Mercury Magnetics - The Emperor's New Clothes?

[MWJB]

"I may be mistaken but I thought that the MM clone transformers were reasonably close in spec to the originals. Close enough that they could be used as a replacement part at least." There's quite a variance in what might be considered "reasonably close in spec". Then beyond the obvious specs you have differing materials etc. E.g. A Super Reverb replacement PT might be anywhere from 325-0-325VAC to 380-0-380VAC and still consdidered "reasonably close".

Often times the original amps will actually have the higher plate voltages.

"Maybe there other brands that also make transformers that are as close or closer in spec and are just as suitable as a replacement part" Yes, there definitely are.

[sportster4eva]

I found the thread with the sound clips over on Harmony Central. Here's the link, but the forums seem to be down right now.

http://acapella.harmony-central.com/....php?t=2289285

I liked the Heyboer best FWIW.

[mooreamps]

Sounds like "cork sniffing" to me.. In the past I've found the hammonds to work just fine, and I have no experience using the MM's ; thus I can not comment on them. However, the path forward on my future builds will be using the toroidal O/T's. Supposedly less E field radiation from them..

-g

[Chuck H]

on my future builds will be using the toroidal O/T's. Supposedly less E field radiation from them

I can totally get behind toroid PT's but there are some ??? for me with toroid OT's. Some good long haired reading in a few threads here indicates that toroidal OT's are especially sensitive to any imbalance in PP operation and can easily reach DC saturation. Sounds like a bad idea for guitar amps that often and typically run imbalanced. Maybe good for high end audio where your not intentionally overdriving the bejeezus out of the tubes. Anyway, might be good to search the threads to avoid some pit falls that have already been discussed.

[olddawg]

I could maybe understand a botique OT being raved about. Especially if it was a reproduction of the cheapest they could find at the time, off the self original that had that special random mojo. 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?

[ThermionicScott]

I built a copy of a Marshall 20W amp for someone a while back and used MM transformers that were supposed to be clones of the originals. I had a problem with the B+ being too high causing the EL84's to redplate. I needed to use a zener to get the voltage down. I have also read on this forum that other people have had similar problems with their Tone Clone power transformers. I thought that possibly this is a problem now because of higher voltages out of the wall and less robust power tubes than the past. Otherwise, the amp sounded good but did not try with any other tranformers to compare.

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.

As for the thread topic, I've built a handful of amps using Weber, Hammond, and recent OEM Fender iron, and they've all sounded good to me.

- Scott

[Chuck H]

IMHE which OT you use can make a big difference in overall sound. But a PT? Really?

I'm with you bro. The only way a PT can alter the tone of an amp is if the original is grossly under rated and the replacement is not, or vise versa.

Mercury actually uses a customer quote in their Vintage Guitar magazine ad where a guy replaced his PT with a Mercury product and the customer can't believe how much better the tone is!?! Yeah... And my a$$ is a banjo. Pick it.

[mooreamps]

Mercury actually uses a customer quote in their Vintage Guitar magazine ad where a guy replaced his PT with a Mercury product and the customer can't believe how much better the tone is!?! Yeah... And my a$$ is a banjo. Pick it.

If they shelled out that kind of money for a VG ad ; what else do you think they would say ?

-g

[Chuck H]

I get that. But do they think people who actually know about this stuff won't see it??? Why not just go with a different, more credible customer comment?

[mooreamps]

I get that. But do they think people who actually know about this stuff won't see it??? Why not just go with a different, more credible customer comment?

It probably was.. You swap out the stock output transformer from a "Valve Junior" ; with "anything" ; and it's like ya, it probably would sound better...

-g

[Chuck H]

The topic we were discussing was power transformers. As is the customer comment in the Mercury ad. To put it another way, what are the tonal detriments or advantages between two similar power transformers?

[mooreamps]

Sorry. My mistake.. That part was not very clear in the first post... When I look at power transformers, I just read what they are spec'ed for. I don't think any one has any different tonal contribution over another ; unless you're talking about the differences between a conventional EI core verses say a toroidal core PT..

-g

[Chuck H]

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.

[mooreamps]

I once had a link to wind a high voltage toroid power transformer from a kit, but now I can't find it... I guess my GF whacked it when she dumped my saved history tags.. :[

-g

[teemuk]

MM's adverticles also "teach" us some invaluable stuff, like that lamination rust makes transformers more efficient.

But for some reason you never see this marvellous idea utilised in reality.