16 OT posts removed.
19 OT posts on a Blazer amp moved here,
http://www.diyaudio.com/forums/everything-else/268171-blazer-500-1000-watt-amplifier.html
The clue is in the title. This is primarily a picture thread which is a showcase for your DIY efforts together with a little on topic chat about them if anyone asks a specific question.
If you want to start a debate about a design or whatever then please start a new thread.
Yes , but that does not seem to be low enough C/W without
forced air cooling. 12 MT-200's = 800W + !
OS
Another "beast" ... full range "spooky" leach -
The more refined version of the "hungry sub" amp.
Just a humble "leach amp" (with servo).
(below 1/2)
.3mv offset - takes 1 second for the servo to get it there.
30.5mv Re bias drops to 29.9mv when I "cooked it" at 150ma per device.
I guess a slight negative thermal co-efficient is good.
Smaller NJW0281/0302 equal a modest 200W/ch amp , but I wanted something
to match the HK990 I recently heard. My PS is overkill (1KVA - 80Kuf 73V).
I set 17mv (75ma per device) - cool running /silent precision.
OMG - this thing has some scary dynamics ! I could not turn it up without the
5 pairs before ... whoa. Need bigger speakers
.
So far so good ...
OS
The more refined version of the "hungry sub" amp.
Just a humble "leach amp" (with servo).
(below 1/2)
.3mv offset - takes 1 second for the servo to get it there.
30.5mv Re bias drops to 29.9mv when I "cooked it" at 150ma per device.
I guess a slight negative thermal co-efficient is good.
Smaller NJW0281/0302 equal a modest 200W/ch amp , but I wanted something
to match the HK990 I recently heard. My PS is overkill (1KVA - 80Kuf 73V).
I set 17mv (75ma per device) - cool running /silent precision.
OMG - this thing has some scary dynamics ! I could not turn it up without the
5 pairs before ... whoa. Need bigger speakers
.So far so good ...
OS
Attachments
Here's the "whole" amp , Thimios.
Still running "junk box" capacitors on it.
I've yet to stuff a CFA to plug in - I'm seeing if I can burn in .. (burn out) the
output stage first.
OS
Attachments
Another "Beech" amp .....
Thank you Bonsai ... reading material on your site and the "CFA" thread
started all this.
(below ) is the next step. Sir Apex(audio) said I could make IPS's of his creations ,
I have 3 more on the "burner" as well.
The amp in the pix is now being REALLY cooked (It's cold here now) - what
a heater - 135mv across the.22R emitter resistors.
I don't care if I burn this one - Found the Sanken 2SC4388/2SA1673's in an
old scrapped CAR amp ! No exposed metal slug on these outputs -
a "TO3PF /FM100" case style (no insulator required) .
They don't seem to mind 600ma of bias each ! I actually can feel the drivers
getting warm on this build.
The "beech" amp will "cook" many flavors of input stages - running a blameless
on it now .... perfect "test dog"
Edit - these particular outputs cycled 3mv at the "cooking" bias , down at 17mv
bias .05mv ! These are the closest to the MT-100 harmon kardon devices.
Beats the harmon kardon 680 by a factor of 10 (thermally). Cool .
OS
Wow - very nice OS! Congrats
Thank you Bonsai ... reading material on your site and the "CFA" thread
started all this.
(below ) is the next step. Sir Apex(audio) said I could make IPS's of his creations ,
I have 3 more on the "burner" as well.
The amp in the pix is now being REALLY cooked (It's cold here now) - what
a heater - 135mv across the.22R emitter resistors.
I don't care if I burn this one - Found the Sanken 2SC4388/2SA1673's in an
old scrapped CAR amp !
No exposed metal slug on these outputs -a "TO3PF /FM100" case style (no insulator required)
.They don't seem to mind 600ma of bias each ! I actually can feel the drivers
getting warm on this build.
The "beech" amp will "cook" many flavors of input stages - running a blameless
on it now .... perfect "test dog"
Edit - these particular outputs cycled 3mv at the "cooking" bias , down at 17mv
bias .05mv ! These are the closest to the MT-100 harmon kardon devices.
Beats the harmon kardon 680 by a factor of 10 (thermally). Cool .
OS
Attachments
Last edited:
Kypton C super-pair IPS
It lives ... Very stable ... clips like a Valve.
Nice to have the "beech" amp/OPS to burn it in.
Without a servo , simple matching will only get 80mv offset with a CFA
like this. SMD matched P/N input pairs might be better.
But , this one has a servo ... I just did not insert it yet.
I shall see what all the CFA "hysteria" is about , finally .
Edit - yup , "bomb proof" VSSA ... input pair temperature does not change
at all with hours of heavy VAS saturation (a CFA weakness).
OS
It lives ... Very stable ... clips like a Valve.
Nice to have the "beech" amp/OPS to burn it in.
Without a servo , simple matching will only get 80mv offset with a CFA
like this. SMD matched P/N input pairs might be better.
But , this one has a servo ... I just did not insert it yet.
I shall see what all the CFA "hysteria" is about , finally
.Edit - yup , "bomb proof" VSSA ... input pair temperature does not change
at all with hours of heavy VAS saturation (a CFA weakness).
OS
Attachments
Last edited:
Hi OS you have pull out servo i.c without any other modification?It lives ... Very stable ... clips like a Valve.
Nice to have the "beech" amp/OPS to burn it in.
Without a servo , simple matching will only get 80mv offset with a CFA
like this. SMD matched P/N input pairs might be better.
But , this one has a servo ... I just did not insert it yet.
I shall see what all the CFA "hysteria" is about , finally
Edit - yup , "bomb proof" VSSA ... input pair temperature does not change
at all with hours of heavy VAS saturation (a CFA weakness).
OS
Yes - the resistor at the mirror virtual ground was designed into it. (bomb proof ! )
The other module is only 12mv offset with a both a matched a1381/c3503 and
c1845/a992.
I did not have any more 3503E grades for the posted one (80mv offset).
What ? , think the IC will degrade sound ? NO WAY , it's not in
the signal path.
I won't mind the 1/10th mv offset it will give me. Edit - with the IC , raise or remove the ground resistor ... input
pair then "sees" the PSRR of the IC and zener shunt regulator , as well.
(another CFA "weakness".)
OS
Last edited:
Yes - the resistor at the mirror virtual ground was designed into it. (bomb proof ! )
The other module is only 12mv offset with a both a matched a1381/c3503 and
c1845/a992.
I did not have any more 3503E grades for the posted one (80mv offset).
What ? , think the IC will degrade sound ? NO WAY , it's not in
the signal path.
OS
What ? , think the IC will degrade sound ? NO WAY , it's not in
the signal path.
I won't mind the 1/10th mv offset it will give me. I don't think so but pulling out the servo is a good test to see matching condition.
Now i have only one pair 3503E ,1381E
Most DC servos inject a signal into the -IN input of the amplifier they are monitoring.What ? , think the IC will degrade sound ? NO WAY , it's not in
the signal path.
I don't think so but pulling out the servo is a good test to see matching condition.
Now i have only one pair 3503E ,1381E
Any DC servo that does this is in the audio path.
