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

[Xplorer]

Hello ! hopw is everyone going ?
been a while !

marshalls are special ... for a month, i swear that one el34 didn't light anymore ... no color on the plates, nothing ...
then today for some reason it's alive again ! lol

[shakti]

I'm still around, just busy. Still tone hunting...looking at the guitar at this stage. Stay tuned.

And still of course anxious to try a 3 transistor West Coast fuzz...nudge nudge...

[daveweyer]

Yeah, I'm thinking about it. Just have too much work right now to get the time, but the FF units are sitting on the bench.
I'm working on some pics too. Found an old one of yours truly wearing a blown out speaker as a hat at the old work bench. It needs a little repair. Also found a couple of pics of the crew out back by the pool at the Laurel Canyon house where the recording of the Great Kazani was made. (the girls are naked, hope that's okay)

[Xplorer]

yes, it's okay, we'll deal with naked girls he he
that's great news !

you mean that the picture needs a little repair ? i can help if you need, it's one of my jobs.

[Froumy]

I am SO late to this party. (absent for ages) What a party!!!!

Just finished 63 pages, every word. Best read I've had in years.

Dave. Thank you so much for offering your experience, and stories(yes, I love the stories), to the community.

You made me want to play, again. That means a lot to me.

Sincere thanks. Think I'l dust off my JTM45, and see what happens. You have, indeed, affected at least a few of us. For me, that's what it's all about.

Thanks, again.

Bob

[Froumy]

"Billy Batz", Do you have any of your old 6550 BOG recordings available to post? They are all gone. You were damn close. Bravo. They we're my fav DIY BOG tones, for years. Dave is giving credibility to something you figured out on your own. I think they will compare favorably to the current,"informed" clips. If nothing else but for for forensics, I believe your unconventional ear figured out part of the puzzle years ago. The ear is as important as the knowledge. Your ear is impeccable, and I really wonder if Dave's input will get you closer than what you already have. I think he can help. Hope you can re-post.


Ohh.. Feel free to re-post that Hotel California solo, too. It was good. And i f the Walsh part wasn't on a tweed, I'm going to borrow a tele and see if I can piss you off for a moment. Always in good fun, of course.

Post your 8 year? old 6550 clips, pretty please. You may have, indeed exhausted the possibilities. As someone who naturally heard this, I'm really curious if Dave can push you up a notch, if you're interested.

No offense, shakti, xplorer, CTH, etc..(everyone who posted clips). You guys are totally kicking ass. Keep going. Dan got something when people were laughing at him. He may have a built in ear for the WC perspective. I''m very curious to hear if the WC perspective works for the right player. Fun to see who that guy is. you're all game.

[Xplorer]

yes please Dan, re post your clips, maybe a soundcloud or something, they were great !
Froumy, yes please, play something, mod some amps, and post it !

other than the superlead WC style, i'm thinking that a 45/100 modded this way could probably be a beast too, might try both at some point.

[daveweyer]

Froumy, Glad to have your input. Maybe we can get Bill fired up. I'm planning to add some more too, just have to get through some big jobs first.
Xplorer, the pics were Polaroid and they got some water damage. They're all checked like an old painting. I have to fiddle with a way to scan them--I noticed if I rubbed spit on them the checks disappeared for a minute--I might have to scan them wet.
I asked a photoshop guy if we could recreate missing detail, like the amps which were on the bench when the pic was taken. He told me it was a bit of a job, and we might have to photograph identical amps and insert their images.
Anyway, good to get some energy here.

[Xplorer]

i'm a pro photoshop guy too ..
you shouldn't use some amps from other pictures ! keep it fully original and just enhanced, repaired. i can do that if you like.
but adding bits from other pictures, this isn't authentic, not right for such work

[John_tucker66]

Double post

[John_tucker66]

Ok, this my first post... I'm a huge jimi fanatic as it seems most on here are as well. My hat goes off to you guys for putting this kind of time and effort into modding your amps and fuzzes, I applaud you Xplorer, Tazin, Bill Bokey, Tone seeker, shakti, frenchie... And to all the ones I can't remember right now.

Dave, this is such valuable information that you have shared with us. I've been studying this thread as well as the hendrix fuzz and 6550 thread on metro too and I just have to say, WOW! This is awesome and I thank you sincerely. It's all starting to make sense now. Woodstock, BOG, Isle of Wight, totally 6550 marshall tone to my ears. Also listening back to some stuff off of the recent People, Hell and Angels album, "somewhere", "bleeding heart", "izabella" and many others on the album sound so much like a cranked 6550 marshall. Possibly the governor?? I'm not sure but I am pretty sure that those songs are not a fuzz face with guitar volume rolled back. I've been doing some experimenting and there's something so pure about the tone on that posthumous album that screams 6550 marshall, especially "bleeding heart". It also seems very apparent on the recent album First Rays of the New Rising Sun. Songs like "in from the storm" and "hey baby (new rising sun)". Although the former has been worked out a lot more in the studio, I feel that the 6550 tone is there.

Anyways, it seems that I have blown my pt on my 72 super lead. And in the process of that my power tubes could probably stand to be replaced as well, so I think I'm gonna try my take on the west coast hendrix marshall. I'll do the filter caps since they're original too. So I've found a pt from classic tone that is a 45/100 replica, complete with 560v b+ tap!! I'll probly be getting that. They also have an output trans for the 45/100 that has 4k primary. I'm tempted to get that as well because I'll be buyin a set of 6550's to bias up and I don't really want to mess too much with mismatch impedances to try to get in a good ballpark.

Dave, out of the repro dynaco a431, and the classic tone 45/100 ot, which should I go with? The classic tone is 4k primary, and the dynaco is 4.3k.

[daveweyer]

The 431 has a better frequency response. This means more deep bass (way deep) subharmonic stuff, and extended HF.
Probably get more distortion from the clone.
You'll be safe with either, I only mentioned the 431 because I made some real nice mods with it. If you have high B+ it gives the tubes a little room to breath, but 4K is right in the ballpark.
Got a little extra money? Get 'em both and compare. Now that would be great fun for everybody.

[John_tucker66]

Alright, the transformers, filter caps, 6550's and a few resistors for trying the 12at7 PI stuff has been ordered. I went with the dynaco OT, and the classic tone 45/100 PT (560v B+). I may try other transformers in the future but I felt like this is a good place to start. There are a lot of good tranformers out there to experiment with. The good news is I won't be playing a whole lot in full square wave clipping, so my PT regulation won't have to be as good as what Dave usually screened for. Also the 6550's are tung sol ri, and 50uf/50uf filter caps. I almost feel wrong for modding the '72 this way but since the PT blew, the timing is right. And what stands to be gained is a lot more than one amp, as these topics have made me learn a lot just to keep up with what the big picture is of these amps. I'm really diggin this stuff, so much so that I'm gonna change my super lead into a fire breather, if it wasn't already haha.

Another big reason for me wanting to do this is all the clips that have been posted of your guys modded amps. These tones are astoundingly close the the band of gypsys stuff. C J H's iphone recordings of machine gun, whoa...

Dave, I'm not a very experienced ampsmith, although I am learning, how would I know what my actual impedance is coming off of my OT secondaries? Say, 560v B+, 4.3k OT primary like you've mentioned in some mods. There are some posts of mismatching impedances (head/cab) to get a higher primary impedance for 6550's at that voltage. At the specs I mentioned above, am I ok to trust my impedance selector on the back of my amp to deliver the correct impedance?? Or close enough anyways? I'm just trying to gain a more big picture amp knowledge as I'll have the help of a very experienced tech, but I don't just want him to do it for me. The next step after this would be to build a '68 clone...

[daveweyer]

John, a pair of 6550s running at your plate voltage will have a nominal P-P impedance of nearly 5000 ohms. Four tubes will cut that in half. So you will have a situation in which you can run an 8 ohm cabinet on the 16 ohm tap to get the maximum power out of the tubes. But you don't need to do that, the tubes will run cooler if you just use the 8 ohm to 8 ohm arrangement, and they will still put out 100 watts no problem.
When you say you have 560 volts on the plates you probably mean at idle, most capacitor input power supplies will deliver only about .707 of that at full load, but it also depends on the regulation of the power transformer.
To accurately figure the load impedance you need to use the full load voltage, most likely around 400 to 450 volts. This lowers the P-P load to about 3000 ohms, or 1500 ohms for four tubes. In this case, using the 16 ohm tap for an 8 ohm cabinet will be fine. Just switch the impedance selector to see which sound you like the best, no rules here but hearing the result.

[daveweyer]

Okay my Marshall amp friends, I have a chance to work on what appears to be a West Coast modified 1966 or 1967 Marshall Major. From what I remember, the 1966 had dual rectifier bridges, 39K plate resistors on the driver tube, and V1 shared cathode. From what I can see the amp in question has V1 shared cathode, but 47 K plate resistors on the driver, and a single Motorola bridge.
The Tolex is purple, but I am curious if it has been replaced. Did Marshall use gold piping around the front plate, and was it a larger size? Was the cabinet all made of pine on these?
Was the Tolex job real good on these or where there rough edges, like on the inside of the vent curves and so on. Was the Tolex cut with a serrated shears?
The serial is 03379 but it seems to have elements of both the 1966 and 1967. It's a plexi of course.

If it works out, I may have chance to show the forum a still intact "Big Boy" mod from West Coast Organ and Amp, like the one I call "The Governor". I know we've been all through the Governor story and mine is different, so we don't have to rehash all that.
Anyway, this is probably the most untouched original West Coast Organ and Amp modded Marshall I have seen in years, and it would be the identical mod I did for Jimi.
I'm hoping the owner will consent to a real thorough going-over and exposition on the forum.
I don't know how many purple Tolex Majors they made though, and the likelihood of this being a genuine original.

So, any helpful hints or tips?