Repairing The Questionable £25,000 Tom Evans Audiophile Pre-Amp

[jipihorn]

Hello,
Is there anybody that took a look at the schematics showed in the original video, the part after the passive RIAA network (which is only partial, I guess) ?
It doesn't make any sense at first sight, so i tried to simulate it with spice, and, as expected, this does not work correctly at all. Did Mark made a mistake when reverse engineering it ?
Even if there is a mistake somewhere, the overall topology is non sense; most of the op amps are useless.
Or I missed something. I don't recall that Mark made it available.

The other "smart technologies" are absolutely not new, paralleling stuff is know for ages and loading the output of opamps is a way to shift the operating point (output biasing); all of this is described in Douglas Self books (and Burr Brown application notes shown by Mark). If he used 5532 for this wonder, the current sources are in the wrong way, but who ever know ? References of op amps are only known by the creator himself. Please, don't let him discover the world of Jim Williams or Bob Pease, he would have a stroke.

Not very impressed by the analog stuff, let alone the overall construction... Did he found a large batch of plastic stand-offs of the wrong size for very cheap, so he has to stick several of them together ?

The worst of this : in audiophile forums, people don't see any problem with this. They are so far from industrial production constraints and possibilities that they don't even see the difference between a teenager school project and an automobile industrial product. Even worse, they would trust the former and discard the latter.

Jerome.

 

[TimoJ]

I don't get it. So it was sent to repair by the manufacturer i.e. Tom Evans? Why? Does he know Mark? If so, why hasn't Mark talked with him?

 

[Dialectic]

I don't get it. So it was sent to repair by the manufacturer i.e. Tom Evans? Why? Does he know Mark? If so, why hasn't Mark talked with him?

That Evans would send the ridiculous preamp to Mark for repair sounded implausible to me, too.

In the original video, I think Mark referred to the purchaser of the preamp, implying that a hapless audiophile (who may have gotten it on Audiogon or ebay) sent it in for repair.

 

[AnalogSteph]

Is there anybody that took a look at the schematics showed in the original video, the part after the passive RIAA network (which is only partial, I guess) ?
It doesn't make any sense at first sight, so i tried to simulate it with spice, and, as expected, this does not work correctly at all. Did Mark made a mistake when reverse engineering it ?

I see what you mean. It absolutely doesn't make sense as shown. I suppose there are a few incorrect connections. Reverse-engineering tends to be quite error-prone IME, some descrambling is usually required.

BTW, with only a 1.33µs time constant in the x605 preamp stage, I reckon overload margins aren't exactly super great.

 

[Roland68]

Compared to Tom Evans Mastergroove SR mkIII, the effort, materials and price of the MBL 6010 D appear in a whole new light.
In comparison, the MBL 6010 D is a valuable special offer.

 

[harkpabst]

That Evans would send the ridiculous preamp to Mark for repair sounded implausible to me, too.

In the original video, I think Mark referred to the purchaser of the preamp, implying that a hapless audiophile (who may have gotten it on Audiogon or ebay) sent it in for repair.

The way I got it, the original customer sent the mighty(ly humming) MasterGroove SR Mk3 to "Honest Jake" Phillips "Honest Tom" Evans, but "the genius at work" refused to repair it due to the damage done at some point in transit.

Then the customer asked "Honest Tom" Evans to forward the 25000 GBP bargain to Mark, which he did, stating that Mark couldn't repair it anyway due to its high level of sophistication.

Maybe we all got "Honest Tom" Evans wrong, though. Maybe he filed the copyright claim because of his own blatant plagiarism concerning the Intel inside logo when designing the logo for his unique "Lithos local regulation circuit", which "virtually eliminates the power supply noise".

Don't believe manufacturers hype when they say their power supplies have been developed to produce no noise. Not my words, straight from the mouth of the genius himself. Virtually eliminating the power supply noise is OK, though. It will live in a special domain then, the Nanovolt domain!

 

[MCH]

Yes, it is avaliable here:

CLICK> LINK TO VIDEO - PREAMP TOM EVANS



View attachment 412535

Another link to the video courtesy of eevblog, in case:

The £25,000 Pre-Amp that went Wrong - Tom Evans Mastergroove SR mkIII

mirror of video mend It Mark that was taken down elsewhere for reference Repairing The Questionable £25,000 Tom Evans Audiophile Pre-Amp

odysee.com

 

[Dialectic]

The way I got it, the original customer sent the mighty(ly humming) MasterGroove SR Mk3 to "Honest Jake" Phillips "Honest Tom" Evans, but "the genius at work" refused to repair it due to the damage done at some point in transport.

Then the customer asked "Honest Tom" Evans to forward the 25000 GBP bargain to Mark, which he did, stating that Mark couldn't repair it anyway due to its high level of sophistication.

Maybe we all got "Honest Tom" Evans wrong, though. Maybe he filed the copyright claim because of his own blatant plagiarism concerning the Intel inside logo when designing the logo for his unique "Lithos local regulation circuit", which "virtually eliminates the power supply noise".

View attachment 412596

Don't believe manufacturers hype when they say their power supplies have been developed to produce no noise. Not my words, straight from the mouth of the genius himself. Virtually eliminating the power supply noise is OK, though. It will live in a special domain then, the Nanovolt domain!

If Tom challenged Mark to fix it, he is an idiot. Mark goes to astonishing (and frankly uneconomic) lengths to finish repairs for his YouTube channel.

 

[Punter]

The other thing I find amusing about the situation is that Mark diagnosed the fault as a shorted tantalum capacitor. As a consequence, the teardown of the device reveals that it's loaded with tantalum caps, they're everywhere. This is pointed out humorously by Mark in his follow up video when he creates an analogue of the amp with some scraps of wood and PC board. Subsequently, the amp which Mark "wouldn't be able to fix" is just one tantalum cap away from another fault.

I didn't pay much attention to the "Lithos Inside" sticker initially but having discovered that old mate Tom claims to be designing his own "noiseless" DC linear regulators, the "Lithos" regulator no less, brings the blatant appropriation of the "Intel Inside" logo into sharp focus. Maybe Intel should be alerted to this breach of copyright and trademark?

 

[Roland68]

The other thing I find amusing about the situation is that Mark diagnosed the fault as a shorted tantalum capacitor. As a consequence, the teardown of the device reveals that it's loaded with tantalum caps, they're everywhere. This is pointed out humorously by Mark in his follow up video when he creates an analogue of the amp with some scraps of wood and PC board. Subsequently, the amp which Mark "wouldn't be able to fix" is just one tantalum cap away from another fault.

I didn't pay much attention to the "Lithos Inside" sticker initially but having discovered that old mate Tom claims to be designing his own "noiseless" DC linear regulators, the "Lithos" regulator no less, brings the blatant appropriation of the "Intel Inside" logo into sharp focus. Maybe Intel should be alerted to this breach of copyright and trademark?

The biggest harm to this logo connection is probably to the device itself.

Or do you think that real audiophiles would buy something with an "Intel Inside" sticker?

 

[kemmler3D]

In normal manufactured products like when I was involved at Garrard and with cars the production cost was about 10% of retail.
In high end stuff it may well be less like this sort of thing and Bugattis! They don't sell many so the price will be "how much money do I want to stay in business"/number sold per year.

That's exactly it. If someone forced me to build phono stages to sell, I would have to charge something like this to remotely be able to put food on the table. He is saying that only 10 are built per year. At $20,000 each, that is just $200K gross! He is lucky if his take home pay is $50K after producing such complex monstrocity with all those boards and such.

The main issue here is the copyright strike. There is no just to justification for this. Google should have a system in place for this. The man has no music or borrowed videos in there. How could there be a copyright strike???

+1 to this... I am not disputing the price because in very low quantities the price is driven by many things other than simple BOM and assembly cost. Maybe like needing to pay a mortgage with <1000 sales per year.

I was just saying the case probably doesn't cost that much to fabricate, not that this proves the MSRP is unfair.

The copyright thing shows bad faith and/or deep ignorance of the law, a much greater sin than charging caviar money for bespoke hand-scooped tuna salad.

 

[sq225917]

Lots of chatter and speculation from people who've neither seen nor heard one. And Louis muddying the waters by incorrectly showing noise on the broken rail. It's a bit of a dog pile....

The physical internal build is a dogs dinner, but working right, its a fine phonostage, as good as any I've heard, at any price north of 5k.

All we know for sure, is that it broke and was inappropriately shipped and sustained more damage. I expect it was bought cheap, 2nd hand, already broken, electrically.

I'd suggest on initial receipt by Tom that he quoted a full service and re-case cost, the owner balked at the price so it went to/ back, to Mark. Tom probably wound mark up telling him he couldn't fix it, some mark showed him....

Tom sells to trade, at generous margins, so he's seeing probably £10-11k a unit. After costs and vat that's probably £6k, assuming based on the scatty build that he runs a loose ship. I bet there 20-30 hours build, assembly and testing time in one of those. Factor in the years he's spent designing and developing his range of kit, business costs etc and the numbers he sells, he's not getting rich.

 

[Purité Audio]

Is it a better phono that the Michael Fidler designs ( at 1/25th the price)
Keith

 

[antcollinet]

as good as any I've heard, at any price north of 5k.

It might even be as good as those south of 0.5k.

 

[kemmler3D]

Tom sells to trade, at generous margins, so he's seeing probably £10-11k a unit.

Not picking or trying to stir things up, just wanted to say IME this would be only slightly, not dramatically higher than standard dealer / retailer margin, which is around ~50%.

 

[restorer-john]

I'd suggest on initial receipt by Tom that he quoted a full service and re-case cost, the owner balked at the price so it went to/ back, to Mark. Tom probably wound mark up telling him he couldn't fix it, some mark showed him....

And when Mark asked for a service manual or schematic, the 'genius at work' told him where to go. At that point Mark decided to not only fix it, but draw up his own S/M as a bit of a "screw you" type payback.

Same thing as the Topping PA-5 fiasco. It took someone to melt/dissolve the module, reverse engineer the module, produce a schematic, make their own PCB and help others, because no service manual or schematic was forthcoming.

 

[WillBrink]

The video got taken down now, it appears to be a sensitive subject...

Has this one been posted?

 

[antcollinet]

Has this one been posted?

Yes.

And only on the previous page

 

[harkpabst]

So probably not often enough.

Again, I don't care how much money "Honest Tom" Evans makes with his gear, not at all. I cannot imagine it's super special, but that's true with so many expensive kit out there, and I still don't care. @sq225917 could well be right regarding what Audio Design quoted for a repair, but we don't know for sure. What would have been an appropriate amount? 5000 GBP? More than that?

What's not OK is trying to suppress the successful repair performed by Mark.

 

[oceansize]

That Evans would send the ridiculous preamp to Mark for repair sounded implausible to me, too.

In the original video, I think Mark referred to the purchaser of the preamp, implying that a hapless audiophile (who may have gotten it on Audiogon or ebay) sent it in for repair.

I'm not saying that anybody that would buy this product is a Dick, but...