2SD2081 I get from Bdent per Jeff's recommendation, otherwise I think 2SD2014/2SB1257 should be fine.I've made a little progress with the great "template" from Jeff.
Unfortunately there are some problems to get "real" 2SD2081 and OPA604 (ATM)
Would there be adequate substitutes for them?
BR Falk
OPA604 partsconnexion has them, also Cimarron technology has them in soic-8 plus adapters, otherwise i'd probably do another stage to drop the rail for the opamp supply to run other types.
Hello everyone,
After building the WHAMMY, "NOIR," and an F6, I would like to create the HPA-1 Jeff version.
It will be equipped with 2SK170/2SJ74 for the JFETs, KSA992/KSC1845 for the BJTs, and FQP3N30/FQP3P20 for the MOSFET
I have taken the latest schematic (as far as I know), kept the main architecture, and made changes only to the power supply by switching to a CRCRC configuration. The 5V will be separated, and the relay control (power/inputs/outputs) will be managed by an ARDUINO.
I have revised the PCB layout and added a few test points. Do you have any comments or improvements to suggest?
Regarding the 5V circuit, I am replacing the BA7812 with a BA7805. Should I modify its surroundings?
Have a nice day, Jérôme
After building the WHAMMY, "NOIR," and an F6, I would like to create the HPA-1 Jeff version.
It will be equipped with 2SK170/2SJ74 for the JFETs, KSA992/KSC1845 for the BJTs, and FQP3N30/FQP3P20 for the MOSFET
I have taken the latest schematic (as far as I know), kept the main architecture, and made changes only to the power supply by switching to a CRCRC configuration. The 5V will be separated, and the relay control (power/inputs/outputs) will be managed by an ARDUINO.
I have revised the PCB layout and added a few test points. Do you have any comments or improvements to suggest?
Regarding the 5V circuit, I am replacing the BA7812 with a BA7805. Should I modify its surroundings?
Have a nice day, Jérôme
Attachments
You might want more clearance on the 230V lines. While IPC2221 says 0.4mm is enough with a conformal coating, there's no solder mask on the IN/OUT pads, so I'd want more around those. I usually just use 2mm since my designs aren't that dense and I can afford the space.
You may need a bit bigger transformer with the CRCRC PSU, depending on what values you're using for C and R.
You may need a bit bigger transformer with the CRCRC PSU, depending on what values you're using for C and R.
Thank you for the feedback, Jeff.
I will correct the traces and the IN/OUT pads.
Regarding the filter, I will keep the 40,000uF by using 3x6800uF capacitors. I don't want to affect the bass frequencies. As for the resistors, I will calculate them using the formula 1/CW with a cutoff at 50Hz, which gives me a value of 0.47 ohms.
Unless I'm mistaken, currently with 2.2 ohms, the cutoff frequency is around 7Hz. Is it necessary to go that low?
The transformer will be a Toroidy 120VA 2x24V.
Have a nice day, Jérôme
I will correct the traces and the IN/OUT pads.
Regarding the filter, I will keep the 40,000uF by using 3x6800uF capacitors. I don't want to affect the bass frequencies. As for the resistors, I will calculate them using the formula 1/CW with a cutoff at 50Hz, which gives me a value of 0.47 ohms.
Unless I'm mistaken, currently with 2.2 ohms, the cutoff frequency is around 7Hz. Is it necessary to go that low?
The transformer will be a Toroidy 120VA 2x24V.
Have a nice day, Jérôme
The first set of capacitors need to have enough ripple current capacity. The 10,000uF ones I used (Nichicon LLS 50V) have about 5A, which give a large safety margin. You probably don't need that much, but don't go too low.
The resistance is not so much about the cutoff frequency. It's really a trade-off between how much voltage you lose, how much heat you generate, and how much you pound that 50Hz ripple flat. The series regulator after the CRC doesn't need a lot of headroom, but it still needs some. (I used a 25V transformer to give me a bit more headroom with the 2R2 I used.)
I'd suggest playing with the values in PSUD2.
The resistance is not so much about the cutoff frequency. It's really a trade-off between how much voltage you lose, how much heat you generate, and how much you pound that 50Hz ripple flat. The series regulator after the CRC doesn't need a lot of headroom, but it still needs some. (I used a 25V transformer to give me a bit more headroom with the 2R2 I used.)
I'd suggest playing with the values in PSUD2.
