The nicest capacitor in sound is the lack of it. Distinguishing the presence of such in the signal chain is easy.
Hi, In power pcb, c25 and c26 (safety caps) could be 0.1uF rather than 0.01 that it is proposed?
C19, C25, C31, C32 are decoupling capacitors. Using 100nF rather than 10nF might reduce hf noise on the supply rails a bit but I'd be surprised if it made much difference in practice.
C25 y C26 are those in the diagram, 0,01uF 275V.
I already have a 0,1uf. That is why i ask. Can i use them rather than 0.01uf in that position?
I already have a 0,1uf. That is why i ask. Can i use them rather than 0.01uf in that position?
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Ah sorry, I thought you meant the power amp not the power supply. C25 and C26 on the power supply board are used to quench arcing across the mains switches and, hopefully, prolong their life. I don't have a feel for an appropriate value - I'd need to research it. In general its usually best to stick with the designers original value - at least to start with.
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Well its only unity gain and the single ended inputs have a pretty low input impedance. So not really a great match to the Bryston power amp clone.
Thanks Chalky....and please let me know can I add few extra Output transistors to 4b without any problems..?
Thanks
Thanks
In theory no problem. The 28bsst is basically a 4bsst with two extra output pairs per channel. You can find the 28bsst schematic online. Be sure to try and match all the npn devices for Vbe and separately all the pnp devices for best current sharing.
Thanks chalky.....please can anyone send eBay/AliExpress link for switches,xlr and rca connectors in input board
Thanks
Thanks
I build those boards, all except output transistors, the cost would have blown my budget.
The 28b comes with 3 kind of output boards, two monos one like the 4bsst and the one shown in my build.
I am currently rebuilding my 4bsst, some better parts, and this new 2kw toroid, originally it had quad 65 volt, I removed windings and brought it down to 50 volt which I find more suited for the 4bsst.
Fetamp which input board is it?
The 28b comes with 3 kind of output boards, two monos one like the 4bsst and the one shown in my build.
I am currently rebuilding my 4bsst, some better parts, and this new 2kw toroid, originally it had quad 65 volt, I removed windings and brought it down to 50 volt which I find more suited for the 4bsst.
Fetamp which input board is it?
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Fetamp, the right angle switches and xlr conectors are standard parts available from RS, Farnell, Digikey, Mouser etc ( ebay too but they may be more expensive ). The rca connectors are harder to find but this link 2X RCA Socket with BNC Connector Gold-Plated PCB Mount For DAC Player Decoder | eBay will point you in the right direction. Amplitude are you going to stick with the PN100/200 for your rebuild or use something like a BC550/560 pair? The BC546/556 may be a better vas pair than the 2N5401/5551 too. Certainly worked well in the input stage revamp I posted earlier.
My recommendations are obviously for the big dual channel input board. The small single channel board is a bit trickier. If you look back to my posts showing a revamp of the small input board you'll see I had to get a bit creative. The rca socket I used was a bit of a kluge, it didn't exactly fit the pcb footprint. I couldn't find a switch that fit the rca/xlr position so I simply used two, small, single pole double throw, pcb mount switches. There is no pcb footprint for an xlr connector so I simply soldered in a terminal block.
Hi chalky, I skipped the input board entirely, I use lme49720 and lme49600 buffer, the solution is not discrete but am amazed about sound quality, and the lme49600 can easily run the output boards.
Its basically a headphone amp.
Its basically a headphone amp.
Hi Amplitude. I was talking about the PN100/200 differential pairs, and the 2N5401/5551 vas pair on the power amp pcb. Sorry if I didn't make this clear.
Arh, no I think I leave them in, as it sounds really nice, dc offset is really low and spot on, I would like to finish all three amps soon and start enjoying some pink floyd, my goal is 3 way active , I finished the active filters and still need enclosure work on the hiraga and jlh, so when it's done it is bryston bass duty, hiraga 30w for midrange, and jlh tweeter duty.
Here's a pic of the filters, linkwitz riley in hammond enclosure
Here's a pic of the filters, linkwitz riley in hammond enclosure
