Mercury Magnetics - The Emperor's New Clothes?

[guitarmike2107]

That’s because rust takes time to corrode, and time is money, so they would probably charge you allot extra.

[guitarmike2107]

Yes but if they advertise in guitar magazines their target audience is not amp builders, it fool musicians. And when those fool musicians come to you, dont talk them out of it, you just say "I can do that and my hourly rate is....." thank you very much to MM for advertising and helping amp techs get paid work on perfectly good amps.

but no we wont use there PT when you can get a custom one made to your specs for cheaper.

[Steve Conner]

Guitarmike, who do you use for custom transformers? I hope they're cheaper than Sowter :/

Teemuk: Sure they use that idea, they just call it an "oxide film".

Hey, there's a thought, transformers aged in oak casks.

[guitarmike2107]

Never used Sowter and probably never will I think they are like the MM of the UK but without the flash advertising.

I have used Transformer Equipment Ltd to make custom trannies, I have really abused some of their PT's and OT in the past.
I used to sell transformers that he made for me but there just wasn’t enough of a market to sustain it at that time.
Torres UK get their transformers from him.

I have also used Majestic Transformers, slightly more expensive, but nice transformers, I know a number of smaller UK Pro builders use them.
If I ever built amps specifically for sale I would probably use these guys

[Enzo]

I'll say that things aged in oak casks have transformed me at times.

Toroid power transformers for tubes? Not cheap, but Plitron makes some:
Low Noise Power Transformers For Vacuum Tube Amps « Plitron

They also make toroidal output transformers and other products.
Vacuum Tube Audio Transformers « Plitron

[jpfamps]

Some of the Mercury OPTs have very strange stacking patterns. Look at their RS clone.

The original RS Deluxe JTM45 transformer had quite an unusual stacking pattern, so I expect MM copied this.

I've yet to find any information on how the stacking pattern affects the performance of the transformer, although obviously not using a 1-on-1 stacking pattern will make laminating the transformer quicker.

[jpfamps]

Guitarmike, who do you use for custom transformers? I hope they're cheaper than Sowter :/

I use Majestic in Poole, Dorset.

Cheaper than Sowter.

Sowter wind most of their OT's on a dual chamber bobbins with each half of the primary wound on a half bobbin.

This ensures that each side of the primary is exceptionally well balanced for all parameters, however it significantly increases the work involved in winding the transformer and hence the higher price.

[frankeg]

Welcome Bruce!
I'm new to the guitar tube amp thing and I must admit I fell for the hype... I learned tubes in the Army Signal Corps and got an EET from PSU through the GI Bill. I should have known better but they do advertise really well. I used their iron in my first build/re-build, the "Valve Jr." and it honestly sounds fantastic! But so do the ones built with other iron... I only wish I knew of this forum back then! I think of it now as the price of admission and I'm ok with that... I do agree that they actually help promote the tube amp business and I'm all for that! Prior to the valve jr explosion, I can't recall so many "new" tube amps on the market, especially in the small amp category. Today, everyone seems to offer one and they're fairly priced, so a whole new generation of "tone snobs" are being created. You gotta love that! Just my 2c

[MWJB]

Olddawg wrote - "But a PT? It just provides a couple of AC taps a certain voltages. How could that be different than any other one that does the same thing? Maybe sag if it is underated? IMHE which OT you use can make a big difference in overall sound. But a PT? Really?"

The point is that many PT's that are advertised as doing the "Same thing" simply don't in practice. Manufaturing tolerances surely play a part, but that's assuming that the manufacturer has even set out to build the "same thing"in the first place.

Let's take a "Super Reverb" PT, could be from 320-0-320VAC to 380-0-380VAC, could be 150mA dc rated, or 200mA (possibly more for a boutique), could be 4A 6.3VAC to 5.5A 6.3VAC (again more for a boutique)...any of these parameters will affect the final tone, yet all are the "same thing". Things that are the same are only the same, if they are really the same...anything else is "different".

If you're trying to build a reproduction of an existing amp, it can be a MAJOR headache when your 315-0-315VAC PT turns out to really be 345-0-345VAC, or vice versa. I see hundreds of tweed Fender bassmans...B+ from 460vdc to 520vdc+ at comparable plate current, same rectifier, 5vdc at the power tube plates is a discernable difference in a controlled A/B test (if not in a practical gig situation).

[GregS]

Per the 20W schematic, the 1960's originals were running the EL84's at 17W+ each, before the wall voltages even had a chance to creep up! Kind of irresponsible for them to take a cathode-biased amp that already pushes the output tubes, and swap in a SS rectifier without making any other changes, such as converting to fixed bias.

I should have mentioned that at the time I was testing out the build I had checked out some old schematics of the PA version of the amp - couldn't find an old schematic of the actual 2061 Lead and Bass but the PA version was very similar. Anyway, the voltages on that schematic were similar to what I was observing before I added the zener, indicating that the PT was similar to the original in terms of the voltage it was putting into the amp.

Greg

[jrfrond]

Tone is subjective. I will say this: Mercury makes REALLY good iron, they know their stuff, and have a lot of replacements you just can't get from anywhere else. In addition, they are super-cool dudes.

Yes, there is other good iron in the world, but from what I've used already, I'd say Mercury is up there.

[defaced]

Right. Then it's more of a noise issue than anything else. I still haven't built with a totoidal PT. Mostly because I build simple amps and I like the tidiness and convenience of having all my secondaries on one unit. When I find an affordable toroid in the voltages I want and a 6.3V secondary I'll bite.

Have you looked at Antek? These are what I'm using. They even got smart and started putting 70v taps off the HV for bias. Antek - Your reliable source of transformers, power supplies, and more.

[GregS]

and have a lot of replacements you just can't get from anywhere else.

That's what I thought too. In the case of the Marshall 2061 build I did I don't think replacements would be easy to come by as it's not a very common amp. Since I built it for someone else who was footing the bill the high price wasn't my issue. I suspect the amp sounds closer to the original (but don't know for sure) than if I'd used something else. That is what the person I built it for wanted.

Greg

[Tom Phillips]

... But a PT? ...

There are lots of special things they do that makes a guitar amp sound better with their PT.
First let's start with the bobbin. They use a paper bobbin. The old amps used transformers with paper bobbins. But the new paper is better because...Ah give me a minuet ta think about that.

Anyway...some manufacturers use plastic bobbins. That's not good because when the magnetic field of the transformer primary interacts with the plastic, as opposed to how the magnetic field interacts with paper, the effect is to...Ah...well ya see...Ah...

In conclusion when one guy pays $300 for a PT and another guy pays $79 for a PT that fits the same application and does the same job then the guy who paid more is sure that his amp sounds better. The seller will agree too. Audiophiles have know this for decades.

[Chuck H]

Holy hell... Those look great. And the prices are sweet too. We have to get these Antek guys outta the dark and into public view so they hang around. I'm using one of their PT's for sure on my next build.

Anyone tried a toroid OT in a guitar amp yet???