Interesting measurements. The choice of capacitor really depends on the rest of the components and your taste too. There is not one good cap. It's the same with opamps. It really depends on the rest of the components and the music you listen too and even the DAC you combine it with and the headphones. I can only describe difference between them in sounding but even then I noticed that some components respond differently than other times with other components.
This is the Finished device for a while.
Nice lookin' ey!
I will build my DAC first and see if I still need to replace the opamp caps.
This is the Finished device for a while.
Nice lookin' ey!
I will build my DAC first and see if I still need to replace the opamp caps.
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The first of the headamps that will be compared to the BCL clone is done.
It's the AD797+BUF634 headamp.
Only had time to listen to it for about 30 minutes, and with Sony IEM's as I never hook my Fidelio X2's up to a new build.
First impressions are good though.
DC offset at max 8.4mV with signal(music playing) and HP's connected. But declining with time.
It's the AD797+BUF634 headamp.
Only had time to listen to it for about 30 minutes, and with Sony IEM's as I never hook my Fidelio X2's up to a new build.
First impressions are good though.
DC offset at max 8.4mV with signal(music playing) and HP's connected. But declining with time.
Yes, the PCB is this one
An externally hosted image should be here but it was not working when we last tested it.
This and the BCL was originally intended as temporary until I got my own perf boarded headamp done.
Now I might keep one of them even when done with mine.
About the XP7, in my own simulations with AD797, I found that an inductor in series with each supply was benefitial.
This PCB does not have that, I might cut the +/- traces to the AD797's and put a low resistance 22uH inductor on each at some point.
Not having much experience with these opamps, I own three versions but don't know which is the better one?
AD797AR, AD797BR or AD797AN(only one of them in DIP8).
If you've not studied it already there are some plots of sims with inductors in the supply lines of a similar composite headamp, here : http://www.diyaudio.com/forums/head...omments-advice-appreciated-3.html#post4482677
Hi there my friend 🙂
No I have not studied that thread, I only compared output FFT with/without inductors on the PS lines for the AD797.
Haha, don't know how great my mind is..maybe more like a beautiful mind...haha.
PS. got a couple of EI33 cores and bobbins last week, alot bigger than the EE25's so should have a wider application?
Still waiting for the counter, and some tools to start building a winding jig.
What you said about different capacitors in different places is so true, and I also should have mentioned that I hadn't used the Panasonic Pureisms anywhere else but on very low current ics, analog applications, ie, a 25v 100uf part where a datasheet called for 10uf 6.3v part.
So maybe that they were derated had something to do with my success, and I dont use the fc capacitors at all, as they are harsh as you described the pureisms.
The pureisms took a long time to settle down as I recall.
Nice that you have it to a point where you can use it.
Oh, must say, looks very nice as well, my stuff looks like kids did it...
So maybe that they were derated had something to do with my success, and I dont use the fc capacitors at all, as they are harsh as you described the pureisms.
The pureisms took a long time to settle down as I recall.
Nice that you have it to a point where you can use it.
Oh, must say, looks very nice as well, my stuff looks like kids did it...
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It's a very good sounding headamp too, it has a bit less dynamics than the Lehmann clone but it's as good and easier on the ears.
Parts selection is critical, though.
If I can I would suggest you to use the same blue dales used by the original manifacturer and, on the contrary, ditching the tantalums.
I've had incredibly good results with LZX on the BUF634 (buy the DIP version, it sounds fuller and better dissipates heat) and Silmics II black/gold on the AD797.
Use FKP2 or Amtrans AMCH for the filter caps, avoid at all cost PFR5 and MKP1837.
I've used Roederstein, Philips and Dale resistors, Silmic II's, MKP380, MKP418 and FKP2 (220pF).
The opamps are AD797AN and BUF634P, I have AD797AR and AD797BR as well.
Got some more parts populated today.
Btw, swapped the FC's for Silmic 100uF and Pana FM 680uF
The 47R by the opamp-socket are 0.1% (Vishay BC MPR24) the rest 1% but all matched.
I used 2x200R and 2x2K2 (in parallel) by the vregs.
The 47R by the Dale's are Vishay BCcomponents MRS25.
The 3R3's are Vishay MR30's.
Thinking of measuring the BC550C/560C's today to find good matches.
Boring and time consuming though...hopefully 50pcs of each will give decently close matches.
Btw, swapped the FC's for Silmic 100uF and Pana FM 680uF
The 47R by the opamp-socket are 0.1% (Vishay BC MPR24) the rest 1% but all matched.
I used 2x200R and 2x2K2 (in parallel) by the vregs.
The 47R by the Dale's are Vishay BCcomponents MRS25.
The 3R3's are Vishay MR30's.
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Thinking of measuring the BC550C/560C's today to find good matches.
Boring and time consuming though...hopefully 50pcs of each will give decently close matches.
Nice update.very curious about the end result. I personally think I've got the maximum performance out of the Lehmann PCB with the parts I've used now. It's just a bit fine tuning on the signal caps for a good match with the next DAC. But this is only flavoring
The amp is punchy, dynamic, fast, ridiculously powerful and crystal clear and without hearable distortion. It's the first amp I've used that can max out the Mad dog headphones without loosing anything. The Mad dogs always keep asking for more power normally.. but the BCL can shut it up and push max out of it.
I am really impressed! I don't think that I need another amp any soon with my headphones in the sub $1000 range.
People say the power supply is the achillesheel of the circuit. What is meant by this? This weak sport would result in what? Less speed? Worse rhythm? Less power? I have no better amp to compare it with, so it's difficult to hear things that are as good as I can have them at the moment.
The only better combination was my STAX lambda classic with the STAX amp that belongs with it. In terms of speed, clarity, instrument separation dynamic and rhythm the STAX is better. But when you bring in the bass for comparison the Mad Dog and the DT1770 do much better with the Lehmann.
I'm thinking about upgrading my mad dog headphones to the Alpha Dog headphones. It would be a real allrounder combined with the BCL clone.
I keep you posted if I make any more changes to the BCL.
The amp is punchy, dynamic, fast, ridiculously powerful and crystal clear and without hearable distortion. It's the first amp I've used that can max out the Mad dog headphones without loosing anything. The Mad dogs always keep asking for more power normally.. but the BCL can shut it up and push max out of it.
I am really impressed! I don't think that I need another amp any soon with my headphones in the sub $1000 range.
People say the power supply is the achillesheel of the circuit. What is meant by this? This weak sport would result in what? Less speed? Worse rhythm? Less power? I have no better amp to compare it with, so it's difficult to hear things that are as good as I can have them at the moment.
The only better combination was my STAX lambda classic with the STAX amp that belongs with it. In terms of speed, clarity, instrument separation dynamic and rhythm the STAX is better. But when you bring in the bass for comparison the Mad Dog and the DT1770 do much better with the Lehmann.
I'm thinking about upgrading my mad dog headphones to the Alpha Dog headphones. It would be a real allrounder combined with the BCL clone.
I keep you posted if I make any more changes to the BCL.
Well, I did measure the BC560C's. Man that is boring...
and very time consuming as I don't touch the transistors except for with ESD-safe tweezers(not wanting temp to effect measurements).
I got some matches, now to find their counterparts amongst the BC550C's.
The 50pcs of BC560C's.
PS.
Listening to the AD797AN+BUF634P headamp as I write this. It has less than 2 hours on it so can't comment about the sound at all yet.
DC offset with nothing connected is -5.1mVdc/-4.8mVdc.
and very time consuming as I don't touch the transistors except for with ESD-safe tweezers(not wanting temp to effect measurements).
I got some matches, now to find their counterparts amongst the BC550C's.
The 50pcs of BC560C's.
PS.
Listening to the AD797AN+BUF634P headamp as I write this. It has less than 2 hours on it so can't comment about the sound at all yet.
DC offset with nothing connected is -5.1mVdc/-4.8mVdc.
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It is kind of a boring job but after that you can make pairs and you will have them ready for future projects.
How did you measure them?
How did you measure them?
Tested all BC550C/560C's I have now.
In this design, if I can't get very close matches for all, what is the priority?
Match for pair(550/560) or match type(closely matched 550's and closely matched 560's)?
I have not gone through all 100 transistors, comparing the numbers yet.
In this design, if I can't get very close matches for all, what is the priority?
Match for pair(550/560) or match type(closely matched 550's and closely matched 560's)?
I have not gone through all 100 transistors, comparing the numbers yet.
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