Yes , this is a "REAL" amp.
No tiny drivers here 😀 , the driver stage is a 40W amp all by itself.
when I build , I will play the drivers DIRECTLY (2-1R resistor) into a pair of speakers !
The big one has a little more room on that 250mm X 76mm PCB. Bigger
driver heatsink + larger driver decoupling caps will go on the "frankenamp"
(5 pair OP).
OS
yes , that is a good idea. I used a bypass across the 10R to mitigate PC
power supply noise in an earlier amp project .A .1uf multilayer ceramic was used .
OS
This project really looks nice! I'm eyeing the 5-output-pair version, because I have this nice little 800VA dual 60VAC secondary toroidal transformer that has been patiently waiting for its time to shine... 🙂
Will definitely stay tuned...
Will definitely stay tuned...
GLA-F "Frankenamp"
Rail bars + large driver caps + more room for driver HS.
As promised...
400 -500 REAL watts.
PS- Andrewlebon made it work on $hit board ... Imagine how it will sing
on these layouts. We are at the level of a $15,000 classe' , minus the "Gold"
rails.
OS
Rail bars + large driver caps + more room for driver HS.
As promised...
400 -500 REAL watts.
PS- Andrewlebon made it work on $hit board ... Imagine how it will sing
on these layouts. We are at the level of a $15,000 classe' , minus the "Gold"
rails.
OS
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Redo for 85V rails.
85V rails .... 😀
27K/820R for feedback ratio- gain of 30+
2.25V is very low distortion, 2.31V is clip (below 1) @ 151V p-p.
Had to increase the differential gain(s)- 68R emitter resistors , also had to
reduce the lead cap to 6.8pF (below2).
The plot is "reset" to 631K unity gain with 74 degree margin - same as
the little GLA amp (below 3).
OS
85V rails .... 😀
27K/820R for feedback ratio- gain of 30+
2.25V is very low distortion, 2.31V is clip (below 1) @ 151V p-p.
Had to increase the differential gain(s)- 68R emitter resistors , also had to
reduce the lead cap to 6.8pF (below2).
The plot is "reset" to 631K unity gain with 74 degree margin - same as
the little GLA amp (below 3).
OS
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Strange .. ???
On the small amp R6,7,8,15,16 were 100R. C6 was 10pF.
On the gain change , these resistors are ALL 68R And C6 is 6.8pF.
Very strange (and cool).
OS
On the small amp R6,7,8,15,16 were 100R. C6 was 10pF.
On the gain change , these resistors are ALL 68R And C6 is 6.8pF.
Very strange (and cool).
OS
GLA SURVIVOR
PS- Andrewlebon made it work on $hit board ... Imagine how it will sing
on these layouts. We are at the level of a $15,000 classe' ,
Hi Ostripper
greetings i want to make it sing better this amp is it possible to share
pcb layout in pdf so i can use iron transfer pcb method to make pcb if its possible all parts are ready i can finish the amp fast
warm regards
andrew😉
PS- Andrewlebon made it work on $hit board ... Imagine how it will sing
on these layouts. We are at the level of a $15,000 classe' ,
Hi Ostripper
greetings i want to make it sing better this amp is it possible to share
pcb layout in pdf so i can use iron transfer pcb method to make pcb if its possible all parts are ready i can finish the amp fast
warm regards
andrew😉
Awesome work OS! I think the Frankenamp deserves a prof. made pcb.
If I use 5 pair NJW0281/0302, what is the output I can get safely into 2R? MG6330/MG9410 are not easy to find & few people have used them, at least on DIYA.
If I use 5 pair NJW0281/0302, what is the output I can get safely into 2R? MG6330/MG9410 are not easy to find & few people have used them, at least on DIYA.
Only the best for the "builders"
5 pair njw0302/0281 - 2R
run at 50V rails - 400W
njw0302/0281 have low SOA at anything above 60V.
MJL21193/4 are much better.
The MG's by semitech are the "cat's meow" (8R- 600w amp).
GLA with 21193/4's will stand "side by side" with my first creation (badger's).
I'm about to build them both !
OS
5 pair njw0302/0281 - 2R
run at 50V rails - 400W
njw0302/0281 have low SOA at anything above 60V.
MJL21193/4 are much better.
The MG's by semitech are the "cat's meow" (8R- 600w amp).
GLA with 21193/4's will stand "side by side" with my first creation (badger's).
I'm about to build them both !
OS
Hi OS nice work, you seem to have a layout preference (signature)😉. Have also been following this thread http://www.diyaudio.com/forums/solid-state/244892-diamond-differential-amplifier-14.html. It would be nice to have someone compare these amps.
http://products.semelab-tt.com/pdf/bipolar/MG9410%20MG9410-R.pdf
http://products.semelab-tt.com/pdf/bipolar/MG6330%20MG6330-R.pdf
5 pair of these will boil water with a calrod. 😀
OS
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WOW , you move fast.
That is NICE.
You should of added (or asked me , I would of made you a driver board)
with extra pads at the drivers/rail inputs.
I suppose you could just add a few holes at the emitter traces and it
would be good.
Run your V+/V- in at the large traces near C18/19 .
OS
That is NICE.
You should of added (or asked me , I would of made you a driver board)
with extra pads at the drivers/rail inputs.
I suppose you could just add a few holes at the emitter traces and it
would be good.
Run your V+/V- in at the large traces near C18/19 .
OS
I read that thread. They use lag/lead on the dual differential plus miller
comp. on the VAS. NO,no....
Also , the Cascoded VAS is best used with a triple (higher impedance).
They also should reference the VAS cascode to the rails - not ground.
Miller just won't work with this topology. careful choice of the lag/lead
(R8-C5-C6) allows one to "shape" the bode plot. Unity gain freq and at
what point the phase margin "drops off" (heads toward 180deg.) are
very easy to customize.
Sansui used 47R-.0015uF + 10pF for the compensation network with 30
year old parts. (770Khz)
I , to be safe 🙂 , slightly increased the margin and lowered the unity gain
point (630Khz) to ensure stability.
My "layout preference" is quite practical , Keep anything "dirty" away from
anything "clean" (NFB returns + input stages). A super silent - "survivor" amp
will result.
OS
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Nope , but the Vsat,hfe vs. Vceo-temp are similar to 21193/4's - just
at double the SOA.
I've seen these used in "pro" amps with typical VFA amplifier topologies.
OS
There is no final schematic, just my idea for topology and 'borys' made his working prototype with this schematic (measurements is in post #111)
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