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Old 15th February 2014, 03:55 PM   #1721
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I am pairing my ACA with the phono preamp from boozehound, both designs have set amounts of gain. What do you think would be best way to add in a volume control ?. The preamp has ~40dB of gain and from what I remember the ACA has about 14dB of voltage gain built in. Would a simple voltage divider between pre and power amp work? Could I implement a dual gang pot into the aca?
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Old 16th February 2014, 12:47 AM   #1722
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Quote:
Originally Posted by 6L6 View Post
flohmann - your photos look good. I think the next step is to grab your DMM and make sure you have voltage (+19V, or close) at the +V on the PCB. Red probe on blue wire, black on black, meter set to DC volts.
Thanks so much! That was it. Listening to them right now. :-)

And thanks for the new build guide -- that would have answered several questions that I was puzzling over from the original build guide. Proves you have never have too many pictures!

I think I'll enjoy them before I start to think about that extra resister fix...

Fred
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Old 16th February 2014, 12:50 AM   #1723
Variac is offline Variac  United States
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Damn! there goes a killer deal on a pair of ACA's

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Old 18th February 2014, 02:09 AM   #1724
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Default Tiny stereo amp build:

Until about a year ago, I used an Altec Lansing setup on my PC. The sound isn't great, and especially so once the subwoofer died. Since then, I've been struggling along with just two of the little, tinny-sounding plastic things on my desk.
Time to upgrade. Bought a Zhaolu D3 DAC off the forum, and picked up a pair of JBL Control One monitors from the dealer. As I listen in the near field (about 1 meter between my ears and each speaker cabinet) amp power is not a concern. Lacking an amplifier, and not wanting something the size of a VCR on my desk, I decided to build a tiny low watt amp from a kit, and fabrication, heat sinks, power supply, enclosure, connectors etc.

So here goes! I was looking for a pretty easy desktop amp to build, a pure Single Ended class A design because it has the more desirable even order harmonics......and has no cross-over distortion. My vote..... would be for a Nelson Pass design. NP designs are solidly engineered and they usually sound fantastic with many different rigs. If the ultimate goal is musicality, the NP designs are well proven and there is a wealth of information and variation out there for you to try. I'm focusing mostly on Nelson Pass' published plans because they're simple and therefore somewhat easier to build. Design elegance also tends to lead to better sound, since there are fewer elements corrupting the signal.

All in all its a fun project. The simple chassis built around the heat sinks. It is about construction techniques, to take an existing PCB-based component and put it in a box. Overall, the look is pleasing and hopefully somewhat different enough to be interesting.

Will post the listening impressions after completing the build.

Thanks for reading
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Old 20th February 2014, 01:35 AM   #1725
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I love using copper on a chassis when you can find it. It's a great size overall and looks like it will conduct the heat away well. I've just bought the ACA boards and will start the project soon. In the meantime, I'm trying to find some heat sinks I can build around. Bigger is better as I'm likely to keep the amp on quite a bit. If anyone has any ideas on where to buy them since the store is out of the complete kit, it would be most appreciated.
Vinnie
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Old 23rd February 2014, 05:42 PM   #1726
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MY ACA
THANKS Mr. PASS
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Old 23rd February 2014, 06:16 PM   #1727
Variac is offline Variac  United States
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Nice! The perforated metal cover with the LED's showing through has a lot of potential- It' looks real cool.
I never really liked that look for tube amps because the glow wasn't bright enough. But with the silver color
and bright LED it looks real techie..
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Old 24th February 2014, 03:46 PM   #1728
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Quote:
Originally Posted by disorder View Post
I am pairing my ACA with the phono preamp from boozehound, both designs have set amounts of gain. What do you think would be best way to add in a volume control ?. The preamp has ~40dB of gain and from what I remember the ACA has about 14dB of voltage gain built in. Would a simple voltage divider between pre and power amp work? Could I implement a dual gang pot into the aca?
I should note I will be using a newer Audio Technica turntable into the phono preamp kit into the ACAs into some vintage "acoustic" bookshelfs. My assumption is that between the preamp and ACAs I could get away with a buffer with attenuation pot somewhere down the line, no need for an active gain stage with volume pot.
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Old 15th March 2014, 12:21 PM   #1729
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I've one for sale
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Old 16th March 2014, 05:15 PM   #1730
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Default IRF640 substitute

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Originally Posted by Loudthud View Post
. My latest build (#6) has a pair of IRF520s. They have a flatter distortion at 1W graph.
Have a bunch of IRF640's as well as tube of 240's. Have you tried the640's??
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