That was my original intention, but after purchasing the capacitors, it turned out that they were too wide. The power amplifier PCB can accommodate capacitors up to 30 mm wide, while the 22000-microfarad capacitors I bought have a width of 35 mm. Hence the idea of placing them on a separate power supply board.
Just as I thought, thank you very much for the tip! Quick question: It would probably be a good idea to desolder the white connector for the audio signal input as well, right?
Thanks @Gerlach! I'm fine but I now I have several real world project so had to temporarily halt my audio hobby activities. I hope to get back soon with several useful results.
I usually make terminals or other quick connections only on the power supply. Everything that concerns sound is only soldering. If the wires are thick, I carefully widen the holes,
press them in there with soldering. But everyone has their own method.
press them in there with soldering. But everyone has their own method.
A very good rule when it comes to soldering audio signal wires. In the previous post, I was referring to the method of connecting the power supply PCBs to the power amplifier board. I have already found the soldering points on the board to bypass the rectifier bridge. I will probably decide to replace the rectifier bridge on the power supply board with some ultra-fast ones.
You can use rectifiers on the main boards. Place a board with additional capacitors between the amplifier boards and connect your 2x22000 in parallel to the main ones for each channel. Or if you have 4 more of these, then add 4 pcs to each channel. It will be absolutely awesome.👍
I'm back to the A60 busines! I have some news.
By the way: where is @vmk2002? I haven't heard from him for a long time and miss his company!
By the way: where is @vmk2002? I haven't heard from him for a long time and miss his company!
Hello Berlusconi. All is well, I visit this thread and read new messages. I was busy restoring old CD-RW (DVD-RW) drives. I want to start recording audio discs. Restored Yamaha CRW-F1 and Plextor Premium. Glad to see you back. I hope you will share news about amplifiers?
@vmk2002
Good to see you again.
How is that your problem with noisy transformer? Have you rectified that?
You helped me a lot with that beautiful schematics of A60.
Right now I have returned from my test bench after testing one channel of a small A60. I have replaced a970/C2240 with KSA992/KSC1845 pairs and c2705/A1145 with KSC2383/KSA1013.
It appears that the replacement worked out well, at least there was no smoke and sparks. Also preliminary measurements seem to be promising. I will go on with this test and report if there is anything new.
I did this change before but I have thought it wasn't promising so I have abandoned that. I'm affraid that I have abandoned this too early, without serious consideration. I have to reconsider this alternative now.
I'm worried because leads of CDIL transistors are magnetic indicating economizing with materials. What if other savings on materials compromised quality of the product? I plan to keep A60 as my primary amplifier and want to make sure it is reliable enough. I wouldn't like to burn my speakers just because someone has saved a penny on materials of a small transistor.
I wish you a pleasant rest of this week-end and hope to hear from you soon.
Good to see you again.
How is that your problem with noisy transformer? Have you rectified that?
You helped me a lot with that beautiful schematics of A60.
Right now I have returned from my test bench after testing one channel of a small A60. I have replaced a970/C2240 with KSA992/KSC1845 pairs and c2705/A1145 with KSC2383/KSA1013.
It appears that the replacement worked out well, at least there was no smoke and sparks. Also preliminary measurements seem to be promising. I will go on with this test and report if there is anything new.
I did this change before but I have thought it wasn't promising so I have abandoned that. I'm affraid that I have abandoned this too early, without serious consideration. I have to reconsider this alternative now.
I'm worried because leads of CDIL transistors are magnetic indicating economizing with materials. What if other savings on materials compromised quality of the product? I plan to keep A60 as my primary amplifier and want to make sure it is reliable enough. I wouldn't like to burn my speakers just because someone has saved a penny on materials of a small transistor.
I wish you a pleasant rest of this week-end and hope to hear from you soon.
I'm thinking to build one with Switching Power Supply. For example with this LLC Power Amplifier Switching Power Supply 600W +- 50VDC
https://www.ebay.com/itm/353254131501?var=622452807414
https://www.ebay.com/itm/353254131501?var=622452807414
I have never used switching power supply for audio purposes, but why you should have redundant power supply? I have tried that but that was pointless and could cause aditional headaches.
The on-board power supply is more than enough. Today I have verified that again with inputs shorted. It is so silent that I had to verify if it is turned on. All you need is (are) transformer(s). I would prefer two separate 230-2X30VAC (or 2X35VAC to have nearly +/-50 VDC at rails) to avoid any problems with ground loops. In this configuration two channels would touch each other in a single point: just connect the RCA input grounds.
Thank you Sajti for the advice! I remember that conversation very well.
I should have obayed that, but as usual I'm too stubborn - I need time to confess my own mistakes. To be fair I simply didn't want to trash a product just because of the Country Of Origin. But when I have seen the cut leads attaching to pliers cutters I have realized they have been splitting hairs on materials.
Regarding the KSC2383/KSA1013: I have previously used ISC 2SA1220/2SC2690 because ON Semi have discontinuied KSA1220/KSC2690.
The only remaining weak point now is UTC SD669 which I plan to replace with Toshiba TTC004.
I sound a bit paranoic, but safety is safety...
Thanks Sajti for good advice 👍
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Surprise, that KSC1845/KSA992 was magnetic too. But Onsemi was changed the location of manufacturing, and the new series is not magnetic any more. TTC004B/TTA004B are good to driver in small amplifiers, or predriver. Too much capacity for VAS application, but good for Vbe multiplier too. For VAS i used the famous KSC3503/KSA1381, but now i have to move the KEC version (KTC/KTA)
No, CDIL was magnetic.
Thanks again: I have 20 KSC3503/KSA1381 pairs. I'll use them. They also have much better heat dissipation and also higher Ft value. My present KSC2383/KSA1013 get almost hot so I was reluctant to run the amplifier to the limits. This change will have additional benefit.
I sometimes don't see an elephant in the room because "great ideas" cloud my judgement.
Your advices are indeed helpful. Thanks. 😎 👍
KSC1845/KSA992 was magnetic too, until 2023. From 2023 you will get JCC1845/JCA992, which are use copper legs. You can check the materials here: Material Composition