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Eric's Bluesbreaker Marshall Combo: new pictures.

B Ingram

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Jan 3, 2016
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730
It's a curious article, based on pics alone because the text is very hard to read. ...

I squinted pretty good to read the article, but could only reliably make out the inset "Why Was Clapton's Amplifier So Different?" and text on that page.

It smelled of "fairy-shit" to me (a mysterious combination of fairy dust & bullshit). There were several things which start at a conclusion (how the amp sounded on record) and asserted pseudo-tech reasons that lead to the conclusions... except the pseudo-tech is described to do things in ways which don't really happen.

The bit about KT66's "loading the driver" is completely bogus as a cause for distortion in the driver/phase inverter. I may be mistaken, but I thought EL34's came along later than the amp discussed, so why do they muddy the waters talking about them? It is true the KT66 requires more drive signal than EL34s for the same output (because the EL34 has higher Gm), but the 5881 has even lower Gm than KT66s and is therefore even "harder to drive"... Which means what exactly?

I also saw reference on the same page of "trick-matching the primary" which is only a "trick" to folks who don't know how transformers work. It's claimed to make the OT or output tubes sound different... More fairy-shit.
 

TM1

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Jun 27, 2003
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8,349
I squinted pretty good to read the article, but could only reliably make out the inset "Why Was Clapton's Amplifier So Different?" and text on that page.

It smelled of "fairy-shit" to me (a mysterious combination of fairy dust & bullshit). There were several things which start at a conclusion (how the amp sounded on record) and asserted pseudo-tech reasons that lead to the conclusions... except the pseudo-tech is described to do things in ways which don't really happen.

The bit about KT66's "loading the driver" is completely bogus as a cause for distortion in the driver/phase inverter. I may be mistaken, but I thought EL34's came along later than the amp discussed, so why do they muddy the waters talking about them? It is true the KT66 requires more drive signal than EL34s for the same output (because the EL34 has higher Gm), but the 5881 has even lower Gm than KT66s and is therefore even "harder to drive"... Which means what exactly?

I also saw reference on the same page of "trick-matching the primary" which is only a "trick" to folks who don't know how transformers work. It's claimed to make the OT or output tubes sound different... More fairy-shit.
Yeah, I was fairly skeptical about that. I tried it just out of curiosity with my Mercury Magnetics RS clone.. Didn't really hear much difference, if any with my amp/speakers... I know my amp with KT66's vs. EL34's or even original 5881's, the KT66's have more headroom and doesn't breakup as soon.. Fairydust indeed..
 

B Ingram

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Jan 3, 2016
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730
Yeah, I was fairly skeptical about that. I tried it just out of curiosity with my Mercury Magnetics RS clone.. Didn't really hear much difference, if any with my amp/speakers... I know my amp with KT66's vs. EL34's or even original 5881's, the KT66's have more headroom and doesn't breakup as soon.. Fairydust indeed..

So the truth in relation the output transformer is that with a given output tube, moving the reflected primary impedance to be higher/lower changes the distortion spectrum to favor more even or odd harmonics. You can see this on that graph on the last page of this 6L6 data sheet. It shows when you hold everything else constant, lower loads lead to more 2nd harmonic distortion while higher loads lead to more 3rd harmonic distortion. There's a point where 2nd harmonic starts increasing again as the load impedance continues to rise, and there's a point where THD may be minimized.

But push-pull output stages cancel even harmonic distortion produced in the output tubes, so the amount of 3rd harmonic is really what dominates. So when you hear a sonic difference due to a change in primary impedance, you're really just hearing a change in the distortion spectrum produced (same reasoning applies for why amps with a pentode/triode mode switch sound darker in triode mode: there is less odd harmonic distortion until the output tube is severely overdriven, and so the bright edge to the sound is gone).

But it is true that EL34's (which are true pentodes) sound different from the aligned-grid or beam-power tubes in the KT66 and 6L6 class. I just wish people wouldn't layer "magic" on top of what could be pretty straight-forward stuff...
 

corpse

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Jun 9, 2007
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That is something- I have never really heard the tonal impact of differences in electrical interaction before- very good description.
 

TM1

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Interesting stuff on those sheets. I'll have to pull my M.O.Valve sheets on KT-66's and see how they compare to each other.
Cheers!

BTW, John...? Did you ever chat with your friend on Eric's amp?
 

becks bolero

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Jul 15, 2001
Messages
1,810
this is an interesting thread!

based on Wilko's overlays, this pic of EC in the studio appears to have a jtm45 trem chassis, to me

even though the amp is on an angle, you can make out that the top cutouts are closer to the trem dimension than the non-trem



clapton-00beano.jpg
 

jrock1

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Jul 3, 2004
Messages
438
Certainly looks wide enough of a cut out to me to be the trem version..again just so much conjecture...

In terms of why it sounds so, well, amazing on the Beano album...please consider:
1. His fingers and attack
2. Mic used
3. Board used (including any effects on the board, such as reverb/echo, which you can hear on at least a couple of songs)

These all have an impact on the tone we're hearIng from the Beano album, not to mention the singular impact of that specific Les Paul.

Of course, the live clips from the era also sound fantastic, but that I believe is due to the fact that it is EC playing and there would be no way to determine from those clips whether it was a trem or non trem version of the JTM45 (sorry for stating the obvious in this last thought).
 

becks bolero

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last time I heard EC play a Les Paul, he sounded quite a bit like the Beano album. I preferred it much more than his boosted strat tones

what do we have to do, in order to get Clapton to record a new album using a Les Paul and a cranked Marshall?

He could call it "back to the beginning" or something

hell, I'm sure people here could hook him up with the real gear, easily enough! if he doesn't have it already
 

F-Hole

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Sep 2, 2015
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2,171
All good, but the only bloke I know who's seen the amp in person, and talked to EC about it........said it's definitely a standard JTM45. He knew his amps too, having loaned Richie Blackmore the first Marshall he ever played through in 67.
 

Flying Fish

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Aug 15, 2006
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632
I'd imagine the handle could potentially be used to help figure out the width of the cab no - if those handles were all the same length?
 

TM1

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Jun 27, 2003
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The strings on his Les Paul would also be a factor. Did he use Nickel or Monel wrapped strings. Weren't too many choices back then and god know that Ernie Ball certainly weren't available in the U.K. in 1965/66. So he had to have used a Round Core string(Hex didn't become popular until the early `70's and even then it was used as a way to have less reject strings/cheaper production costs. Same with Nickel Plated Steel) so the wrap needs to have been either Nickel or Monel wire. Guitar Strings in England was a very small selection. You had Rotosound, Cathedral, Selmer(which were made in Germany by Pyramid), Gibson and maybe a couple others..
F-Hole, do you remember what was around?
I know I can get various sounds from different makes of strings.. Some great some not so great..I like Monel wraped round cores on my Les Paul's as it has that old Sixties tone and Nickel wrap on my Semi's..
Cheers!
 

TM1

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Dude, I was three months old when all this went down.

Sorry mate, I have no idea of anyone's age on here. I just kinda guessed that since you're interested in this stuff that we'd be around the same age +/- 10 years or so.. I'm 64 so this stuff is right in my range. I remember when I heard the Beano LP for the first time in the late Sixties..:dude:
 

Wilko

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It's interesting that you met someone who thinks that EC's amp was a regular JTM45.

Of course, over 25 years ago there were enough people who though it was tremolo amp for Marshall to actually tool-up and start producing the "bluesbreaker" combo with a tremolo chassis.
 

goldtop0

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Aug 19, 2003
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8,931
It's interesting that you met someone who thinks that EC's amp was a regular JTM45.

Of course, over 25 years ago there were enough people who though it was tremolo amp for Marshall to actually tool-up and start producing the "bluesbreaker" combo with a tremolo chassis.


Well yes, could be a popular misconception.
 

TM1

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Jun 27, 2003
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Well yes, could be a popular misconception.

Yes, it could as Marshall kept no records or serial number data in the Sixties. I asked someone who was high enough in the chain to know and he basically said that there are no sales records or serial number logs, etc from the early days. That basically started in around 1969-ish..and even that era is sketchy..
 
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