THD: yes, that's how it is... and the higher order are not negligible (measured on real amplifier).
PMA said:
125bB below output level !
😀
In the real life, below noise level ...
ps. The output stage is in class AAB, Iq=500mA on each pair
I thought it was simulation. For the real amp - excellent result.
Could you also show the same spectrum starting from 20Hz, rather than 3kHz?
Could you also show the same spectrum starting from 20Hz, rather than 3kHz?
re. tougher sound
Hello MikeB,
Now, You are always tell what I'm going to ask,
I have a question, will 10,000uf of rectifier capacitors and a pair of 2sc2922, 2sa1216 be satisfied for a +/-48V Symasym amp.
It's cascoding the input: I have cascoded the input with a pair of fets: 2sk30A and bc546 before I know the definition of cascode.
Going further, how do you cascode U5,u6( MjE15030,15031) on the power stage, I have seen it on a schematic of symasym but I don't know how to do it. Will I use a 5,6V zenner to source the cascode
You put C2==100pf with (r14=r29==22K) &&(r13==2K) How will my C2 be with (r14=R29==10K) &&(R13==500ohm)
You know, I have a lot of problems with my 2sc2922 amp, for this output is very tough to drive. It require lots of base current. I used the attached output stage. Pls tell me how to cascode this output. Still, the sonic of this amp is not quite OK. People said C2922 is a nice trans, but I found it tough.
The symasym version I made with 2sc5200 and 2sa1943 is OK without any modification.
Regards,
Hello MikeB,
Now, You are always tell what I'm going to ask,
I have a question, will 10,000uf of rectifier capacitors and a pair of 2sc2922, 2sa1216 be satisfied for a +/-48V Symasym amp.
It's cascoding the input: I have cascoded the input with a pair of fets: 2sk30A and bc546 before I know the definition of cascode.
Going further, how do you cascode U5,u6( MjE15030,15031) on the power stage, I have seen it on a schematic of symasym but I don't know how to do it. Will I use a 5,6V zenner to source the cascode
You put C2==100pf with (r14=r29==22K) &&(r13==2K) How will my C2 be with (r14=R29==10K) &&(R13==500ohm)
You know, I have a lot of problems with my 2sc2922 amp, for this output is very tough to drive. It require lots of base current. I used the attached output stage. Pls tell me how to cascode this output. Still, the sonic of this amp is not quite OK. People said C2922 is a nice trans, but I found it tough.
The symasym version I made with 2sc5200 and 2sa1943 is OK without any modification.
Regards,
Attachments
I guess your Sankens are fake, symasym already has been used with the 2sc2922 very sucessful and without any problems. (no changes, 36v supply)
Do not try cascoding the output, this is very tricky to be stable.
You should use r13 = 1k, with r14/29 = 10k, then simply double c2 to 200pf.
2sk30 has max Vds below 40v? You should use mpsa42/2n5551 here.
Mike
Do not try cascoding the output, this is very tricky to be stable.
You should use r13 = 1k, with r14/29 = 10k, then simply double c2 to 200pf.
2sk30 has max Vds below 40v? You should use mpsa42/2n5551 here.
Mike
re. amp sound
Hi Mike,
Yep, after making all the necessary modification, my amp is up an running. I think it is up to the capability now, it's sufficient at the moment, the amp provide enough power for my speaker an in turn my 50 m2 room. At higher volume it begin to distort but my ear hurts. That's enough. I like this version the most. C2922 is nice to me now, for its bass is so firm, and sweet treble. At full throttle, the amp get hot like hell, I've got to install a cooling fan for the outputs. My 10A rectifier get hot too, A 2w heat sink is applied there.
thanks for your precious help.
Hi Mike,
Yep, after making all the necessary modification, my amp is up an running. I think it is up to the capability now, it's sufficient at the moment, the amp provide enough power for my speaker an in turn my 50 m2 room. At higher volume it begin to distort but my ear hurts. That's enough. I like this version the most. C2922 is nice to me now, for its bass is so firm, and sweet treble. At full throttle, the amp get hot like hell, I've got to install a cooling fan for the outputs. My 10A rectifier get hot too, A 2w heat sink is applied there.
thanks for your precious help.
Possible, symasym sounds weak / "untough" when oscillating.
Phong, are you really using TIP41 as drivers? That would be a bad choice, hfe=~50, ft=3mhz... max 100v for the C-version.
You might try adding degeneration resistors (~47ohm) to the input transistors.
Mike
Phong, are you really using TIP41 as drivers? That would be a bad choice, hfe=~50, ft=3mhz... max 100v for the C-version.
You might try adding degeneration resistors (~47ohm) to the input transistors.
Mike
amp output
Hi Mike,
I've got a bunch of 2sa1837+ its 2sc from Digikey, can I use these device to replace TIP41/42?. I can see that in some C2922 linear application people are using as big as 65W device to drive 2sc2922. Mje1503x is desirous but not available.
I have one idea then, I will increase quiescent current for my tip 41/42 e.g 120 ma. Will it deliver better sonic. In my c2922 reference schematic, they apply quite high base current capacity to the output
That's the point why I try to reduce my amp global gain: I can not get high Hfe device.
Thanks
Hi Mike,
I've got a bunch of 2sa1837+ its 2sc from Digikey, can I use these device to replace TIP41/42?. I can see that in some C2922 linear application people are using as big as 65W device to drive 2sc2922. Mje1503x is desirous but not available.
I have one idea then, I will increase quiescent current for my tip 41/42 e.g 120 ma. Will it deliver better sonic. In my c2922 reference schematic, they apply quite high base current capacity to the output
That's the point why I try to reduce my amp global gain: I can not get high Hfe device.
Thanks
The Toshiba's 2SA1837/2SC4793 are quite the best drivers, yes use them! (~3times higher hfe, ~23times faster)
http://www.toshiba.com/taec/components2/Datasheet_Sync//66/7632.pdf
Carlos (DestroyerX) used that combination, the Toshiba drivers with the Sanken outputs.
How should reducing global gain help with too low hfe devices? You only increase feedback and make the amp unstable. Try to keep original values / schematic.
Increasing bias will not really help with your hfe problem.
Mike
http://www.toshiba.com/taec/components2/Datasheet_Sync//66/7632.pdf
Carlos (DestroyerX) used that combination, the Toshiba drivers with the Sanken outputs.
How should reducing global gain help with too low hfe devices? You only increase feedback and make the amp unstable. Try to keep original values / schematic.
Increasing bias will not really help with your hfe problem.
Mike
Hot like hell ?
Humm... there's something wrong. My symasym (5.3, no changes), I can push it very hard, I never listened it's distortion because I think that my JBL E60 speakers would blow before I hear it, and the amp don't get that hot.
My amp is so great, I never had a so good amplifier, thanks DestroyerX, he told me many times to build it. You can put your ear at the woofer and tweeter, NO HISS, NO HUMING AT ALL ! Incredible !
At home, I'm running it with 33+33v and a pair of JBL E60, floorstanding speakers. The player is a DVD from LG (I hate LG but...), with upgraded output stage (no eletrolytics, no mute transistors, RC4580 swaped with OPA2134). Sound here is very nice !
What I'm listening more is, Diana Krall, Jane Monheit, Bob James (MUST TRY!!!!), Buddy Guy, Earth Wind & Fire, BeeGees, some B.B. King, and a lot of rock'n roll 😀
I really like my setup.
Listening to Eric Clapton Unplugged is incredible live, because the songs don't have much bass, but when he grab or leave his guitar, you can listen to a deeeep and smoooth bass, that you don't know of where it's coming from. NICE !
Humm... there's something wrong. My symasym (5.3, no changes), I can push it very hard, I never listened it's distortion because I think that my JBL E60 speakers would blow before I hear it, and the amp don't get that hot.
My amp is so great, I never had a so good amplifier, thanks DestroyerX, he told me many times to build it. You can put your ear at the woofer and tweeter, NO HISS, NO HUMING AT ALL ! Incredible !
At home, I'm running it with 33+33v and a pair of JBL E60, floorstanding speakers. The player is a DVD from LG (I hate LG but...), with upgraded output stage (no eletrolytics, no mute transistors, RC4580 swaped with OPA2134). Sound here is very nice !
What I'm listening more is, Diana Krall, Jane Monheit, Bob James (MUST TRY!!!!), Buddy Guy, Earth Wind & Fire, BeeGees, some B.B. King, and a lot of rock'n roll 😀
I really like my setup.
Listening to Eric Clapton Unplugged is incredible live, because the songs don't have much bass, but when he grab or leave his guitar, you can listen to a deeeep and smoooth bass, that you don't know of where it's coming from. NICE !
HI
Mike it is possible to use the 2SA1837/2SC4793 to replace MJE15030/15031 driver in the Symasym .
These transistors would improve the sound ?
Regards
Mike it is possible to use the 2SA1837/2SC4793 to replace MJE15030/15031 driver in the Symasym .
These transistors would improve the sound ?
Regards
Hello everybody,
Just wanted to show my p2p symasym 🙂
No hum, no hiss and was running without rework.
regarding components, I just used what I had at home...
Nice amp,
cheers
Just wanted to show my p2p symasym 🙂
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
No hum, no hiss and was running without rework.
regarding components, I just used what I had at home...
Nice amp,
cheers
yeah, I just love SMD devices, does make some things much easyier.
Camera is a € 1,5 Nikon Coolpix 3700 with defective display which I found on Epay, well, after a couple of Ottakringers I had a very steady hand
Next weekend I'll build Roenders version with ONS Thermaltrak Samples.
Really glad I went for Symasym, Gainclones got boring
Camera is a € 1,5 Nikon Coolpix 3700 with defective display which I found on Epay, well, after a couple of Ottakringers I had a very steady hand
Next weekend I'll build Roenders version with ONS Thermaltrak Samples.
Really glad I went for Symasym, Gainclones got boring
High neg. feedback ratio
I am an Solid State newbie currently building a 5-3, but it will be a while before I can listen. I have been playing with and building tube amps the last 15 years and have become convinced that high feedback is not a good thing.
So, I'm concerned about the Symasym's high feedback ratio and would like some comments on the design rationale and the effects of high feedback on the amp's sound. It is not my intent to criticize; I hope to learn the SS philosophy on gain management .
My question to you Symasymers -- does the high negative feedback bother you; like it makes the sound dry and joyless? I have only seen a few comments on how these amps sound (other than Pavel's short review), but I would be interest to know about your experiences comparing it to other high quality amps.
The Symasym's gain even with the 57 db feedback is very high. One might reduce the gain with a voltage divider at the input, but managing gain in the original design seems to me to have been a better approach. As it is it seems to me too much open loop gain is then reduce to reasonable gain by applying too much feedback.
I am an Solid State newbie currently building a 5-3, but it will be a while before I can listen. I have been playing with and building tube amps the last 15 years and have become convinced that high feedback is not a good thing.
So, I'm concerned about the Symasym's high feedback ratio and would like some comments on the design rationale and the effects of high feedback on the amp's sound. It is not my intent to criticize; I hope to learn the SS philosophy on gain management .
My question to you Symasymers -- does the high negative feedback bother you; like it makes the sound dry and joyless? I have only seen a few comments on how these amps sound (other than Pavel's short review), but I would be interest to know about your experiences comparing it to other high quality amps.
The Symasym's gain even with the 57 db feedback is very high. One might reduce the gain with a voltage divider at the input, but managing gain in the original design seems to me to have been a better approach. As it is it seems to me too much open loop gain is then reduce to reasonable gain by applying too much feedback.
Francois, the Symasym is one of the most engaging and accurate amps I have ever heard, commercial or diy. If you like valve euphonics, (nothing wrong with that, it's all down to taste in the end 😉), it probably won't suit you.
I'm fairly neutral on the whole feedback thing, and I can't really comment on Mike's design choices, but it would be a shame if you disregarded it because of preconceptions about the amount of feedback used, and you will be missing out on a fine amplifier.
I'm fairly neutral on the whole feedback thing, and I can't really comment on Mike's design choices, but it would be a shame if you disregarded it because of preconceptions about the amount of feedback used, and you will be missing out on a fine amplifier.
Hi Francois,
I really like both tube and SS amps, but only when they are good. High feedback is only a problem when it's wrapped around a bad design.
A design that would sound bad anyway will still sound bad with lot's of feedback. The reason you don't see high feedback with tube amplifiers is that tubes are expensive when you need an extra stage or two, and that the phase shifts through transformers make high feedback an almost impossible task. Certainly ill advised.
As for the SymAsym, I've built a couple original 5.3 units and I was very happy with the sound. These are very lively little amplifiers that performed past my expectations. Mind you, it's possible to make them sound bad through poor part selection and component layout. If you build a 5.3 using the recommended board layout, I'm sure you will be happy. There is also a group buy going on for another layout (AAK) of the 5.3, I'm buying a couple to test them. You might want to get in on that buy. Look here : http://www.diyaudio.com/forums/showthread.php?s=&threadid=97640
I would recommend this project as well.
-Chris
I really like both tube and SS amps, but only when they are good. High feedback is only a problem when it's wrapped around a bad design.
A design that would sound bad anyway will still sound bad with lot's of feedback. The reason you don't see high feedback with tube amplifiers is that tubes are expensive when you need an extra stage or two, and that the phase shifts through transformers make high feedback an almost impossible task. Certainly ill advised.
As for the SymAsym, I've built a couple original 5.3 units and I was very happy with the sound. These are very lively little amplifiers that performed past my expectations. Mind you, it's possible to make them sound bad through poor part selection and component layout. If you build a 5.3 using the recommended board layout, I'm sure you will be happy. There is also a group buy going on for another layout (AAK) of the 5.3, I'm buying a couple to test them. You might want to get in on that buy. Look here : http://www.diyaudio.com/forums/showthread.php?s=&threadid=97640
I would recommend this project as well.
-Chris
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