[JakeJ]

wonder if that's not going too far in the "tubey" department.

That's not possible!

[jarcher]

Got a same day response from CJ technical service that :

1) 5751 is the input tube, and will all tube quality is important, this one is likely to be the most noticeable. Sorry if it seemed like I doubted anyone!

2) The MV75's (all versions) can work with KT120's.

Will be interesting to see what they come back with as far as pricing / availability from them on tubes for that amp.

[jarcher]

That's not possible!

Looks like I'm going to have to start a new topic for tube preamp recommendations for this amp.......have my eye on CJ PV8 - PV11 w/ phono sections!

[DustyC]

Looks like I'm going to have to start a new topic for tube preamp recommendations for this amp.......have my eye on CJ PV8 - PV11 w/ phono sections!

When I had my MV75's I drove them with a PV5. System had that tubey goodness in spades. 

[jarcher]

Got a same day response from CJ technical service that :

1) 5751 is the input tube, and will all tube quality is important, this one is likely to be the most noticeable. Sorry if it seemed like I doubted anyone!

2) The MV75's (all versions) can work with KT120's.

Will be interesting to see what they come back with as far as pricing / availability from them on tubes for that amp.

Here's the reply:

Jon,

Cost for the RT75 tube set (suitable for 75, 75A, 75A1) is $495 plus $26.95 for shipping and handling. This tube set comes with Tungsol 6550s. You can upgraded to KT120s for an extra $80. The KT120 does not increase the power output of the amplifier. If you'd like to order a set, complete the attached order form and send it back to us (we recommend using fax if available for added security).

regards,
customer service

Those most be some really high quality stock @ that price........guess I'll be getting my supply elsewhere....good to see that customer service is so responsive though.

[jarcher]

Good news : I got a great CJ PV10A in great condition w/ great tubes at a good price.  Blows away former preamp & will make a nice match w/ the CJ MV75A1.

Bad news : The amp has one bad output transformer & CJ doesn't have a spare (no surprise).  Seems pretty unlikely that I'm gonna find a used spare around, particularly as they soon thereafter went w/ more "modern" wider bandwidth ones.  I can't imagine someone wanting to part out a CJ MV75, but you never know.

SO - if any one has a line on, or recommendations on how to source, a CJ MV75A1 output transformer, please let me know.  Also kicked around the idea of replacing both output transformers with something else, including something new from say Hammond.  Tech even suggested using some Dynaco transformers he has.  D'know : that sorta feels to me like violating the original design / sound.  Change caps, update other parts, ok. But the transformers just seem like the heart & sound of the amp.

Meanwhile considering buying tech's other updated CJ MV75A1 & take some time to mull over options for mine.  Then some day if I can get the part, perhaps have two to use as mono-blocks, even if that's just a bit piggish.  Aside from really liking the sound, kinda like the ideal of having an important part of CJ history as a collector item. 

[Maritan]

I'm curious. How did you figure out that your output transformer was busted? Measurements? Sound? Inquisitive mind wants to know.

[Ericus Rex]

I would imagine that Dynaco trannies would be the closest substitute for the originals.  And if CJ's tech recommends them....  I would also guess that you wouldn't want to use the one in a pair of monos since the OTs would be different.

You might even be able to sell the single good one to another MV75 owner in a similar position for more than the cost of the two Dynacos.

[jarcher]

I'm curious. How did you figure out that your output transformer was busted? Measurements? Sound? Inquisitive mind wants to know.

Let the tube tech guy figure it out. Think he set it on a variac and at some point one of tbe output trannies would just not maintain a stable voltage. Man is sometime frustrating slow to complete jobs, but as he's among other things a factory authorized primaluna tech and had decades of experience repairing tube gear, have no reason to doubt his diagnosis.

[jarcher]

I would imagine that Dynaco trannies would be the closest substitute for the originals.  And if CJ's tech recommends them....  I would also guess that you wouldn't want to use the one in a pair of monos since the OTs would be different.

You might even be able to sell the single good one to another MV75 owner in a similar position for more than the cost of the two Dynacos.

A cheap dynaco would be a decent donor as it has good trannies - and I think the tech has one that he could sell me for parts for next to nothing.

Nonetheless definitely would match both output transformers on one unit, but then yes if you had that + another to use as monoblocks seems like you'd want to match stuff as much as reasonable. So again - sourcing another original correct CJ output transformer is best.

Tech offered to buy my busted CJ - which confirms to me not only that it is desirable particularly because of the rare faceplate + cage, but that the price I got it for was right. So definitely has strong resale value as it lies. But I thinks I'll be patient and piggish at the same time and buy his functioning one and take my time to fix mine if hopefully eventually I can source the original transformer at the right price.

[JakeJ]

Frankly, I think your chances of finding another good, working, fully functional, complete amp are better than finding a OPT, but that's just my opinion.  If you do find another unit then you could still possibly still recoup some of your money from selling the bad amp making the overall investment somewhat less painful.

Just my .02 and one of many options. 

[jarcher]

Frankly, I think your chances of finding another good, working, fully functional, complete amp are better than finding a OPT, but that's just my opinion.  If you do find another unit then you could still possibly still recoup some of your money from selling the bad amp making the overall investment somewhat less painful.

Just my .02 and one of many options. 

Yup - thats basically the direction I'm going in.  I.e. buying the tech's restored + fully functioning one, then maybe selling mine.  Hate to see it go as its got a lot going for it other than the OPT issue.  But if after a reasonable period of time I can't source what I need, then off it goes.  I'm sure I won't lose much if anything, so it was a risk worth taking.