Talking about patience... Chris, already had a chance listening to symasym ? 😉 Al ?
Borys, have you already been able to compare the FJR4315/4215 against the MJLs ?
Mike
Borys, have you already been able to compare the FJR4315/4215 against the MJLs ?
Mike
Hi Mike,
I am just about to load my drill press onto my bench if no one gives me a hand. It's only a 10", but it's too heavy for me right now. I want to finish my Symasym!
-Chris
I am just about to load my drill press onto my bench if no one gives me a hand. It's only a 10", but it's too heavy for me right now. I want to finish my Symasym!
-Chris
Not only the drill bit.... i am needing replacement too...too much old
I never had listened nothing about model 7 because model 7 do not exist....was the ? sign that i confused with digit 7.
I have to replace the glasses...at least my glasses... or a complete "overhaulin" in my internal brain machine.
Also i am waiting for the next model too...as i think that Michael will continue his researches.
regards,
Carlos
I never had listened nothing about model 7 because model 7 do not exist....was the ? sign that i confused with digit 7.
I have to replace the glasses...at least my glasses... or a complete "overhaulin" in my internal brain machine.
Also i am waiting for the next model too...as i think that Michael will continue his researches.
regards,
Carlos
Carlos, maybe you were confused by Pingrs's sym7_1 ?
I still have to do the symasym6... It will only be improved for PSRR at low frequencies, in theory this should give tighter bass and increased dynamics. (does not mean that sym5 does a bad job here) Also, it will be less sensitive to high impedance sources.
Mike
I still have to do the symasym6... It will only be improved for PSRR at low frequencies, in theory this should give tighter bass and increased dynamics. (does not mean that sym5 does a bad job here) Also, it will be less sensitive to high impedance sources.
Mike
Is that "tigh bass" modification in this thread?
I use low impedance source normally...to feed the amplifier...or my computer pré amplifier loaded with 8 ohms...or I pod or Mp3 player.
The bass of the last model is already tigth.... i cannot imagine perfectly how can be better than that...so..better to listen than to imagine.
regards,
Carlos
I use low impedance source normally...to feed the amplifier...or my computer pré amplifier loaded with 8 ohms...or I pod or Mp3 player.
The bass of the last model is already tigth.... i cannot imagine perfectly how can be better than that...so..better to listen than to imagine.
regards,
Carlos
Hi Mike,
I was able to get my wife to move the drill press for me today. Guess what happened?
One heatsink drilled and tapped for a pair of Symasym. Now ready to assemble into my amplifier test jig. 😀 😀 😀 This is where I can do tests and measurements, component subs and so forth. The heatsink comes from a 100W ITT Terryphone amplifier, as does the test chassis and power transformer. I use a variac to reduce the B+ for these lower powered projects.
Finally!
I'll try the MJW pairs first on one to make sure I assembled it properly.
-Chris
I was able to get my wife to move the drill press for me today. Guess what happened?
One heatsink drilled and tapped for a pair of Symasym. Now ready to assemble into my amplifier test jig. 😀 😀 😀 This is where I can do tests and measurements, component subs and so forth. The heatsink comes from a 100W ITT Terryphone amplifier, as does the test chassis and power transformer. I use a variac to reduce the B+ for these lower powered projects.
Finally!
I'll try the MJW pairs first on one to make sure I assembled it properly.
-Chris
Attachments
MikeB
In this week I prapobly will finish FJL version (C14-10p,C3/4-330p).
Can you see any objection to use 2x680uf/63V (ripple current 4,5A, ESR 0,023) against 1000/50 as C12 and C13 ?
Below chassis with tape as a transformer 😛
In this week I prapobly will finish FJL version (C14-10p,C3/4-330p).
Can you see any objection to use 2x680uf/63V (ripple current 4,5A, ESR 0,023) against 1000/50 as C12 and C13 ?
Below chassis with tape as a transformer 😛
An externally hosted image should be here but it was not working when we last tested it.
🙂 Chris, i am really looking forward to your results. The heatsink is really... HUGE... 
Leonida, i guess you meant sym5_3 ? Sizes are 9.9cm x 7.43cm. If you print out the delivered bmp with 600dpi, the dimensions automatically fit.
Borys, nice ! 🙂 As Pavel already said, c12/13 are ok. The 1000uf were guestimated not engineered. But the 100uf+47ohms to the frontend are engineered and should be kept. If the elyts used are of very high quality (low esr), the paralelled filmcaps might/should be skipped. I've read that in some cases bypassing fast elyts with filmcaps can cause resonances.
Another hint, as you have plenty of space left, you might consider a unity gain buffer between volumepot and amps, as a beginning a simple DC-coupled OPA2134 might do the job. You can try that with a simple perfboard and 2x9v battery...
Mike
Leonida, i guess you meant sym5_3 ? Sizes are 9.9cm x 7.43cm. If you print out the delivered bmp with 600dpi, the dimensions automatically fit.
Borys, nice ! 🙂 As Pavel already said, c12/13 are ok. The 1000uf were guestimated not engineered. But the 100uf+47ohms to the frontend are engineered and should be kept. If the elyts used are of very high quality (low esr), the paralelled filmcaps might/should be skipped. I've read that in some cases bypassing fast elyts with filmcaps can cause resonances.
Another hint, as you have plenty of space left, you might consider a unity gain buffer between volumepot and amps, as a beginning a simple DC-coupled OPA2134 might do the job. You can try that with a simple perfboard and 2x9v battery...
Mike
PMA MikeB
Thanks!
Tell me what can improve this gain buffer ? (I have OPA2134)
(Gain buffer has lower output impedance and this is main advantage of this solution. Correct me if im wrong. Thanks.)
Thanks!
Tell me what can improve this gain buffer ? (I have OPA2134)
(Gain buffer has lower output impedance and this is main advantage of this solution. Correct me if im wrong. Thanks.)
Borys, Pavel can explain that better. You can read his review about symasym.
The buffer would present a much lower source impedance to the amp than the pot, exactly as you thought.
I already speculated that you have opa2134, a very nice opamp with best performance/price ratio.
I suggest a simple unitygain noninverting circuit, with maybe a 10k resistor to ground at its output.
Mike
The buffer would present a much lower source impedance to the amp than the pot, exactly as you thought.
I already speculated that you have opa2134, a very nice opamp with best performance/price ratio.
I suggest a simple unitygain noninverting circuit, with maybe a 10k resistor to ground at its output.
Mike
Hi Borys, sorry i missed your edit...
Your circuit is too complex. 😀 In fact this one has gain 1:2.
Simply connect IN- to output. And to ensure a load at DC condition a 10k from output to gnd. (I don't know if that's necessary)
Mike
Your circuit is too complex. 😀 In fact this one has gain 1:2.
Simply connect IN- to output. And to ensure a load at DC condition a 10k from output to gnd. (I don't know if that's necessary)
Mike
Hi Mike,
Those are not the final heatsinks. I have a test setup to develop amplifiers with, and those are the heatsinks that were originally mounted on the case.
I intend to mount these with a vertical convection "tunnel" design with a suitable transformer and better capacitors once I've settled on the final version. I am thinking of a regulated front end power supply if I can measure a large difference. Now this is far removed from the original scope of your design but it's educational for me too.
Aside from my wife's birthday as well, I am trying to mount the transistors today and possibly have the first one running for evaluation. Then I start changing things.
With any luck, my parts from Linear Systems will be here in time. My On Semi parts are half here. Some are MIA. I may end up with a FET differential, cascoded. If I can figure out Eagle, there are some changes I want to try as well.
I'll keep you informed of the positive changes.
-Chris
Those are not the final heatsinks. I have a test setup to develop amplifiers with, and those are the heatsinks that were originally mounted on the case.
I intend to mount these with a vertical convection "tunnel" design with a suitable transformer and better capacitors once I've settled on the final version. I am thinking of a regulated front end power supply if I can measure a large difference. Now this is far removed from the original scope of your design but it's educational for me too.
Aside from my wife's birthday as well, I am trying to mount the transistors today and possibly have the first one running for evaluation. Then I start changing things.
With any luck, my parts from Linear Systems will be here in time. My On Semi parts are half here. Some are MIA. I may end up with a FET differential, cascoded. If I can figure out Eagle, there are some changes I want to try as well.
I'll keep you informed of the positive changes.
-Chris