Before and after

[mistygreenandblue]

Hi Misty,

Welcome to the forum

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

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]

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]

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]

they're just jealous!

Exactly!!!

Marco.

[Marco]

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]

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]

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

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!

Marco.

[lurcher]

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]

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]

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.