Sunn T50C tube recommendation and Bias settings help.

[norke]

Hi everyone,

i'm new here hoping to find some people help me figure out which tubes to get or suggest your ideas.

I have a Sunn T50C amp. It had the original tubes so i bought some last week and when i setted the bias i had a small problem.

In the manual it says 6L6GC tubes, bias should be 30mVDC.

I did the balance without problems but i can't get the 30mVDC with the new tubes.

New tubes are JJ 6L6GC and the old ones were the same but made by fender and sovtek.

The problem is that i can't go up to 30mVDC with the new tubes but i can with the old tubes.

So i'm basicly running the tubes less than i should right?

I can't go up to 30mVDC because the potentiometer for the bias behind the amp gets 24mVDC when it's fully clockwise at it's maximum.

I bought the tubes at thetubestore and i thought i could use any 6L6GC as he did not mentioned me this by email, he just sent me the link to the 6L6 tubes.

Anyways.. feel free to leave your opinion or suggestion about what i should do.

I don't like the idea of driving the tubes less than it should be, i love how it sounds with the old tubes properly biassed.

Thanks a lot!

Here's a screenshot of the manual for the tube section.

http://www.sunnamps.com/pdfs/manuals.../Sunn_T50C.pdf

[Empty Pockets]

Re: Sunn T50C tube recommendation and Bias settings help.

I can't help with your technical problem, but I wanted to chime in and say that I had a Sunn T50C that i wish i never sold so if you ever want to get rid of that thing you could probably sell it to me...

[norke]

Re: Sunn T50C tube recommendation and Bias settings help.

I can't help with your technical problem, but I wanted to chime in and say that I had a Sunn T50C that i wish i never sold so if you ever want to get rid of that thing you could probably sell it to me...

hehe yeah it's really a nice amp, i don't think i will ever sell it but if i do i will try to remember you

[Lake Placid Blues]

Re: Sunn T50C tube recommendation and Bias settings help.

You basically have three options:

1) Run the tubes at less than the recommended setting if it sounds good. The bottom line is how it sounds. If the tubes were running too hot or red plating this would not be an option, but running cold won't hurt anything. If it doesn't sound good though...

2) Get a different set of 6L6s that will bias within the bias range of the amps bias pot.

3) Start adjusting the bias pot range by soldering in different resistors in the bias circuit....

[norke]

Re: Sunn T50C tube recommendation and Bias settings help.

You basically have three options:

1) Run the tubes at less than the recommended setting if it sounds good. The bottom line is how it sounds. If the tubes were running too hot or red plating this would not be an option, but running cold won't hurt anything. If it doesn't sound good though...

2) Get a different set of 6L6s that will bias within the bias range of the amps bias pot.

3) Start adjusting the bias pot range by soldering in different resistors in the bias circuit....

Thanks for your suggestion but #2 and #3 are not possible in my case as i'm not that good with electronics and soldering.

I'm trying to return them to thetubestore online website but he doesnt seems to accept them... i only used them about 5 minutes to test the bias settings...

I will remplace them i think...