5.2k and 6.6k Express OT

[Littlewyan]

I've been doing a lot of reading about the Trannys the Express uses. As I understand it 5.2K was the primary impedance that KF used on later Express Amps. However I've also heard that Pacific only made one Transformer for KF and that was the 6.6K model. So who made the 5.2K OTs and are they used on the Express amps made by JM or does he use the 6.6K OT?

[2tone]

I've never got this straight, and from all conversations with Ken I had the Liverpool and Express both at 5.2k or so. I always thought they were both the same. The pacific spec had me puzzled, that only one impedance was ever spec'd, and that was 6+k??? Plus the old Stancors that were used in Expresses and Liverpools I thought were the same. I have one of each and they seem like the identical transformer in both amps..

[Hogy]

The Stancor A-3801 that was used in both the Express and the Liverpool is 6.6k plate to plate. The later Pacific versions are the same.

If there ever was a Wreck built with a 5.2k, it was a one-off. Maybe for a specific player. That is, if it exists...

There are quite a few variations in Rocket transformers, but that's another story and another reason.

Ken went through a bunch of transformers to pick out the ones he would use. He told me he typically ordered batches of 25, and would use maybe ten of them for Trainwrecks. The rest he used for non TW repairs or gave away to friends.

He'd listen to the whole batch and number the ones he'd use. He'd also mark them as to whether they sounded bright to him, or dark, or crunchy of clear, etc.

Then he'd use them accordingly to finalize an amp, according to what a particular player was looking for, or simply how an amp turned out. If it was a very bright amp, it'd get a dark transformer, etc.

When I originally built a Liverpool for myself, Ken asked me what guitar I'd mostly be using it with and what sound I was after. He then sent me a 6.6k Stancor from his stash that was marked "#4" and pretty much did exactly what I wanted.


Hogy

[2tone]

Interesting Hogy! I guess that must be the fact. I had written down in a couple of places in my notes during Ken conversations that the Liverpool and Express were both 5K and the Rocket was about 4K. I don't know where ken got the 5K thing from?? Maybe he didn't want anyone to know the real value?? Ha...

[Littlewyan]

I've heard that story regarding the transformers as well. Each Trainwreck really was unique. With regards to the JM Express I watched a video of Matt O Ree (think thats his name) playing one and think it sounds similar to Glen's Express but with a bit more fatness to the tone. He may not have had the bright switch on though. Anyway I heard that JM uses his own spec Pacific OT. Be interesting to know what the difference is between that and KF's Pacific OT.

Edit: Although the issue with this comparison is obviously different valves as well and speaker cabinets. Both have the very distinct TW flavour in the tone though.

[BLT]

So Hogy, are you saying that he had a reference transformer and adjusted what transformer, by Ken's ear, went to which amp? Does anyone else have a transformer they reference off of? That was one of those smack me in the face, that makes perfect sense, moments.

[Hogy]

So Hogy, are you saying that he had a reference transformer and adjusted what transformer, by Ken's ear, went to which amp? Does anyone else have a transformer they reference off of? That was one of those smack me in the face, that makes perfect sense, moments.

I'm not sure there was one "reference transformer", just that Ken listened to each transformer individually and then determined what they were good at. Ken had peculiar terminology about this stuff. Like he would say "that transformer sounds bluesey, that one crunches, that one like Strats", things like that.

So, if he was going to build you an amp, he picked a transformer accordingly.

Or, if he just built an amp and it came out overly dark or bright, or lack mids, etc., he'd swap OTs to compensate. It was part of the voicing process.

[Hogy]

Maybe he didn't want anyone to know the real value?? Ha...

I think that happened a lot more often than people realize. Yes, he was helpful and generous, but at the same time fiercely protective of his own stuff. He did NOT want anybody to copy his amps.

And another part was that he had a weird sense of humor sometimes. He would often tell me stuff that was wrong and wait for me to figure it out. Then he'd laugh...

Or send me schematics to build that had mistakes or redundancies in them. He would test people like that to see if they could think for themselves.

With Ken, you just never could know. Was he serious when he said the color of wire insulation mattered? I think to him, it did. He used to tell me that when he'd build an amp, he'd sometimes spend a good bit of time trying to figure out what album to listen to while working. If the music wasn't right, the amp wouldn't come out sounding right. I honestly think that was true for him, not BS.

He truly was one of a kind. I sure miss him.

[2tone]

Yes, Ken had his great sense of humor, and certainly did keep secrets. I knew some stuff he told me was purposely done to guard some secrets. he shared a lot of stuff, tho, and I do believe a lot of the stuff about composition of materials affecting the tone. I'm sure he selected transformers too, because even at the same spec they will have some differences, and I believe I could hear things in the transformers from certain batches (certain years of Express or liverpools) that had a characteristic sound. I had talked to him about this but he just shrugged it off. Other times he would say people put too much emphasis in transformers, and that he could get the sound he wanted out of a generic transformer. I know he selected rectifier tubes for each Rocket out of his batch of Mullard GZ34's.. More stuff to make you scratch your head...

[Mark]

Hi Hogy

You mention there was quite a lot of differences between Rocket output transformers. What transformers were used in the Rockets, and why were they used?

I can see pros and cons with the Rocket, it does single coils exceedingly well to the detriment of humbuckers. I think the DLM followed by the Rocket are the least understood Trainwreck amps.

[Littlewyan]

I've heard about Ken telling people to listen and getting annoyed when they didn't. I mean that is a big part of the recipe when it comes to building amps. Listening. You need to really listen to the amp to voice it. I think this is possibly why he'd try and throw people off by telling them something wrong, to see if they'd work it out for themselves.

[Hogy]

Hi Hogy

You mention there was quite a lot of differences between Rocket output transformers. What transformers were used in the Rockets, and why were they used?

I can see pros and cons with the Rocket, it does single coils exceedingly well to the detriment of humbuckers. I think the DLM followed by the Rocket are the least understood Trainwreck amps.

That's not quite what I said. The transformer specs were always the same for the Rocket, but made by at least three different manufacturers. Ken didn't make many Rockets and never ordered a large batch of transformers for it. He would just go with whomever was willing to do a few, preferably as "engineering samples".

[Mark]

Thanks for the quick reply Hogy. I'm on my computer and I can use the quote button.

There are quite a few variations in Rocket transformers, but that's another story and another reason.

I suppose I see variations as variations to specifications.

Many people would see the Rocket as an AC-30 clone, upon building one I can see how the output transformers makes a big difference, as does Ken choice of B+, but is there anything else that would set the Rocket apart from an AC-30?

The problem the Rocket faces is there are vintage AC-30's as well as clones such as the Bad Cat 30, the Matchless DC-30, the Z Wreck to name a few.

http://www.badcatamps.com/black-cat-30.html
https://www.youtube.com/watch?v=8WPG0dD20lg
https://www.youtube.com/watch?v=GQhxG6hha1k
http://www.drzamps.com/amp/z_wreck/

[Hogy]

Thanks for the quick reply Hogy. I'm on my computer and I can use the quote button.

There are quite a few variations in Rocket transformers, but that's another story and another reason.

I suppose I see variations as variations to specifications.

Many people would see the Rocket as an AC-30 clone, upon building one I can see how the output transformers makes a big difference, as does Ken choice of B+, but is there anything else that would set the Rocket apart from an AC-30?

The problem the Rocket faces is there are vintage AC-30's as well as clones such as the Bad Cat 30, the Matchless DC-30, the Z Wreck to name a few.

Yeah, bad wording on my part. Same specs, different manufacturers is what I meant.


Ken wouldn't deny that the Rocket was AC30 inspired, in fact if you look at his original flyer advertising the new "Liverpool Rocket Amp" it, it says as much.

The different power supply (totem pole vs. radial) makes a big difference, as does layout. Transformer, obviously.

I don't think the Rocket faces any problem. There is no amp that beats it at its own game. Certainly not any of the ones you listed.

The Songwriter is a different variation on that theme. It has become my favorite of the bunch, but a well set up Rocket is superb. It doesn't sound like an AC30 to me, and I'm a certified vintage AC30 nut. I have owned many of them, still have the two best ones I've ever heard. Between those AC30s (they are quite different from one another) and the Rocket, I have never felt redundancy.

The Rocket looks simple and is forgiving to build, but to get it to sound like Ken wanted it to isn't easy. The OT is crucial, but the tubes even more so. That amp responds to tube selection like no other. And without vintage Vox Alnicos, it isn't a Rocket.

I very much wanted to built a Rocket version under the Komet brand, but Ken wouldn't have it. He called it obsolete, because without the tubes and speakers, it would never be a Rocket.


Hogy

[RJ Guitars]

Thanks Hogy and 2tone, it's really decent of you to share a bit of the history. Everything you've said jives right in line with what I've been told by other sources that I believe are reliable.