I might do it in the near future..... although I really like the sound of my stock build 🙂
can you suggest an alternative jfet for the 182mA CCS (instead of the LM317) ?
can you suggest an alternative jfet for the 182mA CCS (instead of the LM317) ?
RCruz - have you a schematic for your own build?
There are a variety of CCS out there, but usually the build is more complex... and LM317 was what I had to hand.
Fran
There are a variety of CCS out there, but usually the build is more complex... and LM317 was what I had to hand.
Fran
You have much more capacitance on the output - did you try different values there? Or try bypassing the cap?
No, I did use what I had in my stock... anyway, it sounds really good this way.
Two series polar caps makes a bipolar one with lower distortion although a little more ESR but it works very well.
Two series polar caps makes a bipolar one with lower distortion although a little more ESR but it works very well.
Salas BiB... double mono... before that I have kentoken Kmultiplier... I experimented a lot with several psu and the design responds to the slightest change.... now it is incredibly smooth with bite and attack. No harshness, just power.
Richard - the boards arrived yesterday safe and sound. I soldered up most of them last night, but didn't get to test - will be powering them up later.
Fran
Fran
My original prototype boards were customized to match high impedance headphones. I made the mistake of setting the circuit gain too high: I ran out of open loop gain, and it was a mess.
I scrapped the custom boards (which were, sadly, rather nice with Nichicon MUSE, 2SK214 FETs) and subbed the stock circuit on the shipping boards. The gain is about 3x (10 dB) so the distortion of the input section is kept well in check. Unfortunately the low gain rules out my HD600s, but I'll keep the amp for low impedance use as it sounds pretty nice.
I scrapped the custom boards (which were, sadly, rather nice with Nichicon MUSE, 2SK214 FETs) and subbed the stock circuit on the shipping boards. The gain is about 3x (10 dB) so the distortion of the input section is kept well in check. Unfortunately the low gain rules out my HD600s, but I'll keep the amp for low impedance use as it sounds pretty nice.
Attachments
Test notes:
With a gain of only 10 dB, this is a bad match for my HD600 references, and I don't have a decent set of low impedance headphones in the house.
Fortunately the JFet input stage means the circuit is tolerant to being used with the volume control cranked up to 2-3 o'clock, so I gave it a try.
Okay, so its surprisingly good! I mean, it doesn't sound like my previous experience with MOSFET followers, which were warm and muddy: this is clean and precise, with no hint of high 2nd harmonic, and it convenes that low-level, micro-perfection of timbre that I associate with single-ended output stages.
If it loses anything to the other headphone amps I have here (see photo), its because the parts quality just isn't quite up to the same standard, the others being fully cost-no-object, high-end equipment. So maybe its a little bit ragged in comparison, but very respectable nonetheless. (And a lot of that might very well be the missmatch between headphone and amp.)
With a gain of only 10 dB, this is a bad match for my HD600 references, and I don't have a decent set of low impedance headphones in the house.
Fortunately the JFet input stage means the circuit is tolerant to being used with the volume control cranked up to 2-3 o'clock, so I gave it a try.
Okay, so its surprisingly good! I mean, it doesn't sound like my previous experience with MOSFET followers, which were warm and muddy: this is clean and precise, with no hint of high 2nd harmonic, and it convenes that low-level, micro-perfection of timbre that I associate with single-ended output stages.
If it loses anything to the other headphone amps I have here (see photo), its because the parts quality just isn't quite up to the same standard, the others being fully cost-no-object, high-end equipment. So maybe its a little bit ragged in comparison, but very respectable nonetheless. (And a lot of that might very well be the missmatch between headphone and amp.)
Attachments
Sounds tight, dynamic with fully controlled bass and finely detailed treble.
Mids are perfectly integrated in the soundstage.
And it is silent 🙂
Mids are perfectly integrated in the soundstage.
And it is silent 🙂
I know, and this is such a rugged little circuit! Runs off just about anything, and essentially worry-free: set the bias once with the trimmer and you're done. With output coupling caps JFET inputs, and protection diodes, it can take more than its fair share of abuse and still sound great.
- Status
- Not open for further replies.