2 Channel Dual Rectifier - Red Channel Failure?

[fretout]

HI everyone! I recent picked up an early (07/1992) Dual Rectifier Blackface (R-05XX), and when I plugged it in, for some reason, the Orange Channel seems really faint and the Red Channel doesn't produce any sound at all. I have no idea why the Red Channel won't work. I have tried all sorts of different settings, just to see if there might be a bad connection somewhere, and it still won't work properly.

FWIW, It's currently running EL34s (STR-447) in the power section, and it's running 12AX7-A (Russian 2) in the preamp. Also, anyone knwo the specs on the preamps tubes?

Thanks!!!

 

[screamingdaisy]

Sounds like a bad preamp tube.

 

[fretout]

Sounds like a bad preamp tube.

Well, a few hours ago I decided to "poke around" at the V1 preamp tube and sure enough a SURGE of volume came from the amp! It seems to be good for now.

So, now I would like to identify the amp itself. Since the Boogie Files website is down, can anyone tell me what revision my Dual Rectifier is? Also, can anyone tell me how to identify the transformers?

As far as the tubes go, I have never seen Mesa-branded tubes that say "Russian 2" on them. Are these some desirable tubes?

Thanks again everyone!!!

 

[screamingdaisy]

I'm pretty sure Russian 2s are EHX tubes.

If I remember correctly Rev D went to around 512. Either way you should have a Mark III transformer as they kept using them until somewhere over 2000 amps (revision G was the first to get the new 'Dual Rectifier' transformer).

 

[YellowJacket]

I'm pretty sure Russian 2s are EHX tubes.

If I remember correctly Rev D went to around 512. Either way you should have a Mark III transformer as they kept using them until somewhere over 2000 amps (revision G was the first to get the new 'Dual Rectifier' transformer).

Except for my amp, which is a 26XX Rev F with the 'new' transformer as well.

 

[screamingdaisy]

I'm pretty sure Russian 2s are EHX tubes.

If I remember correctly Rev D went to around 512. Either way you should have a Mark III transformer as they kept using them until somewhere over 2000 amps (revision G was the first to get the new 'Dual Rectifier' transformer).

Except for my amp, which is a 26XX Rev F with the 'new' transformer as well.

I thought the new transformer was the switch from F to G?

 

[fretout]

I'm pretty sure Russian 2s are EHX tubes.

If I remember correctly Rev D went to around 512. Either way you should have a Mark III transformer as they kept using them until somewhere over 2000 amps (revision G was the first to get the new 'Dual Rectifier' transformer).

Yeah, my amp's serial number is between 500 and 512. So it's a Rev. D? Is there a certian serial number that will designate the transformer as a "Mark III" transformer? Anything I should look for?

 

[screamingdaisy]

Yeah, my amp's serial number is between 500 and 512. So it's a Rev. D? Is there a certian serial number that will designate the transformer as a "Mark III" transformer? Anything I should look for?

Rev D - A bit darker, although tonally not much different than a C. The assumption is that Boogie wanted to improve the rhythm tone. Went from around 280 to 513 or so and ceased production in Aug 92.

Rev E - Not much is known about it as there were only somewhere around 110 to 150 released. Presumably it sits somewhere between D and F in terms of tone. This was a transition version with a lot of mods done to an earlier PCB, so there may have been changes made from amp to amp at some points. Presumably Rev F superseded it as soon as the new PCBs arrived.

My serial number is in the 1200s and I have a Mark III tranny.

 

[fretout]

Yeah, my amp's serial number is between 500 and 512. So it's a Rev. D? Is there a certian serial number that will designate the transformer as a "Mark III" transformer? Anything I should look for?

Rev D - A bit darker, although tonally not much different than a C. The assumption is that Boogie wanted to improve the rhythm tone. Went from around 280 to 513 or so and ceased production in Aug 92.

Rev E - Not much is known about it as there were only somewhere around 110 to 150 released. Presumably it sits somewhere between D and F in terms of tone. This was a transition version with a lot of mods done to an earlier PCB, so there may have been changes made from amp to amp at some points. Presumably Rev F superseded it as soon as the new PCBs arrived.

My serial number is in the 1200s and I have a Mark III tranny.

I wanted to know because I have no idea if the transformers were ever swapped out. They look original. The PCB/Caps/leads all look like they are in GREAT condition!

 

[screamingdaisy]

I wanted to know because I have no idea if the transformers were ever swapped out. They look original. The PCB/Caps/leads all look like they are in GREAT condition!

Can't be of futher help. I ID'd mine using the info on the Boogie Files, but I never bothered to copy it down as I didn't think I'd ever need it again.

 

[fretout]

I wanted to know because I have no idea if the transformers were ever swapped out. They look original. The PCB/Caps/leads all look like they are in GREAT condition!

Can't be of futher help. I ID'd mine using the info on the Boogie Files, but I never bothered to copy it down as I didn't think I'd ever need it again.

Me either. Thanks screamingdaisy!!!

 

[YellowJacket]

I'm pretty sure Russian 2s are EHX tubes.

If I remember correctly Rev D went to around 512. Either way you should have a Mark III transformer as they kept using them until somewhere over 2000 amps (revision G was the first to get the new 'Dual Rectifier' transformer).

Except for my amp, which is a 26XX Rev F with the 'new' transformer as well.

I thought the new transformer was the switch from F to G?

Well, generally the Rev F Duals have the 'magic' tranny but this isn't the case for every one. I compared the parts numbers on mine with what where listed on The Boogie Archives while it was still up. I found that the choke and the power transformer were the same as early duals, but the output transformer was the same as a Rev G. I checked the inside of the amp and it does have Rev F printed on the circuit board. In addition, it has all the other cosmetic indicators on the amp and the chassis. Keep in mind my amp was one of the later Revision F models, close to about the time where the Revision Gs started to appear.

I think Elpelotero explained it best when he said that mesa employees grabbed whatever parts were sitting around the shop to make these amps, using up the old parts before switching entirely to the new ones. This definitely accounts for the mishmash of parts being used early on in the production cycle of the rectifiers. Hey, if I was REALLY worried about my tranny, I could always track down a Mark III model and get that installed in my amp instead. Something tells me it isn't worth it though . . .

 

[screamingdaisy]

Probably not. The change may be counter productive if they made any changes to the circuit to account for the new transformer.