My VTA ST120

corndog71 wrote:

arledgsc wrote:Gulp!      Be sure and bleed those caps before working on the amp..

Nice amp.  All this amp building creativity is giving me the itch to build a KT150 amp.

If you can find suitable transformers let me know.  Sounds like fun!

Edcor.com

450-0-450 vac @ 300ma + 6.3 vac 6amps for power transformers, I got from Edcor.

Edcor.com

450-0-450 vac @ 300ma + 6.3 vac 6amps for power transformers, I got from Edcor.

  That should do it!

I replaced the 12AU7 driver tubes I was using for a set of RAM Labs standard grade 12BH7 tubes. I don't know what the original makes of the tubes are. If I can ever get this amp out of my rack maybe I'll take a closer look. For the time being I'm too busy listening to music.



Noise went down and width, depth, and clarity improved.



I really want to get KT120s but so far these 6550s sound really good. Someday...

I made a small change. I swapped the Clarity Cap ESA .1uF caps for Clarity MR series .1uF caps. It was sounding great as is but I know the MR caps are much more transparent than the ESA series particularly in the higher frequencies. I didn't notice a huge change although separation of instruments in the soundstage seems better. Plucked and strummed strings seem more dynamic. Or it could just be in my head.   

I kinda feel like Skizo by posting yet another pic of my amp  but here goes.



Notice anything different?

Notice anything different?

Just guessing triode/ ultralinear switches ??

arledgsc wrote:

Notice anything different?

Just guessing triode/ ultralinear switches ??

We have a winner!  I forgot to take a pic after installing them so this is an under the hood shot.  Not the greatest but you get the gist.  I didn't even need the terminal strips.



It's getting a bit crowded in here.





I have to admit that triode mode sounds way better than I anticipated. I had converted my first ST70 (with Curcio mods) around a decade ago and for whatever reason didn't care for it. The last few nights listening to Dave Brubeck, Mozart, Chopin, and Vivaldi have been quite glorious.