Mystery hand built amp!

Can an amplifier be designed specifically around its components?

Sounds like a stupid question I know, with a resounding answer but let me explain.

I'm talking specifically about tube amplifiers here, in particular one I just picked up on a bit of a gamble....

Saw it pop up on a certain auction site. Read the description and it matched the specs of what is currently my favorite amp for driving my Quad 63's.

KT88's, push pull and around 35w in Triode configuration.

Messaged the seller and told him I could collect as where he lived wasn't 30 miles from where I work in Gatwick. A few message exchanges later and it turns out the guy works in the unit literally next door to mine in Gatwick and we both travel in 30-40 miles from different directions to work there. I digress, but what are the bloody chances of that!!! Must have exchanged pleasantries and head nods with the guy 1000 times!

Anyway, I still went to his house to pick it up so I could hear it in his system and he told me a bit about the amp.

It's in a generic looking (but actually custom) alloy chassis. Very nicely machined and solid looking. Think Shanling etc. Which is no coincidence as it turns out.

Silver-wired point to point wiring and some beefy transformers which run relatively cool compared to some.

Sorry for the terrible pictures, low light and might have consumed a beer . . . perhaps three.




Attachment 26121Attachment 26122

Here's where it gets interesting. I asked about the origins of the amp and the guy explained that he has a friend at Musical Fidelity (or at least he was working there then) handily, as a head amp designer.

He basically asked him to design a "money no object" amplifier. After a long time of nagging him to do it, It seems that's what he did, and for genuinely reasonable cost.

Normally when you hear this kind of thing its just to help up-sell the amp and as there is no way of proving or disproving the story, must be taken with a huge helping of salt....

You can probably see where this is going and why would I bother telling anyone about an amp I've bought which sounds "good".

Well, it didn't sound good. It sounded bloody lovely.

No imaginative descriptions here. It just makes stuff sound stupidly good. Only tiny caveat was a tiny loss of bass slam compared to my previous amp (due to its RCA pre-tubes I suspect) but it was hardly noticeable on most tracks. Plus the infinite step up in clarity easily made up for it or could in fact indeed be the reason for it and I'd have to adjust my ear to suit.

Never being one to be satisfied I was excited to see the amp was making these sounds with what I could see were "very cheap" generic chinese 6SN7 pre-amp tubes along with some "cheap" EH12ax7's and Svetlana KT88 new production tubes.

I have an assortment of very nice NOS 6SN7's (50's Sylvania/Tung Sol etc) and same with 12ax7's (Mullard/Ei/RCA etc). I also have some spare better KT88's to try.

Great I thought, things can get even better.

Well they couldn't. Even with a few hundred quids more tube in place of the cheap ones the sound was actually significantly compromised.

I was there for hours and each time I swapped the originals back in the amazing sound came flooding back. Tried all configurations but nothing could improve on the originals.

That was until I kept all the original pre-tubes in place and just replaced the Svetlana output tubes with some JJ KT88's. Well now I had the bass slam back and in fact it was deeper and cleaner. Concluded it must have been the JJ's all along providing the wonderful bassline slam on my other amp too and the RCA's were not as responsible for it as I thought.

Listened for ages then swapped back to the Svetlana's just to check I wasn't hearing things. Nope, definitely better with the JJ's. Like 100% better.

I'm now at the point where I truly cannot imagine the setup sounding any better at all. Plus the JJ's are brand new and barely have 3 hours on them so further improvements may actually occur!

So, after all that waxing above here is my question.

Is it possible the designer built the amplifier directly around these specific tubes? Almost using them to "tune" the sound of the amplifier not necessarily audibly but matching the electronic synergy of the components (assuming all amps do not sound "exactly" the same before clipping). As swapping them with equivalents which are 100% known to give improvements in nearly all other circuits instantly deteriorated the sound. Not in a subtle way. I knew straight away the change was for the worse.

Maybe without the restraints of building an amp for commercial production and having free reign on components and configurations the designer was able to "have some fun"??!!

I think the Svetlana's may have been on their way out anyway so replacing the KT88's with the new Svetlana's could have yielded similar results to replacing them with the JJ's. Can't imagine it being better but one day I may try, who knows.

For now I'm more than happy to sit back and let this amp provide the finest reproduction of music to my seat that I've ever heard.

Probably better amps out there of course but in my listening space and my setup it feels like a perfect fit. For now!

Cheers guys,

happy listening.

Chris

Hi Chris,
The amplifier in the picks looks to be very well made, well,,, on the outside anyway, [reminds me of some of the Shanling equipment in its design] so i would expect the internals to be very well constructed too.
However; as to whether the creator of this paticular piece of equipment had a "sound" in mind when he built it, i wouldnt like to comment, all i can say is; if it plays music in a way that connects with you, then that is all that matters.
A...

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Originally Posted by anthonyTD

Hi Chris,
The amplifier in the picks looks to be very well made, well,,, on the outside anyway, [reminds me of some of the Shanling equipment in its design] so i would expect the internals to be very well constructed too.
However; as to whether the creator of this paticular piece of equipment had a "sound" in mind when he built it, i wouldnt like to comment, all i can say is; if it plays music in a way that connects with you, then that is all that matters.
A...

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Thanks Anthony,

that's exactly what it does. It really immerses you in the experience.

As mentioned in the first post it really reminds me of Shanling stuff too!

I'll get some pics of the inside one day. You can see through the little grills on the side that it is very simple and with very short signal paths etc.

Not necessarily a "sound" as such but I was more proposing that if using proper electrical measurements and circuit topology then the "cheap" tubes used were perfectly suited for the design. . . . maybe.

Like you say if it makes me happy it is right. Which it does.

Cheers

:)

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Originally Posted by Opti-cal

Thanks Anthony,

that's exactly what it does. It really immerses you in the experience.

As mentioned in the first post it really reminds me of Shanling stuff too!

I'll get some pics of the inside one day. You can see through the little grills on the side that it is very simple and with very short signal paths etc.

Not necessarily a "sound" as such but I was more proposing that if using proper electrical measurements and circuit topology then the "cheap" tubes used were perfectly suited for the design. . . . maybe.

Like you say if it makes me happy it is right. Which it does.

Cheers

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Just to add, I replaced the standard EL34's in my amp with JJ's and the sound improved dramatically for the better. The amplifier here though looks very impressive so if it sounds as good as that then you definitely have a winner.

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Originally Posted by Haselsh1

Just to add, I replaced the standard EL34's in my amp with JJ's and the sound improved dramatically for the better. The amplifier here though looks very impressive so if it sounds as good as that then you definitely have a winner.

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Hi Shaun,

sounds even better than it looks :smoking:

I'd often overlooked the JJ's as I had an EL84 amp which used them exclusively in both pre (Ecc83) and power sections. Always felt they were middle of the road. Plus the ones that came in my Croft were massively improved on when I replaced them with some NOS Ei and Mullard tubes. I imagine the EL34's have a similar signature to the KT88's and if so, will be great.

New production JJ's look solid as a rock too. Zero drift so far on the bias in my other KT88 amp.

Had a fair few EL34 amps (and hope to again soon actually). Best improvement I had was simply swapping them for Sylvania 6L6 tubes (I think they are direct replacement in most circuits).

Also have some Psvane premium MKII's which are really nice too.

I think the simple answer to your question is yes.

Possibly with a beneficial dollop of synergy. You say it looks simple inside, Simple is good.

I've always loved the EL34 'sound' since owning an Audio Sterling ETSE and living with its syrupy midrange for a few years through Audio Note AZ-2's. A year or so back I borrowed a set of KT88's for my current Prima Luna but sadly didn't get on with them too well. OK so it was the power amp that didn't get on with them, I thought they were excellent and loved the sound. So in spite of my amp being 'compatible' with a whole host of power valves, every time I switched off the power amp I'd get a bloody crack through the speakers. Put the EL34's back in, perfect.

Oh yeah, still have an entry into my bucket list that comprises a custom, hand built valve power amp based upon parallel single ended 300B's.

What a fabulous imagination I have ;)

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Originally Posted by Haselsh1

Oh yeah, still have an entry into my bucket list that comprises a custom, hand built valve power amp based upon parallel single ended 300B's.

What a fabulous imagination I have ;)

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Think I've had the same dream . . . .

300b's with the extra grunt to drive most loads. P.E.R.F.E.C.T

WE's of course Shaun.

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Originally Posted by Firebottle

I think the simple answer to your question is yes.

Possibly with a beneficial dollop of synergy. You say it looks simple inside, Simple is good.

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I have a simple life and enjoy simple things Alan :cool: