sjaak1990

Hello,
I have bought a Marshall dsl 50 second hand.
It is from 1997.
I use the 16 ohm output into the 16 ohm input of my 1960a cab
I did not like the stock mid high character of the stock preamp tubes so i changed them to tung sol tubes. A v1 tube in the v1 and a balanced in the v4.
After 1 hour of playing I killed the tube in the v2 slot, and put a temporary standard tube in it. I got a new tube and tried it again, now it died after a few days and i put a temporary standard tube in the slot again.
Again a new tube this time a JJ v1, I put this tube in v3 and the tung sol i installed in de the v3 in the beginning in v2. After a week the tubes were getting burned in nicely but then the JJ died. I put a stock tube in this slot and after a few days another tung sol died, this was was in the amp for a few weeks and since then I am using the stock tubes.
I hate the stock tubes, but other tubes get killed. Does anybody have an idea about the tube killing, the reason and the solution? The stock tubes keep working and are most likely 11 years old, so can it be due the quality of the replacement tubes?

Thanks in advance...

PS: sorry for my bad English

steelhorse

I know all you're doing is replacing the pre-amp tubes but I wonder about the bias of the amp?

sjaak1990

Uhm you dont have to bias the preamp tubes?
The poweramp tubes are biased at 41mv (82mv).

steelhorse

Uhm yeah I realize you don't have to bias the pre amp tubes...

Just wanted to double check that the -amp- has been biased and the specs you gave are certainly within range in fact they're at the low end.

Sound like another component is fried like perhaps a screen grid resistor?

Definitely get it checked by a tech if it's burning through tubes like yours is.

sjaak1990

Thanks for your reaction.
I have heard that marshall amps have problems with tung sol tubes in the v2 and v3 and that more people have got this problem.

steelhorse

Keep us posted with the results. I hope it will be as good as new once it's repaired!