Which to Build for JMH - The Dilemma

[Tone Slinger]

All the posts here are chock full of great info's/scenario's. Here is what I say concerning specific examples;

Woodstock- Sounds like a stock 1969 super leads. Sounded 'unmodded', must have been bought new at Manny's for that 'special gig'. Sounded like El-34's.

Baggy's/Filmore (Band Of Gypsies)- After having listened to and changed my mind many times, I'm under the belief that Hendrix either used a shared cathode type amp (45/100 ?), or, Eddie Kramer's recording/engineering on those recordings (he did Baggy's rehearsals and the Filmore shows) imparted its 'unique' chaerector, with the amps being Super leads. Remember the big, fat sound he helped Kiss achieve on ALIVE! ? Those were '73-'74 era 6550 equipped Super Leads with the high B+ (mucho headroom).

LA Forum '70/Rainbow Bridge '70- these gigs sound like Hendrix's main gigging super leads with 6550 tubes to me. Basically '68-'69 era that had been converted to 6550's in early '69. It was also said that the speakers were 70 watt types that were used in the Vox 'Super Beatle' amps. The fuzz faces also started sounding quite different by the spring '70 tour (sillicone transistor circuit).

[Lefty Lou]

All the posts here are chock full of great info's/scenario's. Here is what I say concerning specific examples;

Woodstock- Sounds like a stock 1969 super leads. Sounded 'unmodded', must have been bought new at Manny's for that 'special gig'. Sounded like El-34's.

Baggy's/Filmore (Band Of Gypsies)- After having listened to and changed my mind many times, I'm under the belief that Hendrix either used a shared cathode type amp (45/100 ?), or, Eddie Kramer's recording/engineering on those recordings (he did Baggy's rehearsals and the Filmore shows) imparted its 'unique' chaerector, with the amps being Super leads. Remember the big, fat sound he helped Kiss achieve on ALIVE! ? Those were '73-'74 era 6550 equipped Super Leads with the high B+ (mucho headroom).

LA Forum '70/Rainbow Bridge '70- these gigs sound like Hendrix's main gigging super leads with 6550 tubes to me. Basically '68-'69 era that had been converted to 6550's in early '69. It was also said that the speakers were 70 watt types that were used in the Vox 'Super Beatle' amps. The fuzz faces also started sounding quite different by the spring '70 tour (sillicone transistor circuit).

Go to this link page, and read the middle paragraph on page 33:
http://www.nxtbook.com/nxtbooks/newbay/ ... startid=33" onclick="window.open(this.href);return false;

6550's in this case require a 69' SL (or SB) OT to function accordingly. The preamp circuitry appeared to be shared cathode ala the carry over JTM45/100 era amp into the new JMP 100 era, and a PT that supplies B+ of over 500 volts give the headroom and the volume that Hendrix craved by this time after blowing up many previous heads. Next question, is the Vox 70 watt speaker a precursor to the Celestion 70 watt speaker as used in 80's marshall cabinets?

[Lefty Lou]

bmcash, if you desire speakers that are close to Jimi's BOG performances, Scumback has this for you:


H55-PVC
50oz H (heavy weight ceramic magnet), 55hz bass response, 12 inch special design aged cone, small dust cap with vintage correct doping, spider, and voice coil tolerances. A close recreation of the early Kraft paper voice coils used until late 1967. This speaker's tone is woodier, with more upper mids than the H55, but less treble and more bass than the BlackBack BH55 models. Basically it's tone sits between those two models.

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[Xplorer]

i'd definitely recommend the real pre rolas G12H30 75hz 16 ohms for bog. the 55 hz ... i heard some comparisons between both, originals, playing some bog, and it was so evident , for my ears, that the 75hz were the ones.
and yes, IMHO, 45/100, not necessarly Dickinson since it sounds like it stock, but i should give it a try. 500 volts will do fine too.
i love the 69 SL for Hendrix, but since i had this 45/100 built, i don't use the 69 anymore, or rarely.
then, a good Hendrix fuzz cranked, and just playing with the strat's volume from clean to wild will do wonders, from little wing tones ( one rainy wish + experience ) , to bog.
you can also totaly play some Woodstock tones with it.
but you won't sound like the isle of Wight, the 69 sl does , totaly.
hope this helps too.

The JTM45's, and JTM45/100's that Hendrix was known to use had what? Split Cathodes.

once modded ? because they're shared cathode stock. i don't remember if the Dickinson is split cathode.
shared is much better imho
but a switch for both is a very easy and cool mod to do.

[Lefty Lou]

"The JTM45's, and JTM45/100's that Hendrix was known to use had what? Split Cathodes." - LL

I definitely got ahead of myself when I made the statement, as I know that both of the aforementioned amps are "shared cathode". Also, I don't doubt one bit that there was a "carry over" of the shared cathode design (JTM45/100) into the earliest of JMP 100 watt models. JMP 100 watt OT's were designed to accommodate EL34/KT77/KT88/KT90/6550 tubes. Since the link I gave verified Jimi's specific use of 6550's, this would make perfect sense.

[Tone Slinger]

Yep, thats the interview I read much earlier in another mag. It made total sense to me as well. The live '68 stuff was maxed out el-34 sounding/speaker break-up (25 watters), but by '69, the general sound was much more glassy, clean and refined (6550's and higher wattage speakers definately do that). Woodstock is an excepion (sounded a little closer to el-34/25 watt speakers) and BOG (I agree, a specific Super Bass or 'JTM/45/100') had the rounder, boomier type thing (shared cathode and possibly .1 pi couplers, etc). But, as a whole, 'most' of what I hear in the '69/'70 era of Hendrix is regular mid '68 to '69 (basically the same spec from mid '68 to mid '73)Super Leads with higher wattage speakers and 6550 output tubes. Thats what my ears tell me, but hey, how many Hendrix Marshall tops survive today, and of those, how many are exactly as they were when he passed ? Thats the only way to truly verify when it comes down to it.

[Xplorer]

"The JTM45's, and JTM45/100's that Hendrix was known to use had what? Split Cathodes." - LL

I definitely got ahead of myself when I made the statement, as I know that both of the aforementioned amps are "shared cathode". Also, I don't doubt one bit that there was a "carry over" of the shared cathode design (JTM45/100) into the earliest of JMP 100 watt models. JMP 100 watt OT's were designed to accommodate EL34/KT77/KT88/KT90/6550 tubes. Since the link I gave verified Jimi's specific use of 6550's, this would make perfect sense.

i don't understand very well ( my language problems sometimes, sorry ) , split on the 45/100s ?
you meant splitt on the later superleads + 6550 sometimes, right ?

i remember an interview where the tech was clear about the fact that he replaced all tubes, on the later superleads he bought, with some 6550.
well, we can quite comfortably say that Jimi used almost everything from Marshall, with different tubes from era to era, and a few mods sometimes.

one single Jimi amp is still as Jimi left it, after all these years, and with Jimi's tubes !! it's in France. it's his super tremolo from 67. i don't remember which tubes were in it, but this time i think they were el34, not 6550. and he still used this one in 1970. it was brought for a repair ( the transformer was hold by some simple metal wire to keep it in place ) , in england, but meanwhile, Jimi passed.
you could see it on the website of lys amplification. but i can't see it anymore.

[mightymike]

I think you meant shared cathode. Superbass are shared, with no v2a bypass cap, 56k/250pf tone stack, .1uf output couplers.

From my exp, not having the v2a cap ( or a lower v2a cap like a .68uf make an amp more pedal friendly than being shared or split, but shared being the more pedal friendly of the 2 imho.

69 spec is split v1, .002 after the 1st stage, 33k/500pf (or 560pf) tone stack, .022 output couplers.

Dickenson Spec is a crossbreed. Superbass spec but with the 69 spec tone stack with 560pf, and KT66 where the other 2 amps are El34

BOG/Monterrey Pop = Jtm45/100 Dickenson spec. I'm building my second one..

I think the Marshall Hendrix model is a 1969 year replica. 1959 model.

So if you want the big headroom sound Jtm 45/100, but honestly can get good Hendrix tone out of either of these setups with the right gear to go with it.
Heck, even my 12000 is a total bastard spec does it well.

Super Bass, shared cathode and Super Lead, split cathode yes sir. If I mis-stated myself I stand corrected. It really doesn't surprise me about the Dickinson amp specs making it partially a "Super Bass". I was contemplating this subject of modding last night a 10,000 series preamp section with 12,000 series output section OR 12,000 series preamp section and 10,000 series output section. Am I correct in the way I state this mod Mike? In other words a SB preamp section with a SL output section OR a SL preamp section with a SB output section?

So with the Dickinson amp you have a SB (shared cathode) preamp section and a SL output section. Is that correct? Now to the question of OT's and the plate load impedance differences between 6550 and KT66 and their respective OT's. I'm familiar with the dual OT's in the original JTM45/100's and the subsequent change over to a single OT but is the JTM45/100 OT specific to only KT66's/6L6's tubes and the JMP 100 OT specific to only EL34/6CA7/KT88/KT77/6550 tubes in order to more accurately match plate load impedances? The Dickinson amp would appear to have a JTM45/100 OT for the KT66's or 6L6's seen in the pics (from the website) as opposed to a JMP 100 OT. As I'm to understand it any JMP 100 SL or SB amp can be made to take EL34/6CA7/KT88/KT77/6550 tubes. So, if Hendrix was using 6550's in his Marshall amps this would require him to have used JMP 100 OT's, am I correct?

They were all shared cathode Superbass Spec until the 12000 series switch to Dagnall and they to tweak to compensate for less agressive Dagnalls.
The later tone stack on the JTM 45/100 Dickenson spec just means at the time of Hendrix's death that amp was that spec. I could have had the older tone stack at Monterey pop.

As far as impedences go I do know that the 2" Drake Ot in a Jtm 45/100 Kt66 amp has higher primaries that the 2" Drake in a 10000 series Jtm 100 Black Flag El34 amp. 2.2k vs 1.75k IIRC. Yes I said 2.2k Evh guys.

As far as the PT goes, I don't know there were dual taps on the Original JTM 45/100s. What I do know from the voltage charts in HOM is that they were 550 or 560v. My Heyboer has 1 set of taps that I thought were 500v, but when I played it a couple weeks ago it was 520 something.

The Martrans has 3 of taps. I think I will use it on my Endblock build.

Btw cool info on the Gary Moore stuff

[Lefty Lou]

My 74' Marshall 1959 Super Lead 100 Dagnall PT was putting out the range of B+ that you mentioned Mike but, this would be in keeping with that era according to available information on the subject. I gave Yngwie a heads up on the Gary thang since he asked the question, but he must be out of pocket.

[bmcash]

Thanks all for chiming in. There is definately a lot of information to consider. I wish I could make them all!

[Lefty Lou]

As I stated in another thread, one can become too overly obsessed over equipment such that they can't see the forest for the trees. There comes a time after so much "mulling over" that one just has to bite the bullet and make their decision.

[emmjaydubya]

Unless you're Shakti and you build practically every important 100 and 50 watt version that Marshall made using all N.O.S. parts, or Neikeel who has built plenty of his own, restored several, and owns originals also.

On the other hand, I guess they still have to choose which one to plug into every day.

[mightymike]

I had a 73 Superlead. 490ish volts is typical for that Era Metal face

[Lefty Lou]

I had a 73 Superlead. 490ish volts is typical for that Era Metal face

Not mine, I want to say 525 B+ volts "at the very least".

[mightymike]

Wow... That's the highest I've heard since the 45/100