Amp Camp Amp - ACA

[MEPER]

The extra set of binding posts are nice for bi-wire. I use them for that.

 

[12B4A]

This has been discussed previously...some mentioned a method applied in another First Watt amp circuit to prevent the noise, but I read nothing that suggested it would damage anything by leaving it as is...I tested with both 19 and 24 supplies and got the same results.

I vaguely think I remember someone explained it had to do with capacitors charging in the circuit.

My theory before I read that was that I had dirty power in my lines that was giving the ACAs indigestion. Once they “gassed off” so to speak I believe the sound was definitely free of any constipation...definitely a lot more clarity to my ears than my other amps that don’t fart on start up. 😂

The noise is the output DC blocking capacitor charging up. Completely normal and will be the same regardless of PSU.

Thanks guys. Working as intended then.

 

[johnnycamp5]

Mrshazbot.... "Na-Nu..Na-Nu"........ you started your build very quickly!

I check all my component values with one of these-
Mastech Group

Are you following the V1.5 build guide? I have found no guide for this V1.6 kit yet....

 

[poseidonsvoice]

Variac,

A BIG “HIP HIP HURRAH” to you and the crew that made this possible! Thanks!

One error on the note you supplied with the kit...change XTR to XLR.

A suggestion. On the back of this note, have a full schematic printed of the ACA design.

Best,
Anand.

 

[mraudioguru]

My two kits came in today! Whoohoo! Probably need some time for breaking in after being built. Building monoblocks and will delete the rca and extra pair of binding posts. Looking for filler suggestions for the RCA and binding post holes.

If you happen to have an ACE hardware store and it happens to have the aisle that has the hundreds of little bins, there are a couple of the bins that have the really nice black plastic "hole plugs". They look very nice. I buy them all the time to do exactly the same thing. They come in quite a few different sizes.

 

[Mrshazbot]

Mrshazbot.... "Na-Nu..Na-Nu"........ you started your build very quickly!

I check all my component values with one of these-
Mastech Group

Are you following the V1.5 build guide? I have found no guide for this V1.6 kit yet....

I’m using the 1.5 as a guide so far. The PCB layout is slightly different but from what I can tell the resistor values are all the same so I got it put together using the schematic.

However, there are two differences that I can’t figure out. The on / off switch is different and has six pins, not two like the photos, and the power plug Has totally different pins / tabs. I’ll post some pics if I get too impatient to wait for the new guide.

 

[6L6]

I'm working on the new guide. I'll have some photos of the most different spots hopefully today.

 

[6L6]

However, there are two differences that I can’t figure out. The on / off switch is different and has six pins, not two like the photos, and the power plug Has totally different pins / tabs. I’ll post some pics if I get too impatient to wait for the new guide.

If you are using the back panel switch for power, then wire like this -

Also the new barrel connector for the PSU has 2 pins, the center, which is (+) and the tab, which is (-)

 

[RafaPolit]

Well, amidst the usuallyvery busy family weekends, I managed to do half the stuffing of my PCBs today, and have all the resistors done!

Not the best soldering work, but for a first attempt I think it went acceptable enough.

Looking forward to getting a few more hours to finish gem up, and then relaxing to their sweet music!

Best regards,
Rafa.

 

[MEPER]

It is good to have the power resistors lifted a bit from the PCB as they do get a little hot! …...difficult to see if you have some "air" below the resistors.

 

[MEPER]

Regarding the soldering there seems to be no shorts...….so far

 

[RafaPolit]

No air whatsoever! And already cut the legs. Should I beconcerned?

 

[MEPER]

After 10 years of use…….you may see a bit of discolor on the PCB …..but I don't think you should be really concerned. But it is always good practice to lift these power resistors a bit from the PCB.

 

[Extreme_Boky]

Well, amidst the usuallyvery busy family weekends, I managed to do half the stuffing of my PCBs today, and have all the resistors done!

Not the best soldering work, but for a first attempt I think it went acceptable enough.

Looking forward to getting a few more hours to finish gem up, and then relaxing to their sweet music!

Best regards,
Rafa.

Could you please measure the diameter of that white circle where C1 should be soldered? Thanks!

 

[RafaPolit]

The printed circle measures 2.5cm (1") in diameter. But mine is an older kit. New capacitors and / or PCBs may have different sizes. That is why I didn't answer your question elsewhere. So better to confirm with someone that has your same PCBs.

Sorry,
Rafa.

 

[mraudioguru]

The printed circle measures 2.5cm (1") in diameter. But mine is an order kit. New capacitors and / or PCBs may have different sizes. That is why I didn't answer your question elsewhere. So confirm with someone that has your same PCBs.

Sorry,
Rafa.

The new board is the same exact size for C1.

 

[mpitogo]

The extra set of binding posts are nice for bi-wire. I use them for that.

Thanks, good idea. I did as you suggested. Build is complete. Both are now breaking in.

 

[mraudioguru]

Thanks, good idea. I did as you suggested. Build is complete. Both are now breaking in.

SWEET build! Very nice. Hope mine come out half that nice. Did you use the new 24V power supply? I thought the bias was supposed to be 12, not 10 that your VOM shows?

 

[RafaPolit]

Mpitogo,

Incredibly fast and sleek build! Those are seriously good looking monoblocks.

Congrats, and tell us how it sounds?

 

[mpitogo]

@mraudioguru good call. I will need to redo bias for 12V as you suggested, I bought the 1.6 kit but followed the 1.5 build guide and didn’t realize the instructions where for the 19v supply. I read around for the v1.6 build guide it’s not out yet but they did mention the new bias setting.