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

His guitar slung across his back, his dusty boots is his cadillac.

Moderators: VelvetGeorge, BUG

daveweyer
Senior Member
Posts: 654
Joined: Wed Oct 29, 2014 9:36 pm
Just the numbers in order: 13492

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

Post by daveweyer » Fri May 10, 2019 9:47 pm

Hi all, just a few catch up items.
We have talked endlessly about the tubes in Jimi's amps, and damn near shut down the forum over the disagreements, but with the photos of a genuine Woodstock Jimi amp sporting West Coast installed 6550s, the argument sort of died down. You know I tried to get beam power tubes in Jimi's amps for several reasons; reliability, loudness, and tone. The tone seems to be the only thing important left, because it is on so many recordings, and no one plays that loud any more anyway.
But you might like to hear it from the source, The Radiotron Designers Handbook 4th edition.
" Beam Power Valves: The second class includes such types as 6L6, 807, and KT66 which differ from pentodes principally in having sharper 'knees' to their plate characteristics, more second harmonic but less third harmonic distortion.....At lower load resistance the second harmonic rises, the third harmonic decreases steadily, and all higher harmonics are negligible....."
So there you have it, one part of the case for beam power tubes versus types like the EL34, which is a pure pentode.
And also a hint about mismatching the OT to the tubes. Everything changes in hard clipping, but that's where it starts.

Now it seems to me we should congratulate ourselves on reaching 100 pages on this topic, we now have a book about Jimi's equipment and West Coast meddling in it. We are also pushing 100,000 views, not the Kardashians, but not too bad for a little amp forum dedicated to unearthing every bit of information about Jimi and his sound. This is about the number of views those little teenage girls get on their porn videos made in their bedrooms. We should be happy to be that popular.

Now, on to the Guild Thunderbass. To be historically significant it has to be a "Quantum Bass", which is different from the others in its use of the 8417 beam power tube, and a regulated screen supply using a small tube whose cathode is connected to the output screens. Tone Seeker says his Quantum bass is junk, and I have to admit, they are kinda cheaply made. You can make them sound good though, just like a Silvertone amp.

Welcome the new members to the forum. Make yourself at home and ask questions.

poppyc
New Member
Posts: 2
Joined: Wed May 08, 2019 8:05 pm
Just the numbers in order: 13492

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

Post by poppyc » Sun May 19, 2019 12:15 am

Does anyone have information on the Thunderbass head mounting bracket for a Quantum Cab. I'm looking to find one, or fabricate one.

T-Bond
New Member
Posts: 3
Joined: Mon May 20, 2019 3:50 pm
Just the numbers in order: 13492

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

Post by T-Bond » Mon May 20, 2019 11:30 pm

I just found and joined this forum today.

WOW!! I cannot believe that the man that setup Jimi Hendrix's amps and effects is sharing all of this incredible knowledge and history. Thank you Dave Weyer! What a treat. I have been reading this forum on and off all day, amazing! I started playing guitar in 1969 at 13 and my dad bought me a Stratocaster that year because I ate, slept and breathed everything Jimi Hendrix.

I am an average player on and off for the last 50 years and still play Strat's I have a question for the group: I'm looking to get an original 1960's Marshall head and probably one cabinet. I just bought a 1967 Clyde wah with a serial number just over #200 and am looking for a nice original Univibe and FF. What Plexi 100w head would you guys recommend? I just love the Hendrix sound from beginning to end especially the live stuff, Montery, Woodstock and Band of Gypsies. Thanks for any advice!

Terry Good
Last edited by T-Bond on Sat May 25, 2019 11:57 pm, edited 1 time in total.

daveweyer
Senior Member
Posts: 654
Joined: Wed Oct 29, 2014 9:36 pm
Just the numbers in order: 13492

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

Post by daveweyer » Wed May 22, 2019 12:56 pm

Welcome to the forum! Always nice to have another member. Naturally I recommend a model 1959 with all the West Coast mods (I say ever so modestly, hahahaha), but 45/100s are real popular here too.
We best get Explorer and Bill Bokey to chime in, because they have built these mods and amps. Plus there are resident experts on the gear here who come out of the woodwork every once in a while to offer us some sage advice.
Lot of folks have tried lots of combinations if they are willing to share their results.

T-Bond
New Member
Posts: 3
Joined: Mon May 20, 2019 3:50 pm
Just the numbers in order: 13492

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

Post by T-Bond » Sat May 25, 2019 11:56 pm

Thanks for the welcome Dave,
Just bought a Mint 1967 JTM 100 Black Flag and a nice all original 67 cabinet. Would love to find a real nice original 1959 with West Coast mods for sale. Reading the technical discussions here is way over my head as my electronics experience is limited to building science fair projects for school in 1970 that never worked. Looking forward to learning on this forum.

Guitar514
New Member
Posts: 2
Joined: Tue Jun 25, 2019 8:46 pm
Just the numbers in order: 13492
Location: Montreal

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

Post by Guitar514 » Tue Jun 25, 2019 9:28 pm

Hi

Where can i get the west coast mod made.. ? Ive got an old 68 Marshall, that's not in a collectable shape that is readt for them. Ive browsed this thread for 3 hours.. but i wish there was a shorcut For schematics. Im in canada.

Thanks To all.who contributed To this. Really awesome.

Phil

revolver1
Senior Member
Posts: 454
Joined: Thu Jul 28, 2011 1:37 am
Just the numbers in order: 7

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

Post by revolver1 » Sat Jul 27, 2019 4:46 am

Hi Guitar514. Welcome to the forum. This is only my opinion so please take it as such but if I had an original 68 plexi I wouldn't mod it. Even if it's in bad shape as you say, parts can be sourced and it can and should be restored. You are lucky to have a real gem, a piece of history it's an awesome amp.

The amp could be converted if your dead set on it nothings impossible. The actual circuits are not dissimilar from 68 to 69 but there are differences between the 68 and 69 models like laydown power transformer vs stand up PT, also Output Transformer orientation and the 68 has the big filter capacitors inside the chassis where the 69 has them mounted on top of the chassis. So it's never going to be totally right for the purpose.

The other thing that is a big part of the mod is having a high B+ voltage that is provided by the power transformer. That stock 68 P.T wont deliver the necessary voltage and replacing an original transformer like that would be a crime punishable by firing squad. One of the great things about the 68 is the way it collapses as in power supply sag, embrace it, it rocks!

If it were me I'd restore the 68 to its former glory. Theres plenty of info here and visual records on amp archives. If its something you don't think you could do yourself look for a good amp tech and have a chat. Most decent guitar shops will either have an in house guy or be able to put you in touch with someone, failing that do a Google search for someone in your area. Just make sure the guy is familiar and has a love of vintage Marshall's. There are alot of talented techs out there who grew up on Marshall circuits so it shouldn't be too hard to locate someone but if you talk to someone who dosent have any hands on experience or love for the amp I'd pass .

That being said I get it you want a West Coast amp, who dosent??? :lol:

Apparently Dave Weyer has been involved in discussions regarding a production West Coast mod amp with a few different parties so that may be an option in the future.

Alternatively you could look for a second hand Marshall H.W 1959SLP. George did a great thread in the 100w section about tweaking the amp to get is sounding good. You could use it as a base and mod from there.

You do see metro builds come up for sale from time to time, that would be a good candidate for the purpose. Generally if it's not loaded with NOS parts you'll get it for close to cost.

But the best option is to build it from scratch. You will learn loads and the process really is alot of fun but be warned it's highly addictive.
All the info you need is on this site, lay outs, diagrams, bill of materials, instructions it's all on the index page down the bottom. Infact down load the 69 instructions and give it a look over and you'll see how doable it is. Just dig in and read up and theres always tech help here if your unsure about something or need help.

If you haven't already, read up on the 6550 experience thred. On there you can read about the different approaches guys took to the mods and there are loads of great sound clips to demonstrate the mods.

Like I said it's only my opinion but save the 68 it's a peice of history and build your self a West Coast Superlead or fingers crossed wait for the production model to come out. :thumbsup:

If you don't want to restore the 68 then sell it to some one who does. Shouldn't be hard to find a buyer. For what you get for it you should be able to build an amp and still have some change in your pocket which you could promptly blow on some NOS preamp tubes. 8)

daveweyer
Senior Member
Posts: 654
Joined: Wed Oct 29, 2014 9:36 pm
Just the numbers in order: 13492

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

Post by daveweyer » Mon Sep 09, 2019 12:17 am

Looks like the forum went dead this summer. Just passing on the address of the Hendrix Foundation's new website. I have just finished the reproduction of Jimi's 6420 Supro amplifier for the Foundation, and they are planning to offer this amp to a few collectors. I'll try to get some pics up here so you all can see the prototype.
Anyway, check out the Hendrix Foundation website. More is being added each day.

www.jimihendrixfoundation.com

Mike C amps
New Member
Posts: 2
Joined: Fri Sep 13, 2019 1:50 am
Just the numbers in order: 13492

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

Post by Mike C amps » Fri Sep 13, 2019 3:41 am

Hello Dave Weyer,
I just joined the forum tonight. I have been reading through and I'm about 30 pages in so far. You present some interesting information both electronically and on the human level......and the human element really makes it an puts things into perspective in the big picture. I do appreciate the notation that in the heat of the moment that Jimi Hendrix was a client and not a living icon god, that he transformed in to after death at 27 years old.....considering he had around 10 years in playing guitar sort of at the professional level. I think that kind of gets lost in translation a lot of the time where the impression may be that he was a middle age man with years of experience in before he passed away. But to keep that in perspective, I'm not in anyway saying he was green behind the ears as he did his time and paid his dues with diligence and dedication. Personally I'm 57 years old and I know you have a few years on me....., so its kind of like that posture in life when looking at a 27 year old with all the considerations applied....when pondering Hendrix as a human being and a guitar player. I suppose it was interesting in that window of time to be hanging out and interacting since you would all be in the same age range....and a product of those times.....and reality.
But anyway getting passed philosophy.....and being 30 pages in as I read here at my leisure.....You discuss the 6550 tubes in the power section, but I have yet to read and find what pre-amp tubes you were putting in the amps in that era. Usual lore has Marshalls being equipped with Mullard 12ax7's. DId you consistently use or recyle known good 12ax7 mullards or did you use what you may have had on hand relative to USA domestic tube of the era or what you could grab locally in the neighborhood from electronic supply houses.....and the brands they carried. You mentioned the Tungsol 6550's within the first 30 pages, and another forum member uses GE brand 6550's. But in those first 30 pages so far there is not much reference as to the preamp tubes as a flavor enhancer in the grand recipe of the sonics you were dabbling with in conjunction to dealing with "tuning" Hendrix equipment. I think recipe is a good term to use in these matters. My background is that I also do electronics service and amplifier service as I grew up in a family business.....My father was an RCA dealer. I don't have the HAM background as you do though, but I was involved in CB radio when it was a trendy fad in my teenage years though it wasn't with building or servicing the transceivers......I got turned on to broadcasting by a HAM guy that lived across the alley from my dad's building. His HAM shack was more of a bunker hahahaha, but his front porch was the neighborhood gathering place to socialize in the mayberry perspective of my home town where I grew up. Then came the sunspots and my interests evolved to other things.....and little did I know that later in life I'd be involved with vacuum tube technology.....I didn't start playing guitar till just after high school......and that's where the quest started in my world. We did our own service for TV and audio...so I span vacuum tube era through to early solid state......and all my mentors are now passed away considering time and the time line of technology. SO its good that you are getting this information out there before its gone...the tricks of the trade that you don't get out of the tube manuals when examining the circuits presented in them in the back pages or in the other electronic literature of the era....perhaps other than 1950's and 1960's popular electronics magazine articles if you can find an archive. I do appreciate the aspect of longevity and reliability in the posture coming from the platform of servicing electronics.....but in the practical world outside the shop with the amplifier heads riding on top of the speaker cabinets and being subject to the extremes relevant to the vibrations......and vibration being the nemesis of tubes shaking the living daylights out of the guts …...That's part of my inquiry as to what did you use for the pre-amp tubes as I would assume that they were putting up with hazardous duty in combat and really critical since the whole thing is based on driving the preamp section with the solid state boosts in front of the pre-amp tubes/pre-amp section.....aside from their voltages and the influence on their plate voltages....since all 12ax7's have their own tonal flavor and response character when factors are considered in the BIG recipe. As I was reading in to get to page 30.....the member discussions have been concentrated on the solid state boosting end of the sonic pathway. What I could say being only 30 pages in at this point is, what you were doing in boosting the signal was what the KLON pedal was doing so many years later to push the front end of an amplifier.....via IC's as opposed to early solid state transistors. Which would bring up this question......were you using the solid state devices (transistors) based on the data sheets since this was the evolving technology of that window in time.....or were you also giving considerations to the musicality and tonality of the items you chose to use. Personally I cringe when I see a TL 072 IC chip being used in a sold state circuit in late model guitar amps and pedals as I find them to be too clinically sterile where as other chips within that same family can be more musical in response and toneful in the circuit at the practical level...when it comes to tuning sonically...the ears......but then again I come from the guitar player angle in the big picture. There are those subtle intrinsic things that can't be quantified in the mathematics and the data sheets that may be unorthodox on that engineering end beating it with a slide rule....where a field guy would have the insight to make the modifications. Coming from the RCA background, one of the dirty little secrets was that RCA rebranded Mullard 12ax7's for critical audio circuitry.....despite the legends of the black plates and the grey plates. I'm sure I'll be amused as I get passed 30 pages to catch up …..and a re-read at some point....the student in me. SO I don't know if ou have addressed my questions previously in the past postings....but if you'd refresh here in the present.....I'm sure it will be appreciated, not just by me.

Thanks

PS, our RCA dealership ceased when my dad retired way back. I did not take it over as I was in college going in a different direction.....little did I know. But there is a consideration of the times...our location was in the suburbs of Pittsburgh and steel was in decline and the economy here was suffering as a result.....till Reaganomics permitted the corporate raiders to sack the country......Pittsburgh used to be the third corporate city in the country behind NYC and Chicago and now we aren't even on the radar.....before the next trend of off shoring took place

Mike C amps
New Member
Posts: 2
Joined: Fri Sep 13, 2019 1:50 am
Just the numbers in order: 13492

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

Post by Mike C amps » Fri Sep 13, 2019 5:30 am

One more question Dave,
Being new on the forum here....
Relative to a Marshall with the trem circuitry and thus an extra pre-amp tube, and with the premise that gain & sustain was the mission, why didn't you convert the trem heads to using the extra tube as another gain stage for the pre-amp much the same way as the JCM800 series evolved with adding a singular gain stage in front of the classic pre-amp and cathode follower......or better yet as the Laney approach with using both halves of the 12ax7 as a gain stage relative to the signal inversion that happens as it passes through a tube gain stage......dancing around trying not to say the term phase/polarity (which ever term you'd use to apply to the subject). I noticed that some of the members had an aversion to the trem heads as opposed to a standard non trem head......regardless if the gut components are the same signal caps and transformers. My experience would lean on the amp with trem but converted to the extra gain as being a real sleeper hidden in plain sight.....two extra knobs on the front control panel to adjust the extra gain stage and the factory extra tube....who'd know its not for the trem function. Much the same way that the pedestrian Fuzz Face sitting on stage might not be pedestrian.....hiding the big block or a hemi under the hood.
Which I guess I should present another question/inquiry.....about the Fuzz Face units you did in that window in time. Since the Fuzz Face was extremely similar to a 2 transistor Tone Bender......and in the 30 pages I have read in to so far where you mention going to 3 transistors.....which the Tone Bender pedals also went, Did your evolution of the Fuzz Face modifications ever go to using clipping diodes in the mix of things to introduce...for lack of a better descriptive term, artificial clipping of a soft variety in the boosting of clean gain to get the result of sustain......other than gaining up the transistor to induce clipping.....with regard to the premise the fuzz control was held to be between zero and 2 on the dial or not much beyond that. And that's with respect to the members that speculate the Fuzz Face Fuzz control was turned up wide open. In my studying of early fuzz/distortion pedals that are transistor based, only a very few use the clipping diodes on a transistor gain stage, where as most modern era IC based solid state fuzz/distortion pedals use the clipping diodes whether it be in a symmetrical or asymmetrical fashion. Which I guess I should bring up....were you thinking wave form symmetry or asymmetry in the formula for the signal boosting in the quest for sustain.

In what I do, being very similar to what you did in the era.....I often use the phrase of being a sound tailor when I work with clients as an analogy of buying a man's suit off the rack in a men's store and having it tailored to you. I'm fortunate to have a client/friend that's a natural talent on guitar and playing blues based stuff.....A young guy that's around 30 but started on guitar at around 10 years old.....just a born natural talent......I describe him as a cross between Hendrix and Beck if they had a child. But he had never played an amp that got feedback and sustain due to gain and being tuned.....when I was introduced to rehab some of his stage amplifiers. So when I got done and it was presentation time and to have him play the reconditioned amplifier with my tweaks......he was like a kid in a candy store......he couldn't believe the sound......he kept saying that he could only get what was happening by using pedals before......and he's just plugged in straight to the amp in this moment. And now after the fact with his effects gear added in....its just insane. I can imagine you there when Hendrix plugged in after you finished your work. Myself as a player and in process of tuning an amp I'm doing for a client......I tend to find it intoxicating to play the unit and not want to stop or even give it back hahahaha, but it is very rewarding to make the presentation and see the reactions when they fire up the beast for the first time after being revived...and healed

User avatar
plexified
Senior Member
Posts: 849
Joined: Sun Dec 25, 2005 12:49 pm
Just the numbers in order: 13492
Location: amidst the wreckage of a hot Plexi

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

Post by plexified » Tue Oct 08, 2019 2:38 pm

That's Amazing News Dave. The new site is beautiful and the West Coast project is eagerly awaited.

Thank You my friend!

Roe
Senior Member
Posts: 5042
Joined: Thu Apr 13, 2006 1:36 pm
Just the numbers in order: 7
Location: Drontheim. Norwegen
Contact:

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

Post by Roe » Wed Oct 23, 2019 4:32 am

good news! keep up the good work
http://www.myspace.com/20bonesband" onclick="window.open(this.href);return false;
http://www.myspace.com/prostitutes" onclick="window.open(this.href);return false;
Super 100 amps: 1202-119 & 1202-84
JTM45 RS OT JTM50 JMP50 1959/2203/34/39

daveweyer
Senior Member
Posts: 654
Joined: Wed Oct 29, 2014 9:36 pm
Just the numbers in order: 13492

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

Post by daveweyer » Fri Nov 01, 2019 6:14 pm

This forum has gone into coma! Hard to believe there is nothing to talk about anymore.
The Hendrix Foundation keeps growing and adding new material; one day I'll do a feature on those forum stalwarts who took the time and trouble to do West Coast mods on their amps, and then if possible post clips of Hendrix' tone on the website, and maybe link people up to sound and video files. This forum seems like a wonderful archive of Jimi related material.

User avatar
Xplorer
Senior Member
Posts: 2460
Joined: Sun Apr 19, 2009 5:27 pm
Just the numbers in order: 7

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

Post by Xplorer » Fri Nov 01, 2019 6:38 pm

daveweyer wrote:
Fri Nov 01, 2019 6:14 pm
This forum has gone into coma! Hard to believe there is nothing to talk about anymore.
The Hendrix Foundation keeps growing and adding new material; one day I'll do a feature on those forum stalwarts who took the time and trouble to do West Coast mods on their amps, and then if possible post clips of Hendrix' tone on the website, and maybe link people up to sound and video files. This forum seems like a wonderful archive of Jimi related material.
yes please do !
will post other clips another time. Don't know about the others, on my side i'm just focused on some difficult prioritys that take all my time. But please don't give up on the forum ! Be patient.

Thanks Dave

shakti
Senior Member
Posts: 2049
Joined: Tue Apr 05, 2005 9:06 am
Just the numbers in order: 7
Location: Ramnes, Norway

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

Post by shakti » Sat Nov 02, 2019 1:40 pm

True, the forum is in a bit of a slump. It's never quite been the same after Metroamp stopped doing kits, but now it is downright comatose. I'm guilty of not contributing much currently, but that's probably because I am currently deep into Hiwatt territory. I still love my West Coast amp and fuzz.
JTM45 RS OT, 1973 18W, JTM45/100, JTM50, JMP50 1986, JMP100 "West Coast", AC15, AC30, BF Super Reverb, Boogie Mk 1, Hiwatt CP103, DR103

Post Reply