Merren built Express output transformers

[AdvisableOwl]

I'm surprised he even has offered to make them again, last I heard he wouldn't do it since Ken passed, but things change.

[cerrem]

For those interested in why Kenny rejected so many OT's....
Pacific was not building them to spec...they were using different wire gauges and sometime trying to substitute different core material...

-Chris

[RockinRocket]

For those interested in why Kenny rejected so many OT's....
Pacific was not building them to spec...they were using different wire gauges and sometime trying to substitute different core material...

-Chris

Did you ever get your hands on the 2014+ pacific reissue transformers??
Hope they got em right as I still have a bunch of their transformers..

[geetarpicker]

I seriously doubt Ken had the $ to order 50 transformers at a time. I once sent a Celestion pre rola G12H speaker to Chris to be repaired, but he lost my speaker in a move...

[Mark]

That is a disappointing outcome. I'd be quite annoyed about that. I thought Chris just made the one transformer and Pacific copied it?

I doubt Chris will make any transformers, but doubt it would make a whole lot of difference.

[Mark]

For those interested in why Kenny rejected so many OT's....
Pacific was not building them to spec...they were using different wire gauges and sometime trying to substitute different core material...

-Chris

Chris, how do you know this without pulling the transformers down or measuring the diameter of the wire?

[Littlewyan]

Why would Ken need to order so many transformers at once? Didn't he only build roughly 100 Trainwreck amps? Or did he use these as replacements in repairs as well?

[LD50]

Brian Wallace at Marstran lists some TW spec trannies, can't vouch for these particular ones but I rate his vintage Drake spec products.

[RockinRocket]

Brian Wallace at Marstran lists some TW spec trannies, can't vouch for these particular ones but I rate his vintage Drake spec products.

To complicate things Merren rates his Marshall Drake power transformers at 100mA and Heybore told me Marstans are 250mA. Merrens, IMO sound better. To add even more mystery to all this Classic tone (if I remember correct) are rated at 150mA

[Mark]

More current means less sag. Surely, the higher the gain the likely the sag will be a good thing?

[zephyrblau]

all;
did this ever happen ? inquiring minds want to know

[Mark]

It all came to naught, Merren would have order a lot of steel (E I laminations) to make these transformers and he doesn't feel the demand is there. Which is probably right.

[dartanion]

There are quite a few options for transformers that work for Wrecks, if you know what you are looking for. There have been many incarnations made by Heyboer, various lam types/stacks, cores and windings. Triode has/had A470 clones made by Heyboer. Many other folks have had various versions of A470s made. The AC30 type OTs work well for Rockets too. Haven't tried one in Liverpool or Express though. I was using Pacific sets for my amps for a few years once I gained access to the line card. The Pacific units are really the gold standard in my mind for the money. Chasing down vintage Stancors is a challenge for sure. If you can find them, the hope is that they are still operational and won't cost an arm and a leg. Nothing wrong with Heyboers from my experience.

For those of you willing to experiment, a big bottle Rocket with an Express OT is well worth building. I built some with the Pacific Express set and they sound pretty damn good with any popular octal power tube.

[Mark]

I thought that Chris Merren didn't have a lot to do with the A470 Triode transformer, just the A380 transformer.

I've heard the Marstan A380 transformer is good. RJ guitars has quite a few option too.

[dartanion]

G'Day Mark

No reference to Merren making A470s, just that there are clones available as it's the preferred Rocket OT. Works great for a pair of EL34s too. It was OEM on Dynaco ST-70 amps. Those were pp pairs of EL34s running A470s as a HiFi amp. Maybe Chris has made these as well. Pacific has Rocket specific OTs, so maybe he spec'd those for Ken too? I've a few sets of Pacific left over, which will be used in something soon. I can compare those Pacific Rocket OTs to the Heyboer and the TDS 1326 equipped Torpedos I still have. The TDS 1326 is what Matchelss uses in the DC30. Closer to a Woden style AC30 OT. A slightly different flavor, yet still quite tasty.

To further elaborate, I recall working with a few others to get some variations on AC30 style OTs with different lams: M6, M19, and M50. I think Moose even had hybrid lam stack versions made, but I can't recall completely as it was years ago. Mercury has also made TW transformers, just a tad more expensive than even the Pacific units when they were introduced. High quality for sure, just seemed odd to price them above the real deal. Looks like they still have them at around $300 each, so $600 for a set. No Rocket OT though.