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Steve Toy
05-06-2008, 10:58
Before

One Puresound A30 selling for £1100 in the UK and offering superlative performance at this price point. It is fitted with Electro Harmonics 6550 main valves with Chinese stock driver and rectifier valves.

http://img241.imageshack.us/img241/8017/21042008299fz2.jpg (http://imageshack.us)

After

The amp has been more than breathed on by our resident engineer Anthony TD. The circuitry has been reconfigured to give more ooomph, better dynamics, transparency and finesse, the preamp circuitry has been ripped out to make it a power amp only and circuit paths have been shortened. All of the valves have been replaced. The main output valves are Cryogenically treated Svetlana KT88s, the driver valves are rare-as-rockinghorse-shit military spec Philips JAN 6SN7 and the rectifiers are Mullard GZ34s. It has also been named to commemorate this forum:

http://img394.imageshack.us/img394/280/pictures050608015nj7.jpg (http://imageshack.us)

Marco
05-06-2008, 11:23
Where's the 'After', ya numptie? :lolsign:

Marco.

Filterlab
05-06-2008, 11:26
Wait for it...

:lol:

Maybe it'll come in a couple of weeks time? :)

Steve Toy
05-06-2008, 12:12
After now added and more will follow:

http://img165.imageshack.us/img165/5682/pictures050608017ps6.jpg (http://imageshack.us)

Filterlab
05-06-2008, 12:17
Ooooh, that's nice. The more I read about valve amps, the more I want to take a trip to Anthony's place and go listening. :)

Steve Toy
05-06-2008, 12:20
Go to Anthony's by all means but you can make your way up here too.

http://img236.imageshack.us/img236/2905/pictures050608012oj2.jpg (http://imageshack.us)

http://img299.imageshack.us/img299/7964/pictures050608014fq0.jpg (http://imageshack.us)

Mike
05-06-2008, 15:43
Nice! (don't like the power switch though)

Any changes to the transformers? or any planned?

;)

BajaGringo
05-06-2008, 15:55
Nice! (don't like the power switch though)

My thoughts exactly. The only thing I would change...

Ian Walker
05-06-2008, 16:38
Nice! (don't like the power switch though)

Any changes to the transformers? or any planned?

;)

Mmm looks fine to me,rather have it there than rooting round the back for it.

Nice work Anthony:).

anthonyTD
05-06-2008, 17:50
thanks guys for all your comments so far, much apreciated!
anthony.:)

Marco
05-06-2008, 18:16
Looking good, Steve! We want to see a full, 'proper', write-up in the Blank Canvas - make it about your journey from sorry-state, oops, solid-state to the nirvana of valves :)

Superb work, Anthony :smoking:

Are you ready for your next project? Subject for surgery: 1 x Chinese valve amp that used to be known as a 'Yaqin MC-100B' ;)

:gig:

Marco.

Mike
05-06-2008, 18:32
Are you ready for your next project? Subject for surgery: 1 x Chinese valve amp that used to be known as a 'Yaqin MC-100B'

Ah that's easy, you could do that on yer own, I'll lend you my chain saw! :lolsign:

Steve Toy
05-06-2008, 18:40
The switch was my choice. Not Anthony's fault. I like it so there!

Marco
05-06-2008, 18:41
Mike,

Haha... Aye!

Seriously, though, the Yaqin will be getting the same front panel as Steve's amp, and it will also be getting similarly, or rather even more extensively, 'raped' :eyebrows:

Btw, Glenn Croft delivered my upgraded Charisma-X preamp today... All I can say is F*CKIN HELL, WHAT A DIFFERENCE!!! :eek:

Full report tomorrow, or when I can tear myself away from the music :rock:

We had a nice chat, too, about the new range of amps he's introducing shortly. Needless to say yours truly will be getting an exclusive listen to the prototypes and AOS will have the first pictures/review of the new gear when it's completed.

Marco.

Mike
05-06-2008, 18:43
The switch was my choice. Not Anthony's fault. I like it so there!

Cheapskate! :ner:

BajaGringo
05-06-2008, 19:27
The switch was my choice. Not Anthony's fault. I like it so there!

Just giving my dos centavos, which is about all it's worth...

:)

anthonyTD
05-06-2008, 19:32
Looking good, Steve! We want to see a full, 'proper', write-up in the Blank Canvas - make it about your journey from sorry-state, oops, solid-state to the nirvana of valves :)

Superb work, Anthony :smoking:


Are you ready for your next project? Subject for surgery: 1 x Chinese valve amp that used to be known as a 'Yaqin MC-100B' ;)

:gig:

Marco.
thanks mate,
when your ready, we will see what can be done!:)

Marco
05-06-2008, 20:00
No worries, mate :)

I'm going to let the Croft burn-in and enjoy that for a bit first :smoking:

Marco.

mistygreenandblue
05-06-2008, 20:00
I kinda followed this *thread* over from PFM where it all started going a bit pear shaped.....

Can I ask some questions which might be viewed as abuse of the wooden spoon, but in all honesty are just some simple questions rattling around in my head?

Marco
05-06-2008, 20:07
Hi Misty,

Welcome to the forum :)

Carry on. I'm not sure I know what you're on about, though... :scratch:

Marco.

mistygreenandblue
05-06-2008, 20:16
Hi Misty,

Welcome to the forum :)

Carry on. I'm not sure I know what you're on about, though... :scratch:

Marco.
Hi, and thanks.

OP had posted matching thread on PFM, Richard Dunn and a few others made various comments and it got 'trimmed' somewhat...

Without wishing to step on any toes, either Anthony's, or Guy's (Puresound), I'd like to ask Steve / Anthony why, given the total outlay of £1800, and the fact that the A30 has been (or at least to my simple knowledge) changed so much beyond it's original form (about 80%??) why didn't you just build a power amp from scratch? Have I misunderstood how much the original amp has been changed?

Marco
05-06-2008, 20:28
I could answer, but it should be Steve who does it. I missed some of the discussion on PFM but seen the 'aftermath'. Some people seem to have nothing better to do with their lives than moan! The negativity shown towards Steve was pathetic and ridiculous. I see that Tony's tidied up, though.

However, basically, to answer your question, you need to know the history of Steve's system recently and his discovery of valves :)

I'm sure Steve will be along later to explain properly.

Marco.

Filterlab
05-06-2008, 20:30
The switch was my choice. Not Anthony's fault. I like it so there!

I have to say I like that type of switch too, I like an industrial edge to styling to be honest, but for minimalism's sake I may have had the switch on the rear panel by choice.

Than again I know that sometimes it's a qualitative choice to not have the power switch wiring running past the valves.

I like you amp Steve - the others do too really, they're just jealous! ;)

Marco
05-06-2008, 20:37
they're just jealous!

Exactly!!!

Marco.

Marco
06-06-2008, 07:16
Misty,

FYI from PFM (by Steve):


OK, so what was my reasoning behind buying the Pure Sound with the intention from the outset to have it modified?

The answer is I heard the Yaqin 300B in my system and was mightily impressed by it. I wasn't impressed with the idea of having to use a step-down transformer with it though. I also wanted something that could use safely for a while ahead of being modified that I knew would definitely drive my speakers to my satisfaction in my listening environment.

I made a few enquiries with Tony at Coherent Systems, Guy Sergeant who is the distributor for the Pure Sound amp and Anthony Matthews of Tube Distinctions who had agreed to perform the modifications. Guy agreed in principle to the idea of the amp being modified and even sent Anthony the schematic diagram for him to look at, especially as Tony had already performed his own mods to the amp, a prototype of which I heard at his place. It seemed like it was an excellent product to begin with for the money and it worked well in my system driving my speakers to my satisfaction in my room unmodified, as Tony had demonstrated having brought it to my place for me to hear in early April.

Good as it was it seemed obvious to me that it was ripe for improvement. The involvement factor was already there in abundance but better dynamics, clarity and a touch more refinement wouldn't have gone amiss. Also, rather than buying something off the shelf from the likes of EAR, Prima Luna etc. I really fancied the idea of going down the bespoke route, getting something that was unique to me and built to my specification. The attraction of fettling a Chinese-built amp rather than getting one built from scratch locally was getting value for money. The cost of the chassis and transformers alone if sourced from within Europe would be considerably more than the whole working amp from China even with any distributor and dealer margins thrown in for good measure.

I knew I was taking a risk that I may not like the finished product but I've every faith in Anthony's abilities as both a designer of valve amps from scratch and as a fettler of imported Chinese ones. Initial impressions were very pleasing indeed but I'm not out of the woods just yet regarding the risk as the valves need time to burn in. The dynamics from the bottom end up and clarity are all there but tonally the sound is sound a little thin and bright at the moment. I have been assured that this will ameliorate over the coming days/weeks.
Including the cost of carriage to and from Anthony's place I've broken even on the cost of this amp on the proceeds from the sale of the Densen.

It is called AOS Classic Series to commemorate the Art of Sound and the same acrylic facia plate will probably be used for any future amp imported from China and modified by Anthony of Tube Distinctions.


Steve should have posted his answer here, too, but he's a bit of a lazy arse sometimes ;)

I would add that the reason Steve didn't buy a 'Bewitch' (the "cheap Chinese" version of the Puresound, as asked on PFM), rather than buying the Puresound for £1100, is because at that point he didn't know the Bewitch existed, otherwise he would have done the same as me with the Yaqin and imported it direct from China and then sent it direct to Anthony for modifying. I guess hindsight is a great thing...

Marco.

pure sound
06-06-2008, 08:17
The A30 is a different design to the Bewitch 6550. I liked the chassis, the configuration and indeed the valve complement used in the Chinese design. However, the A30 is a 30W per channel class A amplifier (as opposed to a 60W AB design) and as such, the output stage needs to see output transformers with a different primary impedance and a mains transformer giving a lower HT voltage but higher current. The output valves are of course biased differently and, because the Class A circuit produces less distortion the feedback configuration is also different. There are also certain other component changes that were specified, just because I prefer them that way! The first 10 amplifiers imported by me were actually badged Bewitch. But, because the factory also makes certain other products (AV amplifiers, some little speakers, a DVD player) also branded Bewitch but which I have no interest or involvement in, it made sense to have this product badged Pure Sound. I thoroughly QC check every piece that arrives here and do add one further very minor mod to each one.

If someone wants to import the 60W version for themselves they are welcome to, but be warned, it isn't the same product & they will be dealing with the HK based re-seller if they have any service issues with it. They should also hurry. I don't think that particular design is to be available via the re-seller for much longer.

Marco
06-06-2008, 08:50
Hi Guy,

Thanks for the clarification - most interesting.

There's still the option, though, of buying the Bewitch 6550 direct from China 'au naturel' and sending it to the likes of Anthony to carry out the same modifications you've done, or indeed what he's just done to Steve's amp, and end up with something special and an absolute bargain in terms of audio performance. I believe you can buy the Bewitch for around the same price as I paid for the Yaqin (approx £300). What you'll end up with then is a truly hi-end design for about £900, after mods, that will compete with much more expensive commercial designs.

If Steve had initially gone down that route he would have saved quite a bit of money, as rather than buying an £1100 A30 and having it modified he could have bought a £300 Bewitch direct from China for the same purpose and ended up exactly where he is now. What you're saying regarding specifications is true but only applies to people who intend to use the Bewitch 6550 or Puresound A30 as stock items :)

I see the importing of hi-fi equipment direct from China and modifying by respected British electronics engineers such as Anthony, Nick and you as the way forward for enthusiasts to obtain a truly high-end product at a bargain price. Quite simply, you end up with much higher sound-per-pound value and also something which can be tailored to your own specifications. As an enthusiast looking for top-notch performance at the lowest possible price that's a win-win scenario :smoking:

I'm not sure some UK dealers would see it that way, though... ;)

I can't wait to have the Yaqin fully modified. It's awsome as it is now just with a change of valves and a few minor tweaks. It's a truly frightening thought what it will be like when our resident Mr Matthews has fully gone to town on it! :eek:

Marco.

lurcher
06-06-2008, 09:04
I think your numbers will still work Marco, but remember that to get to where that amp started, from what Guy was saying, you would need to add a new pair of OP TX's to the amp to make the most of the AB -> A change. so that will eat up £300+ of the budget.

Marco
06-06-2008, 09:24
Yep that's true, Nick. Even after that, though, you'll still have a bargain compared to how much a commercially produced amp offering the same performance (maybe!) would cost. I remember the demo of the Unison Research integrated at Owston ;)

The sound-per-pound value of some commercially produced valve amplifiers is frankly shocking.

And even getting you guys to build one from scratch would cost more because you couldn't even buy the empty casing for the Bewitch or Yaqin in the UK for £300!

Marco.

SolidState
06-06-2008, 09:30
Before people get on the bandwagon of thinking they're getting a superduper valve amp for an absolute bargain, I'd just like to say, I got a Mr Liang EL34, which is suppose to be one of the better offerings from China.

Nick and me looked into it. This amp was nothing short of a deathtrap for the unsuspecting. To get this amp right it needed a full circuit redesign and all new components. In fact there were no components worth 'recycling' in it.

So be warned unless you know what your doing it's better to be safe than sorry, or worse case live to regret it.

pure sound
06-06-2008, 09:38
I don't think you'd want to be trying to draw 330mA of current continuously from the HT winding of the AB amp either so the mains transformer would also need to be changed for Class A operation which, for this type of amplifier, is the optimal way to configure it imo.

Marco
06-06-2008, 09:41
Mo,

I thought Ali's Mr Liang was ok? It certainly sounded that way at Owston! :)

Have you discovered something since to disprove that?

Marco.

SolidState
06-06-2008, 09:50
Marco,

I'm referring to an EL34 integrated, which is a push pull. Ali's amp is a 845 SET amp.

lurcher
06-06-2008, 10:12
Yes, that hilights another point, it doesn;t seem to be possible to say "brand A is great, get that", the quality seems to vary wildly between amps with the same name on the front.

The el34 amp Mo mentioned, just had some bad design decisions, the caps after the valve rectifier were just to large, the absense of the chassis earth was unforgivable, and the feedback circuit was missing components that meant the amp wasn't even slightly stable.

The MrLiang 845 seems on first sight to be much better, but I think its as much a case of luck as good design. The circuit is one that could be drawn by twenty different designers and the use of the 845 restricts many of the decisions, one of which is the use of SS rectifiers, so that avoids the problem with the rectifiers. And to be honest its hard to make a very bad single ended amp (whats hard IMHO, is making a very good one). In many ways push pull is much more complex.

As Marco says, they are almost worth it some times just for the cases.

Then as we have seen, there is the big question of the mains voltage, its a bigger issue it seems on push pull amps, as they seem to be aimed at getting the most power from the valves, so they are closer to the edge. What I have stared doing for folk, is making an torroid autoformer step down in a nice ali fronted case, using a specifically wound 800va autoformer from a UK winder. Makes a huge difference to a lot of amps, without increasing the supply impedance at all (in fact it actually lowers it a tad).

Marco
06-06-2008, 11:04
Interesting stuff, Nick. And Mo, my apologies for getting the amps mixed up. I just seen "Mr Liang" and automatically presumed you were referring to the one Ali brought to Owston! :doh:

Nick, I agree 100% with what you're saying, however, I don't think there's much to worry for anyone buying a Yaqin or a Mr Liang direct from China as long as they don't even bother plugging it in and send it straight to the likes of Anthony or you to check over and modify if necessary. They will all certainly need step-down transformers or new transformers fitted that facilitate UK voltage.

That's the safest and most sensible route for those wanting to try it and also likely to be one that ensures you'll end up with a top-notch amp which is also a total bargain! ;)

Marco.

pure sound
06-06-2008, 11:27
It'll be interesting to see whether Anthony actually wants to do so much of this kind of thing and undertake the warranty responsibilities for such products once fettled.

I'm not sure that the performance of some of these amplifiers, particularly with regard to output transformer quality, necessarily warrants the effort. I've repaired a few different Chinese made amplifiers that I certainly wouldn't bother 'breathing' on or providing a warranty for. And as Nick says, some of them are woefully ill conceived not to mention dangerous as far as their construction is concerned.

Filterlab
06-06-2008, 11:31
Would Anthony be better simply building something from scratch rather than overhauling somthing which could be ill conceived?

SolidState
06-06-2008, 11:35
Rob, yes he would, I was gonna reply to Marco, rather than modify a chinese amp it is actually cheaper to design and build from scratch.

Marco
06-06-2008, 11:35
I'll let Anthony speak for himself, but I think he said the output transformers on the likes of the Yaqin are pretty good, although of course they could be bettered. This is one of the mods I intend to undertake when my Yaqin is further modified.

I know what you're saying, Guy, and in many cases it's true, but I've got to say that in the case of the Yaqin, apart from the time I stupidly used it without the step-down transformer and it popped a capacitor, I've had nothing but a positive experience so far, and since it's come back from Anthony's it's not given me a moment's bother, bearing in mind that it's in use for approximately 10-12 hours a day :)

It also sounds bloody fantastic!

Marco.

Marco
06-06-2008, 11:36
Rob, yes he would, I was gonna reply to Marco, rather than modify a chinese amp it is actually cheaper to design and build from scratch.


It's not necessarily cheaper if you want it housed in a nice case ;)

That's where most of the cost comes in.

Marco.

Filterlab
06-06-2008, 11:37
I should have stated that of course not ALL chinese amps are ill conceived, I have heard some horror stories, but as Marco will attest to there are some amazing amps being built in China.

Marco
06-06-2008, 11:43
There are indeed, Rob. You just need to know what you're doing. This sort of thing is for experienced enthusiasts only and people who are willing to 'speculate to accumulate', which is me down to a tee :)

Marco.

lurcher
06-06-2008, 11:46
Rob, yes he would, I was gonna reply to Marco, rather than modify a chinese amp it is actually cheaper to design and build from scratch.

Well, it won't be cheaper, but I think the point is you can decide just where to spend the money, if the case is important, there are several far east suppliers who will supply uncut metalwork. But its down to what you want. As you know Mo, if you want a bespoke amp, you will get asked a lot of question, and some you might not know the answer for, so it can take time.

Like a bespoke suit, at the end it will be just what you want, and will fit just right, but you will have to go for several fitting sessions to get to the end, and for a lot of folk, that time taken can be more important than any cost.

For a lot of folk (I don't mean those around here) its the little britain "I want that one!".

SolidState
06-06-2008, 11:52
Yes Nick I was going to mention the chassis point. I have yet to come across anyone in the UK who can make a chassis at a fair price, it is quite cost prohibitive.

And yes as for bespoke amp I know all this too well, I know for a fact it's going to take me a long of time to reach my desired result. I've only touched the tip of the iceberg so to speak.

At the end of the day it does really boil down to the individual of what they want and how much they want to spend.

Marco
06-06-2008, 11:57
Good point, Nick.

The thing is, having heard your own designs and getting to know what you're about, I wouldn't have the slightest hesitation in buying a Chinese amp direct, one which had the basic essentials I was looking for (i.e. push-pull or SET, dual mono, or whatever) and having either Anthony or you 'tune it up'. I would have absolute faith in your ability to improve it and make it quite special, and there are others who think the same.

The problem is getting the rest, particularly those used to buying 'sorted' commercial products from dealers, to take the initial leap of faith. However, if there are enough modified amps around the country in various locations, then through this forum and others, interested parties can come and listen to the results before embarking on importing from China.

If this can be done effectively then I foresee it being quite a big success and could, if you are interested, be good business for you both :)

I'm all for people getting maximum sound-per-pound with hi-fi - it's why I champion the Sony CDP, SL-1210, Croft preamp, and the Yaqin. All are fine examples I feel of this methodology.

Marco.

pure sound
06-06-2008, 12:00
The Hammond enclosures are a reasonable price if a little basic. However if you are more concerned with how the amp sounds than how it looks they are certainly adequate. Here's a 300B amp I made for a friend a couple of years ago.

http://i75.photobucket.com/albums/i318/murrayjohnson/toysamppainting032.jpg

Utilitarian perhaps but it does the job.

anthonyTD
06-06-2008, 12:03
Before people get on the bandwagon of thinking they're getting a superduper valve amp for an absolute bargain, I'd just like to say, I got a Mr Liang EL34, which is suppose to be one of the better offerings from China.

Nick and me looked into it. This amp was nothing short of a deathtrap for the unsuspecting. To get this amp right it needed a full circuit redesign and all new components. In fact there were no components worth 'recycling' in it.

So be warned unless you know what your doing it's better to be safe than sorry, or worse case live to regret it.
you have a fair point there,
and that is why myself and others like guy [puresound] have looked hard at which ones are worth doing, i must emphasise that the amp that was originaly the puresound a30 was a good amp to start with, i spoke with guy briefly about some of the further improvements that i would conduct, and i think guy would be in agreement with what has been done, but i can also see and except that guy would have had to put up the price of the thing to offset the extra time and effort needed to have gone into the design in more depth the way i did, and its not a case of guy couldnt have done what i did, because i am quite sure if he had wanted to improve it further he is more than capable.
i think in this paticular instance its just a simple case of how far you are a willing to go for what you get in return!
anthony:)

Steve Toy
06-06-2008, 12:04
This was the full statement I made on PFM last night that Marco quoted from:

OK, so what was my reasoning behind buying the Pure Sound with the intention from the outset to have it modified?

The answer is I heard the Yaqin 300B in my system and was mightily impressed by it. I wasn't impressed with the idea of having to use a step-down transformer with it though. I also wanted something that could use safely for a while ahead of being modified that I knew would definitely drive my speakers to my satisfaction in my listening environment.

I made a few enquiries with Tony at Coherent Systems, Guy Sergeant who is the distributor for the Pure Sound amp and Anthony Matthews of Tube Distinctions who had agreed to perform the modifications. Guy agreed in principle to the idea of the amp being modified and even sent Anthony the schematic diagram for him to look at, especially as Tony had already performed his own mods to the amp, a prototype of which I heard at his place. It seemed like it was an excellent product to begin with for the money and it worked well in my system driving my speakers to my satisfaction in my room unmodified, as Tony had demonstrated having brought it to my place for me to hear in early April.

Good as it was it seemed obvious to me that it was ripe for improvement. The involvement factor was already there in abundance but better dynamics, clarity and a touch more refinement wouldn't have gone amiss. Also, rather than buying something off the shelf from the likes of EAR, Prima Luna etc. I really fancied the idea of going down the bespoke route, getting something that was unique to me and built to my specification. The attraction of fettling a Chinese-built amp rather than getting one built from scratch locally was getting value for money. The cost of the chassis and transformers alone if sourced from within Europe would be considerably more than the whole working amp from China even with any distributor and dealer margins thrown in for good measure.

I knew I was taking a risk that I may not like the finished product but I've every faith in Anthony's abilities as both a designer of valve amps from scratch and as a fettler of imported Chinese ones. Initial impressions were very pleasing indeed but I'm not out of the woods just yet regarding the risk as the valves need time to burn in. The dynamics from the bottom end up and clarity are all there but tonally the sound is sound a little thin and bright at the moment. I have been assured that this will ameliorate over the coming days/weeks.
Including the cost of carriage to and from Anthony's place I've broken even on the cost of this amp on the proceeds from the sale of the Densen.

It is called AOS Classic Series to commemorate the Art of Sound and the same acrylic facia plate will probably be used for any future amp imported from China and modified by Anthony of Tube Distinctions.

I was definitely under the impression that the transformers were an issue of cost as well as the chassis if you get your bespoke amp built from scratch. At least I can feel confident that the ones in the Pure Sound are of decent quality.

Steve Toy
06-06-2008, 12:07
Marco sent me the following link that may go some way to explain my tonal issues - the (slight) shrillness I'm hearing:

http://www.watfordvalves.com/product_detail.asp?id=328 (http://www.watfordvalves.com/product_detail.asp?id=328)

Marco
06-06-2008, 12:17
Like I said, Steve, take Anthony's advice on it.

All I can say is that I tried the higher gain version of the Philips JAN 6SN7 (the 6SL7) in the Croft and it exhibited the "treble forwardness" as stated in the Watford valves site.

In my opinion, you need to get a set of 'genuine' (I use "genuine" because to me genuine NOS means pre 1960 - I believe the Philips you have are of 1980s origin) NOS 6SN7s, such as the military spec RCA ones from the 1950s I use in the Yaqin, or Mullards (ECC32, CV181), Jung-Sol, etc, to get the tonal sweetness you're looking for.

I heard a huge difference when I went from the Philips 6SL7s to ECC35s in the Croft, and also similarly when I changed the new stock Electro-Harmonix 6SN7s in the Yaquin to NOS RCA.

You're almost there, mate, but not quite. Don't worry audio nirvana is only a small step away... :smoking:

Marco.

Filterlab
06-06-2008, 12:21
Utilitarian perhaps but it does the job.

I love utilitarian styling, always looks like it means business. Besides which, why spend money on casing when the cash can be invested in better components to improve the sound?

SolidState
06-06-2008, 12:23
Rob me too. I mean my EMT turntables are nothing special to look at but they do the job, and that is more important for me than looks. Me personally I like all wood chassis for valve amps.

Marco
06-06-2008, 12:25
Some of these guys use 'bread-boards', though, Rob, with all the internal components (and lethal voltages!) exposed to the world. That's a bit too whacky even for me, and some of the 'home-made' efforts in terms of casing I've seen leave a lot to be desired ;)

However, Nick and Anthony are exceptions to the rule and both are highly capable of utilising quality chassis in their designs.

Marco.

Filterlab
06-06-2008, 12:35
Rob me too. I mean my EMT turntables are nothing special to look at but they do the job, and that is more important for me than looks. Me personally I like all wood chassis for valve amps.

Definitely mate, wood always seems to give a hi-fi component a more natural sound, less influential.


Some of these guys use 'bread-boards', though, Rob, with all the internal components (and lethal voltages!) exposed to the world. That's a bit too whacky even for me..

Yeah, that's a bit too mad for me too - should at least be enclosed. Once I move house and get a workshop set up in a big shed I'll be making wood cases and speakers with every spare minute I get. They won't all be brilliant, but at least I'll be having fun! :)

anthonyTD
06-06-2008, 13:09
Like I said, Steve, take Anthony's advice on it.

All I can say is that I tried the higher gain version of the Philips JAN 6SN7 (the 6SL7) in the Croft and it exhibited the "treble forwardness" as stated in the Watford valves site.

In my opinion, you need to get a set of 'genuine' (I use "genuine" because to me genuine NOS means pre 1960 - I believe the Philips you have are of 1980s origin) NOS 6SN7s, such as the military spec RCA ones from the 1950s I use in the Yaqin, or Mullards (ECC32, CV181), Jung-Sol, etc, to get the tonal sweetness you're looking for.

I heard a huge difference when I went from the Philips 6SL7s to ECC35s in the Croft, and also similarly when I changed the new stock Electro-Harmonix 6SN7s in the Yaquin to NOS RCA.

You're almost there, mate, but not quite. Don't worry audio nirvana is only a small step away... :smoking:

Marco.

marco is bang on,
the 6SN7 [jan spec] tend to have this agravation in the treble extreemes, but the problem is getting good new manufactured 6SN7 that test any good! that was the reason for putting the jan spec ones in for steve, because they tested fine, but they are not the last word in the sonics department, and as far as new old stock mullards etc are concerned the jan spec are a long way down the sonic front, i am sure marco will definately agree with me on this after his own experiences.
anthony...:)

mistygreenandblue
06-06-2008, 16:15
Misty,

FYI from PFM (by Steve):



Steve should have posted his answer here, too, but he's a bit of a lazy arse sometimes ;)

I would add that the reason Steve didn't buy a 'Bewitch' (the "cheap Chinese" version of the Puresound, as asked on PFM), rather than buying the Puresound for £1100, is because at that point he didn't know the Bewitch existed, otherwise he would have done the same as me with the Yaqin and imported it direct from China and then sent it direct to Anthony for modifying. I guess hindsight is a great thing...

Marco.
Hi Marco,

I'll aim my reply towards you, since you were the only person to do likewise.

I think the *chinese amp* part of the equation is neither here nor there, as far as my original question goes anyway...

What I cannot get my head around (and I don't know the facts, which is why I've asked the question) is buying a brand new donor amp, and then stripping it right back and doing a rebuild....Given that so much has been changed, and that Guy provided a schematic diagram of the A30, why not just do a bespoke build from scratch?

I guess what it boils down to is this....after stripping the donor unit back, the parts left (chassis, trannies etc) was there £1100 worth of bits used on the rebuild? After all, Steven planned to have this unit rebuilt from day one, it wasn't as though it was an amp he already had and decided to mod, surely it would have been more cost effective to have purchased a case, trannies etc and have Anthony build it that way? or have I got my math totally wrong?

I'm not saying there is any right or wrong here, I just don't understand why the build happened as it did, unless Steven was just paying respect to Tony for the demo(s) and Guy for the original ideas behind the A30. All I can think of in relative terms is buying a brand new Naim 250, then handing it over to Les at Avondale for him to use a few bits of it to build one of his ZAP amps with all the trimmings....it would be more cost efective to let him build it from scratch....or has my lack of knowledge in what goes into building / re-building the A30 / AOS clouded my judgement?

I guess re-reading your comments above re the bewitch amp remove my thought process as per Tony, but that still doesnt cover / answer the costings issue as per bespoke from the ground up...

My head hurts.....I should stop trying to think! :doh:

Steve Toy
06-06-2008, 16:38
Misty,

Don't worry, my head still hurts and you've touched on a few truths anyway. Sorry I didn't get to answer you directly although I hope your questions have now been answered nevertheless.

pure sound
06-06-2008, 21:50
Misty.

I take the view that once someone has bought something, whether it's a car, a house or an amplifier they can do what they like to it. I was aware from the outset that Steve wanted to make changes to the A30 & I realised it would make life a good deal easier for Anthony if he had the schematic to hand rather than having to work it out. I don't hand these diagrams out to just anyone though. From what I can tell, much of the material content of the amplifier has remained although the circuit has been altered. The A30 (like many line integrated amplifiers) is basically a power amplifier with input selection and a volume control in front of it so removing those functions is not such a big deal. Amongst the revisions made, I gather that Anthony has made changes to the input circuit. At some point I may get the opportunity to hear the effect of these changes and it will be interesting to hear what difference they have made. The amp has been fitted with an entirely new set of more expensive valves. NB, more expensive doesn't always mean better or more reliable. In this particular case they may be but I've occasionally bought high priced NOS valves in the past and have been thoroughly disappointed by them. High priced NOS valves can't be given any blanket recommendation. It takes experience to know which types are worth a premium and which types give a particular result..

I'm not sure as much of the amp has been discarded as you might think. It seems Anthony has implemented a topology he prefers and has applied his experience in choosing replacement valves and passive components to give that particular result. There is understandably a charge for the craft, the experience and the premium components that this entails. For what I understand has been done, it seems a fair amount. I might have done things differently as would many other designers. I'm actually flattered that Steven felt the amp was worthy of such attention in the first place.

Mike
07-06-2008, 10:08
Some of these guys use 'bread-boards', though, Rob, with all the internal components (and lethal voltages!) exposed to the world.

Pah!..

Yer big girly party frock. :ner:

Marco
07-06-2008, 11:45
Hehe... I just don't like things looking like a fifth year science project! :lol:

Hi Misty,


What I cannot get my head around (and I don't know the facts, which is why I've asked the question) is buying a brand new donor amp, and then stripping it right back and doing a rebuild....Given that so much has been changed, and that Guy provided a schematic diagram of the A30, why not just do a bespoke build from scratch?


The key thing, as I've already alluded to, is the chassis/casing. If the final product was going to look good (and I believe this was a fairly high priority for Steve) then it would have cost much more to have been built from scratch with a bespoke high quality, attractive, casing sourced in the UK than using the original Bewitch chassis and then 'putting your own bits in', which is essentially what's happened with Steve's amp.

Also, it's just the way things worked out. Originally Steve heard my Yaqin and was blown away by it but didn't like the idea that it wasn't 'CE approved' (thereby not being insured in the event of something going pop and perhaps causing a fire) so without too much lateral thinking, and knowing about the existence of the A30 which was already CE approved, that's what he decided to go for.

Initially it was the intention of using it in stock form if it was good enough, which it was, but I guess that knowing me and the modifications Anthony from Tube Distinctions had carried out to my Yaqin, etc, the temptation was too high not to have the A30 similarly (although more extensively) modified to see how good it be, which brings us to where we are now.

I trust that everything is now somewhat clearer :)

Marco.

pure sound
07-06-2008, 11:47
Chassis? Who needs one? not one of mine btw!

http://i75.photobucket.com/albums/i318/murrayjohnson/845parafeed-1.jpg

SolidState
07-06-2008, 11:58
whoaaaa, KINKY :)

Mike
07-06-2008, 12:09
It's great. All it needs now is for the dog to come flying through the room and landing in the middle of it all!

:lolsign:

Filterlab
07-06-2008, 12:45
I hope there's no trip hazards around that collection of bits, wouldn't like to be the chap who stumbles and lands in the middle of it all!

Marco
07-06-2008, 17:52
Imagine if you've got a hum loop trying to find out where the problem is... :mental:

Marco.

Filterlab
07-06-2008, 18:47
Imagine if you've got a hum loop trying to find out where the problem is... :mental:

Marco.

Judging by that lot it's probably at the nearest sub-station. :)

Mike
07-06-2008, 19:06
Apart from all that. How does the 'after' bloody well sound then?... Steve?

lurcher
07-06-2008, 19:14
Also, it's just the way things worked out. Originally Steve heard my Yaqin and was blown away by it but didn't like the idea that it wasn't 'CE approved' (thereby not being insured in the event of something going pop and perhaps causing a fire) so without too much lateral thinking, and knowing about the existence of the A30 which was already CE approved, that's what he decided to go for.


Just FYI, the moment one resistor is changed in the amp, the previous CE marking falls off.

lurcher
07-06-2008, 19:20
whoaaaa, KINKY :)

You call that a valve, this is a valve...

http://home.lurcher.org/nick/audio/visit_to_paul/Pict0002.jpg

Mike
07-06-2008, 19:22
MMMmmmmMMM....!!! :smoking:

Wassat then? Looks like a 211 after taking steroids. Many steroids! :)

anthonyTD
07-06-2008, 19:29
MMMmmmmMMM....!!! :smoking:

Wassat then? Looks like a 211 after taking steroids. Many steroids! :)

if i am not mistaken, that looks like a DA100?
go on nick, put us out of our misery!
:):):)

Filterlab
07-06-2008, 19:29
WOAH! What's that valve's intended purpose, nuclear submarine?

Mike
07-06-2008, 20:12
I'm thinking it's something like this:

http://www.mif.pg.gda.pl/homepages/frank/sheets/125/4/4211D.pdf

;)

SolidState
07-06-2008, 20:42
LOL Nick I was referring to the actual breadboard, reminded me of your mercury rectified 211 breadboard.

Now I swear I've seen that pic before:)

Gentlemen, the valve in question if I'm not mistaken is a 212.

Mike
07-06-2008, 22:46
Gentlemen, the valve in question if I'm not mistaken is a 212.

Maybe!.... doesn't quite look like this one though. :scratch:

http://www.r-type.org/exhib/aaa0287.htm

mistygreenandblue
07-06-2008, 23:25
Misty,

Don't worry, my head still hurts and you've touched on a few truths anyway. Sorry I didn't get to answer you directly although I hope your questions have now been answered nevertheless.

Hi Steve,

Thanks for the reply. :) I wasn't joking about my head, yesterday produced a thumping headache that didn't die down until late tonight...posting on forum boards wasn't the brightest of ideas....anyway, from what seemed like a very simple question (in my head..) didn't seen to translate that way in practice....I think from reading Marco's comments a few posts down, he has provided me with my *simple answer* I sometimes see life drawn in black and white, when in reality, there are also many shades of grey.

lurcher
07-06-2008, 23:35
Yep, its a 212, actually that was a 4212, none are mine unfortunantly

http://home.lurcher.org/nick/audio/visit_to_paul/Pict0003.jpg

In some ways its relation to a 211 is the same as a 2a3 to 45. Can produce a stunning sound, there is a review of someone listening to a 212 amp Sakuma San produced, and the descripyion is spot on, But the practical problems are immense. They came in several sizes, but were still teh same basic valve, here is a family photo, with a ecc83 and 211 for scale, and a gm100 just to provide a sense of perspective :-)

http://home.lurcher.org/nick/audio/visit_to_paul/Pict0009.jpg

mistygreenandblue
07-06-2008, 23:50
Misty.

I take the view that once someone has bought something, whether it's a car, a house or an amplifier they can do what they like to it. I was aware from the outset that Steve wanted to make changes to the A30 & I realised it would make life a good deal easier for Anthony if he had the schematic to hand rather than having to work it out. .

Hello Guy,

Thanks also for your reply :) I fully fall into line with your thought process over ownership of an item once paid for - my sister owns a listed property, and it drives me mad that she is dictated to by the local council what she can and cannot do with it - more so than it does her I think.

I viewed an earlier post by Steve over at PFM which basically stated what you have commented on above re - prior knowledge of the modifications that would take place to the A30. I also viewed all the *extra* comments from others, which is why I explained in my first post that my question(s) had nothing to do with wooden spoons - I just wanted an answer to a question that was rattling around in my head without causing offence to anyone concerned in the actual process.



I'm not sure as much of the amp has been discarded as you might think. It seems Anthony has implemented a topology he prefers and has applied his experience in choosing replacement valves and passive components to give that particular result. There is understandably a charge for the craft, the experience and the premium components that this entails. For what I understand has been done, it seems a fair amount. I might have done things differently as would many other designers. I'm actually flattered that Steven felt the amp was worthy of such attention in the first place.

That is probably where my lack of knowledge lets me down, I did ponder if that was clouding my judgement earlier - trouble is, in this life, you don't learn much without asking questions....I always seem to ask the ones that end up going off in all directions!

Steven detailed the costings in his post over at PFM (maybe also here?) I wasn't questioning Anthony's costings / workmanship, just the original *worth* of the donor amp....Marco has answered that for me....it really was just that simple a question! I really must work on my ability to phrase a question :doh:

I almost get the feeling I've walked into a bar full of football supporters who've just watched their team get hammered in the local derby, and naively asked "Good match then, what was the score?" :doh:

mistygreenandblue
07-06-2008, 23:58
then it would have cost much more to have been built from scratch with a bespoke high quality, attractive, casing sourced in the UK than using the original Bewitch chassis and then 'putting your own bits in', which is essentially what's happened with Steve's amp.
Marco.
Hello Marco,

That's the answer I was looking for....I guess my simple 'black n' white' question rattling around in my head needed a simple answer for er....simple ol' me :lolsign:

I'll go back in the corner now and stick me thicko hat back on....:lol:

mistygreenandblue
08-06-2008, 00:00
Chassis? Who needs one? not one of mine btw!

http://i75.photobucket.com/albums/i318/murrayjohnson/845parafeed-1.jpg
Sweet jesus! That is um....behind a locked door I hope?
Who owns that little lot?

Marco
10-06-2008, 09:46
Some mad professor, probably. I think it operates the door bell to his home :lolsign:

Marco.

Mike
10-06-2008, 16:34
Yep, its a 212, actually that was a 4212, none are mine unfortunantly

There's some for sale HERE (http://cgi.ebay.co.uk/212e-4212e-V1505-Valve-Tube-New-Boxed_W0QQitemZ260199951457QQihZ016QQcategoryZ294Q QcmdZViewItemQQ_trksidZp1742.m153.l1262) if anyone is interested?

<ducks for cover>

:sofa:

mistygreenandblue
19-06-2008, 12:02
Some mad professor, probably. I think it operates the door bell to his home :lolsign:

Marco.
Looks a little fugazi to me....

Actually, more than a little....