"WHAMMY" Pass DIY headphone amp guide

[GADify]

Hey there. I finally finished my Whammy after getting distracted by other things for a while, but I'm at a loss as to where the power LED is supposed to go. It's not on the schematic and there's no obvious spot on the board for it, though there is clearly a spot in the case. I'm sure I could kludge something together but is there somewhere that it's supposed to go?

Thanks

 

[GADify]

Hey there. I finally finished my Whammy after getting distracted by other things for a while, but I'm at a loss as to where the power LED is supposed to go. It's not on the schematic and there's no obvious spot on the board for it, though there is clearly a spot in the case. I'm sure I could kludge something together but is there somewhere that it's supposed to go?

Found this: whammy-review

In that review he talks about using a 20k resistor and wiring the power LED up to the C9 pads. Any issue doing that? The location certainly is convenient.

 

[6L6]

There isn't a dedicated spot for the LED on the boards. Powering from C9 is as good as anything!

 

[Denis_O]

another option is to connect an optical fiber to one of the voltage reference LEDs to transport the light from the latter to the front panel.

 

[manus.hattingh]

WOW - I upgraded the op-amp to a Burson V6 Vivid and the sound is now amazing! Huge step up from the Texas Instruments OPA2134PA that I had in before. I am very happy with the sound now and will not tinker any more.

 

[Denis_O]

I just started a related topic regarding a blind-test comparison between the OPA2134PA and Burson Audio v6 Vivid, you might want to have a look:

https://www.diyaudio.com/community/threads/real-double-blind-test-for-opamp-comparison.404951/

 

[RYC2000]

On the most recent kits, the 220uF/50v according to the board and the schematics were replaced with 220uF/35v and 220uF/25v. Can anyone please chime in on whether I should order replacements at the correct value or if these are ok. If replacements are suggested, which brands are recommended.

 

[DSP_Geek]

The 220s face 18 volts at the maximum with very little ripple current so you have lots of margin. I suspect the original schematic used 220uF/50v because Wayne had those in his parts box.

Any of the above voltage ratings would be fine.

 

[wayne]

You would be correct on that, 220/50V and 220/16V are in our stockroom.

 

[Denis_O]

Only the caps C6, C11, C14, C15, C18, C19 in the CRCRC section between the transformer and regulators see about 33V. Here, you need at least 35V-rated caps. After these, the 7815/7915 regs lower the voltage further down for the rest of the circuit.

 

[1nfinity]

Hey guys! I haven't connected/soldered in the pre on my whammy yet. Is there a guide on how to connect this and where to connect this? Thank you so much again!

 

[Denis_O]

what do you mean by "the pre"? Are you referring to the opamp?

 

[1nfinity]

I was referring to the preamp out, I wanted to use speakers. (sorry I am still new to this)

 

[danico]

I am sure its somewhere in this tread........ you can use a DPDT switch or a switchable jack connector. and 100 Ohm resistors on the pre out.

 

[Denis_O]

yes, indeed. Let me state the obvious anyway: You still have to use a power amp between your speakers and the Whammy, you can't connect the speakers directly to the Whammy.

 

[1nfinity]

yup! I have a power amp. I have everything ready to go. just need to know how to connect the pre out properly. I saw an image of it going straight to the headphone jack but the otherside. Is that right?

 

[Denis_O]

if you look carefully, there is a resistor between the headphone output jack and the preamp out on the back

 

[1nfinity]

I see, I thought that was for the LED about the headphone jack?

 

[Denis_O]

Actually, I think you are right. I didn't see the LED on top of the jack!

 

[6L6]

In a perfect world you put a 100ohm (or so, it's not super critical, whatever you have between 22 - 150 ohm) in series with the signal wire to the RCA pins. But it will work fine as you have it.