Why not trying it the way it is ? Then you decide if an " upgrade" is nescessary.
It seems you take for granted it is just a toy.
Good luck to those who want to " upgrade" NP's conceptions. May be you should go straight to a F....
I'm in the try it before you make changes camp. It's a good little amp as it is.
The thread on building the amp with premium parts is interesting and I do believe you can squeeze more out of it. But if you build the amp with the upgraded parts it becomes almost as expensive as building one of the other firstwatt/pass amps. Several of the long time posters here have suggested that the other amps probably exceed even the premium ACA run as a pair.
I'm no expert on any of this but will gladly heed the advice of folks who have a lot of experience.
Based on the sound of the ACA I'm looking forward to building one of the other amps in the future. It's the perfect gateway drug into class A solid state ...
Post #67 detailed a super simple possible non invasive solution to the noise issues:
A possible approach to adding a silent start/shutdown to the ACA
Why not use a red or orange LED at low current to give a soft glow.
While I agree with Macfixer - my ACAs are plain vanilla and work just great - you might get some thoughts from this post:
ACA amp with premium parts
I have used a 24vDC PSU instead of the 19vDC and I have changed the DC operating point to 12vDC without problems.
The power change is noticeable especially with planar magnetic headphones type Audeze. That peak power is especially palpable in the bass.
I still need a Loop Ground Breaker connected to the IEC ground so that the amplifier is totally silent.
As for the temperature, it is increased to 60 ° C (ambient temperature 28 ° C). I think I'm going to opt for a box with heatsinks larger than the originals.
The power change is noticeable especially with planar magnetic headphones type Audeze. That peak power is especially palpable in the bass.
I still need a Loop Ground Breaker connected to the IEC ground so that the amplifier is totally silent.
As for the temperature, it is increased to 60 ° C (ambient temperature 28 ° C). I think I'm going to opt for a box with heatsinks larger than the originals.
It's simple:
R13 (a 10k resistor in the kit) limits the voltage to the LED. Instead use a 30k resistor or thereabouts, and it won't be anywhere as bright! Perhaps even a higher value would still work. Try it and get back to us please. LED's keep getting more efficient so that has caused this problem. The LED has no functional role so it's fine to disconnect it. Don't reconnect the 10k resistor to ground, just let it float.
R13 (a 10k resistor in the kit) limits the voltage to the LED. Instead use a 30k resistor or thereabouts, and it won't be anywhere as bright! Perhaps even a higher value would still work. Try it and get back to us please. LED's keep getting more efficient so that has caused this problem. The LED has no functional role so it's fine to disconnect it. Don't reconnect the 10k resistor to ground, just let it float.
Thanks for the link. Interesting reading at least and maybe I'm brave enough to try something
I will try something like this or using a different color as Mooly suggests. I'm wondering if would be feasible to buy/wind a small electromagnet which would retract a spring-loaded slug that fit into the LED mounting hole.
Hmm, something like this maybe:
DSTL-0418-06 Delta Electronics | Motors, Solenoids, Driver Boards/Modules | DigiKey
Built one ACA in December as a stop gap for my broken Valve amp which was defying diagnosis at the time. The case for my second one arrived today - Parcel tracking from Italy to New Zealand is fun - Fedex are the muts nuts. DHL and NZ Courier post not so much your parcel get's tracked so far then just disappears for week or more. :-( Looking forward to building a second one and driving the pair from XLR outputs from Cambridge DAC magic.
ACA and Wharfedale 10.1?
I have a small office system that typically involves the use of vintage Pioneer SX series receivers. I am curious if a pair of ACA would sufficiently drive the Wharfedale 10.1 speakers. They do not seem like the best choice with nominal impedance of 6ohm and 86db sensitivity. Any opinions here? Sure looks like you guys are having fun with these amps..
I have a small office system that typically involves the use of vintage Pioneer SX series receivers. I am curious if a pair of ACA would sufficiently drive the Wharfedale 10.1 speakers. They do not seem like the best choice with nominal impedance of 6ohm and 86db sensitivity. Any opinions here? Sure looks like you guys are having fun with these amps..
I have a pair of bookshelf speakers in my office that probably have similar sensitivity. I bi-amped them through a miniDSP device and it was plenty loud for me.
there are two resistors in feedback net (observe which one is second one )
to preserve CLG as is , you need to keep ratio of them
so , if you change input ( series) resistor from 10 to 50K , you need to change other one also......
try; if you get lousy highs , back up
or - even better - go to 25K , border value for my gut
if that's not enough - use better tube preamp
I hate preamps with no cojones
)to preserve CLG as is , you need to keep ratio of them
so , if you change input ( series) resistor from 10 to 50K , you need to change other one also......
try; if you get lousy highs , back up
or - even better - go to 25K , border value for my gut
if that's not enough - use better tube preamp
I hate preamps with no cojones
I hadn't soldered for decades prior to the ACA. I did one or two practice components, then jumped straight in.
Mrs Batty will do just great, I'm sure..
