Accuphase P-300 ~ Restoration Part 5 ~ Filter Capacitors, Amplifier & Meter Adjustments, LED Lamps

[@rjdiiorio]

I watched all 5 of your videos, fantastic job and well done! Personally I like the warm white.

[@NovaluxStereophonic]

Thank you Robert! I eventually put the original incandescent back in. Sometimes there’s nothing better then original :)

[@scottroberson2656]

Ben I’ve got a lot of respect for watchmakers but your on another level of respect for working on complicated things ! WELL DONE , PROPER AND THOROUGH ! I Love it !

[@Thechriskraft]

Thanks for all of the videos. Great editing. I’m going to keep in touch.

[@alexzildjian]

Te felicito !!! 😃👌 Hiciste un excelente trabajo de restauración en este equipo , tengo el mismo amplificador, saludos de baja California MÉXICO 🇲🇽😊

[@billd9667]

Excellent work, Ben. You are the quickest, most thorough and well spoken restorer on KZbin. Some may argue with thorough recapping of these units, but if I was in the market for one, I’d like to know that it had all new caps. No one wants to have to return a “new” unit, after all. Its a shame about having to use the 22000uF filter caps, but you were trapped. There weren’t any smaller 40K caps available that would have fit?

[@NovaluxStereophonic]

Thank you for the kind words. A contact of mine actually was able to source an acceptable replacement cap for the main filters and has posted them for sale on eBay. I may pick up a set down the line.

[@betod63]

@@NovaluxStereophonic Better 40k, I think of a more black velvet background. At least that is the feeling when I made changes to the filters of my amplifier for ones of much better quality and that I maintained the capacitance value. Btw, very nice job.

[@dalemettee1147]

Blue is my choice. BTW. this amp is like the bunch of high end power amps such as the Mac, the Crown and the likes. When younger, I remember working for a DOD projects company that made a lot of simulators for the government. One of the projects required several toroidal x-formers. The company we chose was McIntosh. We asked them for ~ 10 each. They said, "No, we can afford to sell you any by themselves" So, our co. bought a bunch of power amps, removed the x-formers and discarded the balance. Just to see those beautiful chromed chassis sitting in the bin was horrific to me. Never forgot the sight!

[@NovaluxStereophonic]

That’s Crazy about the Mac transformers. Thank you for sharing.

[@scottskillman]

I prefer the Cool White. I note that you usually do not list the costs of your parts. That would be very helpful to know and perhaps the hours you spent on the project of phases of the project.

[@NovaluxStereophonic]

I like the cool white as well. I may include the labor and parts info in the restoration review video. This unit gets very pricy on parts especially if the outputs or main filters need replacement.

[@scottroberson2656]

Found #5 accuphase p 300 vid I just didn’t see it on your channel video playlist . I got super lucky and bought the p300 amp and C200 preamp and T100 tuner from a gentleman bussiness man that had original boxes and extra accuphase accessory for remote speakers . All look brand new inside and out although the amp produces a humm in the speakers and right channel started to get very loud static , I would be interested in getting fixed proper , I live near echo wars on audio karma but can’t seem to reach him . Thanks for the excellent vids and maybe can get you to service my P300 ?

[@kasunjayasena]

This is grate video and really appropriate..! Please can you let me know any place to find a service manual for P-300S.. Thank you.

[@larrybud]

New to audio adjustments. Can you explain what the Bias and DC Offset is and what the adjustment is doing? I'm guessing bias is to make sure the levels on each channels are the same?

[@NovaluxStereophonic]

DC offset ensures that the DC level of the speaker outputs is as close to zero as possible at idle. Bias adjustment sets the ideal current of the output transistors to the optimum level to ensure minimal distortion without wasting unnecessary energy as heat.

[@jakeh54]

These videos are terrific. I’m about to overhaul one of these myself. Any chance you’d be willing to list the specific new stock transistors you swapped for the originals?

[@NovaluxStereophonic]

You would need to be more specific. There are so many transistors in this piece that needed replacement. I would encourage you to read up on the Audio Karma posts related to this unit. EchoWars has a parts list posted there for caps and such and a lot of the transistors sub options are discussed there as well.

[@jakeh54]

@@NovaluxStereophonic Sorry I should have been more specific. In video 4, there is a great image where you appear to have replaced Q3-Q6 and Q9-Q14 on the Main Driver Boards. I was curious what you used for Q3,Q5 | Q4,Q6 | Q9,Q11,Q14 | Q10,Q11,Q13. Some of the popular replacements for these listed on the AK forums have gone EOL in the past year, so I was just curious what may be obtainable.

[@NovaluxStereophonic]

@@jakeh54 My notes show that I used KSC1845, KSA992, KSC3503, KSA1381. I do not have it broken down by Q designation for this bird unfortunately but this may get you pointed in the right direction.

[@jakeh54]

@@NovaluxStereophonic Perfect -- thanks so much! This is exactly what I was looking for. Looking forward to seeing more of videos. They are fantastic.

[@marvinclark4237]

Hi. I know this is an older video but I was inspired to replace the filter caps in my P-300 with the exact same you’re using. It appears you’ve placed both of your caps with the negative lead facing right. When viewed from top and front of unit. I think my amp has a copper strip between these two caps. Wouldn’t both caps be installed with the negative terminals attached to this copper ground bar?

[@NovaluxStereophonic]

It’s worth doing some schematic study of power supplies before you go too much further. This amplifier has a positive and negative power supply. If you install the caps the way the you suggest you are in for a light show and blown mains fuse at the very least. When dealing with a negative supply the + of an electrolytic cap goes to ground. If you have pictures of the original parts you should see that this is the case. Drawing a little diagram of how the original parts are installed will help you visualize how to connect the replacements. Good luck in the replacement, be sure to observe the proper safety procedures and if you are not comfortable consider taking the unit to a repair shop for service.

[@NovaluxStereophonic]

Also - if you have not purchased the Nichicon caps yet consider going with the ones offered on eBay (Blue United Chemicon) I reached out to the seller after having trouble sourcing the correct values myself and he was able to source an exact fit replacement with the correct value. I have not personally tried them but it may be something to consider.

[@NovaluxStereophonic]

I also remember having to rotate the caps 180 degrees from their original orientation and construct a new ground bus bar that went to the outside terminals instead of the inner terminals. There is a document floating around on Audio Karma related to installing these exact caps. I would definitely encourage you to locate those instructions. This is not a straight forward cap swap.

[@marvinclark4237]

Thank you. After many hours of reviewing how the replacement caps had been installed, the schematic and audiokarma posts I think I’ve got it. My amp was working nicely before going down this path but a PO had installed 9600 Mfd caps and they were old. Figured I should change them. What I have, assuming looking from the top with the front toward me is : 4 purple/white wires to C1 neg terminal- positive terminal to copper bus. Then C2 neg terminal to copper bus and finally 4 red/white wires to C2 pos terminal. I believe that’s correct.

[@Technical_Audio]

I enjoy your videos, but man, I would not have so drastically reduced the capacitance of those main supply caps. If I had to, I would have hollowed out the original cans and put inside the same or slightly higher value capacitors. With more modern caps the physical sizes are smaller and usually you can do this. I’ve done it a lot for old tube equipment where preserving the original appearance is important but so is electrical performance.

[@NovaluxStereophonic]

Not a big deal to go back in and change in the future. I did eventually find a source for an exact fit cap. If so ever do a swap I’ll try to post a video with before and after measurements and listening tests.

[@Technical_Audio]

@@NovaluxStereophonic That would be an interesting test.

[@frankgeeraerts6243]

Warm white ...........