How should I install the new tubes in my stereo amplifier?


Hi Audiogoner,
It is time to change the tubes in my Shindo El84 amplifier, and I am ordering a new set of tubes which included the two matched pairs of Mullard EL84.
My question is: Should I install one matched set on each channel or split the matched set to half and install to each channel to keep the amp balance?
Thank you
dangcaonguyen
Matched pair in each channel. 
Thanks Newbee,
Is there a reason to install that way? It seems to me if we do that way, the amp will be unbalanced. My be I dont understand clearly of how the amp works.
Thanks
Well I don't know how your amp works either. But I assume two things, 1) it is a pp el84 amp and you have to bias it manually. Some amps have a bias adjustment for each tube, some have one bias adjustment for all of the tubes assigned to one channel. 

If you have the ability to bias each tube individually then even  using 'matched' tubes is just a bit of frosting on the cake, so to speak. A good thing, but not essential.  

 If you have only one bias pot for all of the tubes dedicated to one channel getting matched tubes is essential. If you split up the pairs you would no longer have a optimal bias setting in either channel. 

Its a wild guess but I think your amp has a bias pot for each channel. If that is so what is really essential is to properly bias your tubes initially to the manufacturer's recommended setting and thereafter regularly check the setting to insure they are operating properly. If you find a tube bias' drooping and/or you can no longer bring it's bias up to match the other tube in the same channel you will probably find it beneficial to replace the tube.

Hope that helps a bit.

 


Correction -

1st sentence, last paragraph - 'each channel' should be 'each tube'.
Thanks Newbee.
Yes, it helps a lot. I cant find any bias pot on my amp. I will have to check with someone to see if it is auto bias.
Calvin
Matched tubes must be placed in one push-pull pair per each channel.
Newbee is correct. A matched pair should be placed together. This insures that the amp has the lowest distortion and makes the most power.

If they were to get mixed up, you would be far more likely to experience a channel imbalance! Keep your matched pairs together.
Thanks Gentlemen,
I just talked with Matt at Pitch Perfect Audio. My amp is autobias. I only need to install a good set of tubes and i am good to go. You are right about the matched pair shoud come together.
thanks