heisthl wrote:Yeah, Tremolo, especially photo resistor tremolo is a tone killer. I know some of the brown faces had an tremolo on V1 that was unique sounding but even those played with the tone. The tube oscillator type on the output grids does not seem to affect tone. My favorite is the Fender custom shop circuit
The Dumble amps with tremolo I know myself all sounded fantastic - some of the Dumble amps I liked best.
How do you like the trem of some tube based fx-devices like the Surfbox?
Max wrote:
How do you like the trem of some tube based fx-devices like the Surfbox?
Max
I've never heard one - one of my local customers has a Voodoo labs one that sounds great whenever I hear it - I like the Rocktron's because they only have the 2 knobs, are cheap, built like a tank and sound like a Fender.
angelodp wrote:What about having a volume knob on a tremolo unit to be sure that you don't get that dip in volume when you go for it??
FWIW.. One of the things I liked most about the Demeter was there was no drop in volume..very transparent when switched off... kept it's low end and was also very quiet..no hiss and no tick..
Tony
" The psychics on my bench is the same as Dumble'"
Coming back closer to the #8, I notice on the #40 schematic that the PI is shown as a 7025 but has plate loads of 47K and 51K, more attuned to a 12AT7.
Is the schematic correct? Those values are marked (O) which means observed values on a similar '70s amp.
Since #8 is much earlier than #40, is it likely that #8 would have had a 12AT7 PI rather than a 12AX7?
David Root wrote:Coming back closer to the #8, I notice on the #40 schematic that the PI is shown as a 7025 but has plate loads of 47K and 51K, more attuned to a 12AT7.
Is the schematic correct? Those values are marked (O) which means observed values on a similar '70s amp.
Since #8 is much earlier than #40, is it likely that #8 would have had a 12AT7 PI rather than a 12AX7?
As far as I know, the first generation amps are different in circuit, layout and parts than the second generation amps like #40. At least one of these first generation amps had a 12AX7 phase inverter. Its tone and OD circuit and the resulting gain and harmonic structure was very different from the second and third generation amps I know.
The first generation amp I know was a lot more "fendery" than the second and third generation amps I know. That's why I doubt, that you can clone #8 by using a second or third generation schematic like the one of #40, even if it is correct for #40 what I don't know.
But who knows what was really inside the amp Lindley recorded ROE with, if he even seems to be no longer completely sure (at least as far as I understand it) if he used #2 or #8 for the recording?
#13 which was an ODSR 100 watt was very similar to #40..This amp was built around 8-28-76... Although it had reverb... aside from the different pot values Middle-250k/Bass-1m/Treble-1m/OD-100k/ Vol-1m/Master-1m
It still had 47k/51/k PI plates....100k plate 1.5 w/4.7 throughout..OD entrance the same 220k/w 500pf---33k to ground bypass 1.2M..This being 5 amps away from #8..
Tony VVT
" The psychics on my bench is the same as Dumble'"
I can't really tell for sure if the lower plate PI was designed for an AX or AT maybe Max can clear it up.....I would guess you could use either.. The lower plate resistors on the PI translates to less voltage drop across the resistor lowering the headroom of the PI.. Maybe he liked the tone and linearity of the AT but wanted to get more breakup from it would be the only thing that comes to mind as to why he would go there.. Max Help!!
Postings were from an original hand drawn layout of #13 drawn and signed by the man himself..Layout didn't specify AX or AT Sorry!!
Tony
" The psychics on my bench is the same as Dumble'"
Plus the reports from Max that stated that many 70's ODS owners replaced the 12at7 for a 12ax7 because they liked the OD tone better with the 12ax7 make the actual tube in the socket not a good indicator. The question is: 'What was the designers' intention?'
