Carolina Blues Rocket schem

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10thTx
Posts: 1863
Joined: Sat Dec 30, 2006 1:13 am

Carolina Blues Rocket schem

Post by 10thTx »

Edit: I renamed the amp a Carolina Blues Rocket


The chassis has (at most) room for 7 pots on the front. It would have a paralleled V1 (5751) followed with two gain stages instead of the 3 gain stages of the D'Lite. Also would be cathode biased with some different values in the LTPI.

I am not trying to capture an exact Dumble sound. I am looking more for a tone between Marshall/Fender and Dumble.

The amp I am considering converting is my Plexi 25w reverb amp.

http://s28.photobucket.com/albums/c2...lexi25RMTS.gif

If you attempted using the schematic topology I drew up what changes would you recommend trying?

10thtx
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Last edited by 10thTx on Tue Jul 15, 2008 2:23 pm, edited 1 time in total.
10thTx
Posts: 1863
Joined: Sat Dec 30, 2006 1:13 am

amp is built

Post by 10thTx »

I have now built and tweaked this amp. It sounds fantastic and is VERY touch sensative with incredibly smooth overdrive to it. I am pleased with this amp.

I have built 14 amps prior to this and this is by far the most touch responsive of any I have built or played. Play soft and it stays clean, dig in and it goes into a great sounding smooth overdrive. I don't know if the paralleled V1 (5751) contributes to the smoothness or not?

I am surprised the amp is as quiet as it is at idle. It has NO hum issues at all and no oscillations with everything cranked up to 7-8. Like other higher gain amps, it does have some "white noise" when everything is being cranked up towards 10.

It does not sound like a Dumble, Fender or Marshall but has a unique tone of it's own that I am happy with.


http://s28.photobucket.com/albums/c216/ ... ampcab.jpg

http://s28.photobucket.com/albums/c216/ ... terior.jpg

http://s28.photobucket.com/albums/c216/ ... terior.jpg

With respect, 10th Tx
Last edited by 10thTx on Tue Jul 15, 2008 6:49 pm, edited 1 time in total.
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Bob-I
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Location: Hillsborough NJ

Re: Carolina Blues Rocket schem

Post by Bob-I »

Very cool. Looks like what we've assumed Carlton has been using, only a single OD stage instead of 2, but the parallel 5751 looks like a great idea too. I'd like to hear it.
10thTx
Posts: 1863
Joined: Sat Dec 30, 2006 1:13 am

schematic and layout

Post by 10thTx »

For those who have ExpressSCH installed, there is a editable schematic and layout here:

http://www.el34world.com/Forum/yabb2/Ya ... 1213550415

ExpressSCH
http://www.expresspcb.com

The schematic below is what I ended up with after tweaks.

I currently don't have a means to post sound bits unfortunately.

With respect, 10thTx
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sportster4eva
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Re: Carolina Blues Rocket schem

Post by sportster4eva »

Nice work! That head cab is gorgeous! :shock:
Sometimes I'm good, then I'm bad..
10thTx
Posts: 1863
Joined: Sat Dec 30, 2006 1:13 am

Carolina Blues Rocket 6V6

Post by 10thTx »

The Carolina Blues Rocket is set up cathode biased in a way that I can switch out 5881's and 6V6's without re-biasing.

So I tried 6V6's in this with an Emminence Red, White and Blues speaker. It is the smoothest sustain/overdrive of any amp I have built or played.

I've heard Larry Carlton and Sonny Landreth live playing Dumbles, so I don't think this amp really sounds "like" a Dumble. (it does sound a little bit like Robben Ford's amp on the tune "Bad Sign" but not the same)

However, it does have a smoothness, harmonics and overdrive characteristics somewhat like a Dumble. The amp is so touch sensative that I am finding it both a challenge and an enhancement to my playing. It reveals more mistakes but allows more nuances and expressions in the playing to cut thru.

With respect, 10thtx
10thTx
Posts: 1863
Joined: Sat Dec 30, 2006 1:13 am

Final tweaks for Carolina Blues Rocket

Post by 10thTx »

I got out my resistor and cap substitution boxes and A/B some different components. Plus I added a passive effects loop which works great with a Boss DD-6 delay.

I now have 4 switches:
- PAB
- 44m/.047 nfb on/off
- overdrive gain stage on/off
- NFB from PI on/off

I am VERY pleased with the tone of this build. It's pretty versatile and I can get sort of a nice Dumble/Marshall hybrid tone at decent lower volumes. It's been a very rewarding build with smooth overdrive and nice harmonics to it.

With respect, 10thtx
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10thTx
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Carolina Blues Rocket layout

Post by 10thTx »

I might add that the amp is quiet at idle. Using delay with it, gives it a very smooth sustained "clean on the verge of breaking up" tone as an option.

It is one of the most touch sensative amps that I've played.
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RHGraham
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Re: Carolina Blues Rocket schem

Post by RHGraham »

Cool design, congrats on the build

You'd be able to try some 6L6's in that amp too wouldn't you? Have you tried any yet?

Love that mahogany also...

8)
Randal
Blues Junkie
10thTx
Posts: 1863
Joined: Sat Dec 30, 2006 1:13 am

6L6's

Post by 10thTx »

Sure, you can use 6L6's with the amp. I like the TungSol 5881's and they put out a little less wattage. My guesstimate is the amp is putting out around 23 watts at the volume I play it at cranked.

10thtx
RHGraham
Posts: 57
Joined: Fri Feb 08, 2008 6:36 pm

Re: Carolina Blues Rocket schem

Post by RHGraham »

Well thanks much for sharing the info and schems, gave me some good stuff to think about, cool amp.
Randal
Blues Junkie
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Structo
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Location: Oregon

Re: Carolina Blues Rocket schem

Post by Structo »

Hi, I was checking out your threads at the Hoffman forum.
How come I can't see the layouts in the posts when you refer to them?
Tom

Don't let that smoke out!
10thTx
Posts: 1863
Joined: Sat Dec 30, 2006 1:13 am

schematics and layouts

Post by 10thTx »

Every amp I have personally built has a schematic and layout here:

http://www.el34world.com/Forum/index.php?board=12.0

There are probably a hundred editable schematics in that library & many layouts available also.


With respect, 10thtx
10thTx
Posts: 1863
Joined: Sat Dec 30, 2006 1:13 am

CBR -Jr.

Post by 10thTx »

I tried another version of this amp leaving out the overdrive gain stage. I actually like this one better. It still is VERY articulate and has a nice clean sounding sustain to it.

I'm using a Emminence Cannabis Rex speaker.

It has three switches:

- switch in the NFB around 2nd gain stage. It sounds less compressed
with the NFB off
- PAB
- NFB around the power amp. Switching the NFB off gives a big jump in
gain.

I can get quite a variety of tone from very clean to overdriven with this.
The component values are a result of experimenting with what I like.
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stiltamp
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Re: Carolina Blues Rocket schem

Post by stiltamp »

I'm interested in the Caroline Blues Rocket amp.
In the schematic the plate Resistor of V2a is connected to the power supply node which is marked with E in the layout the node is marked with D.
Which is the the right connection?
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