My woo audio wa 2 is not a good match for low impedance headphones, so I thought that increasing the coupling cap might able to give me more LF for headphones like Audeze LCD2! and AKG K702 which 62ohm!
But I also have high impedance headphones HD650/HD800s, and ATH-R70X(470ohm)!
To use all kind of High End HP with different impedance Is it a good idea to use a Toggle Switch for specific Headphones?
right now I have few caps to try 330uf to 480uf( 100v to 250v).
But I also have high impedance headphones HD650/HD800s, and ATH-R70X(470ohm)!
To use all kind of High End HP with different impedance Is it a good idea to use a Toggle Switch for specific Headphones?
right now I have few caps to try 330uf to 480uf( 100v to 250v).
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With 330uf, and 26 Ohm headphone (26 Ohm is the minimum that amp can support in its manual), the -3dB cutoff point is around 19Hz. If you use 62 Ohm headphone, the cutoff point goes down to 8Hz.
I doubt you can get any improvement with 470uf.
If you experience low LF, I guess it is due to inherited high output impedance of the tube amp, not the output cap.
I doubt you can get any improvement with 470uf.
If you experience low LF, I guess it is due to inherited high output impedance of the tube amp, not the output cap.
I have ATH-R70X but I also want to use 16R if I need to. I use 2200uF in my newer builds, and I consider 470uF the lowest value I would use. I also like my -3dB LF point around 2Hz.
The larger cap will give better LF but if the amp can't provide current, it won't matter. I get about 25mW for 16R but I can get over 1W into the 470R cans... 30mA will only go so far...
To answer your question, a toggle switch will be fine, but I would not disconnect the cap completely. Use 1M or something so the cap will charge - that will get rid of popping sounds when you switch them.
The larger cap will give better LF but if the amp can't provide current, it won't matter. I get about 25mW for 16R but I can get over 1W into the 470R cans... 30mA will only go so far...
To answer your question, a toggle switch will be fine, but I would not disconnect the cap completely. Use 1M or something so the cap will charge - that will get rid of popping sounds when you switch them.
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Thanks for the advice guys, I'll keep the stock muse 330uf(200v), and also solder Sic-Safco 470uf(250v) and use toggle switch inside the chassis and switch before powering on the amp, so I can stay on the safe side.
@kodabmx do you mean 1MR registors in parallel for each caps so they can charge and discharge?
@kodabmx do you mean 1MR registors in parallel for each caps so they can charge and discharge?
When I said 1M I was thinking preamp and small caps. For an HP amp, I'd use like 51k or thereabouts.
Here's a sample schematic of a headphone buffer I just drew to show the setup of the resistor and switch. If you leave out R5, you'll get a loud pop from the charging surge when you switch it.
Incorrect schematic shown in this post removed.
Here's a sample schematic of a headphone buffer I just drew to show the setup of the resistor and switch. If you leave out R5, you'll get a loud pop from the charging surge when you switch it.
Incorrect schematic shown in this post removed.
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Maybe instead of an "either or" switch, it would be safer to have one capacitor always present as a baseline, then the switch would just "parallel add" a selection of a different capacitor. So your baseline cap would be the smallest one you can tolerate, then the others are add-ons you can select.
Agreed... Like in the schematic I showed. 😀
EDIT: which has an error - the bottom tube is 6N6P, not 6N1P. It would still work but the 6N1P will wear out quickly.
EDIT: which has an error - the bottom tube is 6N6P, not 6N1P. It would still work but the 6N1P will wear out quickly.
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Don't use a toggle switch, or multiple output capacitors. There's is no point to this. Just use the biggest one you need.
Plus you'll be tempted to switch it while the amp is on, and that will cause a loud "pop!" Unless you also add an output grounding switch and you switch the output to ground before you switch in the extra cap. But still invariably you forget and switch it live. (been there, done that...) Bottom line: Not worth it.
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Not how I drew it... It will just change the LF point.
The only reason to use a small cap for high Z is the initial cap charging. Most cases, if you leave the headphones in when you turn it on, there is no problem. If the amp has been on for a few minutes, the cap will come to equilibrium eventually and there's no pop when you connect the headphones. If you connect the cap to ground all the time, it'll be charged like the rest of the system and there shouldn't be any "pop". If you use 2200uF with 1M and you plug the headphones in 15 seconds after turn on, they will bottom out because the cap will then charge through the headphones (470R <<< 1M, right?)( 10 second delay and short to ground would fix this and cost a few dollars) Or? 51k resistor? Anything designed to drive 16R - 600R doesn't care about a 51k "parasitic" load and the timing should result in no pop.
The only reason to use a small cap for high Z is the initial cap charging. Most cases, if you leave the headphones in when you turn it on, there is no problem. If the amp has been on for a few minutes, the cap will come to equilibrium eventually and there's no pop when you connect the headphones. If you connect the cap to ground all the time, it'll be charged like the rest of the system and there shouldn't be any "pop". If you use 2200uF with 1M and you plug the headphones in 15 seconds after turn on, they will bottom out because the cap will then charge through the headphones (470R <<< 1M, right?)( 10 second delay and short to ground would fix this and cost a few dollars) Or? 51k resistor? Anything designed to drive 16R - 600R doesn't care about a 51k "parasitic" load and the timing should result in no pop.
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The delayed muting microrelay (shorting to GND)… still a good solution to avoid plops. Both at power on and at power off. Better for the headphones and the person that uses them.
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I haven't tried those. They must be NOS?
I use these and there are fine. EPCOS B43544A9477M000
I bypass them with the TENTA brand version of this --> CORETONG | CORETONG MPX-224K275VAC-B-C5 | Suppression Capacitors - LCSC.COM
I use these and there are fine. EPCOS B43544A9477M000
I bypass them with the TENTA brand version of this --> CORETONG | CORETONG MPX-224K275VAC-B-C5 | Suppression Capacitors - LCSC.COM
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