Questions about amp camp amp and linear power supply

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
Hi,

I'm in the process of building some open baffle speakers with a 12" coaxial with 97db sensitivity and 1" compression driver with 109db sensitivity. Active crossovers and eq will be done with a miniDSP 4x10HD. I'm really interested in building my own amplifiers, but I don't have any experience with it. I am tempted to try the amp camp amp. Will 6 watts be enough for midrange and tweeter with that high sensitivity and in a 25 square meter room?

I'll also be using 15" woofers for 150Hz and down, but I have amps for those.

I was also wondering if anyone has heard the ACA with both linear power supply and with the laptop power supply? If I'm going to build this, I think I want to try a linear power supply if there is much to gain in sound quality from doing this. Is there any build guides for linear power supply for 240V AC?

Thanks!
 
With speakers this sensitive, you won't need 6 Watt. With 1 Watt you can blow out your windows :D

But you will need a very, very quiet amp. I don't know the ACA, but I do know the Aleph (comparable in a couple of ways). This Aleph is not that critical.

I'm always fond of a standard CRC. About 10mf per ampere and burn a few percent of the voltage in the resistor. If you can get everything at surplus prices, such a linear supply is also cheap.
 
Hi Jonse, there is a lot of info the find on the firstwatt.com website. Do you want a standard capacitor type? Take a look on the Zen. Do you want it regulated? Take a look at Zen Variations 3.

You want CRC? Most of the normal Firstwatt and Pass amps use this.
 
Member
Joined 2000
Paid Member
Will 6 watts be enough for midrange and tweeter with that high sensitivity and in a 25 square meter room

In normal rooms 6w this is plenty for tweeter and mid, but in a 25m^2 room, I'm not too sure. I use the ACA on 86db efficient speakers in a small area, say, 5m x 15m area and it's fine. Then again I don't need it to be ultra loud.

I built the ACA with linear ~19v supply and it sound just great. I can't say enough good things about it.

I have not heard the ACA with a SMPS. I'm sure if you use a well made SMPS, it will sound great too.

ACA illustrated build guide

Vince
 
Member
Joined 2000
Paid Member
Some pics.
 

Attachments

  • aca-01-sm.jpg
    aca-01-sm.jpg
    146.7 KB · Views: 1,577
  • aca-02-sm.jpg
    aca-02-sm.jpg
    131 KB · Views: 1,529
  • aca-05-sm.jpg
    aca-05-sm.jpg
    112.2 KB · Views: 1,528
  • aca-08-sm.jpg
    aca-08-sm.jpg
    131.2 KB · Views: 1,507
  • aca-09-sm.jpg
    aca-09-sm.jpg
    375.3 KB · Views: 1,500
  • aca-10-sm.jpg
    aca-10-sm.jpg
    137.7 KB · Views: 703
Some pics.

Great build, looks good! How does the sound quality compare to a integrated/power amps you've had before? Nelson Pass mentions that this amp isn't designed for the best possible sound quality but for easy build. So I'm wondering if I'm better off just buying a cheap power amp like the Topping TP60, Dayton Audio APA150 or something similar.

I see now that the plans for ACA 1.1 is going to be released soon, so I may just wait and build that one instead.
 
Member
Joined 2000
Paid Member
I have a class D amp and chip amp. Fun for 1 hour, then they get irritating. The ACA is not only an amp for builders that need training wheels, but also an elegant amp that has an interesting output stage and holds its own again anything. I would think a person who likes tube amps would also like the ACA. Very smooth. Somehow has amazing bass.

The aca 1.1 is just a slightly upgraded aca. R15 was added and R12 was changed. That info is in the thread.

You could wait for aca 2.0. That's a bit more differrnt, with more power capability, I believe.
 
Last edited:
I just paid $18 US each for 6.5A Mean Well smps.

At least Meanwell is a known Chinese brand.
I semi recently bought 2... 25 Volters for significantly Mo' $ than that... Both subsequently / soon failed, one damaging an amp in process .
Apparently SMPS failures are more common than generally acknowledged.
Dunno .. but certainly 2 was enough for me
Only SMPs that seem trustworthy.. in My mind... are the laptop bricks.
Until well proven otherwise.. I'm only willing to trust to a Transformer.
 
Member
Joined 2000
Paid Member
Only SMPs that seem trustworthy.. in My mind... are the laptop bricks.

They Meant Well...;)

I have access to a lot of unused bricks, especially 19.5v 5A and up. 24v are a little rare at work. Don't know why I pulled the trigger on the Mean Wells, might have to do with keeping everything inside the case. Don't know if there will be much radiation from the supplies. Hope not.
 
Ok, a question for the experts (or at least those with more experience than I):

I've got an ACA (from BA17) running on a 24v 8A switching power supply. I can't hear any hum or ripple, and all the scope shows is a neat little triangle wave at 50kHz (with the expected MHz ring), and a listed 82mV P-P max measurement and an averaged 13mV RMS. Is that quiet enough, or should I be unsatisfied with any visible/measurable ripple?

Or is that a little over the top?
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.