Thanks Peter.
You didn't mention secondary AC output voltage. Is that a 20+20v transformer or 18+18v?
..Todd
You didn't mention secondary AC output voltage. Is that a 20+20v transformer or 18+18v?
..Todd
Good point, my previous comment should be expanded:
With 2 x 20 V AC , 500VA Plitron transformer and 120V AC mains, you will get exactly +/- 26.3V on rails in a working amplifier.
Please note that mains voltage may vary from 110V to 130V. I just measured 124V at my place.
With 2 x 20 V AC , 500VA Plitron transformer and 120V AC mains, you will get exactly +/- 26.3V on rails in a working amplifier.
Please note that mains voltage may vary from 110V to 130V. I just measured 124V at my place.
Peter Daniel said:
I went with a 230V main - 600VA - 2x20 secondaries. I guess I will have the same results...
Original A30 scehmatic?
Hello,
Does anyone have a copy of the original A30 schematic that they could send me?
Would IRFP044s work in an A30?
I am trying to decide between building AX100 and two A30s.
Also, does anyone know the specification of the transformer used in the production A30?
Thanks!
AW
Hello,
Does anyone have a copy of the original A30 schematic that they could send me?
Would IRFP044s work in an A30?
I am trying to decide between building AX100 and two A30s.
Also, does anyone know the specification of the transformer used in the production A30?
Thanks!
AW
Peter Daniel said:
Peter,
I went to the Plitron website, and I cannot find this in their E-Catalog. I am probably doing something wrong. Could you provide us with the part number?
Pendergast said:
I bought that transformer 10 years ago and they don't offer that type any longer. You may still go with 400VA unit in 2 x 20V rating
Thermistor, current limiter
For the A30, what amperage and r for a current inlet rush limiter? 5amp, 10 ohm or? Any rec. for a thermistor from digi-key?
Also, is there an advantage to use 2 diode bridges from dual secondaries? or go with the single diode bridge for two channels? Using the antek 400va 18v+18vac.
Thanks🙂
For the A30, what amperage and r for a current inlet rush limiter? 5amp, 10 ohm or? Any rec. for a thermistor from digi-key?
Also, is there an advantage to use 2 diode bridges from dual secondaries? or go with the single diode bridge for two channels? Using the antek 400va 18v+18vac.
Thanks🙂
Re: Thermistor, current limiter
I think that I you try the search function, you will find a lot about thermistors - I think CL-60 was the one that Nelson used.
Two diode bridges gives you a "stiffer" supply, as the load is divided in two, also it should help suppress 50/60 hz hum.
I would always go for two bridges, given that you have the oppertunity - it is a very little extra expence....
Cheers
Hans
I think that I you try the search function, you will find a lot about thermistors - I think CL-60 was the one that Nelson used.
Two diode bridges gives you a "stiffer" supply, as the load is divided in two, also it should help suppress 50/60 hz hum.
I would always go for two bridges, given that you have the oppertunity - it is a very little extra expence....
Cheers
Hans
Thanks Hans, I found the cl-60 at digikey and will also use 2 diode bridges. The other question is how important is the 75c thermal protection device? can't find this at dk. Also is there a dual bridge power supply schematic I can use for a dual sec. single toroid?. I was planning to use 2 4mh inductors but I see in the A30 ps 4 .5r 10w resistors were used to split and isolate part of the supply. I wonder which is the best or use both? 🙂
doggy said:
Using inductors is good but VERY difficult to deal with the magnetic field. Most people settle for the simple CRC filter instead of the CLC simply due to less implimentation hassle.
I was. Then I wasn't (built a standalone X-BoSoZ). Now I need to get back to the A30 project, though I may make it integrated after all, but use the TXD instead, as it's way smaller and easier to fit. Not sure though.
My wife's only desire is "less wire." Not sure she would be happy with less wire, but "open toaster oven" in the living room with a new baby on the way. But, then again, how many ties is a kid gonna touch it? 😉
My wife's only desire is "less wire." Not sure she would be happy with less wire, but "open toaster oven" in the living room with a new baby on the way. But, then again, how many ties is a kid gonna touch it? 😉
He he, my kids don't touch my amps at all. I told them that I don't ground my chassis'. They looked at me kind of strange.
-sorry to hear it....
BrianDonegan said:
That was the demise of my B&W 805's. Children (under 8 yrs old) dancing and knocking them off the stands eventually broke the tweeter pods off the top. I had to close the mosh pit
...Anyway I solved the issue..
BIG full range speakers with built in amps..
Sources and pre / processor (Proceed AVP, old I know but STILL LOVE IT!) are the only thing showing.. Other than the big spkrs (on the sides) that the kids can't knock over that is..
Well, I guess it's a good excude to make a power conditioner/sequencer. One power cord and short runs from there.
Or work on wireless power, maybe like a Van de Graaff generator... which would also keep the kids away.
omitting output devices for lower heat
If I want to omit 2 of the output devices (and sacrifice output power), do I just need to omit 2 resistors per device (omitting Q7 and Q10), or will I need to change any other resistor values?
I'd like to try and get less heat out of this amp to use with smaller heatsinks (fanless) that I already have ...
Stephen
If I want to omit 2 of the output devices (and sacrifice output power), do I just need to omit 2 resistors per device (omitting Q7 and Q10), or will I need to change any other resistor values?
I'd like to try and get less heat out of this amp to use with smaller heatsinks (fanless) that I already have ...
Stephen
Do you think its possible to use FirstWatt F1 power supply? What would I need to change? It looks like an easy desing to do p2p.
Re: omitting output devices for lower heat
You would need to change the resistor value for the remaining device. Check Aleph Mini schematic, as this is probably what you want to build.
twitchie said:
You would need to change the resistor value for the remaining device. Check Aleph Mini schematic, as this is probably what you want to build.
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