NAD tommorow ! 1978 JMP 50W yummy, yummy !!

[LazyNinja]

What trannies does it have?

[hamfist]

Woooooooooaaaaah.  Just had a look inside. Couldn't believe my eyes !!!


Pre-amp tubes  - 1 x  Blackburn Mullard, 2 x brimar.

Power tubes - nice looking Mullard XF4's

 Sheeeeeet.  I can't believe he sold it to me with those tubes inside. he clearly didn't really know what they were.  he was a pro musician, and sent it of to Marshall for servicing/tubes etc. He told me the amp was re-tubed 18 months ago.  This means those tubes should have loads and loads of life left in them.
   I pocketed the Mullard 12ax7. But the amp will sell with 2 x Brimar ECC83's in V1 and V2, a brand new JJ in V3, and the Mulllard Xf4 power tubes.
  That must put the price up a bit. I'm not quite sure how much though. I need to spend a few mins on ebay to check out the  Xf4's.

[hamfist]

I'm afraid I won't be letting the amp go, with these tubes, for less than £390 - and I think that is still a damn fine deal for someone. That's a BKP forum-only price !

[Twinfan]

Too rich for my tastes I'm afraid.  I really don't get this "paying shedloads for old valves" thing...

[hamfist]

What trannies does it have?

All original

[LazyNinja]

Too rich for my tastes I'm afraid.  I really don't get this "paying shedloads for old valves" thing...

Me neither, probably because I've yet to experience the 'magic'. Every time I bought so called NOS tubes off ebay it was either very normal sounding or a dud :( I'm sure a genuine NOS would sound great though.

Did the transformer have any sticker on it? Like Drake, Dagnall etc.

[hamfist]

Did the transformer have any sticker on it? Like Drake, Dagnall etc.

  I couldn't see a sticker, but I didn't pull the chassis out, just took of the back panel.  If I pull the chassis out, I'll take a closer look.

[gwEm]

mine (1976) has drake anyway

[hamfist]

Every time I bought so called NOS tubes off ebay it was either very normal sounding or a dud :( I'm sure a genuine NOS would sound great though.

   I've had a lot of luck with NOS pre-amp tubes in particular. In my experience with a number of different amps, really good NOS pre-amp tubes like Mullards, Raytheon, Siemens, Amperex, RFT, Tesla, Tungsram can make a big difference.  "cheaper" NOS brands, and most American tubes like GE's, Sylvania, Tung Sol & RCA, I've never thought worth the money. There is a school of thought (and it's pretty logical really) that says that you want old European tubes for British sounding amps, and old American tubes for American sounding amps. It seems to make sense as that's what the manufacturers would have put in the amps when they were made in the 60's and 70's.
  I've also tried several sets of NOS power tubes in various amps (all EL84's), and sometimes I could hear an improvement (always only small), sometimes not.

  I would strongly recommend anyone who runs a non-high gain amp to try a known good 12ax7 in V1 of their amp. Find the right tube, and it can definately be magic. Sometimes its not even the expensive tubes that sound the best. In my AC30, it was an RFT 12ax7 in the input stage of the Top Boost channel that smoked any Mullard I put in there.

  BTW, any forum member is welcome to bring their amp around my house and try out some nice Pre-amp tubes to see if they think it might be worth buying some. Beware, though, Ailean and Prozacbear tried out some of my old tubes in their amps - it was not good for their wealth !!

[ailean]

Beware, though, Ailean and Prozacbear tried out some of my old tubes in their amps - it was not good for their wealth !!

Yeah, not good at all. But I will add that the right tube can definately have a big impact on your amp, and it's not always a case of 'better' sometimes it's just different emphesis / sound balance, but that might be better for what you play.

I'm not sure I'd pay mega bucks for a NOS tube, but I'd pay up to 30/40 quid for a good one if it fits my tone. And that's not that much money compared to the cost of an amp.

Sorry the amp didn't work out Alan, I can't say I'm not tempted myself... must....fight....AAS!

[Woogie]

Ailean, buy it!!

[hamfist]

Right, some bad news about the amp. The Mullard El34's (well at least one of them), are duff. They cause crackle when you prod the amp. With a known good set of JJ's put in, I could not replicate the crackle however hard I hit the amp. Put the Mullards back in and the crackle was instantly easily produced.
  Also, the more I play it, the more I believe that something is just not right with the amp. I really should like the tone, and I don't, It's truly harsh and horrible. I have been through a lot of amps, and read a lot of opinions, and listened to a lot of soundclips to get to the point of buying this amp. I also have a very similar amp, the 1987, which I just love. I cannot believe that this is what a proper functioning 2204 sounds like. Also, there's nowhere near as much gain as I thought a 2204 should have. Also, the amp is definately noisier than I would like
   It's not the tubes, I have replaced all of them with known good tubes - nothing changes.
  I wouldn't be happy to sell the amp in this state, unless it was a "sold as seen". For someone who knows amps and amp repairs it might be a great buy.
   I think my main option is to get a good tech to install some new EL34's, bias it up correctly, and then spend some time troubleshooting the amp.  It could be something as simple as just needing a cap job. The amp is 30 years old after all.  At least then I'll find out what this amp is capable of.  And if I still don't like it, I can sell it with a clear conscience knowing that it was all sorted.
  Great - another money pit - just what I need right at the moment.

[ailean]

Hmm not much luck with that one Alan :(

Oh well at least that removes my temptation to buy it :)

[Twinfan]

Alan,

I may take it off you "as is" as I know someone who could fix it up for me  ;)  I'll happily take it without valves as I have some spares knocking about.

I'll drop you a PM...

[Roobubba]

... however hard I hit the amp...

!