Best Express Output Transformer.

[M Fowler]

MC iron states:

Description: This is a vintage constructed, paper layer wound TW Express style output transformer. It features a 6.6K Ohm primary with 4/8/16 Ohm secondary taps. This has M-19 / 26 gauge steel laminations.

[leadfootdriver]

MC iron states:

Description: This is a vintage constructed, paper layer wound TW Express style output transformer. It features a 6.6K Ohm primary with 4/8/16 Ohm secondary taps. This has M-19 / 26 gauge steel laminations.

I read the MC Top 10 as well! I like that they use a machine to line up the laminations, as well as use a Tightly Formed Copper Flux Band on the PT's.

The last Marshall I owned had a LOT of mechanical noise and hum. It didn't have the flux band on it. The Peavey amps I've owned did have the flux band on the PT's. 'Never had a problem with them.

[Clyde]

I just debugged a Vibroverb build with MC transformers, found the plate voltages to be about 25 volts less than they should have been.

[RJ Guitars]

The Classic Tones are priced right!

http://www.classictone.net/TW-Style-Transformers.html

that priced looked too good to be true... then I looked harder and realized it was per each for quantities of 18 or more. So the price for a single is still good but not as unbelievable as it first seemed...

So, how do they sound?

Does anyone have any clips of a Wreck style build using them? Most proud amp builders will tell us their amp sounds good. In some cases this could be true but without a baseline it's hard to sort out good amps from great amps. This includes everything from a Ceriatone to JM reproduction... but studio sound clips or at least good quality ones take the pride and subjectivity out of the equation.

Hope we can get one of everything to listen to.

rj

[tweedeluxe]

RJ, would you be interested in adding their iron to your store, especially if some good reports come back? I sure would like to try some, but I would much rather order through you.

[leadfootdriver]

I can't find the miliamp spec on the PT.

[RJ Guitars]

I would say there is a market for them if they prove to be comparable to the Heyboers or Pacifics... the big deal is going to be the sonic reports. There are enough of them out there that I think we'll eventually get some reports that will prove them out one way or the other. (by reports I mean quality sound clips and unbiased reviews).

The way James Healey is approaching this is really a strong way to compare output transformers. He is using quick connections to swap different output trannies into the same amplifier and adding his great guitar playing and studio recordings to the project. This doesn't necessarily optimize the circuit for each transformer, but it should clearly identify the significant individual differences in each of them. Maybe somebody who really wants to know will send James a couple other transformers and I doubt he would mind if they threw in a few hundred quid for studio time too?

We have very high confidence in the Pacific transformers delivering awesome sound and there are hundreds of fantastic sounding clones out there with Heyboer trannies as well. These set a high standard for every body to shot at. For your once in a lifetime amp the balance between economics and results may tip the balance toward these proven warhorses in the race until one of the upstarts consistently outruns them...

rj

[rdjones]

Going out on a limb here with my suspicions about what gives the original Express transformer it's character ...
The A3801 has the 250 and 500 ohm windings that are unloaded in any guitar amp scenario.
These 'extra' windings take up space in the interleave.
Normally more tightly interleaved windings give an extended high end response, arguably at or beyond the guitar range.
There's got to be some interplay between the naturally bright circuitry and the inherent rolloff of the transformer design that creates a sweet range of harmonics.
I also suspect that the additional unloaded space in the core helps reduce saturation, but due to the conservative power over-rating this is a negligible trait.

I've experimented with several amps that had 250/500 windings.
An Aireon 1221 jukebox amp has a noticeably gradual and sweet overdrive.
A Bell Pacemaker 75, while UL and very bright still didn't seem at all "HiFi".

Do any of the other OTs used in Express by KF have the 250/500 windings ?
Do any of the current products or clones have the windings ?
Anyone think I'm way off base in this thinking ?

In my case I have a Stancor A3801 so the discussion becomes academic, but highly interesting nonetheless.
Does James Healey have an A3801 for the comparison ?

reddog

[Richie]

Some of those old transformers sound very good. I also wonder in just trying the many that are made like the old stancor.
I've tried a few that were not modeled after the 3801 which also sounded and responed as you described. Which some sounded as good, or i thought sounded better than the 3801.
So if your just comparing the ones made like a 3801,that shouldn't be hard to do. Just think of all the new and old transformers that haven't been tried.

[dorrisant]

I know these are not about the Express... But good food for thought:

From MC
www.classictone.net/PaperVsPlastic.html

From MM
www.mercurymagnetics.com/pages/news/misc/ShootOut.htm

Harmony Central - Product List On Page 3
http://acapella.harmony-central.com/sho ... r-shootout

Tony

Btw... I did have a lot of research done (my "homework"), but it was all in post-it notes on an app for my phone. The app crashed and I lost all my notes. Thanks again guys for stoking this fire and adding to the knowledge base!

[leadfootdriver]

Nobody has tried the Classic Tone iron yet?

[RJ Guitars]

I am going to order a couple of the Classis Tone outputs and see how they look and sound. I can't bring myself to go for the Power Trannies since they are bit more expensive than Heyboer and I have plenty of stock in Heyboer and Pacific at the moment.

I am curious if anyone else would be interested in putting together a test platform and studio clips? I can furnish some hardware or maybe it's still best to send another package to James Healey if he has interest?? Curious if anyone would like to hear the head to head tests (literally... pun intended) enough to collaborate on a sampling effort.

In the mean time can anyone identify this tranny? I bought a pair of them off EBAY and they are physically the same size as the 3801A, but I can't cross reference the numbers.

rj

[rhinson]

I am going to order a couple of the Classis Tone outputs and see how they look and sound. I can't bring myself to go for the Power Trannies since they are bit more expensive than Heyboer and I have plenty of stock in Heyboer and Pacific at the moment.

I am curious if anyone else would be interested in putting together a test platform and studio clips? I can furnish some hardware or maybe it's still best to send another package to James Healey if he has interest?? Curious if anyone would like to hear the head to head tests (literally... pun intended) enough to collaborate on a sampling effort.

In the mean time can anyone identify this tranny? I bought a pair of them off EBAY and they are physically the same size as the 3801A, but I can't cross reference the numbers.

rj

are the laminations buttstacked? have you stuck some voltage on it and ran the ratios? does it have extra sec winding like a 3801? rh

[Joe L]

I have tried the MC iron twice. In a Deluxe Reverb and in an 18 watt Marshall. I also discussed a D*mble build with another gentleman that had the same problem as I did.

The MC iron was very buzzy/fizzy when pushing the outputs hard. It was not subtle at all. In the case of the Deluxe, changing to Mojo's Heyboer OT fixed the problem. In the Marshall 18, I switched to GDS Heyboer and it cured about 80% of the buzz but EL84s are just noisy creatures and I had to add control to the bias to keep it from shifting and causing crossover distortion.

I am not a transformer guru but I'm guessing that Heyboer designs their transformers to compress the high end when pushed hard and MC iron holds firm and maintains bandwidth.

Anybody else experience this?

[M Fowler]

I like both of the other transformer sources you listed and have used them myself.

I have not had any tone problems and noise problems nor can I report that my MC power transformers get hot.

I have used both MC PT and OTs in everything from 18w Marshalls, JTM45, JCM800 2203, JCM800 2204, Dlite, 5E3, Tweed ODS, BF Bassman, Octal Reverb Rocket, etc.

Mark