Amp Camp Amp Kit 1.6/1.8

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Bunno77

Member
Joined 2020
Hi all

Fantastic having a look through these forums.

I might be posting in the wrong area but hoping to hear from others as to if they have run the ACA on Paradigm Tributes or similar models like Studio 100s, S6, S8

Considering trying to build an ACA especially with all this time on my hands at the moment

Thanks
 
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dake13

Member
Joined 2005
Paid Member
I just finished soldering up my ACA 1.6 and I notice in the build guide there is a video showing power up and music playing at step 50, with the DC balance being adjusted at steps 51/52. I'll probably adjust DC balance first just to be safe, but I was curious if this was out of order or might one connect source/speakers first without having adjusted the DC balance?
 
thomasnadeau

thomasnadeau

Member
Joined 2010
Jason said:
Very unlikely. We're running a bit late on the re-supply of this kit as there was an interview with Nelson a few months back which caused quite a few sales right as we were getting to the end of stock. This caught us and our supply chain off guard. All the store's kits are put together by DIYers such as yourself on their proverbial kitchen benches. Often they have one or two parts which are problematic to obtain, or have long lead times. And as the saying goes, sometimes "life just gets in the way".

If you do really want to make the ACA in the meantime, you could buy the ACA PCBs and do-it-yourself. Nelson's article states the parts can cost as little as $15 if you want to go surplus shop hunting for bargains (and can find some 2SK170s/LSK170s, and have your own stash of common connectors, switches, insulators, LEDs, wire, jacks, standoffs, nuts and bolts etc).
Click to expand...


Is there a BOM for Mouser/Digikey for the kit parts? I half-ordered a kit and don't have the chassis parts kit. I have most of the parts on hand, but the power connect which fits a specific cut-out in the kit chassis face plate would be nice. I love supporting the DiyStore and buy my parts there as much as possible to support its efforts, but in cases like this simply having a click-thru BOM might alleviate the pressure on the diystore having to keep stuff in stock all the time.
 
thomasnadeau

thomasnadeau

Member
Joined 2010
This build is so popular I'd be willing to keep it up to date. I am building my 4th one now (build 1.0, 1b and 1.6)!

Besides the BOM, a list of the chassis parts components used for each of the versions would be helpful as they can be cross-referenced.

6L6 said:
The problem with the one-click BOMs is they go stale as parts are out of stock or a part number changes a teeny bit and is therefore invalid... they require attention over time as well.
Click to expand...
 
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Azookey

Member
Joined 2018
Jason said:
Very unlikely. We're running a bit late on the re-supply of this kit as there was an interview with Nelson a few months back which caused quite a few sales right as we were getting to the end of stock. This caught us and our supply chain off guard. All the store's kits are put together by DIYers such as yourself on their proverbial kitchen benches. Often they have one or two parts which are problematic to obtain, or have long lead times. And as the saying goes, sometimes "life just gets in the way".

If you do really want to make the ACA in the meantime, you could buy the ACA PCBs and do-it-yourself. Nelson's article states the parts can cost as little as $15 if you want to go surplus shop hunting for bargains (and can find some 2SK170s/LSK170s, and have your own stash of common connectors, switches, insulators, LEDs, wire, jacks, standoffs, nuts and bolts etc).
Click to expand...
Which interview? 😛
 
astromo

astromo

Member
Joined 2017
Check for Steve Guttenberg (aka Audiophilliac). He did an interview series with our favourite Class A amp master last year. Steve has a sizeable following, so it's no surprise the ACA got a positive jolt from his coverage.
Maybe a case of, "a nice problem to have"?
Look out for the recent interviews between Nelson and Steve G over the F8 - check the Pass Labs board in the forum for that thread. There's also a recent 2 part interview with Audio Excellence Canada out. All worth taking in. I really enjoy knowing that the amps I've built have "personality", rather than a lump of anonymous metal and knobs. Listening to Nelson lay out his journey, really adds to that enjoyment for me.
 
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Liquidsound

Member
Joined 2020
Not sure if this is the right area to post a question... I gave my friend two ACA 1.6 Kits for his birthday. He's got them together successfully and both work great, except for Parallel-mode. He gets no output with using a "Y" RCA cable, yet both L & R channels on each amp work individually. Is there something we're missing on this ? ? ?
Thanks... John
 
Mooly

Mooly

Administrator
Joined 2007
Paid Member
No output at all or low output?

If both amps are built the same, and crucially both have the same gain then paralleling the outputs should work.

If the signal is 'different' though (amplitude and/or phase) then one amp will tend to 'short' into the other amps output and the level be reduced. The ACA is immune to damage from anything like that so no problems there but I can't think of any other reason.

In simple terms if you place two identical voltage sources in parallel then there is no interaction between them and the load should be driven normally. The first thought is that you have the gains set differently between the two or you have the speaker connections of one channel inverted (maybe internally).
 
lt_texan

lt_texan

Member
Joined 2005
The kit was sold out, so I gave it a go bareback buying the boards and 2SK170 from the store, the other components from Digi-Key and heatsinks and aluminum plate off eBay.

I have experience building tube gear, but this is my first solid state build.

And not so good so far.

It is making a small muffled distorted sound at full volume (preamp and amp pot). I am driving it with a tube preamp I built. The preamp line level out is about a CD player's 2V. I recall reading that ACA 1.6 has a 1.73V input sensitivity.

At that sensitivity, I figured I could just put a pot on it.

The voltages are all pretty much in spec.

The RCA 2 inputs through a toggle to the boards and returns check out fine.

But the positive speaker post (wired to ground on power jack and boards) AND the negative posts are a short circuit to ground. Does that make sense.

And yes, this sucker runs hot and I figure my heatsinks are undersized.

Any thoughts while I check the resistances?

TIA Dan
 

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Alan4411

Alan4411

Member
Joined 2011
Sounds like you have the outputs shorted... you're not the first.
Check you have about 1k ohms between the red and black speaker sockets.
Lift those 'clear' wires off the red terminals. Then check.
The outputs on the board are confusing unless you match them to the circuit diagram. The OUT + goes to ground (GND) and the OUT - is 'free' floating.

Yes way too small heatsinking. Twice as much at least or fit a fan? And it still has to dissipate 2 x 36 watts so does get hot.
 
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