Hello
Pls,i need answer of more expirienced people,is it be good working point of ecc88 like cathode follower on 60 volt on anode and 13 ma cathode current (i need for one experiment with headphone amp) Only thing that i have problem is that that i canot put more than 60 volt on anode,that is maximum and i want to get maximum current.Thanks
Pls,i need answer of more expirienced people,is it be good working point of ecc88 like cathode follower on 60 volt on anode and 13 ma cathode current (i need for one experiment with headphone amp) Only thing that i have problem is that that i canot put more than 60 volt on anode,that is maximum and i want to get maximum current.Thanks
That operating point has only about 1/2 Volt negative bias, which is really very small, especially for such a high gm valve. The potential issue is that the grid looks somewhat conductive to the driving source, and conductance will non-linearly vary with signal.
If driven from a low impedance and/or for small signals this might be just fine. Try it and see - can't hurt anything.
All good fortune,
Chris
That's a tough one!
for low voltage and low filament current maybe ECC86 (even so I believe it has more than 0,3A).
Power will be on the short side for headphones, but there are way around that.
For higher power tubes, filament power grows fast...
What SY said....
Nevertheless, we are missing even more data here. For one, what kind of a PSU it is. There are always options for voltage doubling/multiplying if it's derived from an AC source, which lifts the 60V requirement.
Secondly, getting decent current through an ECC88 and siblings at such low voltages practically makes it a requirement to use a CCS in the cathode, and that would of course have to be a semiconductor based one to get the low minimum required voltage for the CCS to work, hence leaving more for the ECC88 (of course one has to figure in the required swing).
Finally, how many ECC88s are at disposal? Multiple sections, with each their own CCS AC coupled (one cap per section into a common output node) can do quite a bit... he does state 300mA heater, so that limits us actually to less than one ECC88 (or exactly one PCC88) but it's not clear if it's per channel or for the whole amp?
Nevertheless, we are missing even more data here. For one, what kind of a PSU it is. There are always options for voltage doubling/multiplying if it's derived from an AC source, which lifts the 60V requirement.
Secondly, getting decent current through an ECC88 and siblings at such low voltages practically makes it a requirement to use a CCS in the cathode, and that would of course have to be a semiconductor based one to get the low minimum required voltage for the CCS to work, hence leaving more for the ECC88 (of course one has to figure in the required swing).
Finally, how many ECC88s are at disposal? Multiple sections, with each their own CCS AC coupled (one cap per section into a common output node) can do quite a bit... he does state 300mA heater, so that limits us actually to less than one ECC88 (or exactly one PCC88) but it's not clear if it's per channel or for the whole amp?
Yes, quite right!Thank you for fas replyit lot of helps me..ok i will answer on question..yes i think to drive 32 ohm headphone but with ecc88 parallel..that means,2 ecc88 for stereo and one for preamp..but it must working on 60 volt.i was thinking that maybe i can have current throw cathode of about 26ma,27ma.and how i think that will maybe be good for 32 ohm headphone.
Thank you
Thank you
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