2. amps-preamps
  3. 1156019648

Tubes to replace stock in Quad II Forty's amps?

Have a pair of Quad II Forty amps and have decided to retube them in an effort to get rid of some intermittent hums and pops. Great sounding , want to them to sound even better.
I have ruled out GEC 's and such , as money is sort of an issue. Svet's, SED, EH, KT88's , KT90's? Etc.. Ideas. Also, will the brand of rectifier tube(5U4G) make difference in overall sonics?
Lastly, will the input tubes 6SH7 matter in the picture.I been told to suspect these as a source of pops and spitting noises on rare occasion.
Thanks, again. I am new to the world of tubes.
montyoldboy
dewald_visser
176 posts
 
Avoid untested tube unless you can test them before you put it in your amps! A faulty input-tube can destroy a power-tube... Be very careful!

Regards,
Dewald Visser
dogberry
804 posts
 

Waking up an ancient thread here! I've owned Quad II/Forty amps for nearly 18 years, and have experimented with various tubes. I haven't found a better rectifier than the Svetlana (St Petersberg) 5Ц3C black plate. I have been using Sophia Electric blue glass coke bottle KT-88s, and have been happy with them. In the interest of widening my options though, I was reading great things about Svetlana Winged C 6550C. Am I correct in understanding that these are a drop-in replacement for KT-88 tubes?

newbee
4,813 posts
 

Those St Petersburg Svetlana/SED 6550's haven't been available for some time. I replaced mine with Tung Sol 6550's. Gold Lion KT88's get the job done as well and seem to be well received by most folks. However I haven't heard these tubes with your amps. 

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