I am looking for a commercial single ended to balanced line out converter or preamp stage. Pre-made units boxed and ready to go don’t seem to be readily available. It seems like a basic thing but not sure why something for say $40 from Behringer or similar doesn’t immediately come up on a search. However, a $10 Sparkfun THAT1646 breakout board with TRS jack did come up. If anyone has suggestions for a commercially made ready to use one, please share here:
Sparkfun THAT1646 breakout board:
https://www.digikey.com/products/en?mpart=BOB-14003&v=1568
Needs a +/-voltage PSU and a panel jack.
I have made simple 2 transistor converters using a CFP in SE Class A and that works well but looking for an ultra low distortion IC implementation here.
Sparkfun THAT1646 breakout board:
https://www.digikey.com/products/en?mpart=BOB-14003&v=1568
Needs a +/-voltage PSU and a panel jack.
I have made simple 2 transistor converters using a CFP in SE Class A and that works well but looking for an ultra low distortion IC implementation here.
MAAC0,
Thanks for that tip - this was exactly what I was looking for. Don’t know why a google search could not turn up something like this. $55 is a great price too. Only thing is the -88dB noise floor. Most of my stuff is -125dB noise floor - but it will do until I make a custom one.
Manual even has a schematic:
Gofar99, thanks for the tip but I want to avoid transformers for the extra 3rd harmonic they can add.
Russo,
Thanks for the tip on the Mesa Boogie clearlink - but I think the Rolls unit is closer to what I was looking for.
Thanks for that tip - this was exactly what I was looking for. Don’t know why a google search could not turn up something like this. $55 is a great price too. Only thing is the -88dB noise floor. Most of my stuff is -125dB noise floor - but it will do until I make a custom one.
Manual even has a schematic:
Gofar99, thanks for the tip but I want to avoid transformers for the extra 3rd harmonic they can add.
Russo,
Thanks for the tip on the Mesa Boogie clearlink - but I think the Rolls unit is closer to what I was looking for.
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not to mention that if this is to be considered standard practice, that in order to maintain true galvanic isolation that no circuit ground should be connected to chassis.
That's the exact opposite of 'good engineering practice'.
If you want galvanic isolation use an audio input or output transformer, but still connect the circuit ground to the chassis.
Circuit analog ground should be connected to chassis/earth safety ground via ground loop breaker 10ohm resistor and anti-parallel diodes or an NTC for safety and hum/RFI reduction.
My Sparkfun THAT1646 breakout boards arrived today. Will probably use a handy 5v to +/-24 DC-DC followed by +/-15v 7815/7915 regulators.
My Sparkfun THAT1646 breakout boards arrived today. Will probably use a handy 5v to +/-24 DC-DC followed by +/-15v 7815/7915 regulators.
I made a +/-15v power supply from a +/-24v DC-DC converter and LM7815/7915 voltage regulators to power the Sparkfun THAT1646 SE to Balanced drivers. Connected it to my TPA3255 Reference Class D amp with balanced inputs. Now I can use SE headphone outputs to drive the TPA3255 rather than always having to rely on the balanced output section of the Focsusrite. These Sparkfun breakout boards are very convenient and sound great.
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Handy piece of hardware you've turned up xrk. I'm filing that one away as a mental note for future. Thanks for the tip.
Interested to see what you come up with as a follow on.
Interested to see what you come up with as a follow on.
Jhofland designed this for me. A SE/Bal to Bal converter with selectable gain of 0dB, 6dB, 20dB using OPA1656 and LME94724. Works great. This is prototype and production version will have SE output as well. So SE/Bal to SE and Bal converter with 0dB, 12dB, 20dB gain.
TPA3255 Reference Design Class D Amp GB
TPA3255 Reference Design Class D Amp GB
Cool. I'll keep my eye on where this ends up.
What's your thinking behind the selectable gain?
Is that to give an SE input signal a boost, so that a user can level things up if they switch across from a Balanced input?
Or just for general flexibility?
If the former, I suppose a selection switch could be rigged up without too much difficulty?
What's your thinking behind the selectable gain?
Is that to give an SE input signal a boost, so that a user can level things up if they switch across from a Balanced input?
Or just for general flexibility?
If the former, I suppose a selection switch could be rigged up without too much difficulty?
Old thread but seems there's still interest. Here's another ready-made option, Nobsound NS-05P passive preamp, converts XLR to RCA or vice versa and provides level control.
https://www.amazon.com/Nobsound-Ful...eywords=Nobsound+NS-05P&qid=1592927693&sr=8-2
https://www.amazon.com/Nobsound-Ful...eywords=Nobsound+NS-05P&qid=1592927693&sr=8-2
Interesting piece of investigative work into the NS-05P from atomicbob over at SBAF:
Goldpoint SA2X - Nobsound NS-05P passive attenuator comparison technical measurements | Super Best Audio Friends
Post #10 summarises the performance differences (low attenuation appears to result in frequency roll off above 3 kHz).
Post #12 fingers the 50k pot in the NS-05P to be the culprit with a comment that a 10k pot would improve matters.
There's also review of the importance of cable selection.
Goldpoint SA2X - Nobsound NS-05P passive attenuator comparison technical measurements | Super Best Audio Friends
Post #10 summarises the performance differences (low attenuation appears to result in frequency roll off above 3 kHz).
Post #12 fingers the 50k pot in the NS-05P to be the culprit with a comment that a 10k pot would improve matters.
There's also review of the importance of cable selection.
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