I appreciate all of the praise for my build of a wonderfully designed and superb sounding amplifier . Hard to step away from the music.
I'm always late to the party. Excited to get started though...
Never tried ClassA having been a tube or hybrid devotee up to now. I'm going to do a 4ohm build for my near field KEF LS50 Metas and start with some surplus Meanwell SMPS and 1.6A bias to start. Thinking 4 CPU coolers should give me heatsinking options if I need to up the bias.
Never tried ClassA having been a tube or hybrid devotee up to now. I'm going to do a 4ohm build for my near field KEF LS50 Metas and start with some surplus Meanwell SMPS and 1.6A bias to start. Thinking 4 CPU coolers should give me heatsinking options if I need to up the bias.
Simon, good luck with your build. Not too difficult, but not a small project either.......
Hugh
Hugh
Why degrade what the AN 4R is capable of by using SMPSs, rather than the specially-designed 'SLB' PSs?
Also, my AN4Rs are biased at 3a ... not sure 1.6a is going to work (well) for the 4R version? (8R version is biased at 1.6/1.7a.)
I happen to have 4x Dell FD841 CPU coolers available, if you can't find any. Also 4x Noctua NF-A9-14 80mm, slim-line PWM fans, if you're interested. (I initially built my 2x AN 4Rs with active cooling but am re-housing them in 5RU chassis as the noise of 4 fans was just a bit too much for me. 🙁 )
Andy
Hi Andy, I've never tried a class A solid state amp before, I'm not sure if it's going to be my flavour, so when I say "to start" it's just a starting point to get a feel for it without committing a ton of money, the low bias , again is to start because I don't have enough heatsinking to cope with 3A...yet. The smps were free, a 600VA linear PSU with ripple eaters (that is too low voltage to use on anything else) certainly isn't!
Thank you for the offer of the coolers and fans. I've done a bit of digging into this; I'm mindful the PC world and audio world have very different agendas! Bigger is quieter for a given displacement, as you can run the fans slower, but a lot of fans will stall much below 800rpm. I'm looking at least 120mm fans close coupled to a cooler, that will run at very low RPM. SilentiumPC make some cooler fans that work down to very low RPM. Of course your dissipation drops accordingly, it's difficult to get good data on how they perform in that condition too.
I do hear what you say though, if I like where the amp is coming from, then a linear PSU and 5U case might well go on my shopping list 🙂
Noctua fans can be run slow and they are inaudible without stalling. They do make the amp heatsink much more compact. There is something to be said for simplicity of a passive radiator though.
I am seriously considering putting my AN in this new custom chassis I designed for another amp. All CNC’d aluminum satin bead blasted and black anodized finish. 23lbs empty. 🙂
I think it’s just enough heatsink area at 300mm deep and 155mm tall. About same as my 4U x 300mm case that I have now.
I am getting new corner pieces that will be hollowed out to provide an integral handle to grip the amp to pull it out of a rack or shelf.
Two 45mm analog VU meters on the front.
I am seriously considering putting my AN in this new custom chassis I designed for another amp. All CNC’d aluminum satin bead blasted and black anodized finish. 23lbs empty. 🙂
I think it’s just enough heatsink area at 300mm deep and 155mm tall. About same as my 4U x 300mm case that I have now.
I am getting new corner pieces that will be hollowed out to provide an integral handle to grip the amp to pull it out of a rack or shelf.
Two 45mm analog VU meters on the front.
Last edited:
Fantastic looking enclosure X! Some amps (like people) live in more luxury apartments than others. I have joined the movement to passive enclosures – busy re-housing my AN to a diy basic enclosure, not worthy of photos. Hope to get it up and running this weekend but I bet it will sound as good as the one in the fancy enclosure.
Thanks guys! I like the luxury apartment analogy. LOL
This was designed for a series production and so I get to play with pre-production samples. One of the perks of being the designer and verification builder. The economics of mass production helps a lot.
This was designed for a series production and so I get to play with pre-production samples. One of the perks of being the designer and verification builder. The economics of mass production helps a lot.
I am thinking this chassis is going to work out swell. I have a pair of custom 200VA 23v trafos. They have auxiliary 12v winding as well for accessories. The All Cee’s PSU normally used for Class AB, if fitted with 15,000uF 35v high ripple current caps will work nicely. Changing to a 10W 0.33R axial resistor will handle the R of the CRC nicely. The GBJ 25A rectifier will be underhung and bolted to the 5mm thick aluminum baseplate. I think this will give me +/-29v under Class A load. Should be good for solid 40w of Class A power. Dual mono in single chassis. 😎
I have the VU meters, the binding posts, the RCAs, the EIC, the front panel power switch - which I will need to see how that’s going to control the on/off. I do have an SFP with remote enable.
I have the VU meters, the binding posts, the RCAs, the EIC, the front panel power switch - which I will need to see how that’s going to control the on/off. I do have an SFP with remote enable.
Last edited:
The outside is fully populated. Now I just need to fill the inside with a PSU and an amp. 🙂
Last edited:
Thanks, Hugh! I have choice of Alpha 20 or Alpha Nirvana. I think I will pick the latter since I have one that’s currently running but in Modushop 4Ux300mm chassis. It might be right on the edge of max temps but won’t know until I try it.
New milled out hollow handles for the amp arrived. Fit perfectly. Finally a place to grip the amp without putting fingers on the heatsink fins.
Waiting for PSU caps to arrive and assembly can begin.
Four 15,000uF caps for 60,000uF per channel with 0.33R CRC. My estimates predict about 25mV ripple under 1.5A Class A load. We will see. That 13W Dale 0.33R resistor will dissipate 7W. 120,000uF total bulk capacitance for the whole amp since dual mono. The All Cee’s PSU PCB was designed for Class AB but I have adapted it here to be a nice Class A supply I think.
The PSU works with 23vac trafo. With 120vac mains I am getting 35vdc. This might be a bit high even under Class A load.
