My impression is this ECL91 tube is unusually bass and
especially mid oriented in tone? I have slowly tweaked the amp over the last several wks (doing a tweak or two at a time). Some things I tried got put back to original.
I kept finding myself trying to dial in more treble or less mids. Where I had .01 coupling caps after the 5879 and into the LTPI ............. I changed those to .0047. I noticed (after the fact) that the "Impact" amp by Darryl used .0047 caps also.
I am attaching the changes I have made from the original schematic. It is already updated in the SCH library also.
What I kept doing is lessening mids, adding highs and then adding smoothing caps. The amp is not far behind in smoothness than the TBM or TOS amps. AND it is getting pretty close to the same in sustain also. However, it doesn't have the "blooming" effect that the TBM or TOS amp has even though the sustain is somewhat similar.
I also would say despite using the .0047 caps that the amp still has similar mid accented tones like the TBM and TOS which is a preference for me. BTW, I find the PAB and mid boost very useful on this amp.
The amp has great harmonics. Since I prefer smoothness over chimey-ness, the smoothing caps sound excellent to me.
The smoothing caps do NOT change the transparency of tone, IMO at all. It does cut down the high end ringing/chimey tone though. IF you like the chimey tone, then leave out the 10pf caps to ground and the 220p cap from V2-1 to V2-3.
This small amp sounds HUGE to me with the digital delay. And it is very touch sensitive and transparent. This is a really fun amp to play. The amp started off as a "great" sounding amp and now has the "wow" factor going for it, to my ears.
I have indicated the changes on the schematic attached.
With respect, Tubenit
I have a hard time getting good recordings of an overdriven nature, so I acknowledge the soundclip is just "ok" but you can get the idea of the kind of sustain it has.
Keo, it
is the recording. I agree with your comment that the (non-backing track) recording sounds a "bit" muffled. The brief lead "solo" part on the recording does a better job of giving an example of transparency than the rhythm and chording.
For some reason, I have a terrible time getting good overdriven recordings. That holds true fot the TBM and TOS amp also in recording. They end up recording being significantly more compressed than in person.
Live, it has a VERY transparent tone compared to the Princeton Reverb I used to own which sounded gritty/muddy to me.
This recording was before the recent changes which improved the smoothness and lessened the mids.
Check out the recording starting at 2min & 30 seconds into it for a cleaner tone example. Ignore the sloppy playing, please.
http://www.soundclick.com/player/single_player.cfm?songid=11187585&q=hi&newref=1
