Hi,
No doubt that many would like a Monster amp, something like an upgraded A-75, that would drive almost anything...
On the other hand, there are several really good Pass amps already out there..
If F4 doesn't satisfy someone's needs, then it would be better to think about replacing speakers and not an amplifier.
So, it would be logical to get a preamp from Nelson to drive F4. But, wait! ZenMod modified the X-whatever-BOSOZ so now there's a decent preamp for an F4.
What some of us may miss, is an active crossover/equalizer.
Some of the DIY-ers already have more than one Pass amps, and would surely like to enable each of them to work in the range where they excel.
Regards,
Vix
No doubt that many would like a Monster amp, something like an upgraded A-75, that would drive almost anything...
On the other hand, there are several really good Pass amps already out there..
If F4 doesn't satisfy someone's needs, then it would be better to think about replacing speakers and not an amplifier.
So, it would be logical to get a preamp from Nelson to drive F4. But, wait! ZenMod modified the X-whatever-BOSOZ so now there's a decent preamp for an F4.
What some of us may miss, is an active crossover/equalizer.
Some of the DIY-ers already have more than one Pass amps, and would surely like to enable each of them to work in the range where they excel.
Regards,
Vix
Hello
I see many pages ago that we can use J109 / K370 as replacement parts for those legendary pair which is the J109 / K389.
But, after have looks in several shops as Mouser or Newark, I've found any Toshiba FET ( but some small signal BJT ). Where you'll get them ?
Thanks you,
Max.
I see many pages ago that we can use J109 / K370 as replacement parts for those legendary pair which is the J109 / K389.
But, after have looks in several shops as Mouser or Newark, I've found any Toshiba FET ( but some small signal BJT ). Where you'll get them ?
Thanks you,
Max.
upgraded A-75! upgraded A-75! upgraded A-75! upgraded A-75! upgraded A-75! upgraded A-75! upgraded A-75! upgraded A-75!
🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂
🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂 🙂
Nelson Pass said:
As you ask publically, dear Mister Pass, whoever you are 😕
.. I will kindly have a look in the matter of
Upgrading Possibilities of A-75 power amplifier
... as I recall it,
'A' stands for Amplifier
and '75' for like 75 Watt output
(which actually is a good choice of max output level
a bit more than most any of, say 90% of, all music lover would need)
I be back with an A75 Upgrade Tutorial for you, Mr Pass.
Just you be patient and wait one day or two.
Let's see what we can do about this problem you have.
Kind Regards
lineup
Chief Amplifier Designer
at
Lineup Audio Labs Inc.
😎
Nelson Pass said:
The A75 documentation is SO Extensive!
like 25 Diagrams and plenty of Photos
and massive text blocks to get through.
I may need 1 month to penetrate this for you.
Hope you can wait dear Mr. Pass ....
What I got so far,
is that this is some 'Homebrew project' someone has done in his garage.
Very ambitious plan and effort, for being a 'home cooked' amplifier.
See this image from web documentation
and you will know somewhat of the type of setup used here
An externally hosted image should be here but it was not working when we last tested it.
A75 Nelson Pass Amplifier - Performance Measurements
hmmm ...
The chap that has made this A75 and these Papers
is a man of great dreams
and maybe this person is not in absolute touch with reality.
No harm in having great hopes,
but how about this
quoted from online documentation:
Performance Measurements: ( A75 Part 2 )
This amplifier has quite a bit of available output current.
It will typically run out at about 70A peak into 0.1ohm loads.
If you perform this test, be prepared to replace output devices, or at least fuses.
The 12 devices in parallel on each bank are rated at pulses
as high as 36A each, for a maximum of 420A.
.... well, well ....
and 
( hot & cannotbe )
Regards again!
lineup
🙂
hmmm ...
The chap that has made this A75 and these Papers
is a man of great dreams
and maybe this person is not in absolute touch with reality.
No harm in having great hopes,
but how about this
quoted from online documentation:Performance Measurements: ( A75 Part 2 )
This amplifier has quite a bit of available output current.
It will typically run out at about 70A peak into 0.1ohm loads.
If you perform this test, be prepared to replace output devices, or at least fuses.
The 12 devices in parallel on each bank are rated at pulses
as high as 36A each, for a maximum of 420A.
.... well, well ....
and ( hot & cannotbe )Regards again!
lineup
🙂
Re: A75 Nelson Pass Amplifier - Performance Measurements
So there's a monster amp already. I hope now that it's gonna be easier for Nelson to decide what to present as a new project. Unless there's something that we haven't guessed yet...(surprize, surprize!)
Regards,
Vix
lineup said:
This amplifier has quite a bit of available output current.
It will typically run out at about 70A peak into 0.1ohm loads.
If you perform this test, be prepared to replace output devices, or at least fuses.
The 12 devices in parallel on each bank are rated at pulses
as high as 36A each, for a maximum of 420A.
.... well, well ....
Regards again!
lineup
🙂
So there's a monster amp already. I hope now that it's gonna be easier for Nelson to decide what to present as a new project. Unless there's something that we haven't guessed yet...(surprize, surprize!)
Regards,
Vix
Well, mine is noisy when I turn up the bias, so I think an upgraded PS would be in order. I suspect it is from the front end voltage doubler, but I am not sure.
Also, perhaps an upgraded front end......simpler and sweeter perhaps?
JJ
Nelson Pass said:
may be by eliminating the dual-differential input stage and changing it into a single diff?
😉
I've read the A-75 article yesterday.
The new J-Fet A-75.
Ah, the itch...
Don't You steen?
🙂
Manuel
The new J-Fet A-75.
Ah, the itch...
Don't You steen?
🙂
Manuel
Re: Re: A75 Nelson Pass Amplifier - Performance Measurements
Yes, really, Vix
I can't remember ever seen somthing like the good old A75 project
by Nelson & his good friend
😎 ... if you aim for something: Do it properly and at 100%
😎 ... if your goal is solid high power: Why compromise?
This is a secret of good life:
😎 ... put your HEART
into what you do
... half hearted doings, are better left undone
... better do something else, what your heart longs for
================================
From the Beginning [ORIGINAL RECORDING REMASTERED]
I have the original Vinyl album from the time.
Small Faces.
Their popularity peaked in August 1966 when
"All or Nothing" their 5th single, hit the top of the UK charts,
which proved to be their only Number One.
100% = All = With All you've got = With your Heart at it
Same message, almost, we have at Rolling Stones song 'Take It or Leave it' 1966
I have this song at original Vinyl album 'Flowers' ( have the CD, too)
But first release of Take it or leave it, was 1966 in album 'Aftermath'
http://en.wikipedia.org/wiki/Aftermath_(album)
Regards
lineup - is not mainly an amp lover, Pass or Not Pass
- he is a Music Lover which is something else, for sure!
😎
Vix said:
So there's a monster amp already. I hope now that it's gonna be easier for Nelson to decide what to present as a new project. Unless there's something that we haven't guessed yet...(surprize, surprize!)
Regards,
Vix
Yes, really, Vix
I can't remember ever seen somthing like the good old A75 project
by Nelson & his good friend
😎 ... if you aim for something: Do it properly and at 100%
😎 ... if your goal is solid high power: Why compromise?
This is a secret of good life:
😎 ... put your HEART
into what you do... half hearted doings, are better left undone
... better do something else, what your heart longs for
================================
An externally hosted image should be here but it was not working when we last tested it.
From the Beginning [ORIGINAL RECORDING REMASTERED]
I have the original Vinyl album from the time.
Small Faces.
Their popularity peaked in August 1966 when
"All or Nothing" their 5th single, hit the top of the UK charts,
which proved to be their only Number One.
100% = All = With All you've got = With your Heart at it
Same message, almost, we have at Rolling Stones song 'Take It or Leave it' 1966
I have this song at original Vinyl album 'Flowers' ( have the CD, too)
But first release of Take it or leave it, was 1966 in album 'Aftermath'
http://en.wikipedia.org/wiki/Aftermath_(album)
Regards
lineup - is not mainly an amp lover, Pass or Not Pass
- he is a Music Lover which is something else, for sure!
😎
Re: Re: Re: A75 Nelson Pass Amplifier - Performance Measurements
That's OK, I've got you covered.
😎
lineup said:
That's OK, I've got you covered.
😎
F3
I see on the First Watt web sites "what's new" section that the F1, F2, F3, and F4 service manuals have been published. The F1, F2 and F4 schematics are available. Is the F3 service manual out for us to read somewhere. I haven't seen it yet? I'm about to finish my Zen V9 and would like to know the difference between the two. I know Nelson posted that the difference is minor.
BDP
I see on the First Watt web sites "what's new" section that the F1, F2, F3, and F4 service manuals have been published. The F1, F2 and F4 schematics are available. Is the F3 service manual out for us to read somewhere. I haven't seen it yet? I'm about to finish my Zen V9 and would like to know the difference between the two. I know Nelson posted that the difference is minor.
BDP