Commonalities - Babel J2 / Aleph J

The thread title should give it away, but I am looking for some insights into why certain amps may sound similar to me.

Background

I've had an incredible time learning a bit about the different amplifiers in the First Watt family and the associated DIY variants. I've built the M2x, F4, F5, Aleph J, SissySIT, and Babelfish J2 (so far). :D

I may be similar to some other DIYers in my lack of knowledge (but gaining) re: circuit designs and understanding the "big buckets" of amplifier topologies. Sometimes ignorance is bliss. It also cuts down on my confirmation/expectation bias. I don't care about a particular topology. I just build and listen with no preconceived notions. I've done some fun "experiments" with bias, but mainly, I just listen.

Over the last year or so, I've taken some reasonably decent notes. I've also done some blind listening. Sadly, I only have two chassis to swap amps in and out of. Woe is me :rolleyes: :D j/k I use identical PSUs (dual mono) in each chassis.

Observation

I have 4 ohm stock Tekton DIs. I generally sit about 14 feet away. Two amps, the Aleph J and the Babel J2, seem to be very similar and dare I say "better" when it comes to:

- low-level clarity and full sound at 65dB or less. They are my best "morning music" amps;
- Bass and mid-bass presentation and timbre (particularly at low levels, but also at 75dB+). "Impact" along with excellent presentation and ability to discern instruments and playing styles / techniques.
- Best experience re: "listener fatigue". I can listen to these amps for days on end with any variety of music. I don't have to "crank it" to hear details. The SissySIT shares this characteristic, IMO.​

When I hooked up the Babel J2, my brain went immediately to the Aleph J. The thing is, I hadn't listened to the Aleph J in quite some time. I put the Babel J2 into the F5 chassis and listened to it immediately following the F5.

Goal

One of the things I have been attempting to do is find commonalities in the amplifiers that I like with these speakers. It helps me narrow down what I may build next, and it helps me learn. Many of us may be looking for what sounds best, but we may have very little idea why one thing or another sounds better to us with our rigs. I'd like to learn a bit of the "why". There are things I love about all the amps, but these two seem to be very similar in these categories. So I thought I'd start there.

What baffles me even more, is after looking at the threads and the First Watt website, to the untrained eye it looks like they'd be "worse" for 4 ohm speakers - providing less power. :confused:

I've also been looking for properly measured impedance curves or other meaningful data re: the speakers, so I can see if there's something about the speaker / amp combination that makes sense.

Question

I'd appreciate any insight re: how more experienced people may categorize amplifier topologies or if there are any key similarities to these designs where you'd fill in the blank below.

Well, DUH! Of course these two amps have those characteristics with your speakers. We could have told you that before you ever built them. :D They both are _______________

If you could do an ANOVA or regression with "SQ" being dependent, what would you pick as independent variables? :D j/k, but you get the idea.

The commonalities I can find are Single-Ended and DC coupled (I think). I believe I have a fundamental understanding of Single-Ended vs. Push Pull. I'm looking up "DC coupled" and what that means. I'm fascinated by the discussions around H2, but I have not delved deeply enough to find a common trend in my preferences. I looked at output impedance across all the amps b/c bass "impact" was a part of the key attributes, and I keep seeing references to damping factor. There does not seem to be a trend there.

Would the amps being SE and DC Coupled (still researching that) tie to those sonic characteristics? Does asking that question make any sense at all?

All insights and criticisms appreciated.

:D
 

vdi_nenna

Member
Paid Member
2000-10-10 7:27 pm
PA, USA
When I hooked up the Babel J2, my brain went immediately to the Aleph J. The thing is, I hadn't listened to the Aleph J in quite some time.

Same thing happened to me when first listening to the M2, then months later, the MoFo amp.
Mind immediately went to the M2 when listening to MoFo.
Did not happen with Aleph-J and M2, which were both built by someone else.

Might have something to do with output stage type- Source Follower/Power Follower, even though the MoFo is SE cap coupled and M2 is PP.
 
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all of them .......... Babelfiish J2 , Aleph J and SissySITY are sharing same characteristic - dominant 2nd harmonic and sorta monothonic dropping down rest of harmonics

which means they all are sounding as your fave $hitty SE tube amp , you remember from childhood ..... or recent pilgrimage to nearest audio fair.... whatever

only - they're having less THD and doing extremes ( lows especially) better than common $hitty toob amp

B. J2 having least THD level of them 3 , then Aleph J , then SissySIT as worst :rofl: , being most tubey of them all

for Aleph J we know ( being Papa's brainchild) it is fast enough ..... and ( as he said ) his fave Aleph ; predecessor (older , mosfet input) was declared as Amp of Century?

for B. J2 and for SissySIT ........ I said they're fast enough , and people are naive , anyway always leaning to Holly Grail seeking , so why not ..... :rofl:

anyway ..... good amp is good amp ...... and one will be always able to find proper spot to use it ....... while world is full with bad amps

just a note - SissySIT could shine with 8R speakers ...... showing that edge of difference .... while with 4R speakers those less sissy amps are closer
 
Thanks @vdi_nenna -

I'll add Source Follower / Power Follower to my list of things to try and get my head wrapped around.

Mighty ZM -

AHA! So, it's not always the "how it's achieved" (topology), but "what's been achieved" - the tuning of the amp so to speak. I've read some posts re: adjusting resistor values to alter harmonics, phase, balance etc. I experimented with the H2, but I did not find any special trend. I can't wait to fiddle with H2 on my F5 (P3 tricks) and using Ishikawa on my M2x, but I need a silly-scope.

At least I don't feel like a total goof putting those three amps in the same posts. They really do seem like "family" to my ears. Knowing a bit re: "why" is extremely helpful. :D

Both - Greatly appreciated. :cheers:

Anyone else - Keep 'em coming.
 
those 3 amps belong in same post , primarily from one reason - they all originated from one Devilish Green

He's having all the fun , while still working hard , each day

btw, for THD Spectra thingie - you don't need scope - you need decent soundcard (preferably standalone usb one) , few itsibitsies for interface box and few proggies
 
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This is true!

Thanks as always to Papa for supporting the DIY community and giving me 1,000s more "why's" to ask.

The funny thing (to me) is that with all these measurements available, I still take silly notes like -

"This would be an incredible amp for learning a foreign language through music" - Vocals so CLEAR, I can hear the accent. Yep, that's really one of my notes. :D :D
 
......
fact hardly new , but often forgotten

well known guy, Alan Shaw , is often speaking about his own references , and reasons behind that ; if speaker ( so any other link in reproduction chain) is not good with voice , there is no need going further

I believe it's mentioned here : YouTube ,certainly more of it on official Harbeth site

I had an extreme pleasure to share few days with Jon Ver Halen and Steven Dear at SR , after BAF 2019. ; while Jon was calm part of small group , I was amused and mostly confused one , listening Steven's talks about hearing and perception ..... few days being too short to even start properly thinking of enormous and important area of knowledge
 
those 3 amps belong in same post , primarily from one reason - they all originated from one Devilish Green

He's having all the fun , while still working hard , each day

btw, for THD Spectra thingie - you don't need scope - you need decent soundcard (preferably standalone usb one) , few itsibitsies for interface box and few proggies

I found this thread interesting

Howto - Distortion Measurements with REW

I am Mac based and this seems like a good way to go

Best

Bob
 
ZM - I would have enjoyed hearing the discussion with Jon and Steven. Thank you also for the YouTube Video. I have never heard a pair of Harbeth loudspeakers, and now I am intrigued. Fantastic discussion re: their philosophy and the discussion of "natural" sounding.

Bob - thank you very much for the reference. I have been lurking on that thread. It may be time to take the plunge and learn a bit more about measurements.
 
when we at philosophy ......... if you want to learn something , while ROFL in most unexpected moments , visit The Dope from Hope | Klipsch

PWK-Examining-2000x1125.jpg
 

Extreme_Boky

Member
2003-12-07 11:57 am
Observation

I have 4 ohm stock Tekton DIs. I generally sit about 14 feet away. Two amps, the Aleph J and the Babel J2, seem to be very similar and dare I say "better" when it comes to:

- low-level clarity and full sound at 65dB or less. They are my best "morning music" amps;
- Bass and mid-bass presentation and timbre (particularly at low levels, but also at 75dB+). "Impact" along with excellent presentation and ability to discern instruments and playing styles / techniques.
- Best experience re: "listener fatigue". I can listen to these amps for days on end with any variety of music. I don't have to "crank it" to hear details. The SissySIT shares this characteristic, IMO.​

When I hooked up the Babel J2, my brain went immediately to the Aleph J. The thing is, I hadn't listened to the Aleph J in quite some time. I put the Babel J2 into the F5 chassis and listened to it immediately following the F5.

:D

You would want to achieve the required gain by as few semiconductors as possible. Aleph J does it with only 2. Well, for this statement to be 100% true, the AC gain should be disconnected. And I urge you to try this with your Aleph J. Its voltage gain stage does not split the analog signal into positive and negative halves. There's no reconstitution of the analog signal at its output neither. Both are required with a push-pull output stage.

There's also an influence of a dominant 2nd harmonic distortion especially at lower levels, that contributes to a "pleasant" sound character.

The simplicity and the dominant second-order harmonic distortion, coupled with the fact that there are no transformers (like with valves) of any kind, is the best there is in analog amplification. This contributes to a very truthful amplification of an analog signal. You noticed this by describing your findings in "Observation".
 
ZM - I would have enjoyed hearing the discussion with Jon and Steven. Thank you also for the YouTube Video. I have never heard a pair of Harbeth loudspeakers, and now I am intrigued. Fantastic discussion re: their philosophy and the discussion of "natural" sounding.

Bob - thank you very much for the reference. I have been lurking on that thread. It may be time to take the plunge and learn a bit more about measurements.

My feelings exactly - hopefully in the next couple of weeks I'll have time to get a system set-up :D
 
You would want to achieve the required gain by as few semiconductors as possible. Aleph J does it with only 2. Well, for this statement to be 100% true, the AC gain should be disconnected. And I urge you to try this with your Aleph J. Its voltage gain stage does not split the analog signal into positive and negative halves. There's no reconstitution of the analog signal at its output neither. Both are required with a push-pull output stage.

There's also an influence of a dominant 2nd harmonic distortion especially at lower levels, that contributes to a "pleasant" sound character.

The simplicity and the dominant second-order harmonic distortion, coupled with the fact that there are no transformers (like with valves) of any kind, is the best there is in analog amplification. This contributes to a very truthful amplification of an analog signal. You noticed this by describing your findings in "Observation".

Thank you for sharing your thoughts. :cheers: I continue to learn. I would be a bit out of my depth in attempting to "disconnect the AC gain" in the Aleph J.

However, the concept of using the fewest transistors for gain is intriguing, and I can follow the logic.

It would seem to follow to only use "as much gain as needed, but no more" I suppose. It was fascinating to learn why where the gain is in the chain has an impact. I've read and re-read the article in the Wiki re: gain staging. One thing that I've been wanting to try is running my source (DAC in this specific case) directly to the amp and using digital attenuation. I understand that there can be some potential drawbacks to using digital attenuation, but it would be fascinating to remove one entire device (pre-amp) from the signal chain and see how things pan out. Future fun.