Oh bugger me. I just noticed that I have the mute resistor connecting to ground! My amp schematic would make lots of quiet! Should be to V- of course.
C
C
Other issues aside, I find the continued copying of manufacturer's
application notes tedious. Doing something different with the
parts is a higher goal for DIY.
😎
application notes tedious. Doing something different with the
parts is a higher goal for DIY.
😎
I reach so high only because I on stand on the shouders of giants. Thank you Nelson, not only for the praise but for creating a starting point from which to explore. All I did was play around with some circuit modelling, build a few circuits and experiemnt with changing various parts values until it worked. Not exactly ground shaking stuff, really!
I must say that it has been a greatly educational journey, and I have learned an enormous amount along the way, not to mention having a great time while doing so. I think that instead I should be heartily shouting:
"ALL HAIL, NELSON!
Nelson Pass said:
Great answer (please keep up the good work). How about expounding on it though. Are there any sonic differences, power handling differences, etc. Metalman or anyone else who has build one. Do you have a standard GC to compare it to.
Thanks in Advance,
Pat
It can swing twice the voltage output as a standard GC, but does not increase the current output capability (I have plans to address that in a future variant). Sonically I find it to sound superior (to my taste at least). It is equally detailed but has less edge (more liquidity), has better bass control, and more three dimensional imaging. Of course, it looses a chunk of the circuit simplicity that GC'ers love.
The caveat to the above statements on sonics is that the only GC I have for comparison is the BrianGT Basic GC version (i.e. no premium parts). However, I haven't used anything special to build my XGC either (Yageo metal film resistors, Panasonic caps etc.) and my layout is a squirrels nest of point-to-point wiring.
Cheers, Terry
Hi, metalman
I ordered two LM3875T to try this GCSS with +/-15V rails.
LM3875T ok?
Otherwise, I need to do change order now. Tks.
I ordered two LM3875T to try this GCSS with +/-15V rails.
LM3875T ok?
Otherwise, I need to do change order now. Tks.
The only difference between T and TF to my knowledge is that the TF is an insulated package, whereas the T requires and insulator.
Glad to have another opinion on its performance and I look forward to hearing your impressions.
Cheers, Terry
Glad to have another opinion on its performance and I look forward to hearing your impressions.
Cheers, Terry
Ok. I will change order for TF.
And 4, not 2.
My counting is always hopeless, even with small numbers.
If I receive them (hand carry) on time, I could report back within this month.
And 4, not 2.
My counting is always hopeless, even with small numbers.
If I receive them (hand carry) on time, I could report back within this month.
Eeek... The specification of LM3875TF says that the supply voltages (rail voltages) to be "minimum" +/-20V. Is this requirement to be kept???
I did not buy the Variac yet.........
I did not buy the Variac yet.........
I'm working on gathering parts for it as well...I do not have any ballanced gear to drive it with though. Do you think I would need a DRV134 circuit to have it sound the best or would a OPA627 buffer be sufficient.
Edit: Now reading Metalman's CC-CCS-X-BZLS Thread.
Edit: Now reading Metalman's CC-CCS-X-BZLS Thread.
Actually the spec indicates a 20 volt difference between V+ and V- rails, so you can operate as low as +/-10V. At 15V rails you will be fine.
To have the benefit of the supersymmetric effect, the circuit requires a balanced source. However, my previous statement that the circuit was not stable with a single-ended input was based on my experiences from an earlier stage of development, and the most recent posted schematic builds an amp that is more stable, so it may be possible that it will work with a single ended input now. I can't say for certain, cause once I got my BZLS up and running I just kept using the balanced connection. If I get a chance I'll switch it over to a SE input and see what happens.
If the lastest version is stable with a SE input, then you will still get the higher power output into higher impedances, and the better bass control, just not the supersymmetric noise distortion cancellation.
On an aside, although I am very proud of my CC-CCS-X-BZLS design and think very highly of it, there are other options for converting balanced to SE if you don't want to go to all the trouble of building a complete preamp. The first that comes to mind is the converter from the Aleph ONO (schematic attached).
Cheers, Terry
Attachments
metalman said:
From experience I can report that LM3875, balanced working, ( but not this fancy cct ) sounds much better with 24 V + 24V than with 12V + 12V - so 15V + 15V might be a bit on the low side if you are looking for optimum performance.
sorry if this upsets your plans...🙁
mike