The Truth about the M125 Mono Blocks from a novice

So, let me start by giving you a quote I gave Bob in my first email:

"I have little confidence these amps will actually work"

Why? I am a complete novice and have not built anything electrical of this nature.

My first M125 build was tough for me ..

However, that being said, it is not impossible either, and a complete novice, with patience and upfront understanding of the level of effort required, can COMFORTABLY build these amps.

Build Time: 1st amp - 20 hours, 2nd amp - 10 (maybe 12) hours. Much better on the second amp... experience, even a little, on soldering will help. 80% of your build time is soldering.... get an old radio and solder the bejessus out of it. Also, get TWO 30 watt soldering pencils, my biggest mistake was not moving over to a new iron when my soldering got messy and ugly.

I finished my two block build in about 7 days, including pretty much solid over a weekend. I wish I had taken it slower... enjoyed the journey more. Biggest piece of advice if you are not a regular DIY electronics builder... SLOW DOWN, GO SLOW.

Now, to my amazement, shock and AWE, BOTH of these amp fired up FIRST TIME and worked prefectly! Eating my words above! :0)

As to the sound/quality/performance
- The amps have been playing for 2 hours, so expect they will improve as everything 'settles in'
- Cannot perceive much difference in triode mode?
- The bass is much 'bigger' and much more noticeable. That's not to say it is boomey, or overpowering, but it is much fuller than on SS apms used before.
- The stage width has DOUBLED - wow !, that's maybe the best part so far
- Where as my previous amps distorted and failed when I pushed the volume to max, the M125 did not even flinch, no distortion... just DAMN loud !
- Lastly, I drive directly from Wadia 21 to the amps and with no CD playing and volume on MAX, there is NO HUM, NOTHING... and I mean NOTHING, ear right up to the ribbons/cones... NOTHING... that's very nice, and certainly NO REFLECTION on the builders ability.. :0)

All in all, I wanted tube mono's above 100w, and these for the price and 140w+ with KT120, are great.

Would I recommend them? YES... just know what your getting into and be PATIENT.

System:
Wadia 21
Carver AL III
M 125 Monoblocks (WZ68/KT120x4)

Shaun,

Thanks for your review. Got any pictures?????

I just finished a rebuild of an ST70, and I love it. I'll have to wait a while before upgrading to these though. Summertime is bleeding money time for me-vacations, etc.....

It's nice to see amps rated CORRECTLY. I say that because many cheap amps are rated some weird way. This is why quality gear (in anything, electronics, cars, tools, etc.) always performs so much better. It's rated to a real standard, and not something arbitrary that makes it look good for the few seconds it can perform at that level. Fuze your speakers with that much power.....At least the tweeters.

Congrats. Especially for a novice. I don't solder much, but have soldered for 30 years or so, and am good at that. And worked on old radios. So I thought rebuilding was a breeze, but I took my time, and it took probably 10-12 hours or so (probably underestimation) for the ST70, so your time seems fine to me. Look at it this way, if it should have took 20 hours, and you pay yourself $100/hr, that's $2000!!!!!! That's probably the most you made in 20 hours in a long time, it is for me......

You done good.....

Jason

Thanks for that review, and congratulations on completing the build. I what way do you feel "underwhelmed" can you elaborate? Do you not feel there is equal detail to the previous SS amps? I'm not very familiar with the M125's is there a 4ohm hookup on them?

I think you are running KT120... What other tubes are you running. What kind of coupling caps are you running? The Russian PIOs?

Hi, I decided on 4ohm hookup as the Carver AL III and the Apogee Duetta Sig's I have coming both suggested 4ohm to 200 watts odd on the amps.

The M125's when I first listened to them seemed to be underpowered in comparison to my original setup which was:

Bi amped: Adcom 5500 on base / Yaqin 2100 on mid and upper ribbons

And, in a raw power comparison, they are... as there is 400 watts in the original system compared to the 125w+ in the M125's. BUT, at 75% power from the line source (Wadia 21 direct) the Adcom/Yaqin setup was screechy/tinny (that a word?) and would ware on the ears after an hour or so... However, the M125's at the same level, although they seem maybe a little 'less loud' they don't sound "screechy/tinny' when the volume goes up, and are definitely are much, much better sounding amps.

Are the M125's better sounding than the Adcom/Yaqin setup? Yes.

Are they $1800 better? I am going to say yes... because I am sitting here having played them for 5 hours at a good clip of volume and I don't have a head ache. I am lucky in that I can listen to music while I work, so I spend 30 hours a week listening to music (I do some work at least.. :0) ). So, for me... the quality difference is noticeable, so it is worth the money.

And I suppose that's what it boils down to, I wanted 100w+ tube amps, and these are great for the price... and seem to be improving with every hour that passes.

mantha3 wrote:I think you are running KT120... What other tubes are you running. What kind of coupling caps are you running? The Russian PIOs?

Whatta when who?? Geesh... no idea?! Theres a gold one on the back with a whatsy majig on the front... ohh, no that's two whatsy majigs.. :0)

Jokes aside!

Standard set from Ebay...

Rectifier: WZ68 (1) Weber Copper Rectifier
Preamp/Driver: 12BH7GP (2) - EHX Gold Pin matched and balanced
Power Amp: KT120 (4) - TungSol 60 watt super audio power amps

Re: > "I think you are running KT120... What other tubes are you running. What kind of coupling caps are you running? The Russian PIOs?"

All M-125 amps come with (as standard equipment) both power supply upgrade caps (4 X Low ESR Nichicon 100 uF caps) and matched sets of Russian PIO main coupling capacitors.

Bob

Ahhh... Nice. I think it is a great idea to make the PIO caps and the power supply cap upgrade standard.

shaunst,

These amps will probably grow on you as the "burn in" time time on the caps and tubes passes. I think you won't hear the true sound till you have about 100 hours on the amp.

Thanks for reporting on the build and on how you like these amps. I have the ST120 amp and I'd probaby have done these if they had been available. Oh well, enjoy the amps!