so how does it sound with hd800,lcd? etc...

 

 

really people should build it with xlr jacks on the input, then if necessary use the

neutrik rca to xlr adapters.

 

I'm finishing my second one now, first time I have ever built more than one of the

exact same item. Someone swiped my first one, and the chances of getting that back

are pretty close to nil.

 

part number of the power switch please.

 

need to do a group buy of 4 deck rk27 10kohm...

 

you did remember to remove the jumpers on the power supply board right??

Edited September 27, 201411 yr by kevin gilmore

I've got another section of Canare L4E6S ordered so I can wire up a balanced cable. Single ended it sounds pretty good with LCD2, maybe seems a bit bright. I'll need to double blind with the KSA5 to see if it's just me. I'll take your advice and swap to balanced input at some point.

Switch is from ebay here: http://www.ebay.com/itm/151028998690

Jumpers? I added two for the sense right at the unit....is there one that comes off? Voltage is a little low, 13.3 is what I'm getting out of it now.

I'd be in for a 4deck 10K if the price is reasonable.

Dooooooh, that's what I get for not reading the fine print on the chassis. Thanks!

you did remember to remove the jumpers on the power supply board right??

Ok, snipped the jumpers and re-cal'd the boards. Much better.

--------

Been listening to this for a few hours now....definitely rocks.

--------

Something about this amp I just like......

Edited September 30, 201411 yr by GrindingThud

Balanced output is pretty nice, drives LCD-2.2 very well.

I felt like YELLO:

Edited October 2, 201411 yr by GrindingThud

Just wondering to myself if this would be a significant upgrade to my Dynalo (single-ended, built on a Headamp Dynamic V2 circuit board from when Justin also sold boards).

 

Would a single sigma22 be an appropriate PSU for this?

 

Does anyone still have boards for this? It would appear I would need a pair of amp pcbs? I think I still have enough Toshiba sand around to do one, but could also go with the currently available stuff from Mouser if need be (and the right boards)

 

I do have a dynahi (also SE) built up, but have never finished the casing for it.

Edited October 5, 201411 yr by Pars

I am really liking this amp. (I am possibly biased, usually into class A)

Simple and effective. These boards are for all Motorola parts.

each board is 300ma, so I think a sigma22 would work fine.

Soldered in the CCS adjustment yesterday and fired up the boards for the first time. Initial offsets very minimal, could have worked fine without any trimpot adjustments.

 

 

 

I have also stuffed the digital attenuator boards but have not tried them out yet.

 

Next up is to build and test the ubal to bal boards next weekend, now that I have all the parts.

Just to clarify, is the amp board for this the one at http://gilmore.chem.northwestern.edu/boards/kgdynalobal5.zip?

yep

Great, thank you!

 

Another question: do you recommend using a muting circuit like the AMB ε12?

that circuit flat out does not work for balanced amplifiers

especially with dacs that have output dc.

 

 

you want this

 

http://gilmore.chem.northwestern.edu/boards/protect3.zip

Got it, thanks! On the protect3 circuit, I assume the +VCC and -VCC labels are the two rails from the PSU, right? Is there a specific voltage this circuit is happiest with?

 

On a related note, the silkscreen for the amp boards says 20V, but the schematic says 15 or 20. I assume this means either will work regardless of the silkscreen label? Also, any power supply recommendations other than the sigma22? I'm not sure my electrical engineering skills are up to the task of scaling down the dynahipower5, plus I don't really want to deal with external heatsinks.

anything >+/-12 and < +/-35

 

the amp works fine with 15v or 20v power supplies

 

i am using the power one linears, in 15v mode they

typically can be turned up to 16.5 which works fine

and you can't build anything for the price of those.

or in a bigger box you can buy the 20V units

(24v, turn down to 20)

board version with surface mount outputs is done, just

need to verify.

people with current boards should buy mpsw06/mpsw56 now

Volume pot question: I have a couple of TKD 50k quads on order, which I planned to use for a KGST build (and maybe a KGSSHV). Would that work for this amp, or should I try to find a 10k quad?

Low input impedance amp.

 

10k quad is best.

There was a guy on ebay selling them, but I cleaned him out.

And I need more.

 

Group buy thru partsconnexion is 100 pieces minimum.

Which is stupid.

How about this:

http://www.ebay.com/itm/ALPS-Quad-Potentiometer-RK27114-blue-velvet-10K-Pots-logarithmic-10KDx4-log-/351222293299?pt=LH_DefaultDomain_0&hash=item51c67ae333

If that looks workable, please don't clean this guy out, leave two for me.

I would go for something slightly nicer if you're already going to pay 40, why not a black beauty or noble pot

The problem with that one is that it is incompatible with the way I make my knobs.

 

The same guy had the standard shaft model which is what I cleaned him out of.

 

would love quad black beauty or quad noble pot.

 

new goldpt 47 position quad pot is over $450

might as well buy a P&G

can  you combine decks to make a quad black beauty, I think I have 2 stereos lying around

Edited November 28, 201411 yr by nopants

Kevin will get some TKD's soon as I get my stash shipped from Japan.  The 4CP-601 is only about 5000Yen...

Looking at the protect3 board more closely: Mouser has (what seem to be the correct) 7812 and 7912 parts, but both have heatsink attachment points. There doesn't seem to be a lot of room on the board between the part and the 100uF caps for a heatsink. Is one really necessary? Any hints on which ones to get here?

does not need heatsinks. very low power.

While I wait for my boards and volume pots to arrive, another question occurred to me. What's the stock gain on this amp? I prefer low gain, since I don't listen to my music very loud, and I like to be able to plug in sensitive IEMs at my desk sometimes. What's the best way to adjust it down if it's relatively high?

6db unbalanced

12db balanced