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Amp Camp Amp

nj pheonix said:
OK thanks they look huge against the transistor. I didn't realize heat could efficiently dissipate that far out .
Click to expand...
I think we'd all be surprised if there were some thermal imaging available. Nelson seems to do a good job figuring out what's required in the way of heatsinks.
 
Very good looking Sachin,
Nice job. I really like the Red. don't cover it with wood. I think I would have used a red Led ring power light though. I can criticize , we're friends.
(well we used to be) jk. :)
It really is amazing how much sound can be achieved with just 5 watts. Right?
They do sound very clean for being little fellas....... I haven't built my F5T yet either. Just F5.
Great job Sachin, Omishra's PS is a blessing to all who own one. Fantastic PS.

Ron
 
Thanks Ron,
you have every right to criticize.We are still friends:thmbsp: I am still very new and learning something new everyday:yes: I have not forgotten F5 Turbo.It is still very much in the cards.

Regards,
Sachin
 
Just discovered this thread - I am wondering if these would be OK with a pair of Polk monitor 40's .. 90db efficiency ... the kit looks wonderful.
 
sachu888 said:
2s3j.jpg
Click to expand...

Sachin-

I meant to ask earlier. The ACA build specifies a 19V supply. It looks like you're using one of those push-button "angel eye" switches that seem to be the rage these days. Near every one I search for is only spec-ed for 12V. What is your switch rated at and, if more than 12V, where did you get it? I'm trying to finalize my parts-list and am thinking of the angel eye switch but can't seem to search/find one that works.
 
dodog said:
Sachin-

I meant to ask earlier. The ACA build specifies a 19V supply. It looks like you're using one of those push-button "angel eye" switches that seem to be the rage these days. Near every one I search for is only spec-ed for 12V. What is your switch rated at and, if more than 12V, where did you get it? I'm trying to finalize my parts-list and am thinking of the angel eye switch but can't seem to search/find one that works.
Click to expand...

Hi Joel,
we bought that switches locally.They are 24V.I think they are also available at ebay

Regards,
Sachin
 
sachu888 said:
Hi Joel,
we bought that switches locally.They are 24V.I think they are also available at ebay

Regards,
Sachin
Click to expand...

Ah, 24V. I tried generic searches but got 100's of listings for under-rated switches. Just tried 24V and got a lot of returns. :thmbsp:

I wished I lived somewhere where cool switches were "local". :yes:
 
Just thinking here....:scratch2:
How about placing one of these Optical switches, mounted in a small hole or even placed along side the faceplate. A movement of your hand across the sensor would power the relay to interrupt mains power to the amp. If not already available, the components could all be on a small PCB.
 
westend said:
Just thinking here....:scratch2:
How about placing one of these Optical switches, mounted in a small hole or even placed along side the faceplate. A movement of your hand across the sensor would power the relay to interrupt mains power to the amp. If not already available, the components could all be on a small PCB.
Click to expand...

My 6-year-old would love that. :D
 
Ejfud sent his amp home with me last night to diagnose and I wanted everyone to take a look. Please see the pictures below.

DSC_9231.JPG


It appears to me that it may be an issue with the wiring of the power switch and supply. To me it appears as though I need to switch the wiring at the power supply port. What do the experts think?

Here is the amp from the DIY build...

x780d1349642616-fs3-28-power.jpg.pagespeed.ic.HqRYapqTEb.jpg


DSC_9234.jpg


DSC_9238.JPG
 
Looks right to me. I'm also the moron that wired it in the first place and couldn't get it to work.

Thanks again for having a look see!
 
Most chassis jacks are wired for DC (+) through the center pin. It's hard to see from the pictures what is wired to what. If you're sending the power to ground instead of to v+, yes, that would not be a good thing.

In the DIYbuild example, it appears the DC (-) is switched. Check your polarities.
 
dodog said:
Sachin-

I meant to ask earlier. The ACA build specifies a 19V supply. It looks like you're using one of those push-button "angel eye" switches that seem to be the rage these days. Near every one I search for is only spec-ed for 12V. What is your switch rated at and, if more than 12V, where did you get it? I'm trying to finalize my parts-list and am thinking of the angel eye switch but can't seem to search/find one that works.
Click to expand...

You can convert a 12V spec'ed LED switch to work at 24V.
See LED calculator links below. For 12V, there is a 1.5K (or ballpark) resistor
in series with the LED. For 24V, that would be about 3.3K. So to use the 12V
LED switch at 24V, you need an additional resistance about 3.3K minus 1.5K,
so about 1.8K,
So a 1.8k resistor in series with one LED terminal on the switch and you
should be good.

http://led.linear1.org/1led.wiz?VS=12;VF=2;ID=8
http://led.linear1.org/1led.wiz?VS=24;VF=2;ID=8
 
I can't tell but do you have +V and G coming from the same pin? Looks like +V is coming off the jack (if it's the appropriate tab (see what westend said)), to the switch, to the board. Also looks like G is coming off the same tab to the board. It should be:

G: straight from ground tab on DC jack to the G on the PCB
+V: From "hot" on the DC jack, to one tab on the switch, off the other tab on the switch, to the + on the PCB.




As long as you have this out and ready to boogie, "ground breaking" news has been released. Nelson Pass monkeyed with it and found that adding a 2.2K resistor from B to E of small bjt - Q3 , ZTX450 results in this baby putting out 6W! of class A. It's only 1W more but still. :) See the discussion here:

(post 1452, 1453 and on)

http://www.diyaudio.com/forums/pass-labs/215392-amp-camp-amp-aca-146.html
 
1) The soldering on Q2 doesn't look that great (is the right leg even connected?). Try reflowing all those joints for Q1 and Q2.
2) Check to make sure you're actually getting +19V off of the blue wire when the power supply is hooked up (it is a 19V supply, > 2A, correct?).
3) Are those 3W resistors (R1-R4) toasted or are they just dirty from grubby fingers? They should be elevated from the board but it's probably too late if the leads have been clipped.
4) Is the board mounted on standoffs or is it just supported by the MOSFETs and clamped on the opposite side? If it's not on standoffs, you could be shorting things out if any of the soldering is touching.
 
dodog said:
1) The soldering on Q2 doesn't look that great (is the right leg even connected?). Try reflowing all those joints for Q1 and Q2.
2) Check to make sure you're actually getting +19V off of the blue wire when the power supply is hooked up (it is a 19V supply, > 2A, correct?).
3) Are those 3W resistors (R1-R4) toasted or are they just dirty from grubby fingers? They should be elevated from the board but it's probably too late if the leads have been clipped.
4) Is the board mounted on standoffs or is it just supported by the MOSFETs and clamped on the opposite side? If it's not on standoffs, you could be shorting things out if any of the soldering is touching.
Click to expand...

1. I will resolder tonight.
2. I am afraid to hook it up, as Gary said it smoked the first time he plugged it in. Is there a safe way to power it on?
3. I cannot tell. I scrubbed them with my finger and the brown did not come off. Should I just replace these?
4. The board does have the standoffs, but no locking washers. Would the washers prevent shorting?

One more question. Can I safely remove the board from the heatsinks as is? I assume I will just need to add more mica when I put them back?
 
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