Here is how a +/- 2V differential input plot looks at 5Khz.
The LM3886 model is not exact, but it should be close enough.
Cheers!
Russ
The LM3886 model is not exact, but it should be close enough.
Cheers!
Russ
Hi Ed,Ed Lafontaine said:Does your mower have headlights?
Well as a matter of fact it does. 😉
Cheers!
Russ
Yes, I have a single side PCB which I will post PDFs for tomorrow after I have had a chance to verify the layout. I have already built the circuit, but with an older layout which needed major rehab. 🙂
I will post my current circuit schematic and layout tomorrow.
I will very likely also get some PCBs of Terry's circuit made too. It is an excellent circuit. I am listening to it right now. 🙂
I couldn't say mine improves on the sound at all as Terry's discrete circuit is already awesome, but I can say that I like the fact that it needs no caps in the signal path, and turn/turn off behaviour is a bit better(no woofer movement on turn on and no pop on turn off) and certianly the sound is no worse. 🙂 There is zero DC(well < 1mv) offset at the inputs or outputs.
I also will try the OPA1632 in the morning. It should work just fine.
Cheers!
Russ
I will post my current circuit schematic and layout tomorrow.
I will very likely also get some PCBs of Terry's circuit made too. It is an excellent circuit. I am listening to it right now. 🙂
I couldn't say mine improves on the sound at all as Terry's discrete circuit is already awesome, but I can say that I like the fact that it needs no caps in the signal path, and turn/turn off behaviour is a bit better(no woofer movement on turn on and no pop on turn off) and certianly the sound is no worse. 🙂 There is zero DC(well < 1mv) offset at the inputs or outputs.
I also will try the OPA1632 in the morning. It should work just fine.
Cheers!
Russ
Actual schematic
Here is the actual schematic for my THS4131 based amp:
Still hoping for some input... Nobody has any thoughts?😕
Cheers!
Russ
Here is the actual schematic for my THS4131 based amp:
Still hoping for some input... Nobody has any thoughts?😕
Cheers!
Russ
I dont have any constructive input yet...but with a pcb layout I will try to build it over the next few days. Although, I would probably want to lower the rail voltages and gain (for now) to avoid multiple power supplies (and because my speakers do 103db/W).
I have been toying around with OPA1632s coupled to LM3875s for the last couple days. Three seperate feedback loops though. Nothing working well here yet.
Thanks Russ for the work you've put in.😎
regards,
PSz.
oops, I meant four seperate feedback loops!!!
I have been toying around with OPA1632s coupled to LM3875s for the last couple days. Three seperate feedback loops though. Nothing working well here yet.
Thanks Russ for the work you've put in.😎
regards,
PSz.
oops, I meant four seperate feedback loops!!!
I think that I placed some basic information about OPA1632/GC compilation in this thread.
http://www.diyaudio.com/forums/showthread.php?s=&postid=458253&highlight=#post458253
http://www.diyaudio.com/forums/showthread.php?s=&postid=580497&highlight=veteran#post580497
I don't like the idea of putting OPA1632 into GC feedback - this op-amp is very susceptible for oscillation (track length, etc). It's better to keep them separate.
If you wont - tomorrow I can draw some schematic 😉
http://www.diyaudio.com/forums/showthread.php?s=&postid=458253&highlight=#post458253
http://www.diyaudio.com/forums/showthread.php?s=&postid=580497&highlight=veteran#post580497
I don't like the idea of putting OPA1632 into GC feedback - this op-amp is very susceptible for oscillation (track length, etc). It's better to keep them separate.
If you wont - tomorrow I can draw some schematic 😉
PSz. said:
Can you place few more details about your OPA1632 application/schematic? Maybe I can help 😉
veteran said:
That kind of application with seperate feedback loops is elementary. I have already designed such a circuit.
The idea is to get the same sort of SuSy effect as we get with the discrete circuit.
BTW in case you did not catch it before, the circuit is built and tested and is stable, with no oscillation. 🙂
Cheers!
Russ
Single Side PCB PDFs
Here are some PDFs for a single side layout for my THS4131 based approach.
It by no means a perfect layout, but it works fine. I am working on a much better 2 sided layout. But this is the layout I am using now, and it works just fine.
Cheers!
Russ
The copper is not mirrored and the silk is mirrored for toner transfer.
PDFs
The resistor values seems to work fine, but feel free to exeriment, do not take the values on the silkscreen as set in stone.
Cheers!
Russ
Here are some PDFs for a single side layout for my THS4131 based approach.
It by no means a perfect layout, but it works fine. I am working on a much better 2 sided layout. But this is the layout I am using now, and it works just fine.
Cheers!
Russ
The copper is not mirrored and the silk is mirrored for toner transfer.
PDFs
The resistor values seems to work fine, but feel free to exeriment, do not take the values on the silkscreen as set in stone.
Cheers!
Russ
My stuff is definately remedial. I'm still just playing at this point.
However, I thought SUSY had been locked up in the 1632 et al. Wouldn't "she" still be working hard with seperate feedback loops?
Regards,
PSz.
However, I thought SUSY had been locked up in the 1632 et al. Wouldn't "she" still be working hard with seperate feedback loops?
Regards,
PSz.
PSz. said:
With seperate feedback loops it just your basic bridged amp. Not really the point of this thread. 🙂
It's good to see folks making progress, 'cause I sure ain't!
Been way too busy other places in life right now, so my stuff hasn't seen any attention since I went through and did my last round of tests.
C
Been way too busy other places in life right now, so my stuff hasn't seen any attention since I went through and did my last round of tests.
C
Hi everybody,
Russ, I'm so glad you had success with THS4131 in SuSy amp. I'm looking forward to see how the opa1632 will perform in the same situation. I'm very fond of this circuit but my 4 ohms speakers won't let me build it. If I exchange them for 8 ohm speakers, the Susy amp is going to be first thing on the "to be built" list.
Did you try the original approach - without R7, R8, R9, R10 and pins 3 of LM3886s connected via 50K-100K resistors to pins 8 and 1 of THS 4131 (I'm refering to your schematic in post #566). The way you are doing it now is a bit different compared with Terry's circuit. For example, the outputs of THS4131 are feeding with signal simultaniously both inputs (+ and -) of LM3886s which are excluded from the global SuSy feedback. Now it looks more like a standard bridged amp., not a SuSy.
Thanks for sharing,
cheers all
Russ, I'm so glad you had success with THS4131 in SuSy amp. I'm looking forward to see how the opa1632 will perform in the same situation. I'm very fond of this circuit but my 4 ohms speakers won't let me build it. If I exchange them for 8 ohm speakers, the Susy amp is going to be first thing on the "to be built" list.
Did you try the original approach - without R7, R8, R9, R10 and pins 3 of LM3886s connected via 50K-100K resistors to pins 8 and 1 of THS 4131 (I'm refering to your schematic in post #566). The way you are doing it now is a bit different compared with Terry's circuit. For example, the outputs of THS4131 are feeding with signal simultaniously both inputs (+ and -) of LM3886s which are excluded from the global SuSy feedback. Now it looks more like a standard bridged amp., not a SuSy.
Thanks for sharing,
cheers all
Hi Juma,
You are absolutely correct. Terry had pointed me in the same direction as you, but I was affraid of using the high value resistor for the global feeback to the THS4131.
Well it turns out my fear was misplaced! 🙂 I ran a simulation this morning then quickly soldered in the following (see attached schematic) resistors on my old PCB. Voila!!! It works!!! And true "SUSY" operation!!!
Terry, Juma, you guys rock. Thanks for pointing me back in the right direction.
Here is the new schematic:
You are absolutely correct. Terry had pointed me in the same direction as you, but I was affraid of using the high value resistor for the global feeback to the THS4131.
Well it turns out my fear was misplaced! 🙂 I ran a simulation this morning then quickly soldered in the following (see attached schematic) resistors on my old PCB. Voila!!! It works!!! And true "SUSY" operation!!!
Terry, Juma, you guys rock. Thanks for pointing me back in the right direction.
Here is the new schematic:
Here is the plot for a 5Khz balanced 2V signal. The small signal is the input. The next larger is the output voltage of the THS4131 before the voltage divider(throwing away gain), and the large signal is the output.
Cheers!
Russ
Cheers!
Russ
Hi George,
I hate to try to describe sonics, but I believe it is very good. Sound is practically the same as the discrete version, but there are some definite gains as far as practical things go. Parts count is less. No signal caps. The turn on and turn off behavior is much improved with zero pop or offset. Good resistors are a must here I think. I am using some dale RN55s and some Pheonix resistors I had lying around. I am going to order a set of Pheonix all the way around for the next one I make. This is just a prototype.
I have only been listening too it at low levels because I am at the office, but I can say it drives my sealed Cryolites very well. There is no hiss at all. Very pleased with the results so far. The amp is stable. And actually runs cooler at idle than my(Terry's) discrete version does.
I will push it harder tonight at home. 🙂
PCB PDFs coming here shortly.
Cheers!
I hate to try to describe sonics, but I believe it is very good. Sound is practically the same as the discrete version, but there are some definite gains as far as practical things go. Parts count is less. No signal caps. The turn on and turn off behavior is much improved with zero pop or offset. Good resistors are a must here I think. I am using some dale RN55s and some Pheonix resistors I had lying around. I am going to order a set of Pheonix all the way around for the next one I make. This is just a prototype.
I have only been listening too it at low levels because I am at the office, but I can say it drives my sealed Cryolites very well. There is no hiss at all. Very pleased with the results so far. The amp is stable. And actually runs cooler at idle than my(Terry's) discrete version does.
I will push it harder tonight at home. 🙂
PCB PDFs coming here shortly.
Cheers!