Before and after

[Filterlab]

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]

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]

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]

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]

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...

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]

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!

[Steve Toy]

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]

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]

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.

[Marco]

Hehe... I just don't like things looking like a fifth year science project!

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.