search4sound wrote:I read somewhere that one reason why tremolo (aka vibrato) is removed from Twin Reverb and other amps with similar trem circuit is that this circuit can load down the circuit creating suboptimal tone. Any truth to this?
In the case of Jerry's TR mods, I assumed the reason for removing the trem was to free up the tube to be used for an extra stage. Maybe it was both? Related to this, I wonder if anyone has the vibrato mod and has A/B'd the normal channel (stock) and the vibrato channel (extra stage, no vibrato). How do they compare?
In the case of the Princeton, I read that the way the trem is connected does not load down the circuit. So I presume that I can turn down the intensity to 0 and the vibrato should sound the same as the normal channel?
+1 on the tonestack mod. I'll do the cathode bypass caps on the triode stages as well. I suppose I should consider replacing all the electrolytic caps, that amp is almost 40 years old.
Thanks for you recommendation not to upgrade the speaker to 12" or increase the gain - I've long wanted a push pull amp that sounds good at lower volumes. So do you still get shimmering Garcia clean with a 10" speaker?
What about preamp tapping the Princeton? Anything keeping me from doing that? Is it done the same way as with a TR?
search4sound wrote:Yes, Waldo's site shows how when the TR is used as a preamp with McIntosh for amp, the vibrato channel is used but the vibrato itself is removed from the circuit.
I'm not sure if this frees up the vibrato triode to be used as an extra gain stage, or if it is completely out of the circuit and the exctra stage I've heard referred to is actually the triode associated with the reverb that gets used in the vibrato channel. Now would thet be a 12AX7 or a 12AT7? And does the dry signal before the reverb get amplified before the signal splits off to the reverb, or does the signal split off and then only the reverb signal is amplified before being mixed back into the dry signal?
Return to Grateful Dead Equipment Discussion
Users browsing this forum: Bing [Bot] and 4 guests