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
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:
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:
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.
Any DC servo that does this is in the audio path.
