Copy...snip....edit....paste.....snip...paste..... (Isn't this how ZenMod got his name?)
Modify your B1 with modulated current sink turning it into a White cathode follower/Borberly source follower, i.e. BoFo. Lowers Zout, doubles current drive, a little higher distortion than unmodded B1.
Looking at the complexity makes me appreciate the elagance of the complimentary version. There are just so many more choices of N-channel JFETS though. Probably will use the LSK389 duals I just got. The P-channels are the tough ones to get.
I still need to listen to both to decide which to go with, still like the primarily 2nd ordered harmonic distortion of BoFo. That was the original goal M2-like amp SE.
Papa Borbely's White Cathode follower is better than other (shown here) JFet followers when feeding heavier loads ; with benign loads , it's unnecessary complication and (to my ears) slightly worse (in other words - more ) sounding
on last iteration of Iron
follower pcb I have provision for Borbely WCF (parts) and in that case (even if Iron Turtle AVC is known and benign load) , one can choose between two type of buffers and leave one which THD spectra suits better/more
will you add the edcor trafo?
I should have cut and pasted Papa M2 trafo and zobel as well. Yes, that's what I'm listening to now. Evolution went:
Source -> Slagle AVC -> MoFo (muffled sounding)
Source -> Slagle AVC -> B1 (U401 jfet) -> MoFo (no gusto)
Source -> Slagle AVC -> B1 (U401 jfet) -> Edcor PC600-10k AF -> MoFo
(better but still, where's the bass/beef?)
Oh, B1 output cap too small, was 2.2uF which worked on 50k+ loads, not so good on 1.4k edcor load. 10uF much better. (Bass there, still strained sounding)
Source -> Slagle AVC -> B1 (LSK170B jfet) -> Edcor PC600-10k AF -> MoFo
(getting there still too forward)
Source -> Slagle AVC -> passive baffle step corection -> B1 (LSK170B jfet) -> Edcor PC600-10k AF -> MoFo
(Tonal balance right, lacking dynamics)
Source -> AVC -> BSC -> BoFo -> Edcor AF -> MoFo (Ah, now now we're talking... I mean singing...)
Papa Borbely's White Cathode follower is better than other (shown here) JFet followers when feeding heavier loads ; with benign loads , it's unnecessary complication and (to my ears) slightly worse (in other words - more ) sounding
on last iteration of Iron
I'll have to take some time to read ALL of your Iron
thread instead of reinventing already perfected wheel. Although lots learned through trial by fire.... "Ouch! that didn't work." Concepts locked in mind much better by hard lessons. ZM, you (along with Papa) inspired me to give it a try and get more iron in my signal chain and to let transistors do what they do best, current amplification.
I'm glad I did.
in that case , try as I suggested above
choose input tap on AVC to have enough oomph for MoFo
of course , include your BSC if you need it ..... maybe in between AVC and MoFo ......
I've often wondered if it makes sense to have:
source -> AVC (-27dB to -15dB) -> Buffer -> AVC (+14dB) -> MoFo
or
source -> AVC (-27dB to -15dB) -> M2 (+14dB)
Why not mount the AVC in the middle of the amp for attenuation control? Of course can wire AVC for some gain. The only drawback I see would be power available to speakers is limited by music source voltage. That and the Slagle-former is WAY more $$$ than Edcor PC series little iron gems. Remember my being a penny pinching miser.
Works if full blown partying levels attainable at listening position with +6dB. The speakers are fairly sensitive at +92dB SPL@1W1m.... Let's see 2Vpk, +6dB gain makes 4Vpk. That's about a 1W amplifier. Listening position about 2m, double the distance, so +92dB - 6dB SPL = 86dB. Great for low level listening but not rocking out.
Maybe a switch on the MoFo to for 0dB or +14dB, bypassing or not the Edcor???
everyone must do what he considers most 'fair and congruous with his possibilities' and what' identifies as closer to his ideal of final sound.well , it seems everyone here is having it's own strong weed .......
As for me, now that the experiment of placing a battery of polypropylene capacitors immediately after the smps has further magnified the performance of my two monoblocks, I'm more and more convinced that the maximum performance can only be obtained with the tubes but in a separate preamp with its well-structured power supply.
My pre is a single stage (common cathode with 6SN7 with plate loaded by autotransformer) without buffer supplied with a 5Y3 + CLC completely made of polypropylene.
No pre jfet I've tried (DCB1 - Pre Juma - JC-2 clone by J.Curl) manages to have the same reproduction quality especially in terms of dynamics, vitality in the midrange and soundstage. With my pre the Mofo now also appears without power limits (my speakers are the Diapason Adamantes II). I am very satisfied.
Great Amplifier. To be recommended to anyone.
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Yes sure.exactly what I was saying
But I made a statement after trying both SS and tubes and, to tell the truth, I would have preferred that the j-fet or any SS devices prevailed as more practical to use, trying to refer to devices considered in general excellent performance ..... and here he speaks as if it were clear and almost obvious that the jfet are a reference ..... but so does not appear.
So .... the suggestion of Mr. Rotacher to use tubes as a front-end I believe the proof of the facts that is to be taken into great consideration. In fact, I bring my contribution in this sense ..... and I did not expect it.
My tube buddy at work is planning to design and build a tube pre/driver stage for his MoFo. We have had many discusions about how tubes rule in the voltage domain and transistors (FETs) rule in the current domain. So, let each do what they do best.
My experience and comfort is with SS and, as you said, there is a simplicity that is appealing, especially in the power supply. When I started building these simple Zen-like power amplifiers I said to myself, "Oh... I'm building power supply here." Half of the cost in parts is in the PS, the other half in the heat sink/case.
Tubes are their own heat sinks.... cost is mostly in iron.
The other thing I have noticed is that you have to work really hard to get the hum levels low in tube circuits. I have listened to his parallel feed SE amp, which sounds really nice. The only thing I could complain about was that the noise floor wasn't as low as I'm used to and prefer.... me like the jet black noise floor
ZM said it, pick your own poisen.....weed.....pro/con..... compromises.....preferences....one man's trash is another man's treasure.
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Hi El Reino....it is surplus material (used) but in perfect conditionHello sontero, you have some BIG caps
look THIS
Even with the tubes you have to carefully evaluate which configurations to adopt, tube type, the necessary gain and take care of the power supply. For me any configuration without cathode follower is a winner (almost always the buffer ruins the sound unless you use a mosfet as a buffer ....for my experience)
I said .... I was expecting more 'from configurations to SS that I realized on purpose .... they sound very good but do not reach the level of the tubes
I know the problem .... but it goes beyond trying to take care of the layout well. in my realization I have an absolute silence so much that I have to watch the LEDs to be sure that the equipment is on.The other thing I have noticed is that you have to work really hard to get the hum levels low in tube circuits. I have listened to his parallel feed SE amp, which sounds really nice. The only thing I could complain about was that the noise floor wasn't as low as I'm used to and prefer.... me like the jet black noise floor
I'm not a fan of tubes at any cost (for many years I've been) and indeed ... I repeat ... I would have preferred to use SS.
For example. for my self-built DAC I preferred by far the analog section to SS .... the tubes were inadequate and not for the noise
Dear Cinco do what you think is right .... I'm sure you will have great satisfaction
Another MoFo
I've been lurking around for some time now. Had a lot of fun with DDDAC and all its variations. Built an Aleph J which sounds amazing. Now, needing another fix, I put together this big MoFo. I biased it at 2.7 amps. I have a little hum probably from the 500va unshielded transformer. Each major piece of this project seemed to weigh about 10 lbs., so this thing weighs over 50 lbs. I mounted the inductors so that I could remove them fairly easily with thumb nuts and Molex connectors. I need to build a BA3 preamp to properly drive it.
I've been lurking around for some time now. Had a lot of fun with DDDAC and all its variations. Built an Aleph J which sounds amazing. Now, needing another fix, I put together this big MoFo. I biased it at 2.7 amps. I have a little hum probably from the 500va unshielded transformer. Each major piece of this project seemed to weigh about 10 lbs., so this thing weighs over 50 lbs. I mounted the inductors so that I could remove them fairly easily with thumb nuts and Molex connectors. I need to build a BA3 preamp to properly drive it.
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Good!!
another fan
I like your design ..... but ... some photos of bottom would explain more