nice results, I'm looking forward to building mine

 

Might skimp on the power supply though to get it to fit in a smaller case. Thinking about just P2P-ing the KGSSHV LV supply

 

If someone has the regulated krell supply I would be willing to purchase that, good size

Edited May 8, 201511 yr by nopants

Plenty of 7815/7915 supplies on ebay.  Just replace the caps as they are probably fake. 

birgir always delivers

 

http://www.ebay.com/itm/POWER-ONE-HAD15-4-AG-Linear-Supplies-100-VAC-to-264-VAC-15-VDC-LS2-/251792767872?pt=LH_DefaultDomain_0&hash=item3aa004bb80

 

the long lost twin of the stax psu's lv supply

 

also 

http://www.ebay.com/itm/POWER-ONE-Power-Supplies-lot-of-4-/151675134365?pt=LH_DefaultDomain_0&hash=item23508ae19d

 

mouser lists these at 71 a pop??

Edited May 9, 201511 yr by nopants

use plenty of heatsinking... 320ma on each

 

it should be noted that the distortion figures above

are unbalanced in, unbalanced out.

 

balanced out reduces the second harmonic by about 6db

resulting in a thd of less than .002%

 

at these levels its silly and very expensive to go any further.

 

singlepower squarewave into 50 ohms is .055%

(no matter what Mikhail said, never designed to drive 50 ohms)

Edited May 9, 201511 yr by kevin gilmore

I have a 49.9 Ohm 120W 1% Dale resistor as per:-

 

http://www.mouser.com/ProductDetail/Vishay/RE80G49R9J01/?qs=%2fha2pyFaduhhfrsghxysLXiUQh20YutnwBgHPOs6mFo%3d

that is slightly excessive, plus its not in stock.

building up a parts order now.

getting tired of $5 in parts and $7.50 in shipping

Use their economy shipping (Mouser). I just placed a small order on Wednesday and got it today ($4.99 shipping).

 

BTW, mounting my multiamp on a piece of veneered plywood for now. Any recs for a fuse? I have a 2A fast blow in right now, no issues, but seems a bit high?

Edited May 9, 201511 yr by Pars

I use a 750mA slow-blow, as recommended for 115V use in the haa15 power supply documentation (fuse is Mouser part 576-0239.750TXP). Works well.

I found the sola equivalent of the power one supply for 18 usd on ebay, http://www.mouser.com/ProductDetail/Sola-Hevi-Duty/SLD-12-1010-12T/?qs=Fhl5NpiNeCWhwKaPb%252bAczA%3D%3D

 

1.62" for those who are height conscious

 

Are MPSA parts still good for this? I was looking at some of the silkscreens and MPSA became MPSW at some point

Edited May 10, 201511 yr by nopants

the mpsa parts cannot handle the 1W for the output devices.

everywhere else they are ok.

same silicon, smaller package

If anyone is interested in two 12V supplies to build this in a dual-mono configuration, I have 2x power one  HTAA-16A-A supplies

 

-/+12V @ 400mA

I was reading some threads on diyAudio, and found this power supply: http://www.diyinhk.com/shop/audio-kits/50-17uv-ultralow-noise-dac-power-supply-regulator-1215v-1a.html

 

In +/-15V mode, it seems like it should power the Dynalo well enough. It should also be quite a bit smaller than the power one haa15 units, even factoring in the size of the transformer. (And this gives the option of using a nicer transformer that doesn't hum.)

 

Has anyone heard anything about diyinhk? Any thoughts on whether this PSU is any good?

That's what I used for swapping out the switching supply in the lavry da11. It's ok but as someone else mentioned the negative regulator just regulates ground, if that matteres to you.

gepardcv, haven't measured it myself, but this supply -despite what they say about it- is very noisy.

Some have experienced this at DIYAudio.

Personally, I wouldn't dare.

Is the hum from the premade supplies a real issue?

you really want to use the dual linear supply, or something like amb's supply.

Works much better at 16+ volts

Is the hum from the premade supplies a real issue?

 

I can hear a slight hum in a quiet room, assuming there isn't much noise coming in from open windows, nearby refrigerators, fans, or other noisemakers. Can't hear it with music playing, of course. It might bother other people less, but it bothers me just enough that if I build another one of these, I will definitely not use a Power-One unit. They are nice enough, but probably not intended for audio. I was thinking of making a Dynalo for a friend (I certainly like the amp enough to want to share), and would not feel comfortable with the result if it buzzes.

 

Thanks for the comments and advice, everyone. I'll look into the sigma22.

Edited May 13, 201511 yr by gepardcv

You can consider other things like super regulators or shunt regulators if you're that concerned. Might be interesting to see what the differences are.

 

Kevin gave the current draw so it's pretty easy to dial in a shunt regulator. I have Salas Boards if you're interested.

 

Diyaudio's store has the Super Regulator back in stock, I picked up a few boards.

there is no hum whatsoever in either of mine, but I'm using power supplies that

are probably 15 years old.

 

most of it I would expect is radiation from the transformer.

 

so with a really good torroid, you should be able to make it absolutely quiet.

Is there a way to convert to TRS from 4-pin XLR from this amplifier if it's always putting out balanced drive? Didn't really seem obvious to me without installing a BAL/SE switch

Don't know what you'd do about the ground sleeve contact on TRS when connected to 4-pin XLR. I just added two Neutrik hybrid jacks (http://www.neutrik.com/en/xlr/combo-i-series/ncj6fi-s), and their TRS outputs work.

The problem with that is that you need a breakout cable to go from 2x3pin to 4 pin...maybe it makes sense just to have a 5 pin at the amplifier and make dedicated breakout cables for everything?

Yes, yes it does. Welcome to the Team!

oh that's what your posts have been talking about this whole time? damn I feel like I solved a mystery

so I guess there are either mini 5 pin xlrs or lemo connectors as the normal choices

Edited May 14, 201511 yr by nopants

Is this amp powerful enough to drive vintage orthos, insensitive beasts - often heavily damped as well - that crave current?