I love all your videos I'm going to be 64 this year and I've been trying to fix electronics all my life and only been watching RUclips for maybe four and a half years now really learning how to really how to fix my stuff! Keep doing what you do best and I'll keep learning
1. The anti-oscillation 100pF cap should be placed in parallel with the R119 12k feedback resistor, not directly between the pins. 2. Increasing the voltage divider resistor of the feedback loop, R123, decreases the gain of the circuit. The correct way of extending the low end was increasing the capacity of C111 and maybe even C105. 3. Since you already have the OPA134s, decrease the zener resistors from 7k5 to 4k7 and try them on again, it will totally be worth it. 4. To increase the gain increase the 12k R119 resistor to the value that gives you 56V from a 1V input, most probably to 18k. 5. And again, thank you for the 4k😊
i wish you a speedy recovery tony and i also thank you. i would rather "waste my own time " watching you mod an amp and learn stuff along the way than watch you drop in a pcb.
again the best vintage audio repair/upgrade channel on YT thanks a ton tony ps mouser thanks you as well ... ill be starting an adcom gtp-400 preamp restoration here the next few days waiting on a few capacitors i didnt have in stock
Thank you for sharing, Great Job. Yes, I am totally agree with you. Fixing things for our self are not just save money but learning, gain knowledge and it is a challenging. I always feel good after repair. Sometime cost more than buy a new one.
Tony, wishing you a speedy recovery. It's always interesting to see when things don't go as planned how you debug and correct things. That's where I think I learn the most.
I agree with your choice, and statement of using the original PCB and doing some minor modifications in order to improve the circuit's functionality, instead of doing the new board purchase. I also wondered, what difference setting a bias level to a designers specs rather than using that as a starting point, and then, checking the THD / crossover distortion and seeing if a change could be had, is a viable process to testing & adjusting an amp when servicing, and I think you showed that it may be worth while to do this with any amp with adjustable bias, as an improvement may be made by doing so.
Lovely job, Tony. It's good to see your on the mend too, but don't over-do it as this can lead to getting run down and infection can creep in. Stay safe and well, prayers and thoughts to you and yours. See you soon and thanks for sharing.
there are many ways to analyze a project, one is a cost basis with time a consideration added. that is a very commercial way to look at it. The idea being to do it in the shortest amount of time and with the minimum of parts needed in order to make the desired profit margin. That is not the only way to look at it. Some will try to bring the device back to the condition it had right off the factory floor, more time and expense some do what ever it takes up to a point to get it to work quick and dirty sometimes is good enough so long as it works. Then there is the wasting time and money way trying to understand what is happening and making improvements when they make sense. not all projects are the same I am pretty sure that your approach to the medical devices are not done in exactly the same way but with the same care for accuracy, safety and reliability paramount all under time constraints. So take your time down in your basement some of us know dam well that we ain't gona make a fortune repairing these old things but maybe break even and have some fun on the way. thanks again and do all the physical rehab they ask you to do it f'n works.
Tony, do you ever add a capacitive load to test the overshoot and ringing. I just completed testing my amp build and everything measured good until I put a 1uF capacitor in parallel with the 8 ohm load. Massive overshoot and ringing, although damped, no outright oscillation. So adjustment necessary!
Hey Tony. Could you say something regarding Audio grade capcitors versus nonaudio grade. I never hear any stereo electronic personnel discuss using audio grade. Seems that would mean that the audio grade are a scam. Or am I wrong? Great channel by the way.
AFAIK and Tony did say stuff about that in some other videos (I can't tell you which), that standar capacitors are usually made and rated with Line AC frequency in mind and they fall short in the audio spectrum, and audio grade capacitors are made and tested for 20 to 20k hz work I am talking about standard capacitors, not 500 USD per piece audiophile caps
Tony- how do you like your MDD-2204EX Digital scope? Is the spectrum analyzer function useful? I'm looking for a modern replacement for my vintage HP 3580A audio spectrum analyzer, and wondering if the MD-2204EX would be a good candidate?
I'm quite pleased with it. Not really the best for RF work, although it can work in that capacity somewhat as well. For audio, I really like it, especially if you install the frequency analysis (bode plot) app (which is free from their website).
I wouldn’t diss the White Oak boards guy so quickly; he/she has simply chosen a different path. Trust me when I say, that in a production environment your approach to circuit analysis and repair would be ‘respected’; you would quickly and quietly fired, or perhaps transferred to Research & Development. Get it in and get it out is how MOST of the commercial world works, you simply have to respect that ‘performance’ is measured by different metrics in different environments. As you state at the outset of every video, this is a hobby to you; not an economic enterprise. Although I favor your approach, you must realize, in my opinion, respect is a two-way street.
The PL 700 definitely has it beat on power, but its listenablilty may be a different factor. I own 2 - Citation Sixteen (A) amps, and have done some time perusing the schematics for them, so I think I can comment. A Citation Sixteen is only rated ( by HK) to 150 Watts per channel, so, it doesn't compete for power. It was designed to be biased to what would be considered a higher level than most amps, in order to run it into Class A up to a 2 1/2 Watt level and will have expected heat sink temps over 40 , and up to 60 degrees C at idle (from the SM). The original model Sixteen only had a on-delay speaker relay, no DC protect, with relay contacts only rated to 8 amps. The "Sixteen A" incorporated a DC protect with the delay, but, that function was disabled then delete by 2 service bulletins that followed, I am betting because the relay contacts were being fried if made to open or close repeatedly at high power levels.
This amp will bite you if you are not extra careful with bias voltages, various caps to prevent ringing, correct resistor wattages, etc... Not the most robust amp design !
![SahBabii - Viking [Official Music Video]](http://i.ytimg.com/vi/D37cL92JX0I/mqdefault.jpg)
Well done Tony. Great job. Get well soon..
I love all your videos I'm going to be 64 this year and I've been trying to fix electronics all my life and only been watching RUclips for maybe four and a half years now really learning how to really how to fix my stuff!
Keep doing what you do best and I'll keep learning
Please Tony do not over do things take care of your self when you need rest you need to rest.
Hope you're feeling better Tony and I wish you have a UF recovery, lol
1. The anti-oscillation 100pF cap should be placed in parallel with the R119 12k feedback resistor, not directly between the pins.
2. Increasing the voltage divider resistor of the feedback loop, R123, decreases the gain of the circuit. The correct way of extending the low end was increasing the capacity of C111 and maybe even C105.
3. Since you already have the OPA134s, decrease the zener resistors from 7k5 to 4k7 and try them on again, it will totally be worth it.
4. To increase the gain increase the 12k R119 resistor to the value that gives you 56V from a 1V input, most probably to 18k.
5. And again, thank you for the 4k😊
i wish you a speedy recovery tony and i also thank you. i would rather "waste my own time " watching you mod an amp and learn stuff along the way than watch you drop in a pcb.
Great job Tony….awesome video, you’re amazing 🤩 thanks for the fun and best wishes that you recover quickly
again the best vintage audio repair/upgrade channel on YT thanks a ton tony ps mouser thanks you as well ... ill be starting an adcom gtp-400 preamp restoration here the next few days waiting on a few capacitors i didnt have in stock
Tony, you're an awesome educator. Thank you!
Thank you for sharing, Great Job. Yes, I am totally agree with you. Fixing things for our self are not just save money but learning, gain knowledge and it is a challenging. I always feel good after repair. Sometime cost more than buy a new one.
Nice result on this complete rebuild. Wishing you a speedy recovery.
Thank you Tony, i learned so much with you 👍☺️
Really nice job Tony. Nice improvement.
Tony, wishing you a speedy recovery. It's always interesting to see when things don't go as planned how you debug and correct things. That's where I think I learn the most.
Changing that resistor at the input also changed the closed loop gain as well as the rolloff.
Congrats, Tony!
👍 Pink Floyd and phase linear amplifiers, those were the days. Great job Tony, take care.
thank you for the video tony, hope you get well soon. 100% "anybody can buy a board and plug it in"
435 watts per channel!! Why? Really neat build. Thank you! Get well soon.
Buy a white oak board and improve it ! Thanks and speedy recovery. This was fun and I learned so much.
Thanks for the vid! Always something to learn. Not sure what's going on with the phase shift in the specs. Mend yourself too......
I agree with your choice, and statement of using the original PCB and doing some minor modifications in order to improve the circuit's functionality, instead of doing the new board purchase.
I also wondered, what difference setting a bias level to a designers specs rather than using that as a starting point, and then, checking the THD / crossover distortion and seeing if a change could be had, is a viable process to testing & adjusting an amp when servicing, and I think you showed that it may be worth while to do this with any amp with adjustable bias, as an improvement may be made by doing so.
Lovely job, Tony. It's good to see your on the mend too, but don't over-do it as this can lead to getting run down and infection can creep in. Stay safe and well, prayers and thoughts to you and yours. See you soon and thanks for sharing.
amazing how you are keeping up with the sore back stuff, sir.
pls take care .
Tony, You Da Man !
there are many ways to analyze a project, one is a cost basis with time a consideration added. that is a very commercial way to look at it. The idea being to do it in the shortest amount of time and with the minimum of parts needed in order to make the desired profit margin. That is not the only way to look at it. Some will try to bring the device back to the condition it had right off the factory floor, more time and expense some do what ever it takes up to a point to get it to work quick and dirty sometimes is good enough so long as it works. Then there is the wasting time and money way trying to understand what is happening and making improvements when they make sense. not all projects are the same I am pretty sure that your approach to the medical devices are not done in exactly the same way but with the same care for accuracy, safety and reliability paramount all under time constraints. So take your time down in your basement some of us know dam well that we ain't gona make a fortune repairing these old things but maybe break even and have some fun on the way.
thanks again and do all the physical rehab they ask you to do it f'n works.
Nice job Tony!
Rollofd at 40 Hz? Sounds more like a Sherwood. They were usually rated 40-20k.
Tony, do you ever add a capacitive load to test the overshoot and ringing. I just completed testing my amp build and everything measured good until I put a 1uF capacitor in parallel with the 8 ohm load. Massive overshoot and ringing, although damped, no outright oscillation. So adjustment necessary!
Hey Tony. Could you say something regarding Audio grade capcitors versus nonaudio grade. I never hear any stereo electronic personnel discuss using audio grade. Seems that would mean that the audio grade are a scam. Or am I wrong? Great channel by the way.
AFAIK and Tony did say stuff about that in some other videos (I can't tell you which), that standar capacitors are usually made and rated with Line AC frequency in mind and they fall short in the audio spectrum, and audio grade capacitors are made and tested for 20 to 20k hz work
I am talking about standard capacitors, not 500 USD per piece audiophile caps
Thanks.
Get back to “yo ole” self real soon Tony. No heavy weights and pinch nose when sneeze is coming 😂.
Tony- how do you like your MDD-2204EX Digital scope? Is the spectrum analyzer function useful? I'm looking for a modern replacement for my vintage HP 3580A audio spectrum analyzer, and wondering if the MD-2204EX would be a good candidate?
I'm quite pleased with it. Not really the best for RF work, although it can work in that capacity somewhat as well. For audio, I really like it, especially if you install the frequency analysis (bode plot) app (which is free from their website).
HELLO DEAR WERE ARE YOU AT ? I NEED FIX MY FISHER X202B SO
I wouldn’t diss the White Oak boards guy so quickly; he/she has simply chosen a different path. Trust me when I say, that in a production environment your approach to circuit analysis and repair would be ‘respected’; you would quickly and quietly fired, or perhaps transferred to Research & Development. Get it in and get it out is how MOST of the commercial world works, you simply have to respect that ‘performance’ is measured by different metrics in different environments.
As you state at the outset of every video, this is a hobby to you; not an economic enterprise.
Although I favor your approach, you must realize, in my opinion, respect is a two-way street.
hey Tony, which were all your mistakes on this amp ?
Phase Lunear... )
Is Harman/Kardon Citation 16 better than this?
The PL 700 definitely has it beat on power, but its listenablilty may be a different factor. I own 2 - Citation Sixteen (A) amps, and have done some time perusing the schematics for them, so I think I can comment. A Citation Sixteen is only rated ( by HK) to 150 Watts per channel, so, it doesn't compete for power. It was designed to be biased to what would be considered a higher level than most amps, in order to run it into Class A up to a 2 1/2 Watt level and will have expected heat sink temps over 40 , and up to 60 degrees C at idle (from the SM). The original model Sixteen only had a on-delay speaker relay, no DC protect, with relay contacts only rated to 8 amps. The "Sixteen A" incorporated a DC protect with the delay, but, that function was disabled then delete by 2 service bulletins that followed, I am betting because the relay contacts were being fried if made to open or close repeatedly at high power levels.
@@poormanselectronicsbench2021Thank you for the answer :)
often it is not always possible to calmly listen and test the devices at home...
Dave wins
This amp will bite you if you are not extra careful with bias voltages, various caps to prevent ringing, correct resistor wattages, etc... Not the most robust amp design !
It's also said, "you're the entertainer and we are the audience" ,work with it. Looking forward to the sound test, thanks "Professor"!