Works stable and sounds more than just fine with triode tubes but I`m wonder if this old OTL amp concept from early 50` is applicable for modern various J-Fets and SIT power devices ? ,
short circuit description ; Q1 is the input transistor which achieve major voltage gain and is AC coupled to Q2 gate , Q2 is phase inverter where its drain is 100% positive bootstrapped from loudspeaker output line which achieve dynamic asymmetric drive for SEPP output power pair , Q2 drain drives Q3 gate and in the same time Q2 source out of phase drives Q4 gate , P1 trim-pot regulate current via Q2 and in the same time regulate Iq of the output Q3 & Q4 SEPP power pair , B+=48V is chosen for deep A class of operation of SEPP- OPS ,
yours suggestion and critics are welcomed , guys with Spice skills also is welcomed .
short circuit description ; Q1 is the input transistor which achieve major voltage gain and is AC coupled to Q2 gate , Q2 is phase inverter where its drain is 100% positive bootstrapped from loudspeaker output line which achieve dynamic asymmetric drive for SEPP output power pair , Q2 drain drives Q3 gate and in the same time Q2 source out of phase drives Q4 gate , P1 trim-pot regulate current via Q2 and in the same time regulate Iq of the output Q3 & Q4 SEPP power pair , B+=48V is chosen for deep A class of operation of SEPP- OPS ,
yours suggestion and critics are welcomed , guys with Spice skills also is welcomed .
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you know saying in your neck of wood - everything is possible, even wooden stove 🙂
me, being short these days with time, will not think much of it
however, if you need some small signal JFets to play with, just say
can't help with big ones, unfortunately
btw. I know you did draw that neg PSU just in principle
me, being short these days with time, will not think much of it
however, if you need some small signal JFets to play with, just say
can't help with big ones, unfortunately
btw. I know you did draw that neg PSU just in principle
Man thanks for your offer ! , but big ones J-Fet`s or power SIT`s is also problem for me , and that neg. PSU is not some my principle sketch but exactly how is connected on the amp with triode tubes .
well, you know that that neg PSU is no go without proper rectification and filtration
I mean- it'll work ( as it works in myriad tube amps, guitar or not), but nowadays diodes are cheaper than in ancient times 🙂
I mean- it'll work ( as it works in myriad tube amps, guitar or not), but nowadays diodes are cheaper than in ancient times 🙂
Agree with you ,of course that neg. bias PSU can be better designed with let say full wave rectification and RC filtration , but same as by tubes amps without of any regulation just to dynamically follow changes in B+ line holding OPS Iq steady .
Thanks for your input Mr.Pass !
, honestly I have no idea how to implement single supply for this amp , maybe ZM can suggest some solution ,
but IMHO this amp is already with single supply (B1) except that there`s another one low power negative supply (B2) as power source for Q2 driver J-Fet transistor and in the same time as bias source for output power SEPP-SIT pair ,
YT video shows OTL tube amp based on Sinclair Peterson concept , mine DIY OTL amp is only slightly different since use 10 x 6S19P and one 6SL7 double triode .
, honestly I have no idea how to implement single supply for this amp , maybe ZM can suggest some solution ,
but IMHO this amp is already with single supply (B1) except that there`s another one low power negative supply (B2) as power source for Q2 driver J-Fet transistor and in the same time as bias source for output power SEPP-SIT pair ,
YT video shows OTL tube amp based on Sinclair Peterson concept , mine DIY OTL amp is only slightly different since use 10 x 6S19P and one 6SL7 double triode .
Attachments
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