Grey Bell Stancor A-3801 clone by Mercury Magnetics

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

Post by RJ Guitars »

Yeah David, KF had his way of doing things and occasionally it's possible that improvements exist... but you have say that hypothetically around here!

Meanwhile - today I had time to try out three more transformers in my test amp. Not a bad one in the bunch but I did quickly focus in on one clear favorite. I used the same Hamer Monico III with the P-90 style pickups that I have used in all of the previous testing. I additionally tried a stock Strat and allowed myself to diddle with the knobs on the amp to dial it in a bit.

I started out with an old black Stancor A-3801 with cloth wiring. I pulled it from an old amp i had traded up and was it ever a sweet sounding tranny! It maintained it's clarity a little longer than the rebuilt Grey end-bell that MM rewound for me and it also just seemed to love volume. Sweet chimey full sounding. I've had this around for a while but I was able to have a conversation recently with JM over at TW and he said that the old black A-3801's were absolutely wonderful sounding. That inspired me to try it and it is really a nice sounding tranny! It was immediately among the top few I've tested, especially loved it with the Strat! I tried to get some clips but I just couln't get the recording to sound like the real thing... I need to get the SM57 mic back from my son then I'll be able to do some recordings.

The Magnetic components had a good tone range and broke up really nicely as things started to get loud. It did seem to get sorta squishy when I really pounded it... a good tranny but it didn't have the clarity and richness that the old Stancor did. I would also describe this as a loud and bright transformer... good qualities if you want to add some flavor to a Wreck that is sorta dark sounding. A decent tranny especially at reasonable volume levels. It didn't take much work to find a sweet spot or two and in many ways it sorta reminded me of the Ceriatone tranny I tested earlier. I might think this is a case where the tranny needs to get old and used and I'd like to hear it again after it's broken in.

The last one was just something that I found when I was going through cabinets and clearing out unused stuff. It was a 40 Watt open frame tranny that I bought from Musical Instrument Power Supplies. They used to do a lot of sales on EBAY and were a very affordable option for building an amp on a budget. I bought this thinking of using it for a Fender style amp and had never heard one of these before... it was a bit of a spontaneous buy. I had very low expectations of this tranny and in fact almost didn't test it... but it was easy so I did. It was a great surprise and gave me several really nice sounds. I had to tweak the knobs a lot to get what I wanted out of it because it was just a little starved in the mids. After I backed the bass control off it started to sound pretty good. It also broke up early and I had to have a pretty soft touch even at low volumes to keep it clean.

More tests and hopefully some clips coming in the future.

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

Post by rooster »

Thanks for posting this RJ!! 8)
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by RJ Guitars »

Thanks, I hope to get back to it sooner rather than later. I have setup some decent recording gear although I find it hard to get exactly what my ears hear so lots to learn on that frontier.

I put the original TW Pacific part# tranny back in the test amp and I am again struggling to find any real passion for it. Hopefully I can get some decent clips and see if you all think my ears are missing something.
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by martin manning »

Good stuff, and I bet you're really liking your test rig for this sort of thing!
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Littlewyan »

It could be the pacific transformer just doesn't match your rig RJ. Since I changed the capacitors in my amp the JTM45 Transformer that I'm using has started to sound really good. Could be that it just matches the speakers and guitar that I'm using. Although I think I may still swap it for a Pacific as the Express still sounds a bit bright even when turned right down with an attenuator and I reckon the Pacific may help to lower the brightness a bit. Will have to wait after xmas though.

Look forward to hearing recordings of the different transformers.
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Mark »

So far the black Stancor sounds like the money. I wonder what the difference between the grey and black transformer is (other than paint of course.)

I believe there are Heyboer versions of the Stancor, most notably the Marstan version. I have heard this transformer once through an open back cab with 65 watt Celestions and I wouldn't call it chimey.
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Fretts »

rooster wrote: Mon Apr 21, 2014 7:36 pm I have a black bell cover Stancor OT and funny thing here, I talked with the Pacific guy that posted here a while back about making a clone of this. He is an interesting guy, nuff said, but he told me - after checking with his 'people' - that Pacific was not interested in cloning this OT....
Recently watched a youtube video interview with Bob Gjika - ampmaker and friend of Ken's. He remembers the custom-ordered Pacific transformers being terribly inconsistent, very frustrating to Ken who had to hand-tweak each 'Wreck to get it to match his benchmark reference amp. Sometimes had to just throw one tranny out and put in another and try again. Gjika said that's why they are all a little different - it was the transformers coming from Pacific. Both guys liked the Stancor very much and were very disappointed when that unit was dropped from the line.
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by RJ Guitars »

Interesting... I have notes from Pacific that basically indicate their Wreck Express tranny is basically a clone of an old Stancor.

With the modern production trannies I've got from Pacific they all seem to have a distinct and consistent sound to them. When I had Mercury Mag clone my old Grey Bell Stancor they said it was crudely made and it was unlikely that they would have been consistent from one to the next. I did think the Mercury Mag clone actually sounded better than the old Stancor but each had it's own sound and neither sounded exactly like the Pacific. I actually like the sound of the Heyboer Express spec trannies (the later "vintage" series) as much as I liked any of them.
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by rooster »

Yeah, the Gregg Levy connection (friend of Ken's in the day) and his report was that they found a guy who was a transformer whisperer (actually it is reported that this person could sense the magnetic field of the tranny) that held the various trannies and helped Ken make his decisions. The report I got was that maybe 3 or 4 from a batch of 10 were good, the other 6 were marginal. Which I assume isn't to say that Ken could afford to toss them, but that he adjusted the circuit to make the 6 better. This might be why you see that .002 poly/.002 ceramic cap (parallel thing) on stage 2 that was documented. It may have existed only as a result of Ken 'correcting' an OT.

It has also been reported that Ken had his group of friends audition a particular tranny swap on at least one occasion - a blind test to the group using the same amp - and the OTs (Pacific), were found to be remarkably different. The same build OT, the same batch of 10, the same laminate material, all DC resistances being equal. One was very musical, the other 'junk' (Ken's description and supported by the group's blind test).

Also, regarding the Black Bell Stancor OTs, I sold one to Chris Merrin some time back and he reported to me that the 8 and 16 taps from the factory were swapped internally. Something to think about.
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Mark »

RJ, so the old Black Stancor A-3801 output transformer is still king?

How did the Stancor A-3801 compare to the Marstran/Heyboer Stancor clone?
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by RockinRocket »

Mark wrote: Tue Jan 30, 2018 9:45 am RJ, so the old Black Stancor A-3801 output transformer is still king?

How did the Stancor A-3801 compare to the Marstran/Heyboer Stancor clone?
Its questionable if the Black and Gray a 3801 are identical constructed. I have yet to see a black one in Kens amps and these don't have PVC coated wires.
Specs seem the same.. but are they actually wound the same??

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

Post by pompeiisneaks »

Lol was going to say, doesn't look like Warez to me :D

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

Post by RJ Guitars »

In units I've had in my hands, the old black Stancor and the grey ones are subtlety different in construction although to my ears they sounded similar. The lams and endbells appear a bit different although I don't have enough statistics to really a strong case for anything but the few units I've had my hands on.

For the money, the Heyboer is my modern production favorite although it doesn't have near the cosmetic quality when compared to any of the other brands. I think they wind them really well but then they tend to get a lot of shellac all over them and don't pad the shipping boxes all that well when they ship out a box full of them. I usually have to ask for a few replacement endbells after I receive a big order. They are great guys over there at Heyboer, just not as focused on the cosmetics as some of the other places.

The Pacific definitely sounds like "The Express" OT but it seemed to go quickly from clean tone into breakup and it was hard for me to get that in-between sound with warm harmonics and clarity that was common in the Heyboer and Mercury. It really has a cool sound but sorta has only that sound where I think some of the others offered more variation in what you could coax out of them.
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by Mark »

Thanks RJ that is good info. Does that mean the Pacific transformers do the clean to mean thing better than the Heyboer transformers?

Also it is my impression that there are several Heyboer winds, the Marstran is the other Heyboer wind that comes to mind, is there much difference between the various winds.
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Re: Grey Bell Stancor A-3801 clone by Mercury Magnetics

Post by RJ Guitars »

Sorry, I know this is old... I'm not getting a notice when the new posts come in on a thread. Anyway, but it did spark a thought when I caught up with it.

The Heyboer I like best is what they called "The Vintage" series part number HTS-9384 and also has the 11415-2 number associated with it. This was one of the later iterations and was said to be a little smoother sounding than some of the previous versions. I've got a couple of the older ones here but only in the 5.2K version so I don't really have a good data set on the older 6.6K style.

I keep a couple of the more recent "Vintage Spec" OT's in the 6.6K version around because they sound so good that I can use them to tell if the amps I'm building are delivering everything to the OT I want to hear. They have just a little more breadth and clarity to them them than the Pacific 11415 which sounds a little darker. Each has it's place and the Pacific "is" the Wreck sound so the Heyboer might be a bit too sweet sounding for a pure Wreck tone but I really like them, especially for the harmonics I hear from them.

... and yes, I think that's fair to say that the Pacific does the clean to mean thing the best. It breaks early and has this meaty darkness that begs for power chords and raging solos. I will also have to add that I've heard some Geetarpicker recordings where he brings some terrific sweet harmonics out of his Pacific OT wreck so YMMV with your driving habits.
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