carlosfm said:And how does it sound?
I'm terrible at describing what I hear, but I'll give it a shot.
Compared to the "standard" gainclone values (22K and 680ohm) I noticed a shift away from the HF, which I always thought was a little exaggerated before. I also noticed some separation and textures that I'd not heard before - and this was on music with which I'm quite familiar.
This was with only a couple of hours on the amp. It's certainly worth trying! I think I'm going to prefer it in the long run.
-in.
carlosfm said:
I figured you had it sorted Carlos.
I just wanted to point this out to others who might build. I saw some people using 1/8W resistors in their photos of other projects.
I used a .6W Beyschlag metal film. It's the perfect size to fit between the pins on the underside of the board.
Listening some more this morning, I remain very impressed. Good work!
Update: a hell of an amp
With the second snubber near the chip, there are advantages in using bigger caps than 100uf.
I started testing with 470uf and yes, extreme bass gets tighter.
Then I tested 2,200uf and...
This is it!
Midband and treble are gorgeous, as ever, but the bass is really on another league.
PS: If you are wondering, I do not test amps with choral music.
There's a good recording from the beginning of the 90's (!) that always was a good test: Counting Crows - "August and everything after".
Believe me, very few amps can drive my Epos speakers with this disc.
This one does it:
With the second snubber near the chip, there are advantages in using bigger caps than 100uf.
I started testing with 470uf and yes, extreme bass gets tighter.
Then I tested 2,200uf and...
This is it!
Midband and treble are gorgeous, as ever, but the bass is really on another league.
PS: If you are wondering, I do not test amps with choral music.
There's a good recording from the beginning of the 90's (!) that always was a good test: Counting Crows - "August and everything after".
Believe me, very few amps can drive my Epos speakers with this disc.
This one does it:
Attachments
homer09 said:
Buy the CD if you find it.
It's all good, a peasure to listen.
The bass is impressive, and a joy to listen when it's really tight and detailed. You have to follow the finger on the string.
I can pick these tracks for testing:
2. Omaha
4. Perfect blue buildings
5. Anna Begins
6. Time and time again
7. Rain King (notice the guitar on the left channel)
8. Sullivan street (shocking bass guitar!
)11. Raining in Baltimore (close your eyes and follow this
)So... it's almost all the album.
The tracks I left out are very good music too.
PS: This Is to be heard LOUD AND CLEAR.
Re: Re: Update: a hell of an amp
Sorry about the ealier post. I fat fingered the post button accidently. Moderator pls delete it.
Carlos,
I am about to begin building a Brian GT 4780 amp with your snubber. I would very much like to incorporate your newest upgrades. What would I need to change, if anything to adapt this to the 4780. I am about finished with the chassis and will probably begin on the PSU either this weekend or the next. I would really appreciate any advice/help you can give me. I would love to post the results. My experience is limited however in that I've only built two Brian GT 3785s. This will be my third DIY amp.
Thx
Mike
kestrel200 said:
Sorry about the ealier post. I fat fingered the post button accidently. Moderator pls delete it.
Carlos,
I am about to begin building a Brian GT 4780 amp with your snubber. I would very much like to incorporate your newest upgrades. What would I need to change, if anything to adapt this to the 4780. I am about finished with the chassis and will probably begin on the PSU either this weekend or the next. I would really appreciate any advice/help you can give me. I would love to post the results. My experience is limited however in that I've only built two Brian GT 3785s. This will be my third DIY amp.
Thx
Mike
Counting Crows
I don't usually agree with CarlosFM, but I have to say that he is correct in that the Counting Crows album- "August and everything after" is a great reference recording, all the way through. I have used it myself continuously since it was released. The other (subsequent) Counting Crows albums are not as good. Speaking of reference recordings, check (and add to) this post (my contrubtion here). Hey, I mention this one, check out the others.
I don't usually agree with CarlosFM, but I have to say that he is correct in that the Counting Crows album- "August and everything after" is a great reference recording, all the way through. I have used it myself continuously since it was released. The other (subsequent) Counting Crows albums are not as good. Speaking of reference recordings, check (and add to) this post (my contrubtion here). Hey, I mention this one, check out the others.
cjd said:How does it sound regulated?
I am testing.
Let me answer to that here:
http://www.diyaudio.com/forums/showthread.php?postid=625807#post625807
carlosfm said:
Carlos,
Can the 2.21K / 66 be used in order to get x33 gain as 22K/680 version?
I have the following [costly] things on hand and considering if it worth giving it a try using these components?
2x LM3875TF
2x 2.21K Dale RN60D
2x 66 Dale RN60D
2x 15K Dale RN60D
2x 0.22 /3W 2% Dale ( audio grade).
2x 220 Dale carbon film ( audio grade).
4x 22K Kiwame carbon 2W
4x cap 1,000UF 50V Pana FC.
2x cap SCR MKP 2.2UF250V
ALPS Blue pot 100K
Transf 18-0-18 180VA
Transf 25-0-25 250VA
.
.
.
If so, what is the best config/things it can get with NAD CD521 BBE Speaker 88 W/Db/m ??
?
nina said:
Please stay with the 100R resistor to ground and use 3.3k for feedback.
nina said:I have the following [costly] things on hand and considering if it worth giving it a try using these components?
...
2x 2.21K Dale RN60D
2x 66 Dale RN60D
2x 15K Dale RN60D
Keep them for something else.
Concentrate on what really makes a worthwhile difference.
nina said:
This is not good.
You will have much better results by using a 10k or 20k pot.
nina said:
Use the 25-0-25 trafo.
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