Hey all,
Attached are set up instructions for the Futterman H3 OTL amp written up by JF himself from way back. I have used this for a while now (read years) to set up my Futterman OTL's. Never questioned the crossed out original numbers and the written in red new ones. Any thought on these changes from the rest of you guys? I suspect many of you have seen this before out on the web. Just wondering what you guys might think about the reason the voltages are changed.
Thx A
Attached are set up instructions for the Futterman H3 OTL amp written up by JF himself from way back. I have used this for a while now (read years) to set up my Futterman OTL's. Never questioned the crossed out original numbers and the written in red new ones. Any thought on these changes from the rest of you guys? I suspect many of you have seen this before out on the web. Just wondering what you guys might think about the reason the voltages are changed.
Thx A
Attachments
I have always heard, and believed, that Futterman amps were a never ending work in progress with continued revisions and updates. This just seems like further conformation of that. Are these red notations by Futterman himself or that of someone else like a previous owner? Do they apply to your amps specifically or to another model? Perhaps they are there to improve tube life and/or performance.
These are set up instruction that apply to the Futterman H3 OTL only. I do not know if these changes were made JF himself or not. I got this document years ago from someone and just started using it with no real issues but I was rebuilding my latest Futterman H3 amp and just for the 1st time said to myself... I wonder if...
1. would it not be better if the voltage was down at 225 as opposed to250.
2. would it be better if the 45 volt bias remained there as higher bias voltage would mean less current which for an OTL current can always be the killer if things start to run in the wrong direction. The revised number is 40 volts.
3. why change all of those above numbers but not the mid tube bias which still stays at 180 v.
Those were my recent thoughts,
Any comments on those would be interesting to here.
Thx
A
1. would it not be better if the voltage was down at 225 as opposed to250.
2. would it be better if the 45 volt bias remained there as higher bias voltage would mean less current which for an OTL current can always be the killer if things start to run in the wrong direction. The revised number is 40 volts.
3. why change all of those above numbers but not the mid tube bias which still stays at 180 v.
Those were my recent thoughts,
Any comments on those would be interesting to here.
Thx
A
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