Babelfish XA252 / Babelfish XA252 SIT / Babelfish XA252 SET

[Zen Mod]

What section in the schematic is doing that

every detail by little

can we adjust it to normal or 2nd harmonic positive phase?

no, fiddling with something in circuitry...............

For simplicity you have chosen the LT3092 or some other reason?

except as already known - flipping speaker phase ........ except***

Switching speakers cables makes the lower frequencies sound weird.

and you'll have same outcome if you do that with magic wand in amp itself


***but! if feeding amp with SE, ground positive input of amp, and feed RCA hot to negative input; you;ll have what you need - positive 2nd

then draw your own conclusions

For simplicity you have chosen the LT3092 or some other reason? How does it affect the sound? 🤔

it's part of biasing circuit; there is no signal going through .......... basic premise - when said circuit is done properly, it is invisible

 

[RainfallSky]

HA! means Handy Addendum

consisted of pair of Cap Bank pcbs and pair of mains NTC pcbs

Cap Bank pcb- CRC per rail, led resistor and led pads, small NTC (10mm Dia) between audio GND and chassis; each C snap-in, max Dia 35mm

NTC pcb - dual - so each pcb covers either dual primary Donut with 1 NTC per winding, or covering two Donuts in case of single primary; NTCs are CL60 format/size

some graphical info, present in most of my Trade threads for amps but anyway

ZM, I like your PSU board pattern.
I start to make a copy of it in KiCad with blade connectors but got distracted by another design and it deviated a bit in the process..
Right now it look like this. Nothing is final yet.



P.S.: I would like to build Babelfish XA252 SIT someday in future too. 🙂

 

[Zen Mod]

 

[mefinnis]

Hey ZM,

I note the changes to Z3-Z4 in the "Final Schematics" as per -> https://www.diyaudio.com/community/...2-sit-babelfish-xa252-set.373443/post-7560120

Given I have been running my straight-MOS version for over a year now, I'm inclined to abide by "if it ain't broke ... don't 'fix' it ...".

That stated, swapping a couple of zeners isn't really rocket science and low risk ... your thoughts ?

 

[Zen Mod]

don't bother

 

[viltsone]

When I decide to go for XA252 SIT version then can I use +-24V rail voltages or I need to have higher voltages for THF-51S? 😊

 

[Zen Mod]

24V being minimum, more preferable, to bring best out of it

 

[NE WAY]

My XA252 has been plugged in providing enjoyment for a month. And I am happy. Mikerodrig27 summed up perfectly the sound of the XA252 in post #652. I will add, listening to Jimmy Hendrix through this amp is an experience. The sound of overdriven tubes breaking up 12” paper cone drivers is intoxicating.

My diy Troels designed SBA-761 speakers have a polite sound through my SissySIT and diyaudio F6, casting a wide sound stage, beautiful imaging, well balanced bass. The XA252 brings all of that with greater intensity and a you are in the room with the musicians kind of presence.

After extensive listening in both SE and Balanced modes with my diy carl_huff Doug Self Preamp from Linear Audio #5, I am leaning hard toward favoring SE. Balanced mode offers a fierce amount of gain but loses that spoonful of sugar present with SE. The amp is dead quiet in either mode.

Okay, so here are some details about my build:

Full MOS. Substituted IXFN140N20P for IXFN140N30P due to availability. PSU CLC. Antek 4428, 4 x 33,000uF, Hammond 159ZJ 10mH 5A. BFF=22R. Iq=1A8. Chassis are Mini Dissipante 5U 400mm modified to monoblock configuration - aluminum panel replaces one heatsink, 10mm front panel narrowed.

Lastly, the XA252 is one hot tamale. In my 19°c room the heatsinks reach just shy of 50°c after a half hour. The amp sounds its best after warming up for about an hour.

Zen! The XA252 is one superb amplifier. And as I built them, two superb monoblocks.

with such a “small” device dissipating so much heat through the heatsink, are there any issue that the heat from pucks doesn’t transmit to all corners of the heatsink quick enough?

What is the temperature difference between the part of heatsink closed to the puck and the edge of the heatsink?

 

[Zen Mod]

it's made for that

 

[Bensen]

Anybody there who did a comparison between balanced and unbalanced input signal for this amplifier?
Is there a difference soundwise, if yes, what do you prefer most?

Possibly I'm bothering to much about the sugar, but I need to order some XLR inputs (not quite cheap) when willing to go balanced.

Monoblocks will be far enough completed next week, to put them in the main system.

Went a week ago to balanced connection and directly checked with many well knows tracks. Directly noticed difference in negative sense. Today reverted back to single ended. And yes, for sure, for me, in my system, SE is clear winner.

 

[Sorenm]

I realize those observations are highly system/component dependent, but still glad to hear that my 'peasant' SE system may be just fine 😉

 

[Zen Mod]

Went a week ago to balanced connection and directly checked with many well knows tracks. Directly noticed difference in negative sense. Today reverted back to single ended. And yes, for sure, for me, in my system, SE is clear winner.

which is more influenced by THD Spectra of preceding gear, than XA252

 

[glenv6]

Went a week ago to balanced connection and directly checked with many well knows tracks. Directly noticed difference in negative sense. Today reverted back to single ended. And yes, for sure, for me, in my system, SE is clear winner.

Hi Bensen - Curious to know what your specific observations are between the two input methods? I built the mosfet version

Went a week ago to balanced connection and directly checked with many well knows tracks. Directly noticed difference in negative sense. Today reverted back to single ended. And yes, for sure, for me, in my system, SE is clear winner.

Went a week ago to balanced connection and directly checked with many well knows tracks. Directly noticed difference in negative sense. Today reverted back to single ended. And yes, for sure, for me, in my system, SE is clear winner.

Back On post #1365 a little over a year ago, I noted something similar. Sometime after that post I started using the balanced input and have not switched back to SE all that much. The reason probably has more to do with the time, money, and effort I put into building my balanced projects than anything else!

 

[Bensen]

Well, I'm not good to explain sound differences to start with.

When going balanced, I noticed music has lost some cosiness, it was less enjoyable, some warmth was missing. No difference was noticed in bass, mid's and treble.
I second the input of Zen Mod, phase and amplitude of harmonic spectra of preceeding gear must have impact.


My system:
- source = DAC (Ian Canada + AD1862 + discrete I/V): https://www.diyaudio.com/community/threads/dac-gallery.166807/page-23#post-7679581
- preamp = Blowtorch clone: https://www.diyaudio.com/community/...d-state-pics-here.96192/page-368#post-7159684
- speakers = Sonus Faber Venere 2.0 using Duelund speaker cable

 

[Vunce]

It’s been sitting patiently, but finally Babelfish XA252 is next up on the bench! There have been slight changes to the pcb’s and schematics over time. I’m building the big MOS version.
@Zen Mod, the attached schematic doesn’t exactly match my 2022 boards,
just want to confirm part values are good to go?
Too bad I didn’t build it sooner, we need some more heat here, it’s COLD outside.🥶

 

[Zen Mod]

there is difference just 5pcs of 0R56/3w in each rail, instead of 3pcs of 0R33/3w, as it was in initial iteration

practically - you can put there whatever you have - 3pcs of 0R33 or 4pcs of 0R47 or 5pcs pf 0R56

 

[gsrchrisu]

If it helps, post #1386 has the schematics for the 5 resistor version. 🙂 Also some changes to the zener diodes I believe, been awhile since I built this one.

 

[Vunce]

Thank you ZM and Chris.

Planning Time now!

 

[Giallograle]

Also, ZD3 & ZD4's voltages were increased from 5.6 to 8.2V to avoid Q1 and R24 occasionally cooking.

 

[Vunce]

I started taking build notes over a year ago, a lot of posts between now and then. Better get out the reading glasses, hehe.