Jimi Hendrix' Gear and Mods at West Coast Organ and Amp

[daveweyer]

Wow, it's been a while since I checked in. I thought everyone had gathered all they needed from these pages.
But to the fuzz issue, the Woodstock pedal may well have been one of the three transistor fuzz circuits. Listening to the recent examples that have been constructed for folks like the Brothers Beckham, Julijan Eric, and Xplorer, seems to make the case for the circuit being used at Woodstock and beyond.

Listen to their use of the pedal in their performances, and tell me if you don't think they have it nailed.

[yladrd61]

Hello Dave and Friends of Jimi,

I just wanted you to know that Nik at Ceriatone has created his interpretation of the West Coast Mod Super Lead Amps that you built for Jimi. I ordered a complete head, less tubes. I can't wait to try it out.


https://ceriatone.com/british-style-west-coast-mod-100/

https://youtu.be/5wKxpZszPeU?si=Mf393K0P1KQE0PlN

[Tek465b]

Hi, though id come in and say hello.
As some probably noticed i was away for quite a long time.

My hearing problem(meniere) really got bad, and i also had(and still do to a lesser extent) have very intense back pain from my pelvic bone that was crushed/broken in 2 along with my femur which didnt heal in the correct position when i was 15 in a car/atv accident.

Also, as this wasnt enough apparently, my dad who have COPD now has cancer since 2022, so far its stable, he dont have to do chemo or intensive stuff as it was catched early. Keeping finger crossed it heal or dont increase in size. The COPD did get worsen and honestly some day are fucking rough.

I also had people break-in my place to steal my tools, damage my property and my 1980 z28 camaro, as i was am in a bad place in life i was low on money and did not have an insurance so its a total loss for me.

We know who they are but obviously police wont do anything because we dont have(direct proof), they even did a false police claim to get my dad arrested(it got removed by judge so we didnt have to do to court), but still a very bad time made worst by a bunch of fucking lame loser.
Once my dad die i wont be able to afford living(hate to say it but am kinda disabled by health problems and there is just no help also only strong drugs keep me going and it suck honestly) so nothing really matter anymore anyway.

Anyway, am starting to feel a bit better latelly(but i have those weird bump appearing on my body, i hope its not cancer, ffs), am not playing guitar anymore but i did get into synthesizer .

I posted the code for the CTP on the CTP section and my website along with the PCB gerber files and Kicad project files, ill try to help with the other stuff if i can.

Am sorry for everyone, i didnt want to just abandon people on here, it was just too hard/impossible for me to do anything. Anyway now am here(for how long, i dont know), once again.

Thanks,
Math

[Xplorer]

Oh my god !!! So sorry to hear this Tek, but glad you're alive ....
Wishing you and your dad hope for better days and healing, solutions, new life ...
And thank you for coming saying hello and sharing some news.

Be well, and may these thiefs face karma .... While you'll recover what you can.

[Roe]

any comment on Tony Frank at Unicord modding marshalls w 6550s etc?!

[Xplorer]

any comment on Tony Frank at Unicord modding marshalls w 6550s etc?!

Hello Roe, it sounds interesting. Maybe you're referring to this page ?
https://www.lespaulforum.com/index.php? ... nk.109458/

And maybe this ?
https://faroutmagazine.co.uk/first-led- ... stack-amp/

Although, i can see West Coast stickers all over Jimi's amps, even Page's amp, and this Jimi amp in switzerland featuring a remaining 6550 ( later put back to EL34 ) .

http://www.vintageunivox.com/history.html

"Unicord designed transformers were used in the imported Marshall amps, because the company didn't think the Marshall transformers could handle the full 100 watts from the 6550 tubes (British Marshalls at the time used KT-88s which were lower wattage). Marshall of England eventually adopted Unicord's transformer design."

When were the first KT-88 Marshalls ?

[Xplorer]

any comment on Tony Frank at Unicord modding marshalls w 6550s etc?!

Hi again Roe, here's what Dave transmitted to me, to copy and paste :

I can’t comment on the forum anymore, it always tells me the server has crashed.

I can tell you this much, I wrote to Jim Marshall advising him to switch to 6550s on his bigger amps, because I was having very good luck with them in holding down output tube failures. His reply was polite, 'but 6550s were too expensive, and they had to be shipped,' making the whole idea a non-starter. Apparently their importer had other plans, because the bass amps started showing up with 6550a, and they weren’t dual volume control amps.

If Unicord decided to use different transformers it was only because they were cheaper, they may have used Woodward Schumacher transformers or likely found a Japanese winder, because I remember seeing the plating material on the bells and noting its similarity to other Asian units. I don’t remember 606 codes on the bells either, but correct me if I am wrong.

English Marshall transformers could handle the 6550 power just fine, so that argument is bogus, remember the article that Xplorer posted showing one of my modified Marshalls which belonged to Jimi putting out 129 watts at Marshall labs? It wasn’t the transformers that couldn’t handle the power, it was the tubes. But we’ve been through all this before.

And if Tony Franks did something to help or improve Marshalls, then wonderful, the story gets wider and deeper. Better get it all or as much as you can, before us old guys check out for good!

[Roe]

any comment on Tony Frank at Unicord modding marshalls w 6550s etc?!

Hi again Roe, here's what Dave transmitted to me, to copy and paste :

I can’t comment on the forum anymore, it always tells me the server has crashed.

I can tell you this much, I wrote to Jim Marshall advising him to switch to 6550s on his bigger amps, because I was having very good luck with them in holding down output tube failures. His reply was polite, 'but 6550s were too expensive, and they had to be shipped,' making the whole idea a non-starter. Apparently their importer had other plans, because the bass amps started showing up with 6550a, and they weren’t dual volume control amps.

If Unicord decided to use different transformers it was only because they were cheaper, they may have used Woodward Schumacher transformers or likely found a Japanese winder, because I remember seeing the plating material on the bells and noting its similarity to other Asian units. I don’t remember 606 codes on the bells either, but correct me if I am wrong.

English Marshall transformers could handle the 6550 power just fine, so that argument is bogus, remember the article that Xplorer posted showing one of my modified Marshalls which belonged to Jimi putting out 129 watts at Marshall labs? It wasn’t the transformers that couldn’t handle the power, it was the tubes. But we’ve been through all this before.

And if Tony Franks did something to help or improve Marshalls, then wonderful, the story gets wider and deeper. Better get it all or as much as you can, before us old guys check out for good!

Xplorer - thanks so much! this makes sense. One source claims that Unicord had a local winder named Otto that did - or repaired - some transformers (improving isolation on majors notably).

Still, the transformers are somewhat elusive here. First, the standard 1.75k primary seems too low for real high voltages. Second, after the 1204-43 dissappeared the power transformers had lower voltages. So were the transformeres modified or did exceptional ones get hand-picked?

[Xplorer]

Xplorer - thanks so much! this makes sense. One source claims that Unicord had a local winder named Otto that did - or repaired - some transformers (improving isolation on majors notably).

Still, the transformers are somewhat elusive here. First, the standard 1.75k primary seems too low for real high voltages. Second, after the 1204-43 dissappeared the power transformers had lower voltages. So were the transformeres modified or did exceptional ones get hand-picked?

Hi Roe, here's Dave's reply to your question :

"If it helps anyone on the forum to understand, the 1.7K impedance on the OT primary coils was a result of radically lowering the B+ voltage on the amps, in order to address the problem of output tube failure. A quick look at the characteristics of either EL34 tubes or 6550 tubes shows that at 450 plate volts, a 1.7K primary impedance is just right for 100 watts output, although lower screen voltage is recommended for reliability, something Marshall ignored. There was no magic invention in lowering the screen voltage, it had been in the tube manual since the beginning. Even using 6550s was a no-brainer, it was so obvious as to be silly.
Bob Hovland and I started using 6550 tubes in the 1950s, right after the first Tung Sols showed up at Electronic Supply Company, and by the mid 60s had pretty well learned how to use them effectively in many applications.
As much as I might wish I could say I invented something by using 6550s in Jimi’s Marshall amps, I can’t. It was a completely obvious conclusion to draw from the existing situation. Jimi asked, “Can you do something to keep my amps from blowing up on stage?” I said yes, and that’s what I did. That they got louder, and the tone changed was part of the bargain, and that it only took 2-6550s to get 100 watts was part of the bargain too. As I explained to 6CA7, once the output tubes were stabilized, I could go back to higher B+ voltages and get an even different tone, and more power as well, all without jeopardizing the output tubes' reliability..
If someone else decided to do this too, it seems only logical. If someone said that they did this and not West Coast, I would have to take issue with that statement.
We have been over and over this subject for at least ten years on the forum, and I have fielded every possible question and answered every possible doubt, with stories and pictures and offerings from many forum posters, and I did not get off lightly either! It was probably Xplorer who asked the first sensible question!"

Much cheers