Hello rewind,
have you ever tried the Nichicon Muse (greensleeve cap)? I can tell you, that it is an excellent cap -
especially at its pricepoint. I would give it a try.
For sure can you use any big foilcap. Also some which have goldplating on the legs, which are handrolled
and soaked up in beewax...
I would use the Nichicon Muse for testing. You could parallel a very small FKP or MKP in parallel to the
Nichicon Muse. Mr. Pass seems to prefer the ELNA Silmics.
The discussion about caps in e-guitars is in my opinion something different. In an e-guitar you are searching
for a special distorted sound...
It is a question of taste (listening taste). And the cap - discussion will never end...
And it is easy to change a cap. If you want to test a lot of caps, you could solder 2 short wires to the pcb where the cap goes in and then you can easily swap caps to the wires - and listen and solder and listen...
If you use a 1µF - cap instead of a 10µF - cap you lower the corner frequency of the buffer cell.
You can try also a 4.7µF or any value close to the 10µF.
Only some thoughts!
Have fun building this excellent active crossover.
Cheers
Dirk
have you ever tried the Nichicon Muse (greensleeve cap)? I can tell you, that it is an excellent cap -
especially at its pricepoint. I would give it a try.
For sure can you use any big foilcap. Also some which have goldplating on the legs, which are handrolled
and soaked up in beewax...
I would use the Nichicon Muse for testing. You could parallel a very small FKP or MKP in parallel to the
Nichicon Muse. Mr. Pass seems to prefer the ELNA Silmics.
The discussion about caps in e-guitars is in my opinion something different. In an e-guitar you are searching
for a special distorted sound...
It is a question of taste (listening taste). And the cap - discussion will never end...
And it is easy to change a cap. If you want to test a lot of caps, you could solder 2 short wires to the pcb where the cap goes in and then you can easily swap caps to the wires - and listen and solder and listen...
If you use a 1µF - cap instead of a 10µF - cap you lower the corner frequency of the buffer cell.
You can try also a 4.7µF or any value close to the 10µF.
Only some thoughts!
Have fun building this excellent active crossover.
Cheers
Dirk
I forgot: If you play around with film caps instead of bipolar caps pay attention on not getting DC-voltage
at the output.
The 6-24AXO is a single-ended-design. The virtual ground of the buffer-cell is at around 12 V DC (railvoltage
is +24V DC referenced to ground - virtual ground is in the mid).
Cheers
Dirk
at the output.
The 6-24AXO is a single-ended-design. The virtual ground of the buffer-cell is at around 12 V DC (railvoltage
is +24V DC referenced to ground - virtual ground is in the mid).
Cheers
Dirk
At the same time, for higher voltage caps the distance has to increase
I am about to start building it now!
Of course I only ordered half of the caps I need for the filter. At 2 AM I only have half a brain and everything is mono. Gives me more time to do some cap rolling. Can try Wima VS Mallory first, since Mallory are cheap.
I don't like the idea of frying my V-Fet lottery amps, so I will trust that the Muses are good enough.
I am about to start building it now!
Of course I only ordered half of the caps I need for the filter. At 2 AM I only have half a brain and everything is mono. Gives me more time to do some cap rolling. Can try Wima VS Mallory first, since Mallory are cheap.
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Just to add: Papa used to recommend Silmics very strongly, many posts about the subject dating back to st least 2004. In for example the ACP+ manual, I seem to recall Nichicons used all around. And if my sources are correct, Pass Labs have swapped Silmics with Nichicon greens. Coincidently the production of Silmics have been moved out of Japan, and they also seem to be EOL.
I second the choice of Nichicon caps.
Btw, Dirk: You often bypass even when bypass caps are not specified in the schematics? Have only tried it with PSUs, not the amp boards themselves.
Hope all is well in Germany! I am not too far away now, in Italy at the moment.
Regards,
Andy
I think a film cap (or no cap) would be the best if it is right in the signal path. Is the bipolar muse cap the only way to protect the amp? Or just the quick and easy way?
Edit: Looks like much smarter people than I am has already debated this. After lots of talk about servos and parallelled film caps, the conclusion seems to be to not question the wisdom of Nelson Pass. Cap in, cap out, like in all Firstwatt preamps. Nothing more is needed. A too complicated protection can lead to failures that causes the accident that it was supposed to protect from. https://www.diyaudio.com/community/...-protection-circuits-for-preamp.336242/page-2
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But why is 10uf used? In the world of non-polarized caps 10uF is easy €50 per cap. And I need eight. Is 1uF just fine and doesn’t change anything?
I meant per se, not nescessarily in this circuit. For example in the BA-3 FE, a non polarized is used, but can be substituted for - or paired (!!) with a polarized with the same value. Changing uF will change rolloff/cutoff freq, but I am not the one to as about the details. At least not right now, tucked away in a cot in an Italian village
We should meet up. I would like to listen to those horns of yours, and come Christmas I can bring my F2J
As long as your crossovers are not passive and designed for voltsge source amps.Regards,
Andy
Hehe, don't give me false hope to rid me of these bipolar caps.I meant per se, not nescessarily in this circuit. For example in the BA-3 FE, a non polarized is used, but can be substituted for - or paired (!!) with a polarized with the same value. Changing uF will change rolloff/cutoff freq, but I am not the one to as about the details. At least not right now, tucked away in a cot in an Italian village
We should meet up. I would like to listen to those horns of yours, and come Christmas I can bring my F2J
Regards,
Andy
You are welcome to Oslo. I hope you like the Frozen soundtrack - also the reason why I need a four year schedule to finish one amplifier.
My crossover is passive from 210Hz. I just hate big coils.
Have fun in Italy. I hear it is not just the wine that is dry!
Thanks, but I can't think of any better bipolar cap then the one in the BOM.The cutoff-frequency fc = 1_
2 x pi x R x C
If you increase the value of C (the value of your cap) in the upper formula - what happens to fc?...
And as long as fc is anywhere below 20 Hz - nothing to worry about.
I have to sleep...
Good night!
Dirk
Without doing the maths, I don’t see why not. No gain involved, should be just fine. There might be a tad more ripple, but you’ll soon know if it works out OK or not. Worth a shot.
what might happen is that the inrush gets to high for the PSU, so that the safety thingomabong trips. You’ll identify that by blinking LED’s at startup.
Usually these things are very low powered, but with this amount of JFETs, I was not sure.
I am thinking about reducing the cable loops by not using two PSUs for what essentially becomes the same preamp/active crossover.
You should be just fine, as far as I can see, as long as the PSU is fine with charging the extra set of caps.
PS: I love Frozen, though fraggle rock is more my cup of tea. And I am in Oslo every day.
You said you were Italian!
Until I finish these crossovers there won’t be much sound at all. I am taking the time between DHL and UPS deliveries to further enhance the horn stack. Latest addition: custom back chamber for 8Pe21, and DIY 1.4-2 inch horn adapters.
