Amp Camp Amp - ACA

In testing my light bulb dim tester... the flickering pulsing happens with both ACA amps, but its very rythmic pulsing. I plugged other items into the dim bulb tester... and of course light does not light up. Keep in mind I know nothing here, but I started to wonder if this is somehow tied to the switching power supply... so I grabbed a MacBook pro and its witching power supply (The laptop is fine and in mint working order, and only a couple years old). The MacBook pro and its power supply would cause the dim light bulb tester to pulse or flicker at a much slower rate... so is this just because of a switching power supply? Am I just being paranoid? Thanks in advance.
 

6L6

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Dudeisms -

You used a bulb tester with the power bricks? That's not going to do anything aside make the brick really mad. Sadly the dim bulb tester isn't going to do anything for the ACA. Unplug the dim bulb and plug in the amp.

As for bias, the stereo/mono switch position will make no difference. :D
 
Dudeisms -

You used a bulb tester with the power bricks? That's not going to do anything aside make the brick really mad. Sadly the dim bulb tester isn't going to do anything for the ACA. Unplug the dim bulb and plug in the amp.

As for bias, the stereo/mono switch position will make no difference. :D



Can’t thank you enough for the quick reply... bye bye dim bulb tester. Both amps powered on, not biased yet... no smoke, just quiet and on... awesome

DSCN3902.JPG
 
I wanted to thank all those who took the time to recommend some speakers suited to the ACAs. I was able to find a pair of Klipsch KG-4s in pretty good shape about 15 miles from my house for $225. It took me a while to figure out how to place them in the room. All the other speakers I've had do best well out into the room. Who'd a thunk they would do best near the corners? Now that they are situated well, I am amazed at how full, dynamic and engaging the ACA | KG-4 combo is. I've always had tubes somewhere in the system to give the magic and body. No tubes needed with these speakers and amps. Even late night listening at low volumes sounds very engaging.

ACA_KG-4.jpg

The subs aren't really in the system, they are just acting as stands for the KG-4s because I had nothing else near the correct height. And the speaker wires really don't look like glow sticks. For some reason they shine like cat's eyes whenever I take a photo.

Thanks again!
 
In my country Belgium import duty is approx 6% or so, but on this value a sale tax of 21%, and approx 25 euro customs cost. Under approx 22 euro, there is no extra cost. I think it would be cheaper to ship the components in 5 packages of 20 euro each. On the case we pay Italian vat, 22% i think. :(

Here almost the same. You pay 21% vat and a duty fee. For two amps it was 74,- Euro.
 
Thank you Mr.Pass, 6L6 & all involved in the ACA 1.6

ACA 1.6 just finished. Since I'm waiting for some cables to connect it to my main system, I connected a pair of cheap old music centre speakers (Sanyo-circa 1970) that I use for testing purposes.

Incredible! The sound I am hearing is entrancing! Those cables can't here quick enough.

Thank you to everyone involved in creating and putting these kits together.

Paul.
 
Yay,
A bag with two boxes arrived yesterday (Number 5064).
Now I just need the chassis to arrive.

Speaking of which, I haven't received any notification about the chassis at all.
Is that normal, does it just show up ?

I know the Italians have their bridge to sort out (condolences to those who didn't survive and their families).

I'm not in any rush, many other things to tend to at present.

P.S.
Many thanks to Papa and all the others that have contributed and made this a reality.
 

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Switches things on and off again
Joined 2000
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Yay,
A bag with two boxes arrived yesterday (Number 5064).Now I just need the chassis to arrive. I haven't received any notification about the chassis at all.
Is that normal, does it just show up?

You should have received your chassis already. Please email contact@diyaudiostore.com to create a ticket and get a speedy resolution.
 
C2 will not be the cause of this fault. It allows the AC output voltage to add to the DC voltage used to drive the gate of Q2. Its a very old technique called bootstrapping.

So no click, no noise.

The DC voltages may be correct but lets confirm the current is flowing. Did you try this ?



You should be seeing around 0.4 volts across R1 and R2 and around 0.55 volts across R3 and R4. The FET's should be hot. I think your measurements above are showing that but lets be sure.

With the amp OFF you should be able to measure your speakers DC resistance by measuring the resistance across R14. This check will go a long way to confirming the speaker is physically connected to the correct points on the PCB. This value will be low, perhaps just 4 to 10 ohms and should be identical to the value you see measuring across the speaker alone.

Lets see what those tests show.
r14 measured 7.3 ohms speaker 7.4 ohms
 
I had a hard time telling from the images which connections used the heavier gauge wire and ended up using too much and running out. (I used it for power supply and speaker outs). I didn’t like the options at my local hardware store. Any suggestions for a good replacement / where to buy? Also is it 14 or 16 gauge? None of mine was marked.

Thanks for helping
 
Yay,
A bag with two boxes arrived yesterday (Number 5064).
Now I just need the chassis to arrive.

Speaking of which, I haven't received any notification about the chassis at all.
Is that normal, does it just show up ?

I know the Italians have their bridge to sort out (condolences to those who didn't survive and their families).

I'm not in any rush, many other things to tend to at present.

P.S.
Many thanks to Papa and all the others that have contributed and made this a reality.

HiFi2000 should still be enjoying the Italian summer for another week, so you shouldn't expect to see an arrival soon (unless the chassis was shipped before they went on break and it's been on a slow plane to Oz).
 
I had a hard time telling from the images which connections used the heavier gauge wire and ended up using too much and running out. (I used it for power supply and speaker outs). I didn’t like the options at my local hardware store. Any suggestions for a good replacement / where to buy? Also is it 14 or 16 gauge? None of mine was marked.

Thanks for helping

Applying strained eyes, the smaller diameter wire appeared to be marked 22AWG on the cable sheath. The large cable was unmarked in my package. It would be handy for reference, to have access to the complete BoM. It will definitely be needed when the ACA PCB only option becomes available.

My verniers tell me the larger gauge conductor ID is around 1.5 mm FWIW. I consider that to be a pretty rough number but it might help until something more reliable comes along.
 
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