My KT120 / M-125's

And the winner is, the 4ohm tap. On my speakers the bass resolution is a lot better on this tap, the 8ohm tap results in a loose and boomy bass. There is no difference in hum level, still 3,5mV on cold power transformers. It rises to 5mV when the amps have been playing for a couple of hours and have reached there top temperature.

Cerakote is a hardened coating popular in the firearms industry. It requires baking the components that were painted and it's supposed to be a durable finish...I may give it a try on an aluminum amp chassis I am finishing. Cerakote works on aluminum, steel and plastic according to the web site. You just don't bake the plastic.

Beautiful job...you certainly are talented.

Absolutely beautiful ! You obviously know what you're doing .

Are those Nelson Pass slot loaded open baffles ( SLOBs ) for bass ? Stunning !

Thanks  The subs are open baffle but I would describe them as a
cross between the subs fro Audio Artistry "beethoven" and the "ripole"
project. Most likely one of the most cost ineffective ways to achive
true subsonic output. They run of a pair of "Hypex ucd2K" amps
@ 16ohm. 1,5kw and some serious amount of dipole compensation.
It sounds great and it's getting even better (I belive) from a total
rebuild of the digital xo/dsp system. I'm leaving dsp (iir) and instead
I'm going for a pc based (fir) filter solution from "Acourate" and some
new hardware on the computer side. It has been quite a mouthfull and
then some, but I'm slowly getting there.

The amps sound great, now I'm running new Sovtek 12au7 tubes on both
positions, not absolutely sure what I like most so I might try the cleartops
again in the first position.

Your system is certainly looking absolutely like the best anyone could ever yearn for . I guess the Accourate solutin provides x-over frequencies, phase correction and levels . Where you using mini-dsp before ?

12au7's are definitely one of my favourites in this configuration . Along with E182CC and 6N6P ( both require re-wiring ) .

Thanks for sharing your experience with us .

"Acourate" does it all. XO, linear phase (fir) filters, driver linearization,
time delay, room correction and so on... I'm still using the "Najda" dsp
that actually works great.    On the other hand I believe that for going
to the next level of performance, linear phase filters is where I will
get the highest payoff. The number of "taps" I will need is not
available in any dsp chip of today so therefore the pc solution.

I also like the 6n6p and I'm using them in two of my output dac buffers, together with 6n30p.

Acourate

A tutorial

The other half

Very interesting , I briefly gleaned over " the other half " , I'll look at it all properly this weekend , when I have some time . And look at your site too .

Thanks again !

The site hasn't been updated in ages and the diy articel on the ribbon driver
could also need some adjustments.
At some time there will at least be some more up to date pictures in the "Diy gallery",
these ones are at least 10 years old.

Dahlberg wrote:The site hasn't been updated in ages   and the diy articel on the ribbon driver
could also need some adjustments.
At some time there will at least be some more up to date pictures in the "Diy gallery",
these ones are at least 10 years old.

Just wanted to drop a line to say you did a stupendous job in assembling these 125's not to mention the artistic design you encased them in with that beautiful wood.
Good tools...absolutely, talent no doubt!

Good job and thanks for posting pictures.
blue

Thanks.  
For now the tungsol 12au7 input tubes will be left in place, they deliver a solid
performance and are (almost) dead quite when they schould be.
Got a mail that there is some parts I have been missing on the way for the dsp project today        
On the other hand it's almost summer  and time for barbecue and beers soo....

Dahlberg wrote:I could not help myself so I had to see how it looked with tubes in place. It turns out a bit lighter on camera then it looks.  

Hi There! I love what you did with the M-125 Amps! I'm putting mine together right now. I was wondering where you sourced the Circuit Card Cover?? I could sure use a couple. The really finish off the Amp quite nicely. Can you point me in the right direction or reproduce for purchase??

Thanks!

Well now summer is almost over so... Sorry but I can't help out
with the pcb covers, maybe someone else on this site has the
possibility ? Why not ask again in a separate thread ?
In retrospect I would have liked a consept with just a top plate
ment for wood frame mounting to start with (and a pcb cover).

Usually I don't like the wood frame/metal plate chassis but the red transformer bell covers and PCB plate makes your amp look very nice.

Thanks, I'm waiting for a set of "Audyn cap-true copper 0,22uf " to try in place of the K40's. Will see how that turns out.

So finally I got some time to mount the "Audyn true copper max" capasitors, great succes
These are some really nice coupling caps. Nice warm tone and still very open in character.
A bit difficoult to work with though, conections are litz wire that doesn't fit directly to the
pcb solder hole diameters.

Ok, so now I have tried the "gz-37 rectifiers as well. I wouldn't say that it was a "slam dunk"
but it wasn't that far of... I lost some definition in the bottom but the level of presence and musical
involvement I have right now is just

Strange experience the last couple of days. I had a plan to sell the amps to get some funds back from other projects that didn't pan out as expected. So since I have a pair of "Yamaha T-5n" amplifiers that have been used in bridged mode for the subwoofers I thought I could use those amps in stereo mode. One channel for sub and the other to replace the m-125's in midbass. So all in place and levels adjusted I started to listen to some familiar records. First impression was that there was additional "control" and a bit more resolution on subtile notes and background vocals, bass response was "dry" and a bit "cautious", but missing a bit of the "flow" I have liked so much with the M-125's. Vocals had also lost some lower midrange so they seemed a bit thinner. It didn't sound bad at all and you might say that in some aspects it was better with the "Yamaha's". The strange thing was that it at the same time went from fun and interessting to listen, to if not "flat out boring" then at least in that direction.  And all of this just replacing amps used at 70-350hz.

So the sale is off and I'm keeping the amps