Excellent, Daniel!
I'm glad that you finish amplifier! Good choice you make!
Did you try with 170mA bias like original design?
I think, Mihai post somewhere in theme, respectful explanation for this...
I'm glad that you finish amplifier! Good choice you make!
Did you try with 170mA bias like original design?
I think, Mihai post somewhere in theme, respectful explanation for this...
Thanks for the nice comments guys,
I do have a little extra room in the case (on purpose)
I have chosen 200 mA which is on the high side of the range, I will go back and have a look at Mihai's post again.
I do have a little extra room in the case (on purpose)
I have chosen 200 mA which is on the high side of the range, I will go back and have a look at Mihai's post again.
There should be no problems there. Those sinks are good for at least 150W a side I would guess.
Myself, I can't really tell when I'm in and out of the class A, so I am thinking of using the biggest Re recommended and turn down the heat as much as possible. Nobody mentioned anything above Re=0.22, but I am guessing you can go even a bit higher without affecting the sound.
Has anyone listened and compared TPA3255 class D designs with RMI-FC100? Class D has come long way and very close, I just wonder how close.
For perspective RC-100 builders,
I have 2 packages of the GB offerred by Rudi Ratlos in 2016. I received them in 2017 and only opened up to see what was sent. One set is with the shunt regulation pcbs and the other is with the LT3062, as I thought I would like both. I also purchased an extra set of RC-100 and shunt boards from Rudy in 2019, as he wanted to get rid of them.
All of these will be going on the Swap Meet page in a while. If you are interested at present, I can guarantee that you will not pay more than what I paid in 2016-17.` Let me know if any interest or check out the swap meet in a short while.
Myles
I have 2 packages of the GB offerred by Rudi Ratlos in 2016. I received them in 2017 and only opened up to see what was sent. One set is with the shunt regulation pcbs and the other is with the LT3062, as I thought I would like both. I also purchased an extra set of RC-100 and shunt boards from Rudy in 2019, as he wanted to get rid of them.
All of these will be going on the Swap Meet page in a while. If you are interested at present, I can guarantee that you will not pay more than what I paid in 2016-17.` Let me know if any interest or check out the swap meet in a short while.
Myles
I still have few boards for sale, new shipments will be questionable considering this hole situation. No better way to spend time in a lockdown🙂
I blew a channel. It looks like one of the outputs wasn't screwed down tight enough and over heated and blew, it's clearly blown. It's an NJL0281 and I will probably have to check the drivers Q19 (2sc3423) and Q3 (mje15035) as well as the other outputs. Does anyone have a matched set of NJL0281 transistors to sell? Would it be a problem if I just dropped one in or should I buy a few and match them?
hi Daniel, I have an order I am about to place with Mouser for another project, and was going to add one of these transistors to it. If you have a matched set PM cost etc, may be a better plan.
Hi Luke
I have two NJL0281's left over from my RMI-FC100 project. Don't know if you are aware of it, but there was a problem with the thermal sensing diodes in the early production of these devices. In production, wrong diodes were installed in the devices making it difficult to set the bias. The irritating part is that these devices were not withdrawn from sale and were being delivered many months after the defect was discovered. I suspect the devices I have are in this category.
I live in the Mitcham area of Adelaide. Feel free to PM me if interested.
Keith
I have two NJL0281's left over from my RMI-FC100 project. Don't know if you are aware of it, but there was a problem with the thermal sensing diodes in the early production of these devices. In production, wrong diodes were installed in the devices making it difficult to set the bias. The irritating part is that these devices were not withdrawn from sale and were being delivered many months after the defect was discovered. I suspect the devices I have are in this category.
I live in the Mitcham area of Adelaide. Feel free to PM me if interested.
Keith
Hi Luke,
I have 3 x NJL0281DG @ hfe of 147 (all 3) with internal diode Vf @ 530 mV, 530 mV, 529 mV
Hi Keith,
I am in TTG area.
-Dan
I have 3 x NJL0281DG @ hfe of 147 (all 3) with internal diode Vf @ 530 mV, 530 mV, 529 mV
Hi Keith,
I am in TTG area.
-Dan
Thanks Keith and Daniel. Keith, I do recall what you are talking about and it would probably better to get later ones ones. Daniel, will PM you.
I have built two channels of the FC100 amp using ZDR's PCB's. When I powerup the front-end PS, all Leds are on but the voltage over de Diode string is not highe than -1.40 VDC. This is not enough to set the bias current.
I have double checked everything but found no errors. Both cahnnels act in exactly the same way. I have also checked voltages and currents according schematic on page 136 of this thread, measured values are all very close to what is stated here.
Enybody any ideas or advice on what else to try to get voltage over de diode string on target (1,5 VDC)
I have double checked everything but found no errors. Both cahnnels act in exactly the same way. I have also checked voltages and currents according schematic on page 136 of this thread, measured values are all very close to what is stated here.
Enybody any ideas or advice on what else to try to get voltage over de diode string on target (1,5 VDC)