"WHAMMY" Pass DIY headphone amp guide

I have been exactly throught that, and must admit, 6L6 is right. For the price, 833N is great. I prefer opa2107 to it, giving better soundstage and treble definition.
I also installed the v6 vivid about 1 week ago. While i did not measure anything, it really sounds great. I have yet to establish if v6 vivid is better than opa2107.

Some remarks about my expérience with the v6 vivid:
- with the LED psu config, the v6 runs really hot. Its max usable voltage is 16.5V (i think that currently it runs at 16v due to r47 drop) but id rather use 15v especially when there is litle airflow in the case.
- i did not use any compensation cap, and all op amps tested so far were stable.
-my op amp socket has some extra decoupling capacitors: 0.33uf wima mkp10 between v++ and v--; and 0.1uf between each v+/- and GND.
- the burn in is clearly needed, to my surprise and to my ears.
- i have 6.8ohms output bias resistors.

I will soon be able to get a scope and AP5xx and check how the different op amp measure.
 

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Yes you would need two of them and some BrownDog adapters. I was just pointing it out as the price is good compared to buying at Mouser or Digikey, if you are interested in trying out the OPA627. I have 2 in my WHAMMY right now.

This sounds incredible to me. Anyone running this opamp setup who likes it should try opa2107 as well (In my opinion).

I have found that these all sound different among different headphones and IEMs to say nothing of music genres and tastes. TOO MUCH FUN.

The BrownDog adapter isn't the most secure connection—in the nicer style socket from the kit.

LM833 in the cart for the next Mouser order! :worship:
 

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Hi~ Guys,
I just finished my Whammy headphone amp.
I use some good stuff that I can get, and the most awesome idea is that I used separated PSU. The amp use op 833 and IRF610/9610 with bias resister Vishay Dale NS-5. And more, I use Muses 72320 as the volume control and it is made as individual unit with some good stuff, like T2575 , CDE Mica capacities, MKT input capacities, and op LME4562 .

Enjoy the pictures.
 

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I've listened to almost all the opamps in this forum except the Burson and the single channels. For overall great sound that is wonderful with all my different headphones, I prefer the OPA1612, only available in SMD package. I believe this is the most current design in the TI OPA series of opamps. A noticeable improvement over the OPA2134 and I prefer it to the much more expensive and older design OPA2107.

I found it well worth the hassle of adapting. I used tall square header pins soldered to the top of an IC socket to raise the adapter board above the electrolytic caps.
 

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@avdesignguru

Looks like there's a couple of versions of the OPA1612. Both marked "low power" but one maxing out at 18V. Seems that's lower than all the initial recommendations on page 1 of the thread. Does it matter? I'm not sure---beyond my current knowledge.

OPA1612AIDR Texas Instruments | Mouser

OPA1612AID Texas Instruments | Mouser

And for anyone that needs these adapter boards—
BOB-13655 SparkFun | Mouser

AIDR is the tape reel supplied version of the AID, for machine production. No electrical differences. Go by the data sheet, not Mouser descriptions.

Data sheet says 40V max supply spread, 36V recommended, a nominal +/-18V supply. My supply rails measure about +/-15.3V, well within the recommendations. No worries. Also, I checked with a scope for oscillation or other bad behavior and found none.
 
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I do not want to turn this thread into an amp rolling discussion. If anybody feels I am doing this please say so and I will stop.
I hope this is useful for somebody (my initial choice of the op amp for Whammy was inspired by reading people's opinions here).

The direct reason for this post is a package which arrived this week from Passive420.
It contained a box with some delights. These include
1. metal cans opa627 on brown dog single to dual
2. LT1361
3. OPA604
4. LT1028
5. and metal cans LME49710

Today I made some time to do some swapping. My benchmark nowadays is Burson V6 classic (as some of you might have noticed), AD823 before.

Here are my initial imressions.
I started with opa627. Wow, very close to Burson, Burson has somewhat warmer sound a notch more live like. Then LT1361, very very good. Then I listened to opa604 which I liked less.
I could not get LT1028 working. I removed all compensation caps as Passive suggested but the amp was still oscillating.

In fact these are all very fine chips and while you can hear differences between them it is really hard to say which one is better. Might be a question of personal preferences.

After some swapping I decided that OPA627 is the one to leave in Whammy to see how I like in the longer run. As I said I prefer Burson, but I want to see how much I would miss if anything when opa627 is playing on a daily basis.

Apologies to those who would prefer blind abx tests...

I missed this Greg, sorry been laid up for a few days.

You must have had one hell of a listening session, well done for getting through them all and very pleased you liked the 627's, considering the cost they should beat everything! I'm baffled as to why you could not get the LT1028's working, this is strange as they fired up no problem in mine.

Can I ask what value pot you have been using? Shouldn't make any difference really but some op-amps don't like a pot in front of them and impedance might be a factor in some performing well.
 
After some swapping I decided that OPA627 is the one to leave in Whammy to see how I like in the longer run. As I said I prefer Burson, but I want to see how much I would miss if anything when opa627 is playing on a daily basis.

Apologies to those who would prefer blind abx tests...[/QUOTE]

Did the DC offsets all check out on the OPA627? Gotta try this one for sure
 
I've listened to almost all the opamps in this forum except the Burson and the single channels. For overall great sound that is wonderful with all my different headphones, I prefer the OPA1612, only available in SMD package. I believe this is the most current design in the TI OPA series of opamps. A noticeable improvement over the OPA2134 and I prefer it to the much more expensive and older design OPA2107.

I found it well worth the hassle of adapting. I used tall square header pins soldered to the top of an IC socket to raise the adapter board above the electrolytic caps.

Have you tried and compared it to the OPA267?
 
I missed this Greg, sorry been laid up for a few days.

You must have had one hell of a listening session, well done for getting through them all and very pleased you liked the 627's, considering the cost they should beat everything! I'm baffled as to why you could not get the LT1028's working, this is strange as they fired up no problem in mine.

Can I ask what value pot you have been using? Shouldn't make any difference really but some op-amps don't like a pot in front of them and impedance might be a factor in some performing well.

I am also puzzled about LT1028.
I used 20K pot. No 2k2 resistor in series with the input (I have the old PCB without this resistor. I saw the modification later, but since I had no problems I decided not to bother, maybe I should now).
Anyway, next weekend I will have another go. Hopefully including xfeed.

I was also very excited about opa627. I almost though you have found the affordable holy grail of op amps. Until I checked the price at RS components. I was mistaken about affordability. Well, it is cheaper than Burson, but not that much... I mean 30% is a lot if you have a commercial venture and you try to squeeze every 1c to increase your profit. But for a DIYer both are kind of pricey opamps.
 
I am also puzzled about LT1028.
I used 20K pot. No 2k2 resistor in series with the input (I have the old PCB without this resistor. I saw the modification later, but since I had no problems I decided not to bother, maybe I should now).
Anyway, next weekend I will have another go. Hopefully including xfeed.

I was also very excited about opa627. I almost though you have found the affordable holy grail of op amps. Until I checked the price at RS components. I was mistaken about affordability. Well, it is cheaper than Burson, but not that much... I mean 30% is a lot if you have a commercial venture and you try to squeeze every 1c to increase your profit. But for a DIYer both are kind of pricey opamps.

If you don't mind mate, get the multimeter out and check the output offset on the 627's, maybe also across the 47R to see what output current. I wrote a load of measurements down on a piece of paper somewhere but don't remember seeing anything alarming on any of the chips.

Also try a couple of resistors on the inputs, I have 1K right on the RCA's maybe this will help with the LT1028 oscillation. If you have the time for another test - put a couple of 0.1uF MKT's or ceramics right on the op amp +/- power rail pins to ground, I used the ground pad on the C1/C3 electrolytic decoupling caps, as close to the op amp pins as possible.

Take your time, have fun....