this is just #2380th post in thread ;
and , if you're fast enough , maybe you will hear some music prior to Boom ........ Big Badaboom
YouTube
apples and oranges
F4 and BA3 OS - they sound exactly as gain stage feeding them
M2 sounds divine ( while being complete power amp , thus having OS and gain stage)
F4 and BA3 OS - they sound exactly as gain stage feeding them
M2 sounds divine ( while being complete power amp , thus having OS and gain stage)
The input jfets on M2 are buffer to drive the autotransformer that gives voltage gain.
So no real transistor gives voltage gain, it should sound transparent as F4 and BA3 PP OS?
Is it possible to use more common jfets with lower transconductance?
Thinkig of K246/J103 or 271/310 or 2n5462/2n5459
or any other you could advice?
170/74 are unobtainium nowdays
So no real transistor gives voltage gain, it should sound transparent as F4 and BA3 PP OS?
Is it possible to use more common jfets with lower transconductance?
Thinkig of K246/J103 or 271/310 or 2n5462/2n5459
or any other you could advice?
170/74 are unobtainium nowdays
they are not unobtanium - buy LSK from DiyA Store
as stressed numerous times - they're not expensive in overall scheme of things
regarding your question about source followers - you're squeezing dry wood , without actually giving proper context for your asking
if used in non-stressed area (current to speakers adequate for number of mosfets) , all 3 OS will sound practically the same , as long they're driven with enough cojones
so , F4 , BA3 OS , M2 sans buffer ...will all sound the same ....... though M2 will loose steam sooner than other two
as stressed numerous times - they're not expensive in overall scheme of things
regarding your question about source followers - you're squeezing dry wood , without actually giving proper context for your asking
if used in non-stressed area (current to speakers adequate for number of mosfets) , all 3 OS will sound practically the same , as long they're driven with enough cojones
so , F4 , BA3 OS , M2 sans buffer ...will all sound the same ....... though M2 will loose steam sooner than other two
to ship in europe LSKs are quite expensive but I know if no one orders them then they will die...
M2 is less tolerant to difficult loads because only one pair of IRFP
in any case I plan to build de PP buffer with one pair, speakers are JBL 2226 and 2447
As I drive it directly from the DAC, do I need the input jfet buffer? and if yes could you advise me on some alternative findable ones?
Maybe I will use a step up transformer à la M2, 3dB gain, as I don't need more with high sensitivity speakers. but I can live with 0dB gain for normal volume listening
M2 is less tolerant to difficult loads because only one pair of IRFP
in any case I plan to build de PP buffer with one pair, speakers are JBL 2226 and 2447
As I drive it directly from the DAC, do I need the input jfet buffer? and if yes could you advise me on some alternative findable ones?
Maybe I will use a step up transformer à la M2, 3dB gain, as I don't need more with high sensitivity speakers. but I can live with 0dB gain for normal volume listening
To me the M2 sounds a little warmer with slightly softer high end. The F4 doesn't really sound like anything, you just hear whatever comes before it.
sorry , you didn't said anything about your DAC , so I can't say what's drive ability
regarding JFet buffers ..... I'm working on something and as soon I have prototype/foolproof phase finished, Greedy Boyz will be informed
There aren't many good through-hole devices left in production. Are you relying on surface mount devices? Maybe MMBFJ271...
considering that load resistance (given in datasheet) is 600R , we can assume that you can connect follower stage directly
though , my experience is telling me that proper additional buffer will result in better sound
as with many other things , you can be sure only after trying it all
if you are content with simplest solution , goal is fulfilled - just enjoy in music and forget all technicalities
though , my experience is telling me that proper additional buffer will result in better sound
as with many other things , you can be sure only after trying it all
if you are content with simplest solution , goal is fulfilled - just enjoy in music and forget all technicalities
plenty of solutions with BF862 around
M2 Iq is automatically set and , say, between 1A2 and 1A5 , depending of parts you actually have
M2 Iq is automatically set and , say, between 1A2 and 1A5 , depending of parts you actually have
I think that's exactly what NP said about the M2's sound. Unfortunately I lost my M2 to a friend and I don't think it's coming back (it's ok, he has some stuff I want to trade with him). I'm listening to the F4 for now and It's preferable to me on some recordings.
as said numerous times - F4 and BA3 OS can't be compared with any other Papamp , simply because they are always paired with some additional gain stage ....... embracing fully (well , 98%) imprint of that stage on sound
OK - yes , in rare occasions , where someone really doesn't need any additional gain , driving source followers directly from source , we can take them as amplifier itself
however , those occasions are unfair to regular (gain-having
) amps
OK - yes , in rare occasions , where someone really doesn't need any additional gain , driving source followers directly from source , we can take them as amplifier itself
however , those occasions are unfair to regular (gain-having
) ampsA friend and me are working on this HA amp. We have a regulated PSU with B+-15 volt and a trafo with 15volt@2.1A x2 and we used your schematic.
We have two issues:
One is when we connect to our amps, B- rail falls to -14.40volt and B+ rail falls to 14,8volt. 😕😕
Other is the Offset around 300~400mVolt (very high for a headphone amp).
We instal a 1k trimpot in serie with R6(10K) on the positive rail (similar to M2 design) and now we have a best control of the offset but the voltaje in both rails is still very different.
I readed notes of Nelson about opto, and he says that the both rail needs to have exactly the same voltage for the opto works correctly so obviously our opto doesn´t work because we have a difference about 300~400mvolt between rails.
My amp sounds (I have a little hum but I think that is a ground problem) but is very unstable. 🙁
Please, can you think of an idea? Am I missing any detail?
Thanks
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