"WHAMMY" Pass DIY headphone amp guide

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#3,341
WhatFirst:
I tried using the Whammy as a loudspeaker system preamp. I liked it but found that I preferred Wayne's BA2018 preamp for loudspeakers and the Whammy for headphones (of all types). Interestingly, you can use the Whammy main rails to power the BA2018 board and it works really well. Probably wise to use the 25 watt version of the transformer if doing that. I also tried using the BA2018 with the large output transistor option as a headphone amp and found I still preferred the Whammy for headphones. So, no free lunch for me. To my ears, both circuits are the best at their individual tasks.

Regardless, it is absolutely essential to have the power amp turned off before energizing either the Whammy or the BA2018 to avoid a dangerous 'pop' in the loudspeakers. And even though a switching headphone jack can disconnect a Whammy from a set of preamp out RCA jacks, I found plugging/unplugging headphones also made an unacceptable 'pop' in the loudspeaker system with the amp turned on.
 
#3,346
deejaymash said:
First post on diyAudio.

Thank you to Wayne, 6L6 and everyone who has contributed here who've made building this possible.

The Whammy is the first diyAudio project that I've completed, I'm definitely hooked! I built two, one with a 15v supply for my friend who wanted to run the Muses01 opamp risk free, and this one for my self with the 17v supply. Please could someone with more experience provide some knowledge in a couple of areas?

1: After building my Whammy I have since read a couple of posts that suggest that the 25va, 2x15v transformer that I selected may not have been the correct choice for the LED supply configuration. The part looks pretty difficult to desolder with the equipment I have on hand, could anyone offer some guidance on this? I would really like my amp to perform at it's best, Is there any point in swapping the transformer out?

2: If I connect headphones to the switched jack with the preamp outs connected to my amp i get some noise coming through the speakers. I have tested this on a couple of friends systems and it is has been inaudible, however on my 101dB speakers you can definitely hear it. Is there anything obvious from the photos that I could do to fix this?

Thanks!
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Nice work, I like the clean layout.

I'm also a fan of having the input switch on the back, my WHAMMY is almost finished and it has a switchable internal DAC input.

Do you notice much difference in sound quality using those Mundorfs?

What volume pot are you using?

What enclosure is that? Did you machine the pockets in the front panel yourself?
 
#3,347
deejaymash said:
2: If I connect headphones to the switched jack with the preamp outs connected to my amp i get some noise coming through the speakers. I have tested this on a couple of friends systems and it is has been inaudible, however on my 101dB speakers you can definitely hear it. Is there anything obvious from the photos that I could do to fix this?
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This has been mentioned before, and there are two main reactions:


  1. Don't do that! You wouldn't connect or disconnect speakers or components elsewhere with outputs on, so don't do it here.
  2. OK, so maybe headphones are different. In that case, we can use a solution similar to what's used in the B1 preamp: a 1Meg resistor from the L/R outputs to ground.
 
#3,351
JermNZ said:
Nice work, I like the clean layout.

I'm also a fan of having the input switch on the back, my WHAMMY is almost finished and it has a switchable internal DAC input.

Do you notice much difference in sound quality using those Mundorfs?

What volume pot are you using?

What enclosure is that? Did you machine the pockets in the front panel yourself?
Click to expand...


I'm not sure about the sound of the Mundorfs honestly. I built another Whammy that uses what are perhaps more sensible component choices. Panasonic FCs, Wima film caps, the sort of components the sound engineer in me would recommend. I used the audiophile stuff in this one as an experiment, I just haven't put the other board in an enclosure to compare them yet.

The pot is TKD 2CP-2500.

The enclosure is the Galaxy Maggiorato GX288 230 x 280, all the custom machining was done by the factory.
 
#3,355
6L6 said:
How hot are the regulator heatsinks? Hotter than 70? If that hot maybe I'd worry a little.

The regulators are working as designed. 15V + the Vfwd of the red LED, or about 17V.

If you want 15V rails, yes, Naked Reg.
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I've fitted my WHAMMY into its final chassis and have been running it with the top on.

If I lift the top off and quickly measure the top surface of my regulator heatsinks, I get 62C. If I measure right near the mounting screw it's more like 66C.

It seems quite hot.

I have actually ordered the taller version of these heatsinks, I'm not sure if these will help but they're 33% taller so it's worth a try.
 
#3,357
I just finished the Whammy in its stock build, and im very pleased with the sound. But I do realise when I turn the volume past 12 oclock theres a faint hiss. is that normal, or its sth thats fixable? I realised tho if my source at full volume i wouldnt really need to go past 10 pm anyway so its not a big deal...
 
#3,358
Hello everybody, I'd very much like to build this wonderful amp, but ordering the pcb from the US to Europe is prohibitly expensive ��

I did download gerber files I found on this forum but JLCPCB told me that the drill file does not match the gerber files.

Can someone point me to a gerber file that should work? I'd be eternally grateful ��
 
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