could you help me out; at 16:10 you make mention of the safety resistors (281 - which i could not see clearly the board label - is the glare covering up the number?) but im trying to find out the manufacturer or product codes for these kinds of large grey 2w resistors (similar to r245,r246,r251) [the four big ones in shot at 15:48] Im working on my c350 and there is some heat damage around these larger resistors. So i wanted to replace them just for peace of mind. Could you help me out with a digikey or mouser part number to get me started on the right path? What are they called? Many thanks!
Hi, Great video where are you based? I have a NAD 7225PE and would like it re capped how much would you charge to do it? I live in North London. If you can't do the recap would you have a list and Capacitor supplier. Thanks mark
Hi as this model is a radio receiver, I would not undertake the work as the unit would require specific alignment after recapping. You could post on www.diyaudio.com/community/ to see there are specialists who can under take the work.
Hello! Brilliant video, i bought two of these amps as faulty and recapped them both and sorted the dry solder joints and they work and sound amazing! Only caps i didnt replace which i need to as they are a little bulgy are the main filters. 22000uf! Cant find them anywhere apart from ebay as 'jccon' and i dont trust them. Can you point me in right direction as to where to find them? Im sure i checked cpc farnell and mouser with no joy. I havent changed those resistors tho or the speaker relay so thats my next job! Astonishing such a good amp used naff capacitors from factory, altho it meant i got them cheap and enjoyed fixing them! I use two of them connected via pre out with mission 734i and the other drives monitor audio rs6. This amp with rs6 playing jazz is mind blowing. Thanks so much again for this very helpful tutorial, thoroughly enjoyed it. Subscribed!
Hi thank you for the positive feedback, much appreciated, also for sharing your repair experience on the channel. Chemi Con www.mouser.co.uk/ProductDetail/Chemi-Con/ESMH630VSN223MA65S?qs=sGAEpiMZZMvwFf0viD3Y3Wd4FpOoUsJZtbzvKrfoeSU%3D Is a good brand
Looking at the schematic, those output transistor emitter ballast resistors are unusually low value, almost as low as the equivalent part on the old Maplin MOSFET design - it was non existent. Thanks for the video.
Yes that's the one, I still have several of the modules knocking about, they were great value for money back in the day although with a slew rate of 10 V/uS they migt be considered a bit slow by today's standards.
@stevesmyth4982 Yes, Maplin same name but very different www.maplin.co.uk/pages/electricals?gad_source=1&gclid=CjwKCAjwyJqzBhBaEiwAWDRJVAIoDbjgB1p_F4yEx9iulziEHFwLNW6uonWrjyYAnJc5M9PaJNmNkRoCulQQAvD_BwE
I fit the new filter caps today, the old ones had rattling internals! The tops were really domed. Thanks for the link to them. Not tried the amp yet, but will there be any difference in audio? Cheers again@AudioAmplifierServicing
@tharkthax3960 The power supply filter capacitors perform multiple roles, the first is to act as a reservoir, storing the voltage and current so it is available on demand, hence as the Amplifier is operating changes in Audio signal level or increasing descreaing the volume control results in no deterioration in Audio is heard. Secondly, they remove low frequency noise. Lastly they ensure a ripple free DC supply so any noise reduction will also result in higher Audio quality.
@AudioAmplifierServicing hello again Novice error - I was reading at the test points for idle current, 1st amp was fine, second amp I accidentally shorted the copper R out line to the test pin. There's barely a gap between them as it is and was very awkward! Anyway the amp powers on, green led on front illuminates but the main power button led stays red. Transistors seem OK so I take it I've cooked the power relay? Need to fix it as I love this amp!
Thanks
Thank you
could you help me out; at 16:10 you make mention of the safety resistors (281 - which i could not see clearly the board label - is the glare covering up the number?) but im trying to find out the manufacturer or product codes for these kinds of large grey 2w resistors (similar to r245,r246,r251) [the four big ones in shot at 15:48] Im working on my c350 and there is some heat damage around these larger resistors. So i wanted to replace them just for peace of mind. Could you help me out with a digikey or mouser part number to get me started on the right path? What are they called? Many thanks!
Hi the resistor is 680 Ohm 2 Watts and can be purchased from here www.tme.eu/en/katalog/?queryPhrase=fusible%20resistor&page=4
Hi - how can I reach you directly need some help with my c352 amp
As detailed in the video email audioamplifierservicing@aol.com
Hi,
Great video where are you based? I have a NAD 7225PE and would like it re capped how much would you charge to do it? I live in North London.
If you can't do the recap would you have a list and Capacitor supplier.
Thanks mark
Hi as this model is a radio receiver, I would not undertake the work as the unit would require specific alignment after recapping. You could post on www.diyaudio.com/community/ to see there are specialists who can under take the work.
Hello! Brilliant video, i bought two of these amps as faulty and recapped them both and sorted the dry solder joints and they work and sound amazing! Only caps i didnt replace which i need to as they are a little bulgy are the main filters. 22000uf! Cant find them anywhere apart from ebay as 'jccon' and i dont trust them. Can you point me in right direction as to where to find them? Im sure i checked cpc farnell and mouser with no joy.
I havent changed those resistors tho or the speaker relay so thats my next job!
Astonishing such a good amp used naff capacitors from factory, altho it meant i got them cheap and enjoyed fixing them! I use two of them connected via pre out with mission 734i and the other drives monitor audio rs6. This amp with rs6 playing jazz is mind blowing.
Thanks so much again for this very helpful tutorial, thoroughly enjoyed it. Subscribed!
Hi thank you for the positive feedback, much appreciated, also for sharing your repair experience on the channel. Chemi Con www.mouser.co.uk/ProductDetail/Chemi-Con/ESMH630VSN223MA65S?qs=sGAEpiMZZMvwFf0viD3Y3Wd4FpOoUsJZtbzvKrfoeSU%3D
Is a good brand
Looking at the schematic, those output transistor emitter ballast resistors are unusually low value, almost as low as the equivalent part on the old Maplin MOSFET design - it was non existent.
Thanks for the video.
Hi do you mean this one, www.muzines.co.uk/articles/mosfet-amplifier/2651
Yes that's the one, I still have several of the modules knocking about, they were great value for money back in the day although with a slew rate of 10 V/uS they migt be considered a bit slow by today's standards.
@stevesmyth4982 Yes, Maplin same name but very different www.maplin.co.uk/pages/electricals?gad_source=1&gclid=CjwKCAjwyJqzBhBaEiwAWDRJVAIoDbjgB1p_F4yEx9iulziEHFwLNW6uonWrjyYAnJc5M9PaJNmNkRoCulQQAvD_BwE
Hi again, that's me just ordered the main filter caps for my 2 Nad C352s. They are snap in - are the originals also snap in too? Cheers😊
Hi Yes they are snap in
I fit the new filter caps today, the old ones had rattling internals! The tops were really domed. Thanks for the link to them.
Not tried the amp yet, but will there be any difference in audio?
Cheers again@AudioAmplifierServicing
@tharkthax3960 The power supply filter capacitors perform multiple roles, the first is to act as a reservoir, storing the voltage and current so it is available on demand, hence as the Amplifier is operating changes in Audio signal level or increasing descreaing the volume control results in no deterioration in Audio is heard.
Secondly, they remove low frequency noise.
Lastly they ensure a ripple free DC supply so any noise reduction will also result in higher Audio quality.
@@AudioAmplifierServicing thanks 😊
@AudioAmplifierServicing hello again
Novice error - I was reading at the test points for idle current, 1st amp was fine, second amp I accidentally shorted the copper R out line to the test pin. There's barely a gap between them as it is and was very awkward! Anyway the amp powers on, green led on front illuminates but the main power button led stays red. Transistors seem OK so I take it I've cooked the power relay? Need to fix it as I love this amp!