Thanks y'all!
Heat sink was surplus I had on hand, cut to height, to fit dimension from the board to the cover. Also cut a couple of fins off. Sorry I don't have a part number.
Hi, friends! Since yesterday a few events made Mighty encourage me to share my experience with you all, in case any of you are as stupid as me.
I was listening to music at work, minding my own business, when an important phone call made me have to unplug my cell phone from the ACP. Yes, I use a phone as source right now, cuz my Bryston DAC is misbehaving.
So, in the rush, I forgot to turn the volume down/change inputs iot protect the ACP from voltage peaks/spikes before unplugging/replugging.. Obviously, I shouldn’t have done that.
After an allready planned replacement of Q5 and 6, to no avail, measurements lead me to Q1 which turned out to be wide open. Being at home sick, enabled me to jig up and re-pair some J74’s, within 0.01mA (thanks Papa!), swap em - and there ya go, it works again.
Lesson is, I guess, don’t mix business with pleasure. Or not to put crap into a Pass product
Regards,
Andy
I was listening to music at work, minding my own business, when an important phone call made me have to unplug my cell phone from the ACP. Yes, I use a phone as source right now, cuz my Bryston DAC is misbehaving.
So, in the rush, I forgot to turn the volume down/change inputs iot protect the ACP from voltage peaks/spikes before unplugging/replugging.. Obviously, I shouldn’t have done that.
After an allready planned replacement of Q5 and 6, to no avail, measurements lead me to Q1 which turned out to be wide open. Being at home sick, enabled me to jig up and re-pair some J74’s, within 0.01mA (thanks Papa!), swap em - and there ya go, it works again.
Lesson is, I guess, don’t mix business with pleasure. Or not to put crap into a Pass product
Regards,
Andy
Early Pass DIY designs like the Bride of Zen included a 20V zener across the inputs to protect against static. This would also protect against this type of incident. A TVS may also work. It can be tack-soldered across the pins of the pot on the board, with some care. If you have only one input, you could just solder the zener across each of the RCA input jacks.
I’d have a look at these. Family friendly, and cheap too.
ReTrak ETAUDFUNIC Retractable Animalz Headphones
FINISHED!!
I finished my basic ACP+ (no ground plane bottom, no other embellishments) a few weeks ago and it has functioned way beyond my expectations both as a headphone amp and a preamp for my Sony P-channel Vfet amp. It works so well that I could not stop listening long enough to put a bottom and glass top on it...
Well, three days ago I finally broke down and moved the ACP+ out of the house and into the garage for its "dressing" session.
I had the brass 1/4" x 1/4" channel as well as a piece of 1/4" glass -- I just needed to get the glass cut and holes drilled & come up with a way to attach the glass to the ACP+. Unfortunately, the glass shop could not drill the holes close to the edge where they needed to be to match the holes in the circuit board. So I told the glass shop to drill the holes as close to the edge as they could and I'd figure something out. That turned out to be some scrap pieces of mahogany that I had in the scrap pile and some brass machine screws and washers and a 12" piece of 6/32" brass threaded rod.
The only "mechanical interference" issue was the power on switch -- it was right in the way of the brass channel on the front right of the amp. So after a bit of head scratching and junk bin digging, I found a solder in switch that fit the board and hung off the side of the amp. Not pretty but functional and I did not have to re-engineer the standoff on that side of the board just to clear the switch.
I think this will do nicely in a minimalist sort of way...
Happy Jack
I finished my basic ACP+ (no ground plane bottom, no other embellishments) a few weeks ago and it has functioned way beyond my expectations both as a headphone amp and a preamp for my Sony P-channel Vfet amp. It works so well that I could not stop listening long enough to put a bottom and glass top on it...
Well, three days ago I finally broke down and moved the ACP+ out of the house and into the garage for its "dressing" session.
I had the brass 1/4" x 1/4" channel as well as a piece of 1/4" glass -- I just needed to get the glass cut and holes drilled & come up with a way to attach the glass to the ACP+. Unfortunately, the glass shop could not drill the holes close to the edge where they needed to be to match the holes in the circuit board. So I told the glass shop to drill the holes as close to the edge as they could and I'd figure something out. That turned out to be some scrap pieces of mahogany that I had in the scrap pile and some brass machine screws and washers and a 12" piece of 6/32" brass threaded rod.
The only "mechanical interference" issue was the power on switch -- it was right in the way of the brass channel on the front right of the amp. So after a bit of head scratching and junk bin digging, I found a solder in switch that fit the board and hung off the side of the amp. Not pretty but functional and I did not have to re-engineer the standoff on that side of the board just to clear the switch.
I think this will do nicely in a minimalist sort of way...
Happy Jack
Attachments
Thank you, great tip! And with two inputs, will one zener across each work or am I missing something?
One zener for each input, left and right. You will need 4 zeners or 4 TVS protection devices. If you use veneers, I would order several (4) more and check them because they do vary and you don't want them to be too low otherwise they may cut-off signals.
The Mosfets dissipate only around 2 to 3 Watts each so there is not a lot of heat. So thermal paste is not critical.
Also the heat sinks and mounting screws attach to isolated areas on the PC board so there is no electrical connection. So electrical isolation pads are not necessary.
I built my ACP+ at BAF2019 and my recollection is that no thermal paste or isolation pads were provided or used. I also just looked at my ACP+ and there are no signs of thermal paste or isolation pads.
However if you have thermal paste and you worry, you can apply some thermal paste.
Also the heat sinks and mounting screws attach to isolated areas on the PC board so there is no electrical connection. So electrical isolation pads are not necessary.
I built my ACP+ at BAF2019 and my recollection is that no thermal paste or isolation pads were provided or used. I also just looked at my ACP+ and there are no signs of thermal paste or isolation pads.
However if you have thermal paste and you worry, you can apply some thermal paste.
It is lovely looking.
I think Zennie may be on to something. A system like those Roomba vacuums that scurry around cleaning, but instead an audio suystem that follows you around serenading you… Like Mariachis in a Mexican restaurant who won’t go away!
I think Zennie may be on to something. A system like those Roomba vacuums that scurry around cleaning, but instead an audio suystem that follows you around serenading you… Like Mariachis in a Mexican restaurant who won’t go away!
isn't that Fugly!
now, put it on the wheels, so amp can follow ya everywhere (I mean , as it's already in Garage)
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