade the 8 resistors around the output to Audio Note Tantalum. I also upgraded the 2 big caps to Mundorf ones and the 5 smaller caps to Audio Note. In basic form, the DCB1 is really good but when upgraded, it is very, very good. The sound quality to cost ratio is astonishing.

[Bigman80]

I have a DCB1 built by a friend (http://teribil-audio.com/2018/06/dcb1-preamplifier/) with the same board. If you want to get better sound from it, upgrade the 8 resistors around the output to Audio Note Tantalum. I also upgraded the 2 big caps to Mundorf ones and the 5 smaller caps to Audio Note. In basic form, the DCB1 is really good but when upgraded, it is very, very good. The sound quality to cost ratio is astonishing.Couldn't agree more with the AN Tantalum. Awesome capacitors.

Just give the legs a rub with wire wool before installing and a little clean as the ones I got were really grubby.

I've made that standard procedure now lol

[Macca]

The sound quality to cost ratio is astonishing.

Forget the quality to cost ratio they are just very good regardless.

Still surprises me every time I use it and mine doesn't have any fancy upgrades.

[Bigman80]

Forget the quality to cost ratio they are just very good regardless.

Still surprises me every time I use it and mine doesn't have any fancy upgrades.We need to give yours the treatment Martin.

New psu caps, tantalums, bigger power. The whole nine. Unfortunately, you could do with a better chassis to dissipate the heat.

You'd love it mate. 100%

[smangus]

Yes , I would say this is one bit of kit where each upgrade on the stock form makes a tangible difference.

Sent from my SM-G950F using Tapatalk

[Bigman80]

Yes , I would say this is one bit of kit where each upgrade on the stock form makes a tangible difference.

Sent from my SM-G950F using TapatalkSteve is my go to guy for trial and error on this kit.

He has changed everything and he says that the only 4 caps to leave alone are the little ones as they didn't make any difference whatsoever.

I'd totally agree.

Great preamp. Whatever the cost imo.

[Bigman80]

How nice would a "stealth" DCB1 Look!!

Soooooo temptedhttps://uploads.tapatalk-cdn.com/20190906/386a2a61f04f6a8a58246f2f39b3e829.jpg

[Macca]

I quite like that mine looks like some el-cheapo Chinese bit of tat.

[Bigman80]

I quite like that mine looks like some el-cheapo Chinese bit of tat.Hahaha, you madman!

If you want a "stealth" one, let me know lol.

[Firebottle]

Link for the stealth box?

[Bigman80]

Link for the stealth box?Yes I have one [emoji23][emoji23]

[mikeyb]

Yes I have one [emoji23][emoji23][emoji23]

[Macca]

I need the writing to remind me what does what. So it'd be no good to me.

[Bigman80]

I need the writing to remind me what does what. So it'd be no good to me.Lmfao!

We can get you some Chinese words on it to make you feel comfortable [emoji23]

[STD305M]

Hi Oliver
The Stealth case looks great but what about ventilation??
Your gonna need it running at 1.2A
Steve

[Bigman80]

Hi Oliver
The Stealth case looks great but what about ventilation??
Your gonna need it running at 1.2A
SteveLittle fans, Steve.

Little fans lol

[mikeyb]

Little fans, Steve.

Little fans lolLittle fans will whine unless run really slow which won't move much air, big fan running slower will move more air more quietly.

But probably not practical to go bigger for to case size, nothing's ever easy [emoji6]

[Bigman80]

Little fans will whine unless run really slow which won't move much air, big fan running slower will move more air more quietly.

But probably not practical to go bigger for to case size, nothing's ever easy [emoji6]To be honest, the case isn't 'ideal' as Steve pointed out and whilst I know the thought of fans is like sacrilege to the audiophile, there are silent fans which could be useful in this case.

Lots of fans in Pro gear which you can't hear.

[Edward]

Have you guys considered making one of these with remote volume control?

[STD305M]

Hi Edward
How's you.
I have a remote setup for the Khozmo
It cost more than the attenuator and is a real pain to fit so I've not bothered for the time being.
The other option at the same quality and easier to fit so I'm led to believe is the Acoustic Dimension
There are cheaper and easier options but I'd rather not use the blue alps pot.

I'll get round to fitting mine one day.

Steve

[STD305M]

To be honest, the case isn't 'ideal' as Steve pointed out and whilst I know the thought of fans is like sacrilege to the audiophile, there are silent fans which could be useful in this case.

Lots of fans in Pro gear which you can't hear.

Hi Oliver
The fan if silent is a great idea but the hot air still needs to be vented out of the case.

Steve

[Bigman80]

Hi Oliver
The fan if silent is a great idea but the hot air still needs to be vented out of the case.

SteveHave it set to draw the air out. Like a vacuum. It's not an air tight case so should suck sufficient air out

[Edward]

Hi Edward
How's you.
I have a remote setup for the Khozmo
It cost more than the attenuator and is a real pain to fit so I've not bothered for the time being.
The other option at the same quality and easier to fit so I'm led to believe is the Acoustic Dimension
There are cheaper and easier options but I'd rather not use the blue alps pot.

I'll get round to fitting mine one day.

Steve

Cheers Steve, I'm fine thanks.

Yes I think you mentioned when I was over that remote was a pain and/or expensive. But still would be a good feature - particularly for lazy old gits like me. :lol:

[Firebottle]

Cheers Steve, I'm fine thanks.

Yes I think you mentioned when I was over that remote was a pain and/or expensive. But still would be a good feature - particularly for lazy old gits like me. :lol:

The Acoustic Dimension is so much easier, and smaller. It is as good as the Khozmo IMO.
A control board to match can be had very cheaply from China.

[STD305M]

Hi Alan
That was the other option i mentioned :)
Easier than the Khozmo remote and on par in terms of quality.
Should I ever build another dcb1 that's what I'll use.

[killie99]

The Acoustic Dimension is so much easier, and smaller. It is as good as the Khozmo IMO.
A control board to match can be had very cheaply from China.

Alan, do you have a link? I've seen the HiFiCollective control board but it's expensive for what it is.

[Firebottle]

https://www.ebay.co.uk/itm/AC-DC-9V-Infrared-Remote-Controller-Volume-Control-Board-ALPS-Pre-Potentiometer/372638880007?_trkparms=aid%3D555018%26algo%3DPL.SI M%26ao%3D1%26asc%3D59535%26meid%3D6d9623f83d36440d a0a6345db0cdb87e%26pid%3D100005%26rk%3D1%26rkt%3D1 2%26sd%3D332686474511%26itm%3D372638880007%26pmt%3 D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851

https://www.ebay.co.uk/itm/AC-DC-9V-Infrared-Pre-AMP-Motor-Audio-Amplifier-Volume-Remote-Control-Board-Safe/202762219962?_trkparms=aid%3D555018%26algo%3DPL.SI M%26ao%3D1%26asc%3D59535%26meid%3Dccc30e43ecf149f3 9abb73f164f99465%26pid%3D100005%26rk%3D1%26rkt%3D1 2%26mehot%3Dlo%26sd%3D183919746494%26itm%3D2027622 19962%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851

Ditch the cheap volume control and just wire the motor leads to the motor on the Acoustic Dimension unit.

[hornucopia]

Surely putting it in an elegant case is vanity, if it needs air circulation to cool it. It's there to sound good; don't affect that aspect. Perhaps you could aerate (grille?)the underside of that case and have a couple of holes in the upper for exit?
i liked both my Pass pre and the Stereo Coffee (with remote!) but my Hafler DH101 sounds as good.

[Bigman80]

Surely putting it in an elegant case is vanity, if it needs air circulation to cool it. It's there to sound good; don't affect that aspect. Perhaps you could aerate (grille?)the underside of that case and have a couple of holes in the upper for exit?
i liked both my Pass pre and the Stereo Coffee (with remote!) but my Hafler DH101 sounds as good.Oh absolutely. But if it looks good, it must sound good surely [emoji6]

[killie99]

Alan, I presume that controller will also work with the TKD motorised pots?

[Firebottle]

I would guess so if the motor is the same at 5V.