Double checked, the last remaining resistors measure 33.2kohm, ready for R13 then, phew. The resistors I've soldered in R10 are obviously measuring differently now, but they are confirmed Orange, Orange, Red, Orange, Black.
Seems like I have an extra/spare 39kohm resistor in my kit - assuming that's just an odd end.
Cheers fellas
Pretty sure the 39k resistor goes on the switch?
Amp Camp Amp V1.8 Change Information - diyAudio Guides
I just found this while reading through the V1.8 change info:
"PS...V1.5/V1.6 owners: In October will be offering V1.5/V1.6 to V1.8 make-up kits for builders who have already built a V1.6 (or earlier) and want to bring it up to V1.8 specification (or build matching monos). We'll email you when they are available."
Did I miss this? I never remember even seeing anything about it, nor did I see it on the DIY store.
"PS...V1.5/V1.6 owners: In October will be offering V1.5/V1.6 to V1.8 make-up kits for builders who have already built a V1.6 (or earlier) and want to bring it up to V1.8 specification (or build matching monos). We'll email you when they are available."
Did I miss this? I never remember even seeing anything about it, nor did I see it on the DIY store.
not meaning to confuse you....but that 332k resistor is not critical imho, you can use anywhere from 100k to 1meg, i believe the lower this value, the lower the noise....
We originally were planning a kit with both the new rear panel and new rails/bolts but the price came in too high in our opinion to offer enough value (really it's just nicer looking bolts on top), so we haven't introduced that as a product. You can however buy the new rear panel, shipping from Italy. We are planning on stocking the rear panel in the US in the future.
Just ordered that rear panels(2). Almost bought the new empty chassis. So my 2018 built ACAs will be 1.8 version. Thank you.
I had so much fun building this that I must build another to run monos! On to the NuTube pre in the meantime until the ACA is back in stock. Thank you for the tips!
you bet, i am building two 48v 29n1 boards and two single 48v ACA, and a pair of 36V two in one amplifier boards, these 36v ACA will use the 2sk117 jfet input buffers....
To reiterate, it’s a piece o’ cake to upgrade any of the “2channels in one chassis” ACA’s to the current 1.8 spec. So if you want to go to 2 monoblocks, just upgrade your old one and buy a second kit. You don’t even need the new back panel as you can just look at the new chassis for reference!
Never seen any actual PCB damage to the ACA from resistors mounted touching the board. I think the build guide mentions it mostly as an educational thing. In some amp designs it might be necessary, so why not start doing it right...
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Just finished my second ACA, running them as bridged mono from my Nutube B1. One thing I've noticed is that in this mode the little "fart" noise on startup is no longer present!
Yeah the farts cancel out....
Hmmm, next time someone obsesses about the noise I’ll just tell them to order a second kit!
Hmmm, next time someone obsesses about the noise I’ll just tell them to order a second kit!
You know you've found your perfect match if your farts cancel...
#nevertoooldforfartjokes
If you power on your ACA first, then your B1 Korg right after, with just the right timing, the B1K cuts it's own little high pitched squeaker.
Sadly, this cute effect largely goes away if you put one of Mark's DC power conditioners in the unit.
Sadly, this cute effect largely goes away if you put one of Mark's DC power conditioners in the unit.
aside from more power, two channels bridged did not significantly differ in sound than a single channel one...
Hi. I have a question about the ACA. I soldered it together and plugged in my Soundcard and some cheap PC loudspeakers. So the sound is really silent. I can barely hear it. The output of the soundcard can drive the speakers way louder by itself. So is it normal that the ACA is, how to say, deamplifing? I don't think so😀. I resoldered everything and checked the connections. No change.
Here some information. I got the board #1b. But I build it like the 1.6 because the only difference seems to be R12, which i adjusted for 39,2K. I also connected the red terminal to the ground as seen in the build guide. The switches are missing because it only runs in stereo mod, the options arent necessary.
Here some measurements.
Output terminals.
0,03V at each terminal (red and black separated) . If I put the tip of the Voltmeter at black and red it is 0V
Channel1
Q2 S=12V D=23,8V G=17,4V
Q1 S= 6,5 mV D=11,98V G=4,6V
Channel2
Q2 S=12,6V D=23,7V G=17,2V
Q1 S=6.6mV D=11,96V G=4,62V
So I thing it is a ground problem or the capacitors are broken. Could this be? Or is there apparently something wrong with the way I build it?
Btw first project of that kind. Only build guitar effects until now and this ACA shall be a Guitar amp.
Thanks for the help and sorry for my bad english
Here some information. I got the board #1b. But I build it like the 1.6 because the only difference seems to be R12, which i adjusted for 39,2K. I also connected the red terminal to the ground as seen in the build guide. The switches are missing because it only runs in stereo mod, the options arent necessary.
Here some measurements.
Output terminals.
0,03V at each terminal (red and black separated) . If I put the tip of the Voltmeter at black and red it is 0V
Channel1
Q2 S=12V D=23,8V G=17,4V
Q1 S= 6,5 mV D=11,98V G=4,6V
Channel2
Q2 S=12,6V D=23,7V G=17,2V
Q1 S=6.6mV D=11,96V G=4,62V
So I thing it is a ground problem or the capacitors are broken. Could this be? Or is there apparently something wrong with the way I build it?
Btw first project of that kind. Only build guitar effects until now and this ACA shall be a Guitar amp.
Thanks for the help and sorry for my bad english
There might be a problem with quiescent current draw.
Lets look at channel 1 first where you say there is 12v on the source of Q2 and 11.98v on the drain of Q1.
That implies only 0.02 volts is across the R1 to R4 low value network and as such no current will flowing.
Are the FET's hot or not? They should be.
There should be around 0.9 volts as measured between source of Q2 and Drain of Q1.
Check the 0.47 and 0.68 ohms are correct values and not high by a factor of 10 or 100.
Lets look at channel 1 first where you say there is 12v on the source of Q2 and 11.98v on the drain of Q1.
That implies only 0.02 volts is across the R1 to R4 low value network and as such no current will flowing.
Are the FET's hot or not? They should be.
There should be around 0.9 volts as measured between source of Q2 and Drain of Q1.
Check the 0.47 and 0.68 ohms are correct values and not high by a factor of 10 or 100.
On my Kef q100 the Aca can be deafening loud. More than enough for real movie sound in my small study. You can connect a computer with jack out directly to the ACA. Should be loud. I use a small dac in between. Preamp is not needed at all in this setup.
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Thanks. Yes it is getting hot and the values are the right ones. Meassured again and now the source of Q2 is 12,7V ..Oo maybe I didnt wait enough til termal stability. Still very silent. Should I maybe resolder everything again? 🙁