Hi Dirk,
No problem with your late response.
Yes, the OPA627/637 are considered by many to be some of the better sounding op-amps. They seem to have a loyal following after receiving a favorable review from tangentsoft's website.
Personally, I prefer the sound of the ADA4627-1 over the outrageously priced Burr Brown OPA627/637 offerings.
You may also want to try one of Scott Wurcer's "oldie but goodie" offerings-the AD744. The dual version is the AD746.
For dual op-amps you may want to try some of the JRC offerings-NJM2068, NJM4558, NJM4565, NJM2114 and NJM4580.
They're all inexpensive and can sound VERY good in the right application.
Other great sounding duals are the LT1361 and LT1364. Both have higher input bias currents so always measure the amount of DC offset at the outputs before connecting any headphones.
Good luck and have fun!
Friends, thanks for the nice comments about the build!
The straight cuts are done with a metal saw at about 1mm inside the final line, and then filed away with a very large flat file. It files a little bit harder than the round one, but still nothing that a sore wrist can't handle after the effort
.
Had I need to do this in a production timeline, then that would be the craziest approach. But as is and only few holes and straight cuts, all is done freehand, yes. After the cut, I sand the rough edge down to achieve a smooth feel and a bit of a bevel.
Given all the above explanation, thanks PC997 for the offer, but I would not make one for selling that could cost anywhere near a good price point since I have to cut everything by hand.
Meper, yes... I was thinking about that... but the original design / case is a blind coffin that has no vents at all! Mine has a larger surface that could help with better dissipation. Do you think vents are a must?
Thanks again,
Rafa.
Actually... yes! Free hand. I draw the circle, and start the hole with a 1/2" drill and then file away with a big round file that is about 3/8" in diameter. It files through the aluminum fairly quickly for two or three holes.
The straight cuts are done with a metal saw at about 1mm inside the final line, and then filed away with a very large flat file. It files a little bit harder than the round one, but still nothing that a sore wrist can't handle after the effort
.Had I need to do this in a production timeline, then that would be the craziest approach. But as is and only few holes and straight cuts, all is done freehand, yes. After the cut, I sand the rough edge down to achieve a smooth feel and a bit of a bevel.
Given all the above explanation, thanks PC997 for the offer, but I would not make one for selling that could cost anywhere near a good price point since I have to cut everything by hand.
Meper, yes... I was thinking about that... but the original design / case is a blind coffin that has no vents at all! Mine has a larger surface that could help with better dissipation. Do you think vents are a must?
Thanks again,
Rafa.
Anyone use the Burson V5i in this?
Burson Audio V5i Opamps | Price & Reviews | Massdrop
Looks plug and play 😊
Burson Audio V5i Opamps | Price & Reviews | Massdrop
Looks plug and play 😊
"The V5i-Dual is a direct replacement of the following opamps: AD823, AD823AN, AD8066, AD8620, AD712, AD827, C4570, JRC4556AD, JRC4580, JRC5532, JRC5532D, JRC5534, LF353, LM4562, LME49860, LM833N, MUSES8920, NE5532, NEC4520, NEC4570, NJM2068D, NJM2114, NJM2214D, NJM4558, NJM4558D, NJM4560, NJM5532, NJM4558P, OP275, OPA1612, OPA2277PA, OPA2132, OPA2134, OPA2604, JRC4558, RC4558D, RC4558P, TL052, TL072, MUSES01, MUSES02, MUSES8820, MUSES8920, MUSES8832, BA15532"
So yes, it should work.
It looks like at very fine 50k pot you have. The kit I got has a 100k ALPS. A 50k should work fine also.
The trafo in kit is 2 x 22.5 V so yours is 2 x 15V …...don't know if this will work. May depend on which opamp you use. If the AD823 can handle the lower voltage it may work but experts should comment here.
The capacitor is between signal ground and protective ground (chassis). It is to decouple noise without having a galvanic connection from to PE which could cause other problems. Some use CL60 (NTC resistor). Hope I got this one right.....
The trafo in kit is 2 x 22.5 V so yours is 2 x 15V …...don't know if this will work. May depend on which opamp you use. If the AD823 can handle the lower voltage it may work but experts should comment here.
The capacitor is between signal ground and protective ground (chassis). It is to decouple noise without having a galvanic connection from to PE which could cause other problems. Some use CL60 (NTC resistor). Hope I got this one right.....
AudioSan is spot on.
All your parts will work beautifully.
Of note, the original transformer (22.5v) was speced for those who want to run 24v rails with the 2604 opamp and have the ability for very large voltage swings on the output, as one of the design goals was to have the ability to use the Whammy to drive an F4 amplifier.
For headphone use and using Whammy as a preamp into essentially any power amp that has some gain, the 15V transformer will be more than enough.
All your parts will work beautifully.
Of note, the original transformer (22.5v) was speced for those who want to run 24v rails with the 2604 opamp and have the ability for very large voltage swings on the output, as one of the design goals was to have the ability to use the Whammy to drive an F4 amplifier.
For headphone use and using Whammy as a preamp into essentially any power amp that has some gain, the 15V transformer will be more than enough.
I just got OPA2604. Should be the original Burr Brown. I am 99% sure it is the original and not a copy from China. If somebody can recognize something from the printing which can confirm this I will be happy and also happy using +- 24V. Then it should be good for the MoFo also.
What was the reason to select a 100k pot for the Whammy kit instead of a 50k?
What was the reason to select a 100k pot for the Whammy kit instead of a 50k?
