That's exactly what I was afraid of. Are those the caps on either side of the op amp socket? Plus I suppose you had to use a riser to get the Sparkos in the socket.
Thanks,
John
Thanks,
John
I did, and compared it to Burson V6 Classic/Vivid, OPA2107, OPA1642, OPA2156, LM833N, LME49720... I was disappointed and did not like it at all 🙄
Althought it sounded less clinical and more organic than most chip op amps, it had good ability to push details up (micro dynamics), but failed to convey good sense of scale (macro dynamics).
Sound stage lacked contrast / depth, as if small details were pushed up too much upfront together with the noise floor, leaving a feeling of uncomfortable "constant pressure" , lack of breathing room.
In that state, I would say that even the OPA2107 outperformed it.
Still, it had a bit less strident treble than the V6 Vivid, and maybe cleaner bass than the V6 classic.
Otherwise it was worse on all other aspects.
I did report scope figures of SS3602 Vs Vivid in #5,073 but never came around to trying C2/C7. 🤔
No, I believe @NIXIE62 refers to C2 and C7 which are decreasing the loop gain in very high frequencies.
I checked all my Op Amps with a scope and the V6 Classic is perfectly stable without any feedback caps.
I don't have the schematic right now, probably the C2 and C7 markings are for the compensation capacitors. With them, a proper square signal is achieved. No oscillations, no overshoot, ringing or rounding.
As I had already planned the SS3602 in advance, during assembly I spaced the electrolytes a little near the DIP 8 socket.
Just get the right one..... The amp was design with those.... I got them from TME, but you can only shop until March without business account. https://www.tme.eu/hu/details/4n35m-ons/transzoptorok-analog-kimenet/onsemi/4n35m/
I rather use https://arwill.hu/ because TME failed me twice so far.
I ready have most parts in hand and the pc817d is really close to the 4n35 in CTR% so on paper if should work.
I've built my Whammy a while ago, but never managed to get rid of some hum. It has been ok with most headphones, but lately I started using some less efficient ones, so I'm revisiting this. The hum is only present with the volume pot about in the middle. It increases with volume until about 2 o'clock and then decreases. With the volume all up there is no hum either. The pot is bolted to the front panel and there is continuation to earth from there. Any ideas?
Thanks! I don't have a scope unfortunately. Any strategies to investigate without? Change opamp and/or install CX?
Does the hum change when you touch the volume potentiometer? Do you have a clear picture of the bottom of the board?
If the amp is connected to a signal source that will generally behave as a low or zero ohm voltage source across the input terminals. When you turn the pot up you are taking the input away from that 'zero ohm' and the input sees highest impedance at the half way point of the control (half way as in resistance, not mechanical rotation if a log pot is fitted).
So the first question is whether the input wiring is picking up hum.
Also could there be some kind of ground loop around the pot and its wiring.
So the first question is whether the input wiring is picking up hum.
Also could there be some kind of ground loop around the pot and its wiring.
When I tried it, the TI TL072 didn't oscillate, neither did the BB OPA2604 (both were original opamps). Get some original TL072 and try it, if the problem goes away then it's oscillation. If the problem remains then there is something wrong with the grounding. Compensation capacitors can only be determined correctly with the help of a signal generator and an oscilloscope.
The hum didn't change when touching the pot. I had the LM833 in and tried chaning it to the RC4580 (and then to the OPA2134) and the hum vanished. So I'm guessing it was the opamp. At the same time I also added 100 / 220k ohm resisters at the pre-out and connected the grounds at the headphone out, though not sure how that could have impacted the hum. In any case, I'm happily playing music without hum 🙂
When the oscillation occurs, everything can be heard from the device. Buzzing, strange noises, crackles and the like. And it doesn't have to be heard in general, it can just be heated more. Sometimes some components are destroyed. OPA 2604 is safe, and better sounding to me than OPA 2134.
I replaced the Muses02 with Signetics NE5532 in the Whammy…
😎
It is like voodoo magic and gives me butterflies in my gut.
DC Offset: Signetics without a line (series 8709D): -3.5 mV and -4.5 mV.
This specific op-amp was removed from an old Yamaha equalizer, where we also salvaged the PCM63P-Y.
😎
It is like voodoo magic and gives me butterflies in my gut.
DC Offset: Signetics without a line (series 8709D): -3.5 mV and -4.5 mV.
This specific op-amp was removed from an old Yamaha equalizer, where we also salvaged the PCM63P-Y.
Hello all, I'm about to start building a Whammy and I have a couple of concerns. (I'm a noob - please forgive me if my questions sound stupid) I'm planning to roll Staccato and Sparkos discrete opamps in the Whammy but I'm a little worried about them overheating. My Whammy came with a 18V PSU, and I'm thinking I might replace it with a 15V Talema. But another thing is I live in Japan and our electricity is 100V. So should I -
Thanks in advance for your advice!
- Not do anything because the 18V PSU is fine and 100V power should be okay
- Get the 15V PSU rather than risk running those expensive op amps too hot
- Get a step up transformer because 100V is going to be a problem
Thanks in advance for your advice!
If possible, change the transformer to one with a 100V primary, rather than use a step-up.
But use a 15V supply. There's no advantage to 18V, but there is definite potential disadvantage.
But use a 15V supply. There's no advantage to 18V, but there is definite potential disadvantage.
100V mains to the included transformer will reduce voltage. This is good. You can keep the kit transformer with no changes.
Choose "naked regulators" configuration, see step 9 in the guide. which will give 15VDC to the audio circuit. https://guides.diyaudio.com/Guide/WHAMMY+headphone+amplifier/3?lang=en#s59
No other changes are needed.
Choose "naked regulators" configuration, see step 9 in the guide. which will give 15VDC to the audio circuit. https://guides.diyaudio.com/Guide/WHAMMY+headphone+amplifier/3?lang=en#s59
No other changes are needed.