LuDEF

[Zen Mod]

First one in last series of xformer FE amps

Even if I really like, adore and prefer level of Organicity, gotten with that approach (buffer- autoformer gain - no overall NFB loop) ....... what's enough, it is enough

so this one is one of "Look Ma, with no hands!!" thingies ( when I was a Kid, first time driving bccle without hands on bars, enduring endless flack right after) .......

So - this one, Look Pa, no SITs!!***

Had a short listening session this evening, right after finishing it on T-Bed, sorta overwhelmed.
Will listen more tomorrow, but have a feeling that I'm not going to change a thing, pretty much done that while prototype was in Ikebana shape

What sims predicted and I got in vivo - insane THD levels; can't explain, can't explain......
Of course - things can be varied a little, but as far as I'm concerned - only in one way - varying Uds of LU +/-100mV ( so down to 2V3 and up to 2V5, now sweet spot being at by Papa prescribed 2V4, F3 Beastie)

So, this one is first, more to come

Rails - usual FW format ( Donut having 2 of 18Vac sec. windings) , Iq and rest of details written on schm

***Dilemma - is LU SIT, or not SIT?



edit on 30.04. : PSU is regular FW Format;
my iteration of same is - per channel - 250 to 300VA Donut with dual 18Vac secondaries, two Graetz bridges, filter bank 33mF-0R1/5W-33mF, per rail

 

[Zen Mod]

pcb renders, just for fun

 

[Zen Mod]

Measurements , 8R load

EMU1212, ZM's crummy interface box, ARTA

 

[Zen Mod]

Measurements , 4R load

EMU1212, ZM's crummy interface box, ARTA

 

[Zen Mod]

two more for 4R load, no space in previous post

 

[Zen Mod]

funny pics, will try to put them in some logical order

 

[Zen Mod]

......

 

[Zen Mod]

.......

 

[codyt]

Yes! This looks fantastic. That THD spectra is a beauty

 

[dantwomey]

 

[Dennis Hui]

Looks like fun.

 

[AlexRivera]

 

[Nelson Pass]

funny pics, will try to put them in some logical order

Now I see why ZM was photographing my bench when he was here.

 

[Zen Mod]

Looks like fun.

oh yeah..... it was (an it'll be) fun .....

LuDEF
SissySIT R.3 (any SIT Ugs)
Babelfish M25 R.2
SET (Schade Enhanced Follower, called Schade enhanced Thingie)
Old Soul (Fat Germanium and usual mosfet in OS)
Old Soul Bip ( Fat Bipolar and usual mosfet in OS)
Il Penitente ( just Fat bipolars in OS) ..........

then all of these - with active FE and overall loopNFB, instead of xformer cell

we'll see which ones would live after final listening tests - all of them passed Ikebana Mono Sessions with ease .......

Though, I have two substantial problems:
1. everything I throw on my spks is sounding at least decent; lazy to devise some burdening cell, to make them working harder
2.lazy to type
3.even lazier



Forgot another one, abandoned completely ( no modesty here ) beautifully executed Babelfish XA25, in favor of Babelfish XA252; first one even with few decent quirks still being too much of original; latter being substantially more different than original, quirks mandatory

 

[Zen Mod]

Now I see why ZM was photographing my bench when he was here.

 

[flocchini]

ZM
Outrageously cool - my head will explode

 

[njepitt]

Looks very cool indeed. 🙂

Although now I have a problem...

I started an F3 build because I had some LU1014 and it looked cool... (still underway)...

Then I bought the M2X boards, the Edcor transformers and started collecting parts, because an amp with a transformer in the signal path seemed cool... (and for some reason I didn't fancy F6. Couldn't tell you why.)

Now you show an amp that uses both LU1014 and a transformer... in one package... I can't keep up yet nonetheless feel the urge to build one... 😀

 

[dBel84]

 

[woofertester]

Very nicely done. How is the LU1014 held in place?

 

[wg45]

Rustling in my parts bin-

Pair of LU1014- Check
Pair of Edcors- Check
Pair of Jensens- Check
Iron or Nickel, hmmm?
Empty 2 Pico toxic masculinity chassis- Check

ZM, you're a crazy genius. I can't wait to build it.