endezone: sorry I have no experience of the F5......
my own report. So I couldn't get the 4" fan I had to fit in the case without serious surgery, so I ended up fitting a single 2" one to the inside back of the case, blowing air into the case. Unfortunately, I couldn't fit a second one in there, again due to size contraints. If needs be I can modify the case of the fan to fit 2 in there (rubs against one of the heatsink on ths PS board).
So I fitted a 170R in series with my 13.5V supply and the fan runs fairly quiet. I can hear it, but not while music is playing. If all this works out, I will probably buy a quiet fan....
So what happened: well, the temperature dropped quite a bit. Internal temp in the case has dropped from c.55 deg C to 45 deg C and the heatsink temp has dropped from a good solid 60 deg C to 53-55 deg C.
Thats with just one 2" fan running slow. So I'm thinking of looking at this again, and going back to fitting my 2 x 2" fans on the outside back of the case and maybe even buying (shock, horror) some quiet ones for this job.
So I feel that the fan has brought the amp back into a safer range. Even in terms of the caps in the PS being a bit cooler - it all helps.
For those thinking of going this route, note that I have mounted the fan in most likely a pretty inefficient way wrt to cooling. Could be done much better I think...
Fran
my own report. So I couldn't get the 4" fan I had to fit in the case without serious surgery, so I ended up fitting a single 2" one to the inside back of the case, blowing air into the case. Unfortunately, I couldn't fit a second one in there, again due to size contraints. If needs be I can modify the case of the fan to fit 2 in there (rubs against one of the heatsink on ths PS board).
So I fitted a 170R in series with my 13.5V supply and the fan runs fairly quiet. I can hear it, but not while music is playing. If all this works out, I will probably buy a quiet fan....
So what happened: well, the temperature dropped quite a bit. Internal temp in the case has dropped from c.55 deg C to 45 deg C and the heatsink temp has dropped from a good solid 60 deg C to 53-55 deg C.
Thats with just one 2" fan running slow. So I'm thinking of looking at this again, and going back to fitting my 2 x 2" fans on the outside back of the case and maybe even buying (shock, horror) some quiet ones for this job.
So I feel that the fan has brought the amp back into a safer range. Even in terms of the caps in the PS being a bit cooler - it all helps.
For those thinking of going this route, note that I have mounted the fan in most likely a pretty inefficient way wrt to cooling. Could be done much better I think...
Fran
Nelson Pass posted a fan control circuit to the forum a while back...
http://www.diyaudio.com/forums/showthread.php?postid=783474#post783474
http://www.diyaudio.com/forums/showthread.php?postid=783474#post783474
Well, the circuit works!!
eh, now I know that seems like I'm surprised that it works, no, its just that I'm surprised that I got it to work!!
I've tried it out with a few different fans. It has some difficulty getting a big 5" one to run, but once running it has no problems. No problems seen with a single 4" fan or smaller, I've yet to try it with my 2 2" fns in tandem. Will be doing that tonight.
For the record, I used some PN4392 jfet in a to92 package (all I had) part no. from mouser:
512-pn4392d26z
Anyway, I'll take a few photos later. The circuit is tiny, I just mounted it on a bit of perf board. It will allow me to mount the 2 fans outside the box blowing in, so should help a bit too.
Fran
eh, now I know that seems like I'm surprised that it works, no, its just that I'm surprised that I got it to work!!
I've tried it out with a few different fans. It has some difficulty getting a big 5" one to run, but once running it has no problems. No problems seen with a single 4" fan or smaller, I've yet to try it with my 2 2" fns in tandem. Will be doing that tonight.
For the record, I used some PN4392 jfet in a to92 package (all I had) part no. from mouser:
512-pn4392d26z
Anyway, I'll take a few photos later. The circuit is tiny, I just mounted it on a bit of perf board. It will allow me to mount the 2 fans outside the box blowing in, so should help a bit too.
Fran
Amp comparrison
Friend and I did a comparrison in the weekend between my Mini-A and an RH84 (single ended EL84 anp).
Prior to doing a real compare I had thought the RH84 top end a bit more airy, more sparkle. However direct comparrisons, swapping back and forth with same music, revealed the Mini-A was the equal of the RH84 in that respect. It was close in the mids/tops but I felt the Mini-A just won in terms of the dynamics making the music was just a bit more exciting. Bottom end the RH84 was fuller and seemingly had more bass but the Mini-A more punchy and better control. I would say the RH84 lacks bottom end control but still very enjoyable.
Although they both cost about the same to build the RH84 has cheapish Edcor OPTs. I have just put in a pair of SAC OPTs into my friends RH84 (we both have one) so will be interesting to see if that closes the gap. Mind you the OPTs aren't cheap and puts the cost of the RH84 up considerably.
Overall I am realy pleased with the Mini-A, I think it will remain in my main system, at least till my next amp is built
Friend and I did a comparrison in the weekend between my Mini-A and an RH84 (single ended EL84 anp).
Prior to doing a real compare I had thought the RH84 top end a bit more airy, more sparkle. However direct comparrisons, swapping back and forth with same music, revealed the Mini-A was the equal of the RH84 in that respect. It was close in the mids/tops but I felt the Mini-A just won in terms of the dynamics making the music was just a bit more exciting. Bottom end the RH84 was fuller and seemingly had more bass but the Mini-A more punchy and better control. I would say the RH84 lacks bottom end control but still very enjoyable.
Although they both cost about the same to build the RH84 has cheapish Edcor OPTs. I have just put in a pair of SAC OPTs into my friends RH84 (we both have one) so will be interesting to see if that closes the gap. Mind you the OPTs aren't cheap and puts the cost of the RH84 up considerably.
Overall I am realy pleased with the Mini-A, I think it will remain in my main system, at least till my next amp is built
Thats very like what I have heard with my EL84 amp - its PP but not in triode mode. Very good amp, clean an all that, but this seems to have more punch. More dynamic too. I'm sorely tempted by an F3 build (or even an F5 - its one with gain isn't it?) but my lack of knowledge puts me off a bit. Was there a group buy of boards for the F5?
Pics of the board - this thing is really tiny so its vey easy to fit into the amp:
And the back of the amp with the fans. I know its ugly, but they can't be seen, and indeed, much more importantly, can't be heard. They start up reliably, run quiet and I have found that the inside the case temp and the heatsink temp is the same as when I had one fan mounted inside but running harder and noisier.
So overall a result I would say. Not the most efficient means of cooling I know, but I'm happier now with the 30-33 deg C rise over ambient on the heatsinks and 25 deg C rise over ambient inside the case.
Thanks to all, and of course to Nelson for the fan circuit.....
Fran
Pics of the board - this thing is really tiny so its vey easy to fit into the amp:
An externally hosted image should be here but it was not working when we last tested it.
And the back of the amp with the fans. I know its ugly, but they can't be seen, and indeed, much more importantly, can't be heard. They start up reliably, run quiet and I have found that the inside the case temp and the heatsink temp is the same as when I had one fan mounted inside but running harder and noisier.
An externally hosted image should be here but it was not working when we last tested it.
So overall a result I would say. Not the most efficient means of cooling I know, but I'm happier now with the 30-33 deg C rise over ambient on the heatsinks and 25 deg C rise over ambient inside the case.
Thanks to all, and of course to Nelson for the fan circuit.....
Fran
PQatPIT said:
The boards are back in stock, and I put up a New Year special, 20% off until the end of the month ($7.20 for either an amplifier pcb set, or a power supply pcb). I put them on the order page here:
http://www.chipamp.com/orders.shtml
Happy New Year,
--
Brian
Balanced input components? (DUMMY ALERT!)
Two questions.
1) When building a Mini-A or Aleph 30 for single-ended input using Brian's (beautiful, incredible value) boards, must one ground the -IN input or is it OK to simply leave out the balanced input components (R9, R10 and C1)?
2) If anyone has built either of these amps using Brian's revision 2 PS boards, could you tell me what the values for D0, C0 and R0 are, and what color LED to use (if it makes any difference)? I've not been able to find a PS BOM and I know Brian is really busy or he would have provided me with one.
Thanks.
George
Oh, by way of introduction, this is my third amp build and my ee knowledge is growing but still stretched painfully thin. In fact, as I did above, I prefaced my questions on the Sym-a-Sym build thread with "Dummy Alert." So, I'm perfectly comfortable with you venting the frustrations of your day on me if and when you respond to my posts. So long as you answer my questions, inane as they are likely to be.
Two questions.
1) When building a Mini-A or Aleph 30 for single-ended input using Brian's (beautiful, incredible value) boards, must one ground the -IN input or is it OK to simply leave out the balanced input components (R9, R10 and C1)?
2) If anyone has built either of these amps using Brian's revision 2 PS boards, could you tell me what the values for D0, C0 and R0 are, and what color LED to use (if it makes any difference)? I've not been able to find a PS BOM and I know Brian is really busy or he would have provided me with one.
Thanks.
George
Oh, by way of introduction, this is my third amp build and my ee knowledge is growing but still stretched painfully thin. In fact, as I did above, I prefaced my questions on the Sym-a-Sym build thread with "Dummy Alert." So, I'm perfectly comfortable with you venting the frustrations of your day on me if and when you respond to my posts. So long as you answer my questions, inane as they are likely to be.
Re: Balanced input components? (DUMMY ALERT!)
It has been a long time since I built a couple of Aleph amps. IIRC, I stuffed all components and connected the unbalanced source to +IN and GND.
I used:
D0 = 1N4004 (or similar) diode
C0 = 10uF 50v capacitor
R0 = 10k resistor
LED = any color. I used a blue one.
Wishing you the best with your build!
--
Brian
Colescuttle said:
It has been a long time since I built a couple of Aleph amps. IIRC, I stuffed all components and connected the unbalanced source to +IN and GND.
I used:
D0 = 1N4004 (or similar) diode
C0 = 10uF 50v capacitor
R0 = 10k resistor
LED = any color. I used a blue one.
Wishing you the best with your build!
--
Brian
diyamps.com docu
Hello Brian,
when I ordered my Aleph-Boards, the site diyamps.com still existed. There was a little documentation on that site, the schematic you used and some textural information on the possible configurations.
It was very helpful because finding the actual implemetation in all those threads here is very difficult.
Would it be possible to post those pages again under a "static" link, on your site or here in the wiki?
Best regards
Flo
P.S.: Perhaps those page exist anywhere and I am too stupid to find them.
Hello Brian,
when I ordered my Aleph-Boards, the site diyamps.com still existed. There was a little documentation on that site, the schematic you used and some textural information on the possible configurations.
It was very helpful because finding the actual implemetation in all those threads here is very difficult.
Would it be possible to post those pages again under a "static" link, on your site or here in the wiki?
Best regards
Flo
P.S.: Perhaps those page exist anywhere and I am too stupid to find them.
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