Question about tube emplacement in a 50/50

[crane]

Hi !

Try to find it out on the forum but couldn't...
Which tube goes to which channel ?

ABBA, ABAB, AABB ?

If someone knows, thanks for the answer !

 

[soundpurist]

It's more like ABBA. I called mesa in the past and they suggest to do like this. You better call them to be sure. 8)

 

[disassembled]

I am not which side corresponds with what channel but it should be like this:


BBAA


If you have two different be sure to put one pair in the BB and the other pair in the AA slots.




Greg

 

[soundpurist]

It's more like ABBA. I called mesa in the past and they suggest to do like this. You better call them to be sure. 8)

By ABBA I wasn't talking about the channels btw it was about the matched pair.(if it's not two duet package of the same color). As I said you better call mesa. I don't understand why they don't show it in the manual???? weird.

 

[disassembled]

It's more like ABBA. I called mesa in the past and they suggest to do like this. You better call them to be sure. 8)

By ABBA I wasn't talking about the channels btw it was about the matched pair.(if it's not two duet package of the same color). As I said you better call mesa. I don't understand why they don't show it in the manual???? weird.

I understood what you wrote and it is not correct because there are basically 2 power amps in the 50/50. If the amp was mono then "ABBA" would be correct.

The tube pairs are arranged as I stated above (although i am not positive which side is A and which is B since i don't have the 50/50 here anymore):

BBAA


Greg

 

[crane]

Thanx for your answers.
I did try switching a bad tube between the sockets and tap on it, it seems that the tubes are arranging like AABB.
I did use only one channel, so I replace tubes only by pairs ^^

 

[chris.goth]

The 50/50 is a MONO poweramp. That is teh real disapointing truth I learned
when I brought mine to a tech asking to mod it.You have control over two channels,
yes, but they're wired in series, instead of being independant.

It will not change anything for you except if you want to have different
tube types (and hence change one transfo). The tube layout is ABBA.
So if you want ont channel to sound slightly different, you can put two
6l6's of another brand in the middle. I personnaly use Mesa STR420
and SED Winged 'C' 6l6's (the original from St. Petersbourg).

Mesa are warmer, looser and the SED are brighter and tighter, great
to cover a full range of frequencies with 6L6's.

 

[Ayin 0]

It's BBAA, according to my tech. I had my 50/50 serviced last monday, and since I'm only using it with one cab right now, the tech pulled the two tubes on the left (standing to the front of the amp).

He also biased it, and that made a huge difference. He put in a little potmeter to alter the bias while I was listening, and the result was amazing.

Mine has Sovtek tubes.

Jan

 

[Hames]

All this conflicting information.....I ordered a matched pair of SED 6L6GCs from Dougs Tubes last week and I don't know what I'm going to do with them when time comes to replace the tubes in Channel A.... :?

 

[ak47]

Considered getting a matched quartet? Position won't matter then...

 

[Hames]

Bit late now, the pair arrived at my doorstep today. It wasn't cheap having them sent from to the US to Australia either.

 

[marantz1300]

If the 50/50 is mono, why is it that when I am running two cabs with my studio pre feeding it, that I have to turn up both volumes on the studio and on the 50/50 to get sound on both channels?Shouldn't there be sound with just one pre volume and both 50/50 volumes ,if it's mono?

 

[GuitarMan]

Ok I have the 50/50 and I am an electronics tech so here is what I have found this amp is 2 independent channels the input for Both A and B goes through one 12ax7 but if you know tubes you know that 12A?7's are a duel triode so one side of v1 is for channel A and one side for channel B now these are fed through the circuit one side to v2 and one to v3 these are the tubes that you could say drive the power tubes which are 6l6 tubes if you are looking at the amp from behind the tubes are the same orientation as the volume knobs channel A first 2 tubes and B second 2 tubes if you are looking from the front they are reversed best way to tell you is that the 2 tubes closest to the output jacks are for channel A and the other 2 are for B. I hope this clears things up thanks.