Never ending rewardding process
New modification... this time I am in awe
I was loading the benz ACE (M) with a 2K21 RC55Y Welwin 0,1% metal film. sound was very good but I missed that final high freq attack and presence.
Based on previous experiments and using the feedback of the forum menbers I decided to use a 2K4 Shinkoh.
Now I am hearing Zappa´s Zoot Allures as never before..... the bass is very heavy but detailed, the highs are powerfull, detailed, with outstanding attack but never strident.
The best part is I can hear small info that was masket before, enhancing imagery, focus and stage size.
There is a sence of independency between the instruments I was not aware of before.
how can I explain these differences ? are shinkoh lower noise then metal film ?
Ricardo
PS:
This makes me remenber my B&O tangencial tonearm while using the saphire cantilevered MCC in my old defunct system. 20years ago
New modification... this time I am in awe
I was loading the benz ACE (M) with a 2K21 RC55Y Welwin 0,1% metal film. sound was very good but I missed that final high freq attack and presence.
Based on previous experiments and using the feedback of the forum menbers I decided to use a 2K4 Shinkoh.
Now I am hearing Zappa´s Zoot Allures as never before..... the bass is very heavy but detailed, the highs are powerfull, detailed, with outstanding attack but never strident.
The best part is I can hear small info that was masket before, enhancing imagery, focus and stage size.
There is a sence of independency between the instruments I was not aware of before.
how can I explain these differences ? are shinkoh lower noise then metal film ?
Ricardo
PS:
This makes me remenber my B&O tangencial tonearm while using the saphire cantilevered MCC in my old defunct system. 20years ago
Power amplifiers 100 to 400 plus watts are used to drive the tiny coils (one for each channel) in the cutting head. They’re like miniature speakers which instead of just moving air, push the stylus that etches the groove in your record. With 20 dB of treble boost, you can only imagine the beating that the cutting head takes from cymbal crashes and the like. The coils are helium cooled but still can reach 200 degrees Centigrade. A circuit breaker is used to prevent catastrophic destruction
Hi nicoch46
Well, maybe what I read before was related with the power amps themselves (D Amps?).
I have another question regarding the 101b opamp, It is rigged as a inverted voltage gain (+IN to GND) and the feedback resistor R1 seems to be a 100k. The input resistor seems 6.9k so the gain must be R1/R2=14.5.
Now the strange part is that there is a small cap in parallel with R1.
What should be the purpose of bypassing the feedback resistor with a cap ?..... Should I remove it ?
Sorry for the offtopic but I really need some advise.
Ricardo
Well, maybe what I read before was related with the power amps themselves (D Amps?).
I have another question regarding the 101b opamp, It is rigged as a inverted voltage gain (+IN to GND) and the feedback resistor R1 seems to be a 100k. The input resistor seems 6.9k so the gain must be R1/R2=14.5.
Now the strange part is that there is a small cap in parallel with R1.
What should be the purpose of bypassing the feedback resistor with a cap ?..... Should I remove it ?
Sorry for the offtopic but I really need some advise.
Ricardo
Its 99% a feedback compensation capacitor. Its related to the original op amp. Fixing it for best performance or even for oscillation without it. This is original designer's territory, and has to do with certain layout and PSU.
As I replaced the original NE5532 by a LME49720 (with uge gains in sonic quality), maybe I can remove them ?
Just looking at the circuit, it seems that at high freq the opamp would not have the same gain as in low freq...
Just looking at the circuit, it seems that at high freq the opamp would not have the same gain as in low freq...
Ricardo, that question gets general answers by definition. A. Surely if a Fb cap helps also other op amps than original there, it is not the same value. B. What value or no capacitor, needs measurements for high frequency square waves and THD so to know. C. General tweaking practice info found mainly in forums of compensation and decoupling for certain popular op amps, may apply or not, but needs measurements for any different PCB and/or PSU design/components. D. If you still wanna tweak, trust your ears for the certain preamp with certain op amp substitutions, but never think that you really got an idea of what each op amp model can really do if surely properly implemented. The faster, the more rebellious.
Thank you Salas
I must read a lot before I do more modifications here.
I really need a good pre with loads of inputs.
Before commiting to the Riaa, I built a jfet buffer but did not finish the project because;
1st - it has output caps
2nd - I am not sure if my amp needs some gain.
Can a jfet buffer + caps sound better than a opamp without caps ? (I could live with less gain)
Ricardo
I must read a lot before I do more modifications here.
I really need a good pre with loads of inputs.
Before commiting to the Riaa, I built a jfet buffer but did not finish the project because;
1st - it has output caps
2nd - I am not sure if my amp needs some gain.
Can a jfet buffer + caps sound better than a opamp without caps ? (I could live with less gain)
Ricardo
Ricardo:
It depends on the quality level you have reached with op amps so to compare. Also on the needs of the main amp and speakers. My general practice is. A. If it sounds good, don't destroy it for checking out new quests. -} B. Make something from ground up if researching alternatives. Just my2c.😉
It depends on the quality level you have reached with op amps so to compare. Also on the needs of the main amp and speakers. My general practice is. A. If it sounds good, don't destroy it for checking out new quests. -} B. Make something from ground up if researching alternatives. Just my2c.😉
Yes
I need some gain.
I like the optivol idea, and Zen´s 1 buffer per output, but I need gain.
I need some gain.
I like the optivol idea, and Zen´s 1 buffer per output, but I need gain.