Amp Camp Amp - ACA

[6sX7]

My brief experience was a spooky reality to the music. Like it was hanging in the room. Guessing this is the noise canceling of balanced operation. Also, the bass got woolly and lumpy (which is why I don't have it configured that way anymore). Output impedance doubles in balanced mode so less control over the woofers in my Halcyons.

 

[johnah5]

I have the NAIM Atom and it is amazing. Works sooo well and sounds great. I recommend it if you want to stream.
When I get parts for my ACA mess up I am going to run the ACAs in mono with XLR cables. Can't wait to hear what I hear

 

[johnah5]

ACA no sound

Does anyone know the part numbers for the q3 and q4 Jefts and the potentiometer?

Searching for replacements so I can solve the mystery of R7

Thanks
jh

 

[Zen Mod]

Q3 is bjt , type written on schematic

Q4 is JFet m type written on schematic

you can buy either that one (JFet) or LSK170A or LSK 170B or LSK170C
Store

 

[johnah5]

I am so stupid, yes I should look at the schematic. I am waiting to hear from DIY store to see if they sell them.
jh

 

[myleftear]

part numbers for the potentiometer?

https://www.mouser.ch/ProductDetail/Bourns/3386P-1-502LF?qs=0VqvB9JLnIvTc%2BG5A5jXhw==

Please verify. It must be a 5k ohms (according to MY bom ) and it must be the P-type (orientation of the pins)

 

[KevinHeem]

I think I've unintentionally connected these amps about every "wrong" way you could think of now (combination of wiring and switch positions)...they seem impervious to it.

 

[canonken]

A solder sucker is the best $15 you’ll ever spend in this hobby.

Or just bank on NEVER screwing up, having a bad part, or wanting to change something.

 

[Nelson Pass]

I like the Soldapult. Bought 5 or 6 20 years ago, still using the first one.

 

[MrJohn]

I just received my kit and am checking inventory and I can't see where these 6 flat washers are used (See Attached). The inventory didn't match exactly with the pictures in the instructions, but from the comments on the steps, it seems to be okay, but no mention of these 6 flat washers.

 

[MrJohn]

I went through the steps again and found use for 2 washers with the 2 smaller hex head bolts/screws for the center of the PCBs... are the remaining 4 flat washers used anywhere?

 

[Alan4411]

They go on the 3M bolts holding the large FETs down.
So; 3M bolt - small flat washer - spring washer - penny washer - transistor / FET.
Really does not matter if you leave them out...

 

[MrJohn]

I've checked the values on my resistors and majority of them are within a 10th or 100th, but my 332k Ohm Resistors are reading 330.2 and 331.2... are these within tolerance and okay to use?

 

[MrJohn]

3M bolt - small flat washer - spring washer - penny washer - transistor / FET.

Got it. Thank you!

 

[Zen Mod]

I like the Soldapult. Bought 5 or 6 20 years ago, still using the first one.

this is best 100E I spent on tool in last few years

(ok, I have some other best spent...... we all know that my approach is always Omnibest )

Basetech ZD-8925

 

[ItsAllInMyHead]

I've checked the values on my resistors and majority of them are within a 10th or 100th, but my 332k Ohm Resistors are reading 330.2 and 331.2... are these within tolerance and okay to use?

Perfectly fine (if you meant 330.2k and 331.2k).

 

[Nelson Pass]

All the resistors on these kits are nominal. The amps will work fine with 10% tolerances.

 

[MrJohn]

Perfectly fine (if you meant 330.2k and 331.2k).

Yes I did. Thank you!

All the resistors on these kits are nominal.

Please excuse my ignorance, this is first amp build. Can you clarify what you mean by this? Google search is telling me that "nominal" refers to the listed value of the component, while the actual value may be a value within a certain tolerance. I'm a little unclear as to what nominal means in your reply.

 

[Signal lost]

Papa said any value within 10% will work.

 

[Signal lost]

I have even forgot to solder both sides of the .47 Ohm resistors on one board and the amp didn't mind. Took me a while to figure that one out. This circuit is very forgiving of mistakes, modifications and new amp builders. Just look at the Amp camp with premium parts thread to see how tolerant it is of fiddling about.