Need to get this out of my system ........
When I was a Kido, just barely moving with my first attempts of building amps and preamps from scratch, desperatelly wandering through any available printed sources ( no www yet) in search of/for Holly Grail .... my good friend just acquired specimen of which is later to be one of my all ever favorite amps - Musical Fidelity A1
(what did I knew that I'll have damn long list of my fave amps, not necesarily good ones or special in any tecnical or performance way, but heck - guy can have feelings, liking things just for liking sake
)
Anyhow - not much time did pass, I had it in pieces, first to figure out schematic, and then maybe to think something clever (hell, yeah
) to make it better
Not much time after that, I had built my own, by wonder it worked right from the bat, by wonder I did guess right what output transistor are (ignore thing that I really knew just 2N3055 and needed to chase its "complementary" ..... so I had proper beginner's luck guessing right ones - 2N3055 and BDX18)
And - no wonder that I made exactly same mishaps as mishaps being implemented in original - I did use 100VA mains Iron for 80W of juiced juice, and mine also had beautiful thermal arrangement as original, resulting in oh boy!!!!!!!!!! temperature of heatsinks
Later, when we did some head to head comparison between friend's original one and my "Clone", awe was that "Clone" sounded better - simply beause I did made just power amp portion, really not being able to include preamp section in said moment, planning that to add in later time
Speak of beginner's luck, again
Conclusion - "Clone" did sound better with line level sources, preceded with just 10K pot, than original one having all bells and whistles
Then we did go wild, trying tube stage in front - finding some "modern" solution - ECC88/6DJ8 fed with humongous voltage of 30V ..... it did help some - fact that it was loaded with current source .....
What we did know that MF will follow same easy commercial pats some later, nicely feeding hordes of us ignorant imbeciles ....... in fact - nothing wrong with nice little pleasing boxes, but I later did found following Myths and Legends somewhat disgusting
Do I need to say that it sounded even better with "tube" stage, however flawed it was?
.......................................... fast rewind to www time, I started chasing Holly Grails in every possible direction, beside other things I did found some few itsybitsies about my (then) still fave amp
If you fancy some reading, see attached pic (schm , few posts down) and visit Mark Hennessy page https://www.markhennessy.co.uk/mf_a1/
M. Hennessy is getting most of facts right ....... and I have impression that he's extremely polite, whenever anything worth commenting he did comment
I'm going to be extremmmmmmely polite, not commenting anything about original commercial MF A1, neither first Gen, nor 2nd (just a gimmick, really, having USBandwhatever) nor present - 3rd or, rather, proper 2nd Gen
In last few decades, I had at least a dozen on my workbench for service and improvement, had at least 4 called "mine" ....... where last one of these 4 is still around (serving one of my friends)........... while my described clone is still somewhere around, supposedly still mine but I really need to stretch my gray cells to decipher where it is exactly .............
huh, tired of typing
When I was a Kido, just barely moving with my first attempts of building amps and preamps from scratch, desperatelly wandering through any available printed sources ( no www yet) in search of/for Holly Grail .... my good friend just acquired specimen of which is later to be one of my all ever favorite amps - Musical Fidelity A1
(what did I knew that I'll have damn long list of my fave amps, not necesarily good ones or special in any tecnical or performance way, but heck - guy can have feelings, liking things just for liking sake
)Anyhow - not much time did pass, I had it in pieces, first to figure out schematic, and then maybe to think something clever (hell, yeah
) to make it betterNot much time after that, I had built my own, by wonder it worked right from the bat, by wonder I did guess right what output transistor are (ignore thing that I really knew just 2N3055 and needed to chase its "complementary" ..... so I had proper beginner's luck guessing right ones - 2N3055 and BDX18)
And - no wonder that I made exactly same mishaps as mishaps being implemented in original - I did use 100VA mains Iron for 80W of juiced juice, and mine also had beautiful thermal arrangement as original, resulting in oh boy!!!!!!!!!! temperature of heatsinks
Later, when we did some head to head comparison between friend's original one and my "Clone", awe was that "Clone" sounded better - simply beause I did made just power amp portion, really not being able to include preamp section in said moment, planning that to add in later time
Speak of beginner's luck, again
Conclusion - "Clone" did sound better with line level sources, preceded with just 10K pot, than original one having all bells and whistles
Then we did go wild, trying tube stage in front - finding some "modern" solution - ECC88/6DJ8 fed with humongous voltage of 30V ..... it did help some - fact that it was loaded with current source .....
What we did know that MF will follow same easy commercial pats some later, nicely feeding hordes of us ignorant imbeciles ....... in fact - nothing wrong with nice little pleasing boxes, but I later did found following Myths and Legends somewhat disgusting
Do I need to say that it sounded even better with "tube" stage, however flawed it was?
.......................................... fast rewind to www time, I started chasing Holly Grails in every possible direction, beside other things I did found some few itsybitsies about my (then) still fave amp
If you fancy some reading, see attached pic (schm , few posts down) and visit Mark Hennessy page https://www.markhennessy.co.uk/mf_a1/
M. Hennessy is getting most of facts right ....... and I have impression that he's extremely polite, whenever anything worth commenting he did comment
I'm going to be extremmmmmmely polite, not commenting anything about original commercial MF A1, neither first Gen, nor 2nd (just a gimmick, really, having USBandwhatever) nor present - 3rd or, rather, proper 2nd Gen
In last few decades, I had at least a dozen on my workbench for service and improvement, had at least 4 called "mine" ....... where last one of these 4 is still around (serving one of my friends)........... while my described clone is still somewhere around, supposedly still mine but I really need to stretch my gray cells to decipher where it is exactly .............
huh, tired of typing
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Anyhow, here's sshot of MF Web page about Tim de P.
I can't find it right now, so sshot instead of (probably more proper) link to
I can't find it right now, so sshot instead of (probably more proper) link to
My friend Aleksandar RAAL gave me a story how he met Tim de P. on some FiFi Fair in Europe, spending some cozy time, talking about everything except Audio .........
There are more details to that (two of them on tobacco pauses on back porch of Fair Facility, porch oriented ditto at show-windows of nearby sex-workers Facility ...... so Tim and Alex having much better fun than inside of FiFi Fair), but I'm not going to say more
Here's schm of more or less basic MF A1, as it was decades ago; Lazy to check is it from M. Henessy's or from somewhere else
There are more details to that (two of them on tobacco pauses on back porch of Fair Facility, porch oriented ditto at show-windows of nearby sex-workers Facility ...... so Tim and Alex having much better fun than inside of FiFi Fair), but I'm not going to say more
Here's schm of more or less basic MF A1, as it was decades ago; Lazy to check is it from M. Henessy's or from somewhere else
Rest of info from linked Henessy's pages, in first post
It's still debatable, at least inside of my skull - is unfortunate line stage result of Tim's musings, or from someone else?
Fact is - power amp is result of proper inspiration, while line stage is far from that ........
Now - I don't have measurements of original A1; luckily - they're easily reachable here ( will not copy-paste anything, to prevent complaints): https://audiosciencereview.com/foru...-mk3-and-b200-vintage-amps-measurements.3141/
It's still debatable, at least inside of my skull - is unfortunate line stage result of Tim's musings, or from someone else?
Fact is - power amp is result of proper inspiration, while line stage is far from that ........
Now - I don't have measurements of original A1; luckily - they're easily reachable here ( will not copy-paste anything, to prevent complaints): https://audiosciencereview.com/foru...-mk3-and-b200-vintage-amps-measurements.3141/
But, what I have is measurements of my own specimen, slightly tweaked
If you're in mood, compare these with those linked in previous post
Forgot to measure gain, but have this:
Vout 4Vrms@8R translates to 3V858@4R
thus Rout=0R3
DF 26@8R, 13@4R
so - pics for MF A1 Almost Stock, load 4R
- line stage tossed out, VolPot connected as usual, JFet buffer after
- emiter resistors for outputs are halved in value ......... altered MOhm resitors, to set Iq back to standard
- altered NFB to have less CLG, more proper to today's sources
- pretty much all elcos replaced with new, solid caps instead elcos where possible
If you're in mood, compare these with those linked in previous post
Forgot to measure gain, but have this:
Vout 4Vrms@8R translates to 3V858@4R
thus Rout=0R3
DF 26@8R, 13@4R
so - pics for MF A1 Almost Stock, load 4R
Attachments
pics for MF A1 Almost Stock, load 8R
Attachments
There is a current production A1, glorified in most places ....... sometimes I need to relax my disgust remembering that my (and our ) stance is from position of someone looking from inside, not from outside
so, ZM being polite
SPh link to new one : https://www.stereophile.com/content/musical-fidelity-a1-integrated-amplifier
I'll just post one pic - showing type of transistors used in new one ........... just one of details showing that they had all chances to (finally) make it proper, but....
so, ZM being polite
SPh link to new one : https://www.stereophile.com/content/musical-fidelity-a1-integrated-amplifier
I'll just post one pic - showing type of transistors used in new one ........... just one of details showing that they had all chances to (finally) make it proper, but....
Attachments
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Proof is in Da Pudding
set to 700mA Iq, same as original
outputs genuine Toshiba TTA0002/TTC0002
Vout 4Vrms@8R, same Vin, Vout 3V888@4R Rout=240mR
DF 33@8R, 16.5@4R
Babelfish happily singing in 4R load
set to 700mA Iq, same as original
outputs genuine Toshiba TTA0002/TTC0002
Vout 4Vrms@8R, same Vin, Vout 3V888@4R Rout=240mR
DF 33@8R, 16.5@4R
Babelfish happily singing in 4R load
Attachments
still 700mA Iq
Babelfish happily singing in 8R load
Babelfish happily singing in 8R load
Attachments
and ........ now! we are talking
funny pics with Iq set to 1A7
outputs genuine Toshiba TTA0002/TTC0002
Vout 4Vrms@8R, same Vin, Vout 3V914@4R so Rout=180mR
Resulting in DF of 44@8R and 22@4R
Iq 1A7
Base current of TTC0002 is 9.4mA , thus Beta 181
Base current of TTA0002 is 11.7mA , thus Beta 145
4R Load:
funny pics with Iq set to 1A7
outputs genuine Toshiba TTA0002/TTC0002
Vout 4Vrms@8R, same Vin, Vout 3V914@4R so Rout=180mR
Resulting in DF of 44@8R and 22@4R
Iq 1A7
Base current of TTC0002 is 9.4mA , thus Beta 181
Base current of TTA0002 is 11.7mA , thus Beta 145
4R Load:
Attachments
not many pics from bench, was lazy
forgot to note Gain - smidge bellow 19db; meaning ~900mV for 1W@8R
forgot to note Gain - smidge bellow 19db; meaning ~900mV for 1W@8R
Attachments
So, schmtc is yours .... go for it
I'll have full kits (pcbs with all parts, including TTA/TTC outputs) as soon I'm able to organize my impossibletoorganize Mighty MySelf
I'll have full kits (pcbs with all parts, including TTA/TTC outputs) as soon I'm able to organize my impossibletoorganize Mighty MySelf
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Wow. Very nice!! In the 80s, the original A1 was my first encounter with 'class A' so there is some nostalgia associated with this amp.
Any comments on how it sounds, or compares to your stable of Bablefishes?
Any comments on how it sounds, or compares to your stable of Bablefishes?
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I made it worthy enough to be called Babelfish
Anyhow, I made some trivial but significant changes, resulting in much better performance even with stock Iq
And then , when brought to our usual level of Iq ( FW form factor - rails and Iq), it finally shines in full glory
Sound - Spooky enough
Anyhow, I made some trivial but significant changes, resulting in much better performance even with stock Iq
And then , when brought to our usual level of Iq ( FW form factor - rails and Iq), it finally shines in full glory
Sound - Spooky enough
Choky,
I like the spectra at 1W 4R. Good work.
I like the spectra at 1W 4R. Good work.
Ha!
Contrary to usual Babelfishes of Papa's, here I Babelfished it to lesser/smaller
Ignoring fact that everything line-stage is, well, ignored ....... here are facts about number of stages of power amp (observe just one - upper or lower half; they're practically working in parallel) :
original ( post #3) - One (differential, LTP) stage + Half ( emiter follower) + Half (emiter follower) + One (output, common emiter); funny Sum being 3 stages
Babelfish (post #8) - One (differential, LTP) stage + Half ( source follower) + One (output, common emiter); funny Sum being 2.5 stages
amp itself is practically unable to get out of A Class, two halves working in parallel, with extremely graceful clipping behavior
in fact, when clipping is of long enough duration, output current just sags ....... circuit practically having self limiting function
all what's needed to recall proper function is to go back with Vol pot to sane level
Contrary to usual Babelfishes of Papa's, here I Babelfished it to lesser/smaller
Ignoring fact that everything line-stage is, well, ignored ....... here are facts about number of stages of power amp (observe just one - upper or lower half; they're practically working in parallel) :
original ( post #3) - One (differential, LTP) stage + Half ( emiter follower) + Half (emiter follower) + One (output, common emiter); funny Sum being 3 stages
Babelfish (post #8) - One (differential, LTP) stage + Half ( source follower) + One (output, common emiter); funny Sum being 2.5 stages
amp itself is practically unable to get out of A Class, two halves working in parallel, with extremely graceful clipping behavior
in fact, when clipping is of long enough duration, output current just sags ....... circuit practically having self limiting function
all what's needed to recall proper function is to go back with Vol pot to sane level