The 2SC5359/2SA1987 are fine but the 2SC5171/2SA1930 while speedy, have extremely poor SOA so I don't recommend those at all.
Jeremy
I have a lead on some Sanken 2SC2922/2SA1216 from a legitimate source at a good price; however, they are Rank Y, which is an hfe range of 50-100. Is that adequate? Thoughts?
Hi guys, as regards output devices emitter resistors, may I use either 0.47R or 0.5R indifferently?
Thanks.
Thanks.
Since they have lower current gain what drivers do you want to use? Lower hfe outputs will stress the drivers more and ripples back to the predriver too, I'd like to know that before giving you the go ahead.
Jeremy
Assuming you're putting 0R47||0R47 or 0R5||0R5 to get 0.235 ohms or .25 ohms per output transistor this should be fine as long as you keep it consistent. Pick 0R47 or 0R5 and stick with it, don't mix them.
Jeremy
Thanks for your response! The plan is...
Outputs: 2SC2922/2SA1216
Drivers: MJE15032G/MJE15033G
Pre-Drivers: KSC3503DS/KSA1381ESTU
71V rails
Edit Don't foresee "difficult loads", but would like this to be as versatile as possible. So if using Y rank is limiting in some way, I'll probably pass.
I don't see any issues with Driver SOA using the mje15032/33 with lower hfe outputs. I was figuring worst with all if them at hfe=50.
Jeremy
I sure hope this combo works as intended, that is exactly what I am running with the Sanken transistors from Ampslab.
Does it matter that they are using Rank G for the 2992s (hfe 90-180) and Rank Y (hfe 50-100) for the 1216s?
I suspect it doesn't really; but I realize there's a lot I don't know, so I never feel sure of my answers.
Hi all,
What would be a good amount of capacitance for the ps?
Im going for 1 50V 1200Va toroidy supreme audio grade transformer.
I have 2 ps boards from the classic alph amp groupbuy by rhthatcher with space for 8 caps per channel.
and i am using the 4 output pairs board.
I am using a 5U x 400 mm modified case.
TIA
regards, John
What would be a good amount of capacitance for the ps?
Im going for 1 50V 1200Va toroidy supreme audio grade transformer.
I have 2 ps boards from the classic alph amp groupbuy by rhthatcher with space for 8 caps per channel.
and i am using the 4 output pairs board.
I am using a 5U x 400 mm modified case.
TIA
regards, John
thanks,
maybe it would be better to go with 45V trafo so i can use 80V caps.
the 100V caps are to big for the ps boards i have (also almost 2x more eexpensive.
That then would be 80.000 uF per channel, seems like a lot though.
regards, John
maybe it would be better to go with 45V trafo so i can use 80V caps.
the 100V caps are to big for the ps boards i have (also almost 2x more eexpensive.
That then would be 80.000 uF per channel, seems like a lot though.
regards, John
There are many threads discussing power supplies and opinions vary on how much capacitance and what diodes (Mosfets) to use. Feel free to investigate.
This is my personal opinion on selecting a power supply for this amp:
For 4 ohms speakers or less, use a transformer with two 40Vac windings. Less stress on the outputs and you can use 64Vdc caps.
For 4 ohm speakers and above, use a transformer with two 45Vac windings. Less stress on the outputs, use 80Vdc caps.
For those who insist on using a 50Vac transformer, be careful on the selection of the output devices and stay away from very low impedance loads. Read the second page in the BOM.
Generally speaking, as you go up in voltage, the cost to build this amp increases.
My preference is to use one transformer per channel. However more room may be needed in a single chassis. Using two chassis is ideal.
If I remember correctly the amps that were tested used 20,000uF (10,000uF||10,000uF) per rail . I would not use less.
This is my personal opinion on selecting a power supply for this amp:
For 4 ohms speakers or less, use a transformer with two 40Vac windings. Less stress on the outputs and you can use 64Vdc caps.
For 4 ohm speakers and above, use a transformer with two 45Vac windings. Less stress on the outputs, use 80Vdc caps.
For those who insist on using a 50Vac transformer, be careful on the selection of the output devices and stay away from very low impedance loads. Read the second page in the BOM.
Generally speaking, as you go up in voltage, the cost to build this amp increases.
My preference is to use one transformer per channel. However more room may be needed in a single chassis. Using two chassis is ideal.
If I remember correctly the amps that were tested used 20,000uF (10,000uF||10,000uF) per rail . I would not use less.
Thanks Audiosan and Harry
My build will be an integrated amp, space does not allow me to use two transformers or two chassis (that would be weird) sadly.
I worry a bit about the heatsinks even if they are big. I want to keep the heatsinks internal inside the chassis, not on the outside.
In the ps 80.000 uF 80V per channel is the max that will fit. The ps boards max cap diameter is 35mm.
regards, John
My build will be an integrated amp, space does not allow me to use two transformers or two chassis (that would be weird) sadly.
I worry a bit about the heatsinks even if they are big. I want to keep the heatsinks internal inside the chassis, not on the outside.
In the ps 80.000 uF 80V per channel is the max that will fit. The ps boards max cap diameter is 35mm.
regards, John
You don't need to worry about the heatsinks. Here is a 5ch Honey Bagder with internal heatsinks. 4U300mm sinks. Running on +/-57Vdc (2x40V transformer), and 70mA bias current pr outputpair.
At normal SPL levels, the heatsinks stays at about 13 celcius above room temperature.
At normal SPL levels, the heatsinks stays at about 13 celcius above room temperature.
that looks good, also i am using bigger heatsinks 5U x 400mm, but moderate spl levels 🤣
regards, John
regards, John
AudioSan, et al:
I'm on the fence as to which HiFi2000 chassis to use for my Wolverine project. I'll be building an integrated amp, combining a Wolverine based on the EF3-3 boards with a buffer (b-board buffer from RJM Audio), as a gift for my parents. The toroid will be 500VA with 35V secondaries, so the rails will be just under 50 VDC. Obviously, the plan is to build a lower-powered amp; under 100 watts/ch won't be an issue for my parents.
Would it be problematic to use a 3U 400mm chassis from the Store? Aesthetically, I think that would look better than the 4U 400mm alternative. Aesthetics will, of course, have to give way to dissipation requirements.
Regards,
Scott
I'm on the fence as to which HiFi2000 chassis to use for my Wolverine project. I'll be building an integrated amp, combining a Wolverine based on the EF3-3 boards with a buffer (b-board buffer from RJM Audio), as a gift for my parents. The toroid will be 500VA with 35V secondaries, so the rails will be just under 50 VDC. Obviously, the plan is to build a lower-powered amp; under 100 watts/ch won't be an issue for my parents.
Would it be problematic to use a 3U 400mm chassis from the Store? Aesthetically, I think that would look better than the 4U 400mm alternative. Aesthetics will, of course, have to give way to dissipation requirements.
Regards,
Scott