Favourite Marshall Amph?

[Eric***]

Also, I always thought the JTM45 was the Bluesbreaker. What's the difference? This thread could be a good chance to air all of my questions about Marshalls.

[markb]

Also, I always thought the JTM45 was the Bluesbreaker. What's the difference? This thread could be a good chance to air all of my questions about Marshalls.

The "Bluesbreaker" is a JTM45 in a 2x12 combo form named for the picture on the John Mayall's Bluesbreakers featuring Eric Clapton album of 1966.



The JTM45 was basically a Tweed Bassman with a different tone stack.

As for my favourite Marshalls it has to be the 1987 model 50w "Plexi" and the various combo versions on the same chassis. Even when they tried to ruin them with a master volume you could just avoid it. The 1974 18w combo was basically a half power version. It all went downhill from the JCM800 onwards for me.

Having said that, I was very taken with a Silver Jubilee 25/50 2x12 combo once but the shop owner wasn't selling. The best cleans I've ever heard from a Marshall.

These days my Marshall needs come from a pedal. Much easier on the back and wallet

[Ch0jin]

The "Bluesbreaker" is a JTM45 in a 2x12 combo form named for the picture on the John Mayall's Bluesbreakers featuring Eric Clapton album of 1966.



The JTM45 was basically a Tweed Bassman with a different tone stack.

Not that I'm an expert, but I did quite a bit of reading on the topic while I built my JTM45, and I believe the difference between the original Bassman and the JTM45 are a little more substantial than that. IMHO, it breaks down like this.

The Bassman has a 12AY7 as V1 and the JTM has a 12AX7. That's a big difference of itself. I've just received a NOS 12AY7 so I can try it in my JTM style amp and see what happens. I would expect much less gain.

The two have completely different output transformers. The Fender with a single 2 Ohm tap, the JTM with multiple taps. They also have different primary impedance's.

I think the chokes were different values

I think both started with 5881 bottles, then the JTM pretty quickly went to KT66's

Then there's the speakers and the various open and closed back designs used.

So yeah, for sure the JTM was based on the 5F6-A Bassman, but I don't believe, based on what I've been reading, that they are as close as often mentioned on the net. Which is, of course, why they sound different. I read one post somewhere that said the difference in sound was down to the fact that one had American parts and one British. I laughed about that for a while.

[bcdon***]

I read one post somewhere that said the difference in sound was down to the fact that one had American parts and one British. I laughed about that for a while.

Now, why wouldn't the difference come down to American vs. British parts? After all, haven't you heard the joke as to why the British don't sale televisions.. they haven't found a way to make them leak oil yet. ;-)

[markb]

Not that I'm an expert, but I did quite a bit of reading on the topic while I built my JTM45, and I believe the difference between the original Bassman and the JTM45 are a little more substantial than that. IMHO, it breaks down like this.

The Bassman has a 12AY7 as V1 and the JTM has a 12AX7. That's a big difference of itself. I've just received a NOS 12AY7 so I can try it in my JTM style amp and see what happens. I would expect much less gain.

The two have completely different output transformers. The Fender with a single 2 Ohm tap, the JTM with multiple taps. They also have different primary impedance's.

I think the chokes were different values

I think both started with 5881 bottles, then the JTM pretty quickly went to KT66's

Then there's the speakers and the various open and closed back designs used.

So yeah, for sure the JTM was based on the 5F6-A Bassman, but I don't believe, based on what I've been reading, that they are as close as often mentioned on the net. Which is, of course, why they sound different. I read one post somewhere that said the difference in sound was down to the fact that one had American parts and one British. I laughed about that for a while.

Certainly a few more changes. The speakers did make a real difference. Same basic circuit, different results. A bit like a smart cover version that sounds original in itself.
In the early days Marshall (and by Marshall I mean Ken Bran) sourced parts from Henry's electronic shop in the Tottenham Court Road at the far end of the no 7 bus route from the shop in Hanwell. As Marshall grew the parts used became more consistent.

[Ch0jin]

... A bit like a smart cover version that sounds original in itself. .

Well said!