Grey Bell Stancor A-3801 clone by Mercury Magnetics

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geetarpicker
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by geetarpicker »

rooster wrote:RJ, Ha! Man, are you kidding me about that Pacific 11415? :lol: The one I bought from you recently is awesome, to my ear anyway. But this reminds me of a conversation I had with Gregg Levy not too long ago. He stressed that Kenny would order his OTs in sets of 10 and then have a friend come in and assess them for magnetic voodoo. The man changed and eventually Gregg became #3 for a brief time. All were described as having the 'touch' to sense something different regarding the magnetism of the OT.

So this is odd, but as I thought about it, if the manufacturer fired these individual pieces up for test - putting a current through them - then its possible the steel would have a slight magnetic charge to it. And make no mistake, using a magnometer of the type used to check for magnetism used in studios with tape machines, a used OT will easily display a magnetic field. But what if they didn't put current to them? Well, then I think they would just arrive as steel and copper - no magnetic charge to them. So is/was every piece given a current test? I dunno. After use in an amp however, an OT will be magnetized. Will it change it's character? I dunno.

OK, another added note from Gregg, is that Ken decided that 1 in 10 of these new arrivals to his shop were what he considered the 'Best', and then there were typically 2 more that were 'pretty good'. Which then left you with 7 duds. :cry:

I'm not making this up. I was also told that Ken did blind tests on the results of these hands-on magnetism voodoo assessments, loading/attaching the various OTs into a prebuilt amp and letting his shop friends/visitors make the call, blind testing them. I was told there was a discernible and notable difference that all there could and would agree on - it was always obvious apparently.

What do all of you think about this? :?: I, personally, am on the fence. I see electricity as very logical. However, I am not so sure about an OT. 8)
Yep I heard the same story from Ken back in the day!
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geetarpicker
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by geetarpicker »

Duplicate post….?
Last edited by geetarpicker on Sun Jun 29, 2014 4:04 am, edited 1 time in total.
Paultergeist
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Paultergeist »

RJ,

I am a bit confused. Based upon your last few posts, you seem much more enthusiastic about the MM and Edcor OT offerings -- with a less than stellar evaluation of Pacific's OT. Conversely -- if memory serves me correctly -- you were more favorably inclined towards the Pacific OT just a short while ago. I am having a hard time following along........
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Mark »

Hi Paul

I suppose it is a good thing that RJ is prepared to change his mind, a lot of people can't do this. I've read the various posts and it seems the Stancor transformer is RJ's thing. I had heard recordings of both transformers and I liked the Stancor too.

The interesting thing will be if RJ changes his mind once he's had all the transformers for a while.
Yours Sincerely

Mark Abbott
Paultergeist
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Paultergeist »

Hi Mark,

Thanks for weighing-in. I guess I have OTs on the brain right now. Here is why:

I recently finished up a Ceriatone-based amp kit based upon the Rocket design. I was one of four people that got these kits all at the same time -- sort of a group-build / class sort of thing. At any rate, I was busy helping others initially, so it took me a while before I ever got around to building my Rocket-inspired amp. While Ceriatone calls their version a "Rock It," I changed quite a few things on my build, among these changes was a swap-out of the Ceriatone OT for a Pacific. Fast-forward, and the builder group has a get together to all play their amps and compare. My amp had some distinct advantages (in my opinion), but one guy with the stock Ceriatone kit build (Ceriatone OT) had a pretty outstanding overdriven tone (amp dimed through a HotPlate attenuator). I would have to say that his overdrven tone was a bit nicer and had a bit more balls than mine. Not what I expected. There are many possibilities, as to why this is so, and the OTs may have little to do with the differences, but it has me thinking.......

One note: the Pacific OT is slightly smaller than the Ceriatne OT......

I appreciate the reply very much.

Paul
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by RJ Guitars »

I'm ready to test #10 in my series... it will be another Pacific. After that I have another 4 or 5 to listen to then, then repeat all of them at least once.

I had sorta expected the Pacific TW part number to be the gold standard so the harshness of that first result caught me off guard a bit. By the time I pulled it out it was starting to loosen up and I'm not ready to give up on it... and if it doesn't smooth out I don't expect that to be typical for this tranny.

I did really like the Mercury Mag tranny as well as the Heyboer I tested, but neither sound exactly like the Stancor A-3801 or Traid S-60.

I have tested a Ceriatone tranny that Poltergeist sent me and it actually sounded good, again different than other Wreck trannies.

I have found that the rebuilt Stancor A-3801, Triad S-60, and the Pacific (K&M) 25575, have some similarities including: Good harmonic content and early breakup. This might be the clearest of the few trends I am seeing and maybe a couple indicators of what a typical Wreck tranny might sound like.
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rooster
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by rooster »

Hm. this is all good. The Ceriatone kit info was interesting to say the least! Ha! Thanks for posting this, Paul. 8)

Also, I would agree, RJ, that the Stancor black plate OT I have here does break up pretty quick, too. In fact, for my tastes, I am not digging it for this reason and prefer the Pacific. To each his own it would seem, and maybe that's a consideration here. Again, RJ, thank you for dogging this!!!
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Paultergeist
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Paultergeist »

Just a quick additional data-point on the Ceriatone clone comparison:

It turns out that the guy with the stock Ceriatone kit was not all that stock, although he did use all the stock Ceriatone iron. Apparently the builder felt as though the stock tone controls were a bit skewed from center; he found it necessary to initially cut a lot of bass and boost a lot of treble. (I have a similar observation, but my tone controls do not seem so far off from an acceptable mid-point on the dials as did this other individual). At any rate, this other builder changed values in his tone stack, and in so doing also helped compensate for signal loss by raising some resistor values. I do not yet have all the details, but it sounds as though he may have boosted gain -- by reducing signal to ground via the tone stack controls -- in the process. It occurs to me that this change may play a role in the "balls-y-ness" his amp seems to have over mine.
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Zippy »

Paultergeist wrote:It turns out that the guy with the stock Ceriatone kit was not all that stock... It occurs to me that this change may play a role in the "balls-y-ness" his amp seems to have over mine.
Hence the beauty of RJ's test platform for comparing trannies.

Thanks for sharing this, Paul. It's all good stuff.
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by rooster »

Hmmm. OK, now I'm back on track. Thanks for reporting this last detail, Paul. :P
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Paultergeist »

Thank you -- all -- for allowing me to engage in the discussion (albeit, a bit late to the party). If I am able to deduce anything more of relevance about this other builder's Rocket build, I'll report back. Specifically, I would like to understand what he did to his tone stack, and try to determine if that might be a part of the noticed difference. My build is still in the "open" chassis stage, so now is the time for mods if there are to be some.

Thanks again, and more info if I run across anything useful......
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by RJ Guitars »

A few more tidbits... I installed an original Dynaco 470 tranny... very cool sounding transformer for sure!. Good overall balance of tones with some added richness and a really nice sounding distortion. It might not be typical Wreck sounding but would make a very good sounding Express.

An interesting thing to report: Early breakup seems more prevalent in the 6.6K primary transformers and less of that early distortion in the lower primary impedance trannies... I need to study this a little closer but it's starting to look like a trend. This seems intuitive and might just make sense but my ears heard it before I thought about it enough to expect it.

I am going to put the MM tranny back in and test it one more time before I give MM a total number of units to send in that first order. I have a list of about a dozen guys that have asked for one, if you are not sure you are ont hat list and want one now is the time to send me a note.

thanks,

rj
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by RJ Guitars »

Finally - I have made my way through the first round of Express transformer testing. It's pretty important to note that this is based on my ears and opinions which is to say isn't based entirely on technical content. I went back and reran the transformers that I initially declared as the best sounding and also the worst sounding or any of them that didn't meet my expectations.

There were several things about this set of tests and my results that will keep me digging to make sure I remain objective in determining and posting my information.

1) The satisfaction of the sound of the Mercury Magnetics rj-3801 wasn't unexpected but made me cautious about my objectivity in how I was listening and rating the results... knowing that in the back of my mind I wanted the Mercury Mag 3801 tranny to sound good. It turned out not to just sound good but it sounds great. I think what I liked best about this transformer was that it not only adds an element of clarity but some low end to the Express sound that few other transformers could match.

2) The performance and my rating of the Pacific 14415 original TW part number transformer actually may not be an indication of an under-performer but rather of an intended ideal match to the performance of the Express circuit. I personally would have preferred to have a bit more chime on the top end and a little more umph on the bottom end. Having said that, I'm not sure that extended tone range is needed or if I would use it. This is a transformer that really excels in bringing out the strong bite and mid range distortion of the Express, something the Express is really known for.

3) I ran the Pacific manufactured K&M Analog 25525 and my own rj-PAC-OTW and found them both to be better sounding than the Pacific 14415. This was so odd to me that I called Pacific and talked to their engineer about the differences. He told me that they used the exact same wire, exact same steel, exact same core stack, exact same wind protocol, etc.. He was also surprised that there was a measurable difference. I didn't have a 2nd 11415 to test but my speculation is that my test unit was just not typical.

4) I was as impressed as I was surprised about how great the Heyboer HTS-9384 OT sounded. Nice balance of tone and harmonics and maybe the biggest surprise of the whole series of testing I did. I have more of these leftover from days gone by and I'll be testing them as well to see if this is a trend or just a great specimen.

5) I tested a rebuilt Stancor A-3801 and two Triad S-60 OT's and they gave me a good idea of what I think an Express OT was intended to sound like... although they did each have individual characteristics. The fact that the Pacific TW 11415 OT sounded like a similar but sonically richer version of them helps me believe that Pacific probably achieved what KF was looking for.

6) I'll be ordering a few other transformers including the Marstran and the Magnetic components so I can add them to the story. I think this study is not really complete without them... and maybe a few others.

This is the end of my round one testing and I am pressing the button on a large Mercury Mag order on Monday July 7. I'll keep the ordering options for anyone who wants to try the rj-3801 for $145 delivered (US - price will be adjusted for overseas delivery) open until noon mountain standard time.

Thanks for all the great help and good input you all provided.

rj
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Trainlover »

Great tests RJ!!! :wink:
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Zippy »

That family photo of the transformers should be a sticky for the next person asking "What is the correct/original Express trannie?" :lol: :roll: :shock:

Good stuff, RJ. Very nice.
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