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"WHAMMY" Pass DIY headphone amp guide
"WHAMMY" Pass DIY headphone amp guide
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Old 20th January 2020, 09:58 PM   #1921
passive420 is offline passive420  United Kingdom
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Quote:
Originally Posted by Gregje View Post
Have you compared Whammy without/with the xfeed? People seem to like these xfeeds.
Hey Greg, yes mate this is the second time building the Whammy and on this board I spent a good few hours with a plain 20K pot before trying the Xfeed with a 10K Alps.

Now the Xfeed is very subtle, don't worry it doesn't add or subtract from the music but seems to place the music in the front and centre but somehow keeping depth. I guess it sounds more accurate and integrated inside your head and it seems to reduce fatigue somewhat, I can listen for hours or as long as I can stand the phones on my head.

So I would say the XFeed works very well, the Danyuk passive version here (you'll be getting soon!) is the most simple version is seems, follow Patricks component values and it will work in most situations but you can tailor the crossfeed point to suit. Interestingly the Xen motherboard has very different Xfeed component values for some reason.

Zen Mod - fixed the pot squelch and noise, I hadn't screwed the front plate properly! The pot was not connected to the chassis earth! Once this was done, no problems.

So running with 1K for R39/40 inputs, 10K for R4/R8 and no compensation caps yet, might try some 47pF.

While I was under the hood, I added some extra 0.1uf MKP decoupling caps to C1/C3 and C9/C28. Everything sounds very good.

My favorite op-amps it seems are two LT1028. Slightly better maybe than OPA627BM.
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Old 20th January 2020, 10:17 PM   #1922
Zen Mod is offline Zen Mod  Serbia
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"WHAMMY" Pass DIY headphone amp guide
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Old 21st January 2020, 09:43 AM   #1923
Gregje is online now Gregje  United Kingdom
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Quote:
Originally Posted by passive420 View Post
So I would say the XFeed works very well, the Danyuk passive version here (you'll be getting soon!) is the most simple version is seems, follow Patricks component values and it will work in most situations but you can tailor the crossfeed point to suit.
Yes, mine is already in transit. I am looking forward to another build.
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Old 21st January 2020, 01:58 PM   #1924
AllanMarcus is offline AllanMarcus  United States
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Quote:
Originally Posted by rich1051414 View Post
Theoretically, this would increase the capacitance from all that extra socketing wouldn't it?
I doubt it is audible, but I would feel compelled to have a properly soldered riser if I did something like that.
Also, distance is a very important thing regarding the bypass capacitor for the op amp power rail, so the distance as well may effect things.

Like I said, I doubt it would be audible, but both things are things you typically try to avoid with op amps.
If I were to use the Burson as the permanent opamp, I would not stack the sockets like that; I would reconfigure the caps on either side to allow for more opamp space. It's a temporary solution so that I could use the Bursons.
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Last edited by AllanMarcus; 21st January 2020 at 02:09 PM.
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Old 21st January 2020, 07:24 PM   #1925
avdesignguru is offline avdesignguru  United States
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Default OPA2107AU vs OPA1612AID

Finally tested an OPA2107AU which requires a SMD to DIP adapter. Very clear and precise with a good sound stage. A bit clinical, cold and unexciting. Not harsh. Some may like it but I prefer the OPA1612AID, particularly on Sennheiser HD650 headphones. I'll be sticking with the OPA1612AID as an upgrade to the OPA2134PA.

The OPA1612AID sounds wonderful on all my headphones, HiFi Man HE400i, Sennheiser HD650 and Masters and Dynamic MH40.
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Old 21st January 2020, 09:58 PM   #1926
Martigane is offline Martigane  Belgium
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I compared the following op amps, and so far OPA2107AU is the very best. Using hd58x modded:
Opa2107
Lm833n
Opa1642
Opa2156
Lme49720NA
And some waiting to be tested:
Ad8599Arz
Lme49860
Burson v6 classic
Burson v6 vivid

Then i ll note my subjective observations and only then measure few key test with apx555.. will be fun
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Old 22nd January 2020, 04:17 PM   #1927
rich1051414 is online now rich1051414
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Quote:
Originally Posted by Martigane View Post
I compared the following op amps, and so far OPA2107AU is the very best. Using hd58x modded:
Opa2107
Lm833n
Opa1642
Opa2156
Lme49720NA
And some waiting to be tested:
Ad8599Arz
Lme49860
Burson v6 classic
Burson v6 vivid

Then i ll note my subjective observations and only then measure few key test with apx555.. will be fun
You should add AD812 to the list. Not technically an audio op amp, but one I really like. I was using it to test the need for the feedback compensation capacitor, but it failed to push the op amp into oscillation without compensation, but it sounds fantastic, very analytical.
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Old 22nd January 2020, 05:26 PM   #1928
Mark Johnson is offline Mark Johnson  United States
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"WHAMMY" Pass DIY headphone amp guide
For the Azul headphone amp I demonstrated at Burning Amp, the one with the output stage chip made in 1971, I think I like the sound best when the first stage opamp is an LT1122. It's a single and I don't think they offer it as a dual; so you will have to DIY a little contrivance in order to try it in a WHAMMY.

LT1122 was designed by George Erdi, the wizard of Precision Monolithics. He also designed the LT1028 which was the world's lowest noise opamp for several decades.

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Old 22nd January 2020, 05:29 PM   #1929
JimmyC23 is offline JimmyC23  United States
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Does anyone know where I can get this part and or it's equivalent?

MKP2D031001FKA00
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Old 22nd January 2020, 05:43 PM   #1930
JimmyC23 is offline JimmyC23  United States
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N/m I found this one which seems to be the same one MKP2D031001F00KSSD WIMA | Mouser
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