Having continual issues dealing with digikey, but mouser is great. Any recommendations for a transformer available from mouser?
I have found this:
25VA Green square 25W Sealed toroidal transformers M25-05 AC dual 18V(2*18V) | eBay
It seems to be compatible from the specs.
All is working great! No issues at all, and sounds great. Now I have a great board to do some op amp comparisons in 🙂 Currently running a TL072.
Can anyone tell me what the input impedance of my Whammy is if I built the amp with the stock components from the BOM?
About to start building up a DSCv2 with Lundahl output transformers and I want to make sure I'm matching things up properly.
About to start building up a DSCv2 with Lundahl output transformers and I want to make sure I'm matching things up properly.
I recently finished and it sounds great.
I was at RMAF 2018 recently and got it measured at Audio Precision's room. They're a great bunch of people and immediately welcomed me. They were happy to measure it.
Due to being an amp, there are many different possibilities when it concerns which setting to measure it at. I told him my default volume listening level, but he also measured at near max, where the performance was substantially better. There are two separate PDFs. Basically as you go up in volume, the performance gets better (please remember your hearing before you go blasting the volume just because it's "technically" a better measurement).
Thought everyone here might want to see that. The amp was built to standard specifications with an OPA2134 op-amp in use. It has virtually no DC offset when measured.
Anyways, this is the Google Drive link to the PDF measurement files: Audio Precision Measurement of WHAMMY - Google Drive
I was at RMAF 2018 recently and got it measured at Audio Precision's room. They're a great bunch of people and immediately welcomed me. They were happy to measure it.
Due to being an amp, there are many different possibilities when it concerns which setting to measure it at. I told him my default volume listening level, but he also measured at near max, where the performance was substantially better. There are two separate PDFs. Basically as you go up in volume, the performance gets better (please remember your hearing before you go blasting the volume just because it's "technically" a better measurement).
Thought everyone here might want to see that. The amp was built to standard specifications with an OPA2134 op-amp in use. It has virtually no DC offset when measured.
Anyways, this is the Google Drive link to the PDF measurement files: Audio Precision Measurement of WHAMMY - Google Drive
Thanks for providing those measurements.
What puzzles me: In the THD measurements there is a strange "bump" between 500mV and 1000mV output (page 25).
Is there an explanation for this behaviour?
On the Almost_Max measurement?
He didn't mention it during the testing. To me, it looks like a short reserve in the capabilities before hitting a true clipping point. He could not make it clip at the default level.
Maybe someone else here knows more about the circuit and why it might do that.
What is the proper way to measure the DC offset?
I am measuring from ground to left and ground to right, and my fluke multimeter is giving 0.3 mv(That's 0.3 millivolts) for left channel and 0.2 mv(That's 0.2 millivolts) for right channel DC. I can't get a reading at all in volts range.
I am going to assume I am doing it wrong xD That's practically no offset at all...
I am measuring from ground to left and ground to right, and my fluke multimeter is giving 0.3 mv(That's 0.3 millivolts) for left channel and 0.2 mv(That's 0.2 millivolts) for right channel DC. I can't get a reading at all in volts range.
I am going to assume I am doing it wrong xD That's practically no offset at all...
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I never measured it that high. It could be load dependent I don't know what the load was but the level would have blood coming out of your ears. The measurements look great overall.
The cable that was hooked up to the headphone jack said 30 ohm.
Agreed. I'm very happy with mine. It was an absolute pleasure to build. Thank you! 🙂
Decision time. Parts are on hand and I could use some input.
Plans to use as pre-amp based around OPA 2134
Outboard transformer 22+22V 130VA
Would 18V regulators with LEDs be best approach?
Is there a better voltage/alternative?
Plans to use as pre-amp based around OPA 2134
Outboard transformer 22+22V 130VA
Would 18V regulators with LEDs be best approach?
Is there a better voltage/alternative?