Grey Bell Stancor A-3801 clone by Mercury Magnetics

[rooster]

Ha, brave man posting those numbers!

But explain a bit to me what '6' means vs. '3' vs.'10' please? Are these 'o'clock' numbers? And basically these are all subjective measurements, too?

Great pic, too! Man, this has never been done before, RJ, thank you for your time and trouble!!!

[geetarpicker]

Specifically what are the rebuild details of the "rebuilt Stancor A-3801"?

Quite odd that out of all the transformers in your evaluation sheet you rank the original Stancor the absolute lowest of the bunch, though this is the transformer that is being recreated.

I'm just going to assume that any noted improvements over the original are still up to interpretation, and that the baseline of an original is perhaps still a moving target due to variation.

[RJ Guitars]

Ha, brave man posting those numbers!

But explain a bit to me what '6' means vs. '3' vs.'10' please? Are these 'o'clock' numbers? And basically these are all subjective measurements, too?

Great pic, too! Man, this has never been done before, RJ, thank you for your time and trouble!!!

Good questions... I used a relative scale of 0 thru 10 but saved the extremes for reporting severe deviations. It's important to know that 10 is not necessarily better sounding than a lesser number but just that it represents a greater quantity of that article... for example: using the amp with the treble all the way up with a MM tranny might be too much of a good thing.

I used high, mid, and low in the frequency range as comparison criteria for fullness. In reality, fullness needs to include the harmonic content and the sparkle as well. I know you can all do the math for that effort...

Specifically what are the rebuild details of the "rebuilt Stancor A-3801"?

Quite odd that out of all the transformers in your evaluation sheet you rank the original Stancor the absolute lowest of the bunch, though this is the transformer that is being recreated.

I'm just going to assume that any noted improvements over the original are still up to interpretation, and that the baseline of an original is perhaps still a moving target due to variation.

Yes, it's fair to say I wasn't impressed with the original Stancor rewind, but it wasn't a total disaster. The Pacific's sound similar but have a little more of everything and slightly more headroom. The first of the Triad S-60's sounded pretty similar to the original Stancor and I felt like I was starting to get some clustering of characteristics between them and the Pacific's. But if you look at that last Triad S-60 (same as Stancor A-3801) it was very different. It was very much like the Mercury Mag reproduction with the only weak spot being that it didn't have a lot of bottom end. I suspect this transformer when used with the right speaker cabinet would sound awesome. So ultimately I am still amazed that everyone of them sounds so unique. That does lend credibility to all the stories we've heard about KF having a big stack of transformers that he went through and characterized.

I'll start working with MM to get some specifications we can look at.

One other factor to look at when you review my test results is that when you subtract out the cosmetic factor, MM and and Edcor drop more than the others.

I bought some recording equipment to see if I can capture any of this and take some of the subjectivity out of the results... but I know it will take time so don't hold your breath. I need a day when I play well and also record well... that could be challenging.

Finally, on my own chart here at the house I have a column called fun factor. This is entirely subjective and couldn't figure out how to translate it into anything legitimate so I left it off of the results I posted on TAG. The last Pacific, the last Triad, the MM 3801, the Hammond, and the first Heyboer I tested all ranked very high in this category... it was that sorta thing that makes you want to keep playing just a bit longer.

[geetarpicker]

Ok, so your "Stancor A-3801" is actually a MM rewind of an original. I think that detail should definitely be mentioned in your comparison chart.

Just trying to clarify do you indeed have a true functioning, original wind grey Stancor A-3801 in your assortment of transformers?

Or is the Triad definitely known to be exactly that, basically from the same last production period when Stancor went to grey end bells and plastic covered wiring?

My original '85 Express has the grey bell Stancor OT, and I also have a NOS one just in case stashed away. Both my '85 Express and the NOS one have the cut outs in the core for the center bolts on either side, though neither actually use these center slots for a bolt. My original '89 Express has Pacifics, though I have played an '89 Liverpool with the Stancor so '89 was the transition year. Both of my Express amps are surprisingly different to play through, though circuit wise they are pretty much identical short of a different brand of pots and one added snubber resistor in the '85 where the '89 has no snubbers. My '85 definitely has a little more clarity on top, and more lows. Overall it seems cleaner and not as loud. I can't say it breakups any earlier, it just seems a little more flat in response and the low end definitely goes down further. It's greater clarity makes the bright switch not as essential even with a humbucker. The '89 is a bit more mid focused and seems gainier, it also seems louder overall. It is not quite as clear sounding but takes well to being played with the bright switch on and then the clarity is quite nice. The '89 is also less forgiving and harder to play, where as the '85 is simply more user friendly. The '85 has enough extra low end to work on a smaller cab if needed, but the '89 seems to shine best on a 4x12 though I'll admit I favor 4x12s when I have a choice. I remember back in the day Ken regarded his earlier amps as better for blues and more delicate playing styles, and his later amps as more hard rock machines. I guess that ball parks it!

[RJ Guitars]

Ok, so your "Stancor A-3801" is actually a MM rewind of an original. I think that detail should definitely be mentioned in your comparison chart.

Fair enough, I can do that. The rewind is a cool transformer and I am curious if that early breakup would show up when it is used in another circuit? I have a black A-3801 that I can try as well.

...Just trying to clarify do you indeed have a true functioning, original wind grey Stancor A-3801 in your assortment of transformers?

Or is the Triad definitely known to be exactly that, basically from the same last production period when Stancor went to grey end bells and plastic covered wiring?

To the best I can sort it out, several companies were using the same transformers - Triad, Stancor, Merit, and others as well. I have two of the Triads and they do not use the exact same end bells as each other so maybe we can assume those two weren't made at the same time - I dunno? Either of them would swap end bells directly with the Stancor and the guts look identical. If you pull the covers off and look at them they are all the same including the HiFi taps.

...My '85 definitely has a little more clarity on top, and more lows. Overall it seems cleaner and not as loud. I can't say it breakups any earlier, it just seems a little more flat in response and the low end definitely goes down further. It's greater clarity makes the bright switch not as essential even with a humbucker. The '89 is a bit more mid focused and seems gainier, it also seems louder overall. It is not quite as clear sounding but takes well to being played with the bright switch on and then the clarity is quite nice.

Thanks Glen for the breakdown on your tones. I think the clean tones on "New Mexico" represents the ultimate clean sound you can get from a Wreck. https://www.youtube.com/watch?v=-U36UxwiHaI This is why I was so pleased with the clarity of the MM tranny. I can get good clean tones with all of the other trannies I tested but the window is pretty small on some of them.

I would love to have your ears to hear all these. They are all different enough I can hear it but I suspect someone like yourself could really hear some important subtle sounds that are significant.

At this point I can't get any two of anything to sound exactly the same so I'm just as curious now as I ever was about what KF was listening for.

[RJ Guitars]

The new trannies are ordered... Patrick said that it would only take a week but I won't be surprised if it takes a bit longer. I look forward to getting these out into your hands so we can get some additional reports on their performance.

[Paultergeist]

.....One other factor to look at when you review my test results is that when you subtract out the cosmetic factor, MM and and Edcor drop more than the others.

RJ,

Can you explain this comment a bit more? *What* is being "dropped" by the MM and Edcor trannies?

Paul

[RJ Guitars]

.....One other factor to look at when you review my test results is that when you subtract out the cosmetic factor, MM and and Edcor drop more than the others.

RJ,

Can you explain this comment a bit more? *What* is being "dropped" by the MM and Edcor trannies?

Paul

Sorry Paul, I didn't see this because I had mysteriously lost my email prompt when a new post went up on this thread.

I had developed a scoring system to help me evaluate all these transformers by the same criteria. Some of that criteria was cosmetic. In the case of Mercury Magnetics and Edcor they tend to shine above the others in cosmetic finish. It doesn't help them sound any better so if this was a purely sonic test they would each score a bit less than I scored them.

A second item to update is to mention is that I bought a Magnetic components Wreck style output transformer to run tests with... I haven't tried it yet but I understand one reason why you guys have a lot of interest in them... they are quite affordable even in small quantities. I've been way busy over the summer and looking like more of the same going into the fall. I anticipate the tests to resume in October.

Finally, all the first round of the MM rj-3801 clone trannies have shipped out. I initially had the wrong schematic posted for it... got that fixed and I'll post it here as well. We should be getting some sonic reports back on these soon.

[Paultergeist]

Ah....got it now......thanks RJ.

[rooster]

RJ, maybe there's another one on the test list. I just saw that Hammond is making a 35 watt OT that matches the A3801 in primary impedance, including the 250 and 500 ohm taps in the secondary. It's called the P-T1650G. Funny, too, here it has a 3.5 ohm tap instead of the 4 ohm, and a 16 ohm tap where the 15 ohm would be. It also has the lineal taps which is maybe the Hammond thing, but surely this looks like a Stancor clone attempt to me.

Has anybody tried this?

[Mark]

What was the verdict on the Magnetic Component transformer set?

I've used the power transformer, as mentioned by others it is larger than other transformers, I also got a little higher voltage from it. In a Rocket build I had 315VDC, I had anticipated 305VDC.

[rock_mumbles]

My brother, a friend and I did some OT swapping around last night.
We used my brother's sort-of Orange SuperBass 50watt 2xEL34 amp ...
We only worked at moderate volumes because of the location ... unfortunately we didn't have a loop pedal to keep the input completely constant and didn't have recording gear ...

We had three OT's, a Triode A470 clone, an rj Pacific A470 clone, and rj's Mercury A3801 clone.

First off all three OT's sounded really good!

There was a slight difference between the Triode and Pacific A470 OT's, it seemed like the Pacific had a bit more low end ... overall they sounded pretty close to the same.

The Mercury A3801 clone sounded different, it had a noticeable difference in the high mids, a harmonic content (distortion) that wasn't in the A470 OT's ... it sounded really nice, a very interesting complex tone! You could tell that it wasn't as 'neutral' (clean) as the A470 OT's.

I'm going to be putting the A3801 clone into my Matamp S2k inspired amp to replace the lackluster sounding OT that's in there now.

[RJ Guitars]

Nice report... I haven't had a chance to listen to the Magnetic Components tranny yet, Sept is going to be real busy for me so I anticipate hitting the transformer testing again in October but don't expect to do much until then...

[RJ Guitars]

Well it's been a while but I am making my way back to this project. The latest thing I did was tweak a little bit on my test amp. I'm surprised you guys didn't catch me in a one omission from my preamp board... I had no cap (C12) across the PI - no explanation?? I put in a 100pF SM cap at c12 and also added .002 ceramic cap in parallel with C8 to bring out a little more low end. I learned a few things on the last two Liverpools I built and believed I could get just a little more out of it... it was never bad but I think it's even better than it was.

I have some new recording gear and wanted to make some audio clips of it to give you something tangible to help quantify my output transformer testing. This is a bit risky because I don't have a studio nor do I know much about recording, nor am I an amazing player, and this is in fact only my 2nd recording with the new gear.

I wanted to record a few clips using my "Jam Man" looper and then run them thru the different transformers to try and keep the input signal equivalent in all tests. I diddled for 15 minutes and then cut out some good representative samples. The biggest disappointment was the Jam Man added a ton of hiss into the amp so I'm not sure my plan is going to work really well. In the attached recording you can hear the hiss although it doesn't seem to get in the way of the guitar tone, just was a bit disappointing...

Anyway, here is the first clip, maybe slightly compressed from the way I think the amp actually sounds but it's a bit better than any previous attempt at recording. I'll try to get more recordings of the other trannies as I go that should help quantify the results in comparing transformers. This clip is intended as a baseline... today I have in the original Grey End Bell Stancor 3801 that MM cloned and rewound for me.

OT = Grey Endbell Stancor
Guitar = Hamer Monico III (3x P-90's)
Entire recording done with 1 amp setting, variations in guitar volume and pickup selection.

[David Root]

Just picked up on this thread Bob. Talk about OCD!! You da man! This answered a lot of questions I had, thanx for all your hard work.

Still don't care for KF's one-point-for-all grounding system but will go along for the ride.