adamus
500+ Head-Fier
- Joined
- Feb 29, 2008
- Posts
- 939
- Likes
- 74
Hi all.
Thought i would post this here.
There has been some discussion on diyaudio about the sonic merits of a mosfet gyrator Vs a CCS anode load for triodes (or in this case a triode wired pentode - the D3a)
I have already built a CCS loaded d3a amp so now i am building a gyrator version to try. The salas HV shunt is used for B+, leds for bias.
circuit here
Power supply is shown below. the only change is that i am using 30r instead of the 56 shown, this gives 60ma total, 40ma for the load and 20ma for the shunt (it needs a margin)
I have just about finished the perf board prototypes. The HV shunt is done and tested so we are nearly there.
IF anyone spots any issues with the circuit, please shout. Rather than go round in circles, there has already been a discussion about the relative merits of parafeed Vs single end OPT, so lets not go through that topic here.
Cost is mostly dependant on the output transformers, whilst testing i am using some super cheap edcors ($20) but if this shows promise then electraprints will be purchased.
My guess is all parts, excluding the case can be bought for <$200
Thought i would post this here.
There has been some discussion on diyaudio about the sonic merits of a mosfet gyrator Vs a CCS anode load for triodes (or in this case a triode wired pentode - the D3a)
I have already built a CCS loaded d3a amp so now i am building a gyrator version to try. The salas HV shunt is used for B+, leds for bias.
circuit here
Power supply is shown below. the only change is that i am using 30r instead of the 56 shown, this gives 60ma total, 40ma for the load and 20ma for the shunt (it needs a margin)
I have just about finished the perf board prototypes. The HV shunt is done and tested so we are nearly there.
IF anyone spots any issues with the circuit, please shout. Rather than go round in circles, there has already been a discussion about the relative merits of parafeed Vs single end OPT, so lets not go through that topic here.
Cost is mostly dependant on the output transformers, whilst testing i am using some super cheap edcors ($20) but if this shows promise then electraprints will be purchased.
My guess is all parts, excluding the case can be bought for <$200