Carolina Blues Special build for a friend

[BarryW]

I wanted to post this build that I'm doing for a friend, as tubenit was so kind to not only document this so well but to answer questions to assist.  What a great guy, and what a superb forum - my thanks to everybody here, I keep learning so much, and so much is due to this forum.

Not the most beautiful build, and it's definitely not done yet.  I used weber W025130 PT and 404248 tranny, as well as their choke and reverb tranny.  I'll post my ugly layout, I do it in my own style so I apologize if it's hard to read.  It's in the tweak stage for me - I love the sound, but the guy I'm building for really needs something with more gain, closer to an 18 watt lite with reverb.  Not sure how much tweaking I'll do, as several other builds await - but I still need to reduce the cathode resistor to get the tubes a bit closer to 12 watts.  I'm waiting for a few smaller resistors now.  I'
I'm finding the reverb a bit thin and tinny, but I'm wondering if that isn't just the reverb pan. 

So for now, here it is, with my gratitude:



Layout is attached, I think -

[tubenit]

Man, I think that looks great!   Thanks for sharing the photo.

It's a very tweakable amp. Lots of tonal options there that you can get.  Still one of my very favorite amps.

With respect, Tubenit

[SILVERGUN]

Nice work Barry....it's always great to see an amp come to life from a pile of parts
In reading your post, I can relate to the idea of being built but not "finished".......mine's been "not finished" for 6 months 

But because of that, I have learned a lot through trial and error, and tubenit (and some other guys) have walked me through a lot of that process......tweaking can be very rewarding AND frustrating, and I hope you are able to get this amp where your friend needs it to be.....

With that said,,,,I'd like to be the first to cast an idea your way (a very obvious idea, but something you may not have thought to do to increase gain)
You can try a 12AX7 in the V1 position, and see how that sounds....
And then you could try placing a parallel resistor (of the same value that is there) across the cathode resistor for that same tube.....that will lower that total resistor value by 50% (from 2.2K to 1.1K) and definitely increase gain in that stage....
With that gain increase will come the potential for some noise, and the only thing I can tell you to try for now, is:
 Replace the wire from your input jack to the 27K input grid resistor to shielded wire, and move the 27K input resistor off of the terminal strip and attach it directly to pin 2 on that tube socket (that is a common method for reducing input noise)

Those 1 or 2 moves might create enough gain to satisfy your friend,,,,,but remember,,,,anything you change from T's design will take you away from T's design........and this amp WILL wind up sounding and feeling differently than originally intended.....and that could be a good thing or a bad thing... 

Good luck, have fun, be safe, and please update us on the results of your tweaking....it's fun for us too!

[BarryW]

thanks for the kind words - yep, I love changing parts into noise.  And you're right, the tweaking is really the fun part.  Yep, I have already tried the 12ax7 - it's closer, but still not there.  I will try dropping the cathode resistor to increase gain at V1 to see what I get.  Yes, I use shielded wire and move the grid resistors closer to pin 2 when necessary, but we'll see what develops.

I have to admit, no matter what I do, I'm more of a gainy guy myself.  I just build a 6v6 plexi, it is nice and juicy indeed.
And again, thanks for the kind words!  If I get anywhere I'll definitely post.  I do so appreciate the quality, kindness, generosity and spirit of this place.  Thanks!

[eleventeen]

You OK with 1/2 watt screen resistors? Kind of asking for it, IMHO.

[BarryW]

They are temporary, as are many parts as this is a test/prototype for this guy. But I do believe they are 1watt CF.

edit - no they weren't 1w, good catch!  I've got replacements finally . . .

[Ed_Chambley]

Nice to see you working on amps again.  You are them man.  Love me some tagstrip.  Please let us know how she turns out.  Is it going to be a head or combo?

[BarryW]

Thanks - it's a lot of fun, I love it. It's intended to be a head.