Mercury Magnetics - The Emperor's New Clothes?

[kg]

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.

the stacking pattern will affect the overall permeability of the core, and thus the magnetic system overall.. usually lams stacked in multiples vs. 1 and 1 will have a larger effective air gap, lowering permeability (and also linearizing it) and making the core more resistant to saturation. lower perm will cause primary L and mutual L to drop.

the gap is one of those "black art" things that takes iterations to find what works the best for a particular application, and the stacking pattern is very closely related to effective gap.

the chapter in RDH4 on trannies has a lot of info.

[kg]

Gary,
I believe you may be thinking about the Toroid Corporation of Maryland. They sell kits consisting of a toroid core with the primary already installed and you add your own secondary windings. I have not bought a kit yet but I’ve been tempted. The kit page is a little hard to find on their web site. When I started at their home page just now I initially thought that they discontinued the kit service but they are still offered. The direct link to the kit page is Transformer Kits Datasheet - Toroid Corporation
Tom

years ago i picked up a 1400va TCoM toroid core.

i wound it for days and days. 1 hv b+ winding, couple of lower voltage plate windings, and a fat heater.

unlike steve i was lucky enough to keep the insulation intact. i used rather heavy gauge magnet wire (20awg iirc) for the HV secondary, which no doubt kept it easier to wind without kinking. i'm pretty sure i was targeting ~750v for a loaded b+ voltage.

no load tests worked out fine... no shorted turns at least!

one thing that's nice about diy winding is that you get to add or remove a turn (or ten) as you see fit. getting the supply voltage right where you want it is (relatively) simple.

i had originally designed it for a 12x el509 amp driving two hammond 1640w output trannies. i still have all the parts, but i haven't touched them in around 10 years (well, once to move them when i bought a new house).

with two daughters, 5 and 1, i haven't the time i once had! maybe someday...

[Chuck H]

Nice to see you still check in sometimes. I know how it can be and I have only one girl and she's eighteen now. I haven't been allowed to be concearned with her life for years My best to you and yours. nice to see you posting.

[guitarmike2107]

No techs are making more $$$ putting in Mercury iron either. In fact we cringe when we have to tell the client how much it will cost and sometimes we may even take a small hit to sell the work order.

Well thats just silly, I understand why you would do that, guilt and all, but if a guy wants the "top part" thats costs three times as much, thats his issue, you still have an hourly rate.

if you cringe at the cost get them to buy the trannies and just install them at a fee.

JM2C

[jpfamps]

the stacking pattern will affect the overall permeability of the core, and thus the magnetic system overall.. usually lams stacked in multiples vs. 1 and 1 will have a larger effective air gap, lowering permeability (and also linearizing it) and making the core more resistant to saturation. lower perm will cause primary L and mutual L to drop.

the gap is one of those "black art" things that takes iterations to find what works the best for a particular application, and the stacking pattern is very closely related to effective gap.

the chapter in RDH4 on trannies has a lot of info.

Thanks for the info. I've read most of the chapter in RDH4 on transformers but must have missed that section. I will go back and investigate. I've not got a hard copy and am reading from a pdf (too tight fisted to print it out), which makes things harder....

[jpfamps]

Winding a high-voltage toroid transformer by hand is an incredible pain in the ass. The last time I tried, I nicked the wire insulation, causing some shorted turns, while fumbling with the stupid popsicle stick "shuttle" that you wrap the wire on. I powered it up for a test and it instantly caught fire and was ruined. You really don't want to do it. If you want a DIY transformer kit, get the usual E-I kind.

The Antek transformers are fine, there are a few forum members using them. If you're open-minded enough to get round the non-vintage-correct donut shape, they're great PTs. HT windings might be hard, but adding extra heater windings is trivial, a few turns of "Romex" or similar will do it.

Not me, though. There's nothing wrong with them, it's just that the cost of shipping from the USA and import duty makes them unattractive. Big heavy things tend to get bought locally.

Tube Town in Germany do a range of decently priced toroidal mains transformers.

Tiger Torroids in the Uk will also wind toroidal mains transformers. I got a batch of very nice epoxy potted tramsformers from them recently.

The speaking to Stephen at Tiger Torroids, the main problem with toroidal OTs is the interleaving. You are OK on the outside of the toroid, but getting all the interwinding insulation to fit into the hole is a problem as you obvioulsy have much less space on the inside.

[bob p]

Sorry, but this post will be a long one.

When I had an account with MM I used to buy transformers in lots of 25 or more at a time to get end-column pricing. Today MM isn't the product line that it used to be. That is to say, their marketing concept and how they position their products in the marketplace has changed so dramatically that I can no longer justify buying from them. Today their products are severely overpriced for what they are.

Back in the late 90s to the early 2000s you could buy MM iron in lots of a dozen, and at that price tier their iron was cheaper than Hammond Manufacturing's iron. The ability to buy application specific iron at a price that was cheaper than generic iron was really appealing. So I set up a "dealer" account with them and I sponsored a lot of group buys so that people here and on some other forums could piggyback on my orders. That was sort of the Golden Age, I guess.

That was in the day when JKB was giving me advice on building the TAB, and I tried just about every OT that was available to compare tone. I mounted a bunch of OT in a circle on a metal chassis, and used a big rotary switch that I scavenged out of a power resistor decade box to switch the OT in real time. One thing that we noticed about OT switching is that your "tone-memory" is pretty short lived, so plug changing type hookups didn't work so well. You really needed a rotary switch so you could make the changes quickly. But I'm digressing.

Back then MM made some really nice application specific iron that was reasonably priced for what it was. The build quality was really high, and the Plexi OT was a really OUTSTANDING piece of iron. We did direct A/B tests against Joe's AES OT and an original plexi OT, and the MM iron was definitely in the game. They started to earn a great reputation, and they deserved it.

But then I noticed a problem that tends to happen with a lot of suppliers -- when you first open an account with a company you get GREAT, high quality inventory on your first few orders. If you regularly and consistently order in volume, they give you the best inventory. If you don't, and you're a "small potatoes" account, then they start to slip some seconds into your shipments to get rid of them.

Mercury shipped transformers to me that had all sorts of problems.

Some had leads that had been cut and spliced and shrinkwrapped. At least they color-matched the wires and the shrinkwrap.

Some of the plexi, JTM45 and "spares" reproductions that I received had serious cosmetic problems that made them unsuitable for boutique builds -- they had been laid on their side, resting the laminations on the leads, while the varnish was still wet, so that the leads were dried into the varnish on the lams. When the leads were pulled free they left some ugly marks behind, with indentations and bare spots in the coating. They were definitely NOT pretty to look at.

Some tweed Fender iron came with torn paper insulation, etc.

There was no question about it, I was paying for first quality merchandise and they were slipping some seconds into my order, hoping I wouldn't notice. That really pissed me off.

To be fair, I called Paul Patronete and bitched about it, and he offered to exchange the iron, but they wanted me to pay the freight. I didn't think it was fair for me to have to ship a heavy box of iron from Chicago back to California and pay multiple legs for shipping their defective product, so I just liquidated the iron on eBay to people who didn't really care to obsess about visual appearance in the way that some obsessive musicians do.

I remember posting photos and complaining about the quality of the iron at Ampage, and then having a phone call with Andy Fuchs to discuss the problem. He used MM iron in the ODS, and he had NEVER had problems like this with MM. He couldn't believe that I was dealing with the same company. I got the impression that he was a big enough account to them that they didn't want to piss him off, so he always got first quality merchandise, and that I was an insignificant customer who didn't really matter to them. So I got the rejects even though I was ordering a minimum of 25 units at a time.

In some respects, dealing with MM was like dealing with a Chinese supplier -- I found that I had to tell them EXACTLY what I was willing to accept and what I wasn't willing to accept -- BEFORE TAKING DELIVERY -- because if I left that stipulation unmade, they'd try to slip marginal product into my orders. That left a bad taste in my mouth. The final straw was when some dummy decided to make their dealer-only price list publicly available on the web site. As soon as that happened, nobody was willing to allow you any margin on a build or a repair. That was pretty much the final straw for me.

Fast forward to today, and MM is no longer marketing their product to builders and techs. Now they're directly marketing a premium priced product to the end users. The prices are so much higher now than they used to be that their products are no longer competitive in the marketplace. (What an understatement!) Their pricing structure commands an obscene premium that's far beyond the incremental increase in performance that their products are capable of delivering.

Today MM iron is all about hype. We're now in an era where an iron winder is putting photos of himself in the ads, in which he's trying to look like rock star. As others have already mentioned, there are plenty of quality iron suppliers that are far more reasonably priced.

[Howlin' Mad Mac]

Yes and when they come back telling you how their friends amp sounds so much better that their amp you can tell them that's because the friend spent the extra $$$ for the ones aged for 12 years instead of the usual 8.

[Ptron]

Anyone mentioned these guys yet? SumR - Richard Sumner Technology Or should I say this guy? I had a custom power/ot toroidal set made by them. They were one-offs, made exactly to my specs (even lead length and color) and still very reasonable priced. Unfortunately, I'm just getting back to the project after a long hiatus so I can't comment on performance. Maybe in a month or two.

[mac1amps]

Even though this is an old "worn out" thread, I can't help but add my own "2 cents" here........I've done several MM tranny upgrades (and a few with Hammond's as well). When you're replacing a POWER transformer, there's [usually] only going to be subtle differences in sound as well as operation, since the signal has no "direct" ties with the power trans.
Whereas when the OUTPUT xformers are replaced, I hear (in EVERY case) a distinct improvement in: 1) low end 2) high-end "detail" (string separation, etc.) 3) Significantly reduced "harshness" in the sound.
I sure don't have the greatest hearing around, but I hear these improvements in EVERY one of the amp's I've done these upgrades to when the upgrade is the OUTPUT transformer (and usually a new "choke" with it).
Call it all a BS scam if you like, but I [along with my clientele] Love what I hear with these upgrades.
ONE reason why some may not hear any improvements with these (just a guess here), may be due to using master volumes set low, that'll kill any kind of "classic" tone IMO. Metal players can "get away" with a little master volume use, since they usually have to add some "processed overdrive" to the mix anyway, but a "classic" [Blues/] Rocker......get rid of that master volume!!!

[Chuck H]

Whereas when the OUTPUT xformers are replaced, I hear (in EVERY case) a distinct improvement in: 1) low end 2) high-end "detail" (string separation, etc.) 3) Significantly reduced "harshness" in the sound.

+1 for noting the PT/OT distinction. And +1 for noting that whatever improvement an upgrade OT offers is most obvious when clipping the power tubes.

I think the point of this thread is really about whether the MM iron is truely better sounding than, say, Heyboer, Hammond, vintage Drake or whatever. So the qualification of your post requires that we know what OT's you replaced with MM units. For example, I can believe that if a player using a 5E3, Pro Reverb, any Blackheart or a Fender HR series is after a bigger, more dynamic tone that almost any upgrade OT will demonstrate significant improvement. But have you replaced any well respected vintage or modern "boutique" OT's? Like a Drake in a Marshall or a Stancor in a Trainwreck? Many vintage amps can benefit from a better OT, and probably most modern production tube amps. So the whether or not MM iron can offer improvement isn't really the issue. Is the MM iron better than other top shelf offerings? There have been a few rough OT shootouts where MM places high but not on top. To me that means that MM is only on par with other top shelf offerings. They're real pretty though. And marketing hype does give them instant clout. But IMHO just waaay too expensive for only "on par with". Several things come into play though. Is MM iron top shelf? Sure. Great transformers. Is your customer ultimately going to be more satisfied with a product most visibly proported to be "the best"? Probably. Mercury also has the most off the shelf options like FatStack, modern voltage corrected vintage replacements and such. So if they make a model that just right for your needs, well there you go. But back to the original question... Is MM really better than other top shelf offerings? I don't think so. Just more famous and expensive.

[diagrammatiks]

onetics, edcor...

great iron and more concerned about supplying top builders rather then advertising.

[mac1amps]

In answer to Chuck H's request.....in addition to a number of ["classic" AND "modern"] Fenders, including a few of my own (Deluxe Rev., Bandmaster Rev., [SF] Bassman), I've also UPgraded O.T.'s in a few Dr.Z's, upon the insistence of the owner (of all 3 "Z's") after having heard the difference in the 1st one I did for him (an A.C. 30 copy). BTW, this was for a seasoned session player who knows a great sound when he hears one.
I'd have to add, that my experience with Heyboer trannies, is that they make fine transformers up to the "standards" of the ORIGINAL [Fender] transformers, whereas the results I've heard with the MM & Hammond [1600 series] transformers significantly surpass those previous "standards".

[JoeM]

A friend who builds told me he will use MM sometimes for customers amps, but for amps for himself he prefers Heyboer. Personally, I feel there's just a perception that something more expensive is 'better'.

[Chuck H]

Yeh, it's all subjective. My personal favorites are also the off the shelf Hammonds (1600 line). It seems that whatever I swap with never sounds as good. But like I said, it's subjective.