Soundhappy, as I know ACA does not need a preamp with gain to be driven to max power. I for myself was listening to it with a B1 in front of for a long time and I did like it. If I hadn't burned the B1 (Salas type with shunt reg) I would still use it.This Diyers have build sucessfuly BA-3 for F5 who have ~ 15 dB of gain.
Why BA-3 is too much for ACA with ~ 10 dB inside gain of the amplifier
Pass BA-3 Preamplifier - Audio Society of Minnesota
Later I discovered, that a bit of gain made it even better for me.
Means, at least for me, if no gain is needed, a lot of gain might be too much. You then only can kill gain by some resistance in order to listen to normal levels.
What I had not taken into account is, that one can reduce BA-3 FE gain to lower levels.
So of course one might use it, even ZM has brought the new for me word constipated into the game.
Cheers, Ernst
I do have similar experience with Diy M2 amp gain=15dB.
Your ACA is the first 14 dB version no doubt.
I can use passive AVC , audio source = 2V without active preamplifier.
My speakers are 98 dB efficiency.
With less efficient speakers 88 dB I do need active preamp imho.
New ACA 1.5 have only 10 dB of gain....
Anyway BA-3 is not constipated by the feedback loop
Your ACA is the first 14 dB version no doubt.
I can use passive AVC , audio source = 2V without active preamplifier.
My speakers are 98 dB efficiency.
With less efficient speakers 88 dB I do need active preamp imho.
New ACA 1.5 have only 10 dB of gain....
Anyway BA-3 is not constipated by the feedback loop
I do have similar experience with Diy M2 amp gain=15dB.
Your ACA is the first 14 dB version no doubt.
I can use passive AVC , audio source = 2V without active preamplifier.
My speakers are 98 dB efficiency.
With less efficient speakers 88 dB I do need active preamp imho.
New ACA 1.5 have only 10 dB of gain....
Anyway BA-3 is not constipated by the feedback loop
R12 is around 68K on the latest diagram; 39.2K on the original diagram. New ACA can only have more gain, not less...
How much of dB ?
You can verify by youself on the left ACA V1.0 on the right side new ACA 1.6
source : http://www.firstwatt.com/pdf/art_amp_camp_1.pdf
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Help with choosing subwoofer amplifier to companion ACA
Like a child on Christmas morning just received one of my two chassis go to ACA 1.6 sitting on top of my original amp camp amp chassis I modified from a old mini computer chassis and just attached heat sinks to that side of it.
Been using the Krong tube as a preamplifier along with comparison the DarkVoice 336 SE and IFI micro Black Label as preamp.
It appears if you wanted to you could mount the Krong PCB inside the chassis of the amp camp amp.
Even the original Amp Camp Amp 1b PCB pictured below is more than enough power then you can comfortably listen to with the BK-20 Fostex speaker cabinet kit using them Fostex FE206En drivers. I will use my original ACA 1b. To drive the tweeters Fostex T90A ( that’s just for the family members who can hear both 15K+ , my hearing starts rolling off at 12k and stone cold death after 15K.) and the new 1.6v ACA to drive the Fostex FE206En Full range. Now just need to build a amp for the subs.
Somebody with experience any recommendations for a subwoofer amplifier, maybe (Honey badger, F5 or F6 Turbo?.) For now will be driving two 12 inch subs.
Like a child on Christmas morning just received one of my two chassis go to ACA 1.6 sitting on top of my original amp camp amp chassis I modified from a old mini computer chassis and just attached heat sinks to that side of it.
Been using the Krong tube as a preamplifier along with comparison the DarkVoice 336 SE and IFI micro Black Label as preamp.
It appears if you wanted to you could mount the Krong PCB inside the chassis of the amp camp amp.
Even the original Amp Camp Amp 1b PCB pictured below is more than enough power then you can comfortably listen to with the BK-20 Fostex speaker cabinet kit using them Fostex FE206En drivers. I will use my original ACA 1b. To drive the tweeters Fostex T90A ( that’s just for the family members who can hear both 15K+ , my hearing starts rolling off at 12k and stone cold death after 15K.) and the new 1.6v ACA to drive the Fostex FE206En Full range. Now just need to build a amp for the subs.
Somebody with experience any recommendations for a subwoofer amplifier, maybe (Honey badger, F5 or F6 Turbo?.) For now will be driving two 12 inch subs.
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It was probably the B1 using the Korg Triode referred to here, as this B1 has some gain. See post Amp Camp Amp - ACA - it looks like a kit is on the distant horizon.
I am currently running my ACA with a B1, but found (like others here) that the ACA really shines with an active preamp. I think this B1 with the Korg could make a great pre for the ACA, and would be great if someone can report on how well they pair.
PS: Spencer - sorry, my post was shortly after yours - I did not see that.
I also see now that ThermalAlchemy's preamp is a Pete Millet Korg preamp. Wonder how that drives the ACA?
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Sorry (Korg NuTube) I was driving and using voice to text when I made post. Definitely Get the tube sound. I only get it ringing if you tap on the case.
Everything I have read suggests the Millet Nutube preamp is incredibly microphonic. Makes me wonder whether Millet got an early batch that happened to be microphonic. Or are the Nutubes inherently microphonic?
Yes I’ve read a lot of articles people talking about then being microphonic . As far as I’ve been able to tell the only thing that gets my in particular pair to ring is if I do tap on them they were ring for several seconds. Probably if you set a coffee Cup down right next to the unit if it was sitting on the same table it may pick up the bump and turn into a slight ring and if you place the unit directly on top of the speaker with loud music I could see that being a problem to but most of us have them on their own stand so I have experience no problem with Microphonics it’s in normal operating conditions.
If the new tube PCB was mounted inside the amp camp and you could throw a headphone jack in the front and use it as an optional preamp for the amp camp amp set up a system so you can turn it on or off using the new tube or only using the amp camp and depending on the sound signature that you desire for a particular set of speakers or recording you’re listening to .
Can't say from experience but if the OEM's info is any guide:
Guide | Nutube – English
I reckon that there's every chance that an issue is likely, when Korg are offering one suggestion to place a lead brick on top of the thing to keep it quiet.
Amp Camp Amp V1.6 - RCA Monoblocks
Hi,
Sorry if this is a dumb question. I purchased two ACA V1.6 kits with the intent on having two 15 watt monoblocks. I currently have a non-balanced preamp, so I need to do the workaround shown in the build guide (Steps 46 and 47). I am a complete noob. Here are my questions:
1. It is noted in the build guide to “Take the extra 68K resistors from the kit and parallel them to make a 34K resistor. (if you'd like to be super precise, use a 39K for the ideal tuning”. I’d like to be super precise, can anyone suggest a good 39k resistor and retailer, hopefully American made?
2. Are there any other parts that anyone would recommend that would improve the amp?
3. Does anyone know if all of the other parts needed to do this (outside the 39k resistors) are included in the kit?
Sorry if I posted this in the wrong spot. Thanks in advance for all of your help.
Jim.
Hi,
Sorry if this is a dumb question. I purchased two ACA V1.6 kits with the intent on having two 15 watt monoblocks. I currently have a non-balanced preamp, so I need to do the workaround shown in the build guide (Steps 46 and 47). I am a complete noob. Here are my questions:
1. It is noted in the build guide to “Take the extra 68K resistors from the kit and parallel them to make a 34K resistor. (if you'd like to be super precise, use a 39K for the ideal tuning”. I’d like to be super precise, can anyone suggest a good 39k resistor and retailer, hopefully American made?
2. Are there any other parts that anyone would recommend that would improve the amp?
3. Does anyone know if all of the other parts needed to do this (outside the 39k resistors) are included in the kit?
Sorry if I posted this in the wrong spot. Thanks in advance for all of your help.
Jim.
39K
Here is a place that has them and will match two for you.
39K Ohm Mills 12 watt MRA-12, Sonic Craft
Hope this helps!
Here is a place that has them and will match two for you.
39K Ohm Mills 12 watt MRA-12, Sonic Craft
Hope this helps!
tjw59 (and others):
The Mills 12 watt resistors you recommended are $6.00 apiece. Soniccraft also sells PRP 1 watt 39k resistors for $0.65. Are high wattage resistors needed for connecting two ACA boards into a bridged amp and, if so, what is the formula for determining the proper wattage?
Regards,
Scott