How much heatsink do I need for the K2013/J313 transistors in the input board? And how much space do I have to work with between them? I don't see this referenced anywhere but the pictures in the original build post.
https://www.mouser.ca/ProductDetail...=/ha2pyFadugpge1dGluweDJ2DvcDZehkralshEOkxSM=
These are fine, used in the guide and by many. A bit larger than the ones Nelson used in the manual. If using higher voltage rails or higher FE bias than spec, these Aavids are fine. Though I would want even more sink, meaning making myself or adapting some larger ones, since ime increasing the FE bias in this circuit can be quite beneficial.
Regards,
Andy
These are fine, used in the guide and by many. A bit larger than the ones Nelson used in the manual. If using higher voltage rails or higher FE bias than spec, these Aavids are fine. Though I would want even more sink, meaning making myself or adapting some larger ones, since ime increasing the FE bias in this circuit can be quite beneficial.
Regards,
Andy
I second what Andy said. Drain to Drain distance is 33mm.
These are the biggest I could hardly fit - works well with 100mA bias.
Kuhlkorper Aluminium Universal schwarz TO220 T247 ca. 64x35x13mm 2 Stuck | eBay
These are the biggest I could hardly fit - works well with 100mA bias.
Kuhlkorper Aluminium Universal schwarz TO220 T247 ca. 64x35x13mm 2 Stuck | eBay
I second 100mA Iq. I have tried approx 70, almost melting the fets. And what a difference compared to 45mA. Also, 100mA is OK without reducing resistor values (22Rs).
I think I have some of those sinks actually. When I make final iteration BA-3, I’ll put them to use
Regard
I think I have some of those sinks actually. When I make final iteration BA-3, I’ll put them to use
Regard
I would suggest using at least a 1/2W resistor for R10/R11 if you run the front
end at 100mA since the their dissipations will be ~1/4W.
end at 100mA since the their dissipations will be ~1/4W.
RN55 are rated by Dale for the military at 0.1W (up to 0.125 at a lower temp). I have been told that with the Dale resistors categorized for military use, the ratings can be doubled conservatively. That is not my own personal knowledge, but I trust the source.
That still does not get into the 0.5W range.
For that... I'd start (within the same Vishay Dale lineup) with the RN60 (0.25W) and work up to the RN70 (0.5W) for what might be overkill. I used RN60s.
That still does not get into the 0.5W range.
For that... I'd start (within the same Vishay Dale lineup) with the RN60 (0.25W) and work up to the RN70 (0.5W) for what might be overkill. I used RN60s.
Brainfart, meant RN60, or that also too low? Read somewhere it’s good to 0.5w. Will recheck datasheet
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I'm using a 600VA transformer with 120v primary and 24v secondaries for my BA-3 build. What fuse value should I use for the A/C inlet?
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You’ll probably need something between 3A5 and 5A slow blow. On 230vac and aame values, I got away with 1A8-2A fuses. 1A8 kept blowing from time to time. Depends on how well your soft start solution works, maybe bias too if you max out. I’d just order up a few different values between 3A5 and 5A and see what ends up just not blowing, as Papa prescribes.
Remember slow blow types is the way to go.
The exact value will depend on several variables, and is probably best answered by someone with those exact transformer values on a 120Vac line.
Regards,
Andy
Remember slow blow types is the way to go.
The exact value will depend on several variables, and is probably best answered by someone with those exact transformer values on a 120Vac line.
Regards,
Andy
No prob, glad to help. Maybe grab a 3A25 too, and 5A25-ish, just in case. Though I kinda doubt it.
Start low, go higher after each blow. If you start high, and use a thermistor for soft start, it will get hot between switches, meaning higher current draw, and you may end you choosing too high a value in the end. Or just wait for it to cool between switches
Start low, go higher after each blow. If you start high, and use a thermistor for soft start, it will get hot between switches, meaning higher current draw, and you may end you choosing too high a value in the end. Or just wait for it to cool between switches
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Edit: math says 5 amps. But the F5T manual sez 4 amps slow blow. That, combined with my own experience, made me recommend you go wide when ordering. If you wanna avoid many values, just wait for someone on 120Vac to give you advice.
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Mouser only had even values in the 5x20mm size, so I ordered a handful of 3, 4, 5, and 6 amp fuses to cover my bases.
Just a positive feedback about BA-3 amp
After 3 weeks of listening, passing through a couple of bias re-adjustment, I can only say what a beauty! warm and detailed, powerful with a great speaker control.
My current setup is standard, 3 pairs output devices x channel (complementary out).
I am now really curious to test the version with 6 pairs
After 3 weeks of listening, passing through a couple of bias re-adjustment, I can only say what a beauty! warm and detailed, powerful with a great speaker control.
My current setup is standard, 3 pairs output devices x channel (complementary out).
I am now really curious to test the version with 6 pairs
