Yes, this red autoformer is fantastic! and the whole machine too. (except for the wiring maybe, but that's my nagging inner wife typing)
The laminations will probably not be thin enough to minimize eddy current losses at HF. Also they will probably not be as magnetically soft as core materials needed for low distortion. Winding technique can also matter lot. If one has to rely on a lot of capacitive coupling between effective primary and secondary windings in order to extend bandwidth, that is different from using only magnetic coupling to produce similar bandwidth.
I have an idiotic question. I have a Slagle autoformer that I DIYed into a box as an RCA attenuator. It works fabulously, I compared it against a resistor pot and the quality gap is immediately obvious.
My question is - is it possible to rewire it into XLR volume control? My idea is to use the autoformer normally between pins 1 (ground) and 2 (hot) normally, then add a fixed 20 H inductor from pin 3 input to pin 3 output, then another fixed 20 H between pins 1 and 3. The idea is that it will be more or less close to to properly balanced when attenuator is at some middle position, but somewhat asymmetric if turned left or right. The RCA variant currently works the way that pins 1 and 3 are shorted in the RCA to XLR cable. Instead of no signal at 3 it can have some fixed negative signal.
The idea why XLR could sound better besides the noise compensation is because the DAC is 2 V at RCA but 4 V at balanced. Will this potentially sound better than RCA or it's a bad idea, the RCA will just sound better because of some artifacts from this approach? Should be a fun question for someone knowledgeable....
My question is - is it possible to rewire it into XLR volume control? My idea is to use the autoformer normally between pins 1 (ground) and 2 (hot) normally, then add a fixed 20 H inductor from pin 3 input to pin 3 output, then another fixed 20 H between pins 1 and 3. The idea is that it will be more or less close to to properly balanced when attenuator is at some middle position, but somewhat asymmetric if turned left or right. The RCA variant currently works the way that pins 1 and 3 are shorted in the RCA to XLR cable. Instead of no signal at 3 it can have some fixed negative signal.
The idea why XLR could sound better besides the noise compensation is because the DAC is 2 V at RCA but 4 V at balanced. Will this potentially sound better than RCA or it's a bad idea, the RCA will just sound better because of some artifacts from this approach? Should be a fun question for someone knowledgeable....
@MagicBus Oh thank you! Very unintrusive experiment, could be wired back if not working as expected. I always had XLR DAC and amp, but never connected them as such, because I have my DIY Slagle autoformer wired as RCA and I don't possess any preamp.
About sound quality - it might be overwhelming to try a classic A-B test, what I did instead, I listened for Slagle for 3 years, and then I swapped it to RCA pot Schiit Sys and listened for 3 days. It changed from track to track, but I had a growing feeling that I've lost something. Just as if the sound became less interesting, but I cannot verbalise what was missing.
About sound quality - it might be overwhelming to try a classic A-B test, what I did instead, I listened for Slagle for 3 years, and then I swapped it to RCA pot Schiit Sys and listened for 3 days. It changed from track to track, but I had a growing feeling that I've lost something. Just as if the sound became less interesting, but I cannot verbalise what was missing.
I guess personal taste is all that matters after all! Long term listening of a reference system helps a lot to evaluate new components.
@gpapag @MagicBus reporting back - thank you, that was a smashing success!
Indeed that was a very counter-intuitive wiring, I would never come to this by myself. While I was preparing and wiring all this, I switched to the Schiit Sys RCA pod and listened it for a few days. It was clean but flat and boring. I suspect that's what most people have with their stereo - kind of good but not exiting.
When I assembled all this it was the explosion of music - wide, deep soundstage, deep controlled bass, perfect imaging, separation and control. And I've got shivers. My shiversmeeter reached some uncharted territory.
Initially I thought the volume went down - but it was an illusion because what I previously considered as an uncomfortable volume when various defects become audible, now is much cleaner and makes no discomfort to listen. I think the volume is about the same or just a bit down, which means that my amp's input stage is actually converting the RCA into fake balanced by inverting it. The real XLR coming from DAC must be superior because the DAC actually has completely separate DACs inside for cold and hot pins, it's made to be used balanced. And I think it's not about noise, but about actually having more details when all 4 DAC channels are used.
That was an experimental build, so I used a wire salvaged from a transformer, and Neutrik connectors. My idea was to kill all the capacitance so I winded the wires around teflon tubes. I don't care much about inductance and resistance, that's a tradeoff. Eventually, this will be upgraded with better parts but not anytime soon, it's already amazing.
Indeed that was a very counter-intuitive wiring, I would never come to this by myself. While I was preparing and wiring all this, I switched to the Schiit Sys RCA pod and listened it for a few days. It was clean but flat and boring. I suspect that's what most people have with their stereo - kind of good but not exiting.
When I assembled all this it was the explosion of music - wide, deep soundstage, deep controlled bass, perfect imaging, separation and control. And I've got shivers. My shiversmeeter reached some uncharted territory.
Initially I thought the volume went down - but it was an illusion because what I previously considered as an uncomfortable volume when various defects become audible, now is much cleaner and makes no discomfort to listen. I think the volume is about the same or just a bit down, which means that my amp's input stage is actually converting the RCA into fake balanced by inverting it. The real XLR coming from DAC must be superior because the DAC actually has completely separate DACs inside for cold and hot pins, it's made to be used balanced. And I think it's not about noise, but about actually having more details when all 4 DAC channels are used.
That was an experimental build, so I used a wire salvaged from a transformer, and Neutrik connectors. My idea was to kill all the capacitance so I winded the wires around teflon tubes. I don't care much about inductance and resistance, that's a tradeoff. Eventually, this will be upgraded with better parts but not anytime soon, it's already amazing.