Thanks a lot.
I have questions Mr......you prefer this amplifier with or without servo?
I have 3 pairs mjw21195/21196 .
Do you think that are proper for output?
Last edited:
MJW21195/21196 will be ok, I use it in SR800 without DC servo for PA, but for hi-fi I suggest to keep DC servo.
Regards
My SR200 is now having a trouble, it has 250mV dc out...Q1-2, Q5-6 are matched pairs..I put 10pf between bQ2 to cQ9,
and values for R11 8k2, R18 2k2...
I need advice to solve my problem.
Thank you so much...
Best Regards...
and values for R11 8k2, R18 2k2...
I need advice to solve my problem.
Thank you so much...
Best Regards...
Attachments
Last edited:
Probing voltage around the LTP and other sensitive nodes is dangerous because the probe capacitance can cause oscillation. If probing LTP voltages, probe through 1k resistors in series with each lead. Otherwise probing may cause oscillation and false results.
Thank you dear Thimios for your suggestions.....
I put back 15k for r11, 1k for r18, using 2X10pf caps in parallel for compensation. DC offset now is 133mV..
But when I disconnect dc servo, offset raise into 2,56V!...and when I put back dc servo offset is back to 130mV...
I am sorry that my background is an accountant just doing my hobby..so I am sort kind a lack of electricity background...
Thank you...
studio referance
Have a taste from Apex sr200 here.Apex sr 200 studio referance in action. - YouTube
Have a taste from Apex sr200 here.Apex sr 200 studio referance in action. - YouTube
Hi Thim, amazing mid isn't? 😀
I see you're making a new SR200, which version is it?
BR,
Junie
Hi Junie how about your vacations?
This version is 3.2? .
Pcb by Alex mm of cource🙂
3 pairs output.
MJW21195/96
Attachments
Last edited:
studio reference
I see that your problem is still there.
Did you have any measurements about ltp transistors?
Q1 Q2 VR11 VR12 VR13 VR16 VR17
Measurments are on the shematic, see post #1337.
Is this a previus running amplifier or a new board?
Hi Arif .
I see that your problem is still there.
Did you have any measurements about ltp transistors?
Q1 Q2 VR11 VR12 VR13 VR16 VR17
Measurments are on the shematic, see post #1337.
Is this a previus running amplifier or a new board?
Last edited:
Add 20pF only if amp is unstable, no need to add compensation on stable amp.
Regards
studio reference
Tell us a simple test in order to check the stability of an amplifier.
Is the parallel capacitor to dummy load the appropriate method ,until what capacity the amplifier must be stable at full volume gain.
Regards.
Hi Mr.
Tell us a simple test in order to check the stability of an amplifier.
Is the parallel capacitor to dummy load the appropriate method ,until what capacity the amplifier must be stable at full volume gain.
Regards.
Last edited:
Ok Thim, thank you so much for your very kind attention. I will do measurement when I am fully recovered from my sickness soon. This is my 4th SR200, I have been Ok with 3 previous Sr200 amps. My friends really love these amps. And I want to build SR200 for myself. No commercial use only for hobby. I am just proud when some one likes my amp...
Dear Mr. Mile S...
thank you so much for your kind advise as always...
I will check my amp again...before it is fine only zobel network was hot when playing couple songs...
Strange behavior is, when first turn on, the dc offset is high, 300mv and more, and getting down after more or less 10 minutes up to 14 mV...
the sound is Ok...really like this amp...