Whammy Build
Today I finished my Whammy.
I tried different op-amps but the posting from JimmyC23 was the most important hint. Try the OPA2107, it is amazing in this circuit.
Thank You very much for all this work.
I am listening with Sennheiser HD 660s, a wonderful combination.
Best regards
Bruno
Today I finished my Whammy.
I tried different op-amps but the posting from JimmyC23 was the most important hint. Try the OPA2107, it is amazing in this circuit.
Thank You very much for all this work.
I am listening with Sennheiser HD 660s, a wonderful combination.
Best regards
Bruno
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@RafaPolit - So happy to hear that your father is doing well and that you're finding some free time to enjoy DIY. Looking forward to seeing what you have going next.
Similar to "tube rolling" - I am curious to try op-amp changes in both the WHAMMY and M2x/Tucson. I've read a few things suggesting that if used properly, op-amps "shouldn't" make an audible difference, and also multitudes of posts re: preferences in op-amps. I'd like to hear for myself. Fortunately, I have enough identically built WHAMMYs (and at least one with the same color chassis as mine) with friends. So, I ought to be able to do a bit of a blind study to see if I/we can hear a difference between any of them, nevertheless determine if anyone has a consistent preference. Overall, I just like to tinker... Tube rolling was a bit of a fool's errand for me, but I still enjoyed it.
Similar to "tube rolling" - I am curious to try op-amp changes in both the WHAMMY and M2x/Tucson. I've read a few things suggesting that if used properly, op-amps "shouldn't" make an audible difference, and also multitudes of posts re: preferences in op-amps. I'd like to hear for myself. Fortunately, I have enough identically built WHAMMYs (and at least one with the same color chassis as mine) with friends. So, I ought to be able to do a bit of a blind study to see if I/we can hear a difference between any of them, nevertheless determine if anyone has a consistent preference. Overall, I just like to tinker... Tube rolling was a bit of a fool's errand for me, but I still enjoyed it.
Hi all,
I'll soon pull the trigger to build one, and could use some advice:
I might be an amateur, but I have a hard time finding it worth to buy OPA2107 (~20euros) when OPA2156 (or alternatively OPA1642 and OPA1656) at available at 2-3EUROS. Am I missing something?
With some luck I'll be able to measure my WHAMMY with APX555, and if time allows compare different OP amps / output transistors / coupling caps.
Thanks a lot for sharing this design with the community.
I'll soon pull the trigger to build one, and could use some advice:
I might be an amateur, but I have a hard time finding it worth to buy OPA2107 (~20euros) when OPA2156 (or alternatively OPA1642 and OPA1656) at available at 2-3EUROS. Am I missing something?
With some luck I'll be able to measure my WHAMMY with APX555, and if time allows compare different OP amps / output transistors / coupling caps.
Thanks a lot for sharing this design with the community.
Thanks so much! It feels nice to be back with creative and hands-on people! I've missed the interactions here.
Those look great! As a matter of fact, yes I think this is the perfect place to try out SMD soldering on those adapters!
My question (and apparently echoed by a lot of people) is... with this myriad of options, are there any characteristics that we could look for on these to know which are prone to be better? Or is it just a trial and error procedure?
What would make one option better to the other? What drives the cost from $0.70 to $50?
The amount of options is kind of overwhelming, as are the reactions to them. There is very little redundancy of opinions: mostly everyone has a different preferred op-amp!
It's really crazy. Lovely, but crazy if you think about it.
Best regards,
Rafa.
As you can see from our replies and preferences... probably not!
I'd still stand 100% behing the OPA2134PA, which at $5 stood perfectly in the middle price range: a 'hi fi' audio op-amp, but not $50, but $5. Also not the cheapest one so as to become the weak link of the WHAMMY.
That was my approach.
Best regards,
Rafa.
It's 100% your own personal preference(s). To discover what you prefer, there's no other workable method except to listen to the candidates, yourself, and then form your own opinions.
The good news is, the cheapest opamps are very cheap, and the most expensive opamps aren't really very expensive. Think about the prices of high end audio cables, for example.
For the WHAMMY you need dual opamps; singles like AD797 (an excellent opamp designed by a still-active diyAudio member) won't work. Why not buy two pieces of every opamp type that (a) cost less than 4 Euro per piece; and (b) at least one person has recommended? That will give you a bunch of candidates for listening evaluation. It will take you a good long time and you may become tired of the effort before you've heard them all.
Afterwards, if you're still not happy with any of them, or if you are afflicted with Audiophilia Nervosa disorder, you can buy and try some of the more expensive opamps. It's still cheaper than tickets to the cinema for a family of four.
The good news is, the cheapest opamps are very cheap, and the most expensive opamps aren't really very expensive. Think about the prices of high end audio cables, for example.
For the WHAMMY you need dual opamps; singles like AD797 (an excellent opamp designed by a still-active diyAudio member) won't work. Why not buy two pieces of every opamp type that (a) cost less than 4 Euro per piece; and (b) at least one person has recommended? That will give you a bunch of candidates for listening evaluation. It will take you a good long time and you may become tired of the effort before you've heard them all.
Afterwards, if you're still not happy with any of them, or if you are afflicted with Audiophilia Nervosa disorder, you can buy and try some of the more expensive opamps. It's still cheaper than tickets to the cinema for a family of four.
Swapping opamps in Whammy was about the closest I've ever been to "blind" or "unbiased" listening when I did it - specifically, I ordered a bunch of opamps that either said "audio" on the data sheet or were video drivers but not with insanely fast slew rates. That being the purchase criteria, I had no preconceived ideas about the various devices and knew little about them, they were all a jumble of numbers to me.
I found I preferred one that costs less than a dollar.
I found I preferred one that costs less than a dollar.
This was more or less my experience as well!
I did however limit my picks to those that would work with 18v as I did not want to change the PSU. That was about the only parameter I used.
I ended up not choosing the priciest one I had purchased, but my ears laded on the $5 one. I did not care for the ultra cheap ones, not because of price, but they made the ACA peak and saturate earlier. I'm extremely happy with my choice.
Was just curious becuase the OPA2107 has, perhaps, more support here than any other op-amp in this threads.
I won't bother everyone again with the fact that I cannot just "go and purchase one of each", because here that would mean nothing... but that's OK. I love my WHAMMY and its sound.
Best,
Rafa.
I stopped at the OPA2134PA thinking "how can it get any better than this?" but curiosity wins out and I have finally ordered some adapters and will be trying the OPA1612. I'm still balking at buying an OPA2107 which is $23 - $24 and seems like it should not cost that much except that maybe as an older 1989 design, it is being phased out. I have built 5 different DIY headphone amps and Whammy is my favorite.
OPA2107 is built using an aerospace grade dielectric isolation fabrication process, which the datasheet is quick to point out. But Burr Brown managed to get high quality JFETs along with NPNs and PNPs, a trick which the other aerospace semiconductor manufacturer of dielectric isolation chips (Harris Semiconductor) never managed to pull off.
Oh! This is interesting! Since you and I apparently share either taste or ears, I'd be most interested in your findings.
Please report back your impressions. Thanks!
I have been using higher bias for about a year with no issue, i like the output devices hotter!
I did try 5.1R, but its finger burning, so i backed off to 7.1R.
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Just pulled the trigger!
Can't wait to build and tweak this beauty.
Thanks
Can't wait to build and tweak this beauty.
- Is the roll off in the lows mostly due to input cap C5 ; or more to C17 & C13 (how fast opto burns DC)?
- Can we remove (short) the R35 and R36 on Op Amp power lines with let's say LM833, OPA2107 or OPA2156 (fastest); or is there an increased risk of Op Amp / system oscillation?
I did not see answer in previous pages, maybe I missed it. - Would adding local decoupling caps real close to output transistors (let's say 1x Pana FC/FR 25V 470uF on each transistor) improve the transients; or help to keep cleaner PSU/GND lines?
Wouldn't this over-stress the regulator?
Thanks
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Martigane -
There is roll-off in the lows?
I’d be very wary of making any changes that could increase oscillation, remember the follower is in the feedback loop, stability is important. I’ve used some of those opamps, I rather like the first one you listed. If you want to try something very fast (although I’m not at all extreme slew rate is beneficial for our needs) the AD823 works beautifully. That said, the 47R/220uF at the opamp power pins are a final and very effective decouplin/ power filter stage. But I wouldn’t touch the resistors. (And if you need physical clearance, you could make the caps smaller by a factor of 10 or 20, things will still work perfectly)
The regulators are sufficiently unstressed because there is so little work on their input, due to the passive filtering. Adding more capacitance downstream is not going to hurt. I would be curious if you find it beneficial. C9, C28 are the output stage reservoir caps.
Most importantly, I completely agree with ZenMod - build it stock first.
There is roll-off in the lows?
I’d be very wary of making any changes that could increase oscillation, remember the follower is in the feedback loop, stability is important. I’ve used some of those opamps, I rather like the first one you listed. If you want to try something very fast (although I’m not at all extreme slew rate is beneficial for our needs) the AD823 works beautifully. That said, the 47R/220uF at the opamp power pins are a final and very effective decouplin/ power filter stage. But I wouldn’t touch the resistors. (And if you need physical clearance, you could make the caps smaller by a factor of 10 or 20, things will still work perfectly)
The regulators are sufficiently unstressed because there is so little work on their input, due to the passive filtering. Adding more capacitance downstream is not going to hurt. I would be curious if you find it beneficial. C9, C28 are the output stage reservoir caps.
Most importantly, I completely agree with ZenMod - build it stock first.