Hoffman Amplifiers Tube Amplifier Forum

Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TIMBO on August 26, 2017, 10:22:44 pm

Title: Cigar Box Guitar Amp
Post by: TIMBO on August 26, 2017, 10:22:44 pm

Hi guys, Completed the CBG and might I say sounds very bluesy.
http://el34world.com/Forum/index.php?topic=22282.0 (http://el34world.com/Forum/index.php?topic=22282.0)

So now to construct an amp.

Searching through our list of local built amps the "AMPLIVOX" looks COOL.
http://www.ozvalveamps.org/amplivox.htm (http://www.ozvalveamps.org/amplivox.htm)

Got pretty much everything I need to build.
(http://i.imgur.com/SQADFNL.jpg)
Thoughts on what this would sound like......

Title: Re: Cigar Box Guitar Amp
Post by: PRR on August 27, 2017, 06:38:43 pm

That has a hell of a lot of gain.

I dunno if guitars were so weak, or if those values are mis-read.

I'd think it would hiss madly if turned up, then when you play hammer the poor 6V6 senseless.

Go ahead and build it. It may work for modern headbanger styles. If too-too much, you can triode strap one of those pentodes.

Title: Re: Cigar Box Guitar Amp
Post by: shooter on August 27, 2017, 08:26:41 pm

Quote

That has a hell of a lot of gain.

my thought was the poor 6V6 doesn't have a clue what's coming :icon_biggrin:

Title: Re: Cigar Box Guitar Amp
Post by: TIMBO on August 28, 2017, 03:18:13 am

Hi guys, My schematic maybe somewhat guessed.
http://www.ozvalveamps.org/amplivox/amplivoxcct.jpg (http://www.ozvalveamps.org/amplivox/amplivoxcct.jpg)

This is the circuit that was the basis of the design and the component values were from other similar circuits that used those valves.

Title: Re: Cigar Box Guitar Amp
Post by: John on August 28, 2017, 04:13:38 am

I'd start with 68k plate, 470k screen resistors if I was doing it. Make 'em easy to change out (or use a sub box) to find the sound you like.

Title: Re: Cigar Box Guitar Amp
Post by: TIMBO on August 29, 2017, 05:30:45 am

Hi guys, One of the local blokes put me onto an amp out of the Radio and Hobbies mag from long ago.
http://americanradiohistory.com/Archive-Radio-and-Hobbies/40s/Radio-and-Hobbies-1942-06.pdf (http://americanradiohistory.com/Archive-Radio-and-Hobbies/40s/Radio-and-Hobbies-1942-06.pdf)
(http://i.imgur.com/qD2SoWY.jpg)
The original schematic
(http://i.imgur.com/N2aoi4s.jpg)
Some values subbed with todays values.
Might work much better.

Title: Re: Cigar Box Guitar Amp
Post by: TIMBO on September 03, 2017, 04:51:38 am

Hi guys, A good day in the shed.
(https://i.imgur.com/U5dODs2.jpg)
(https://i.imgur.com/kqd38F5.jpg)
(https://i.imgur.com/65uE5vA.jpg)
(https://i.imgur.com/zZFJQvH.jpg)
(https://i.imgur.com/egDENLN.jpg)
(https://i.imgur.com/puUUMBI.jpg)
(https://i.imgur.com/gjnerEs.jpg)

Title: Re: Cigar Box Guitar Amp
Post by: DummyLoad on September 06, 2017, 12:34:26 am

sweet amplifimacatin' jalopy!


--pete

Title: Re: Cigar Box Guitar Amp
Post by: TIMBO on September 09, 2017, 06:02:59 pm

Thanks Pete, You know all the right words to say.  :icon_biggrin:

This one has fired up well.
(https://i.imgur.com/aVEN7Gr.jpg)
(https://i.imgur.com/fS9jxm2.jpg)

The schematic shows a 47k/1w in the power supply, but I have a 33k in at the moment.
Would V1 benefit with a higher plate voltage, say changing the 33k to 27-22k.

Sounds good as is.

Title: Re: Cigar Box Guitar Amp
Post by: bnwitt on September 09, 2017, 06:46:51 pm

Very cool.  How's it sound Timbo?

Title: Re: Cigar Box Guitar Amp
Post by: TIMBO on September 12, 2017, 02:20:31 am

Thanks mate, Some finished photo's.
(https://i.imgur.com/0K5lkCE.jpg)
(https://i.imgur.com/dtOaZr8.jpg)
(https://i.imgur.com/NQ7Bcy3.jpg)
(https://i.imgur.com/llOCzdc.jpg)
(https://i.imgur.com/50L1wce.jpg)
(https://i.imgur.com/m0emuUg.jpg)
(https://i.imgur.com/8x0Iz28.jpg)
Some sound clips.
https://www.youtube.com/watch?v=FCUwEmmxAb4&feature=em-upload_owner (https://www.youtube.com/watch?v=FCUwEmmxAb4&feature=em-upload_owner)
https://www.youtube.com/watch?v=QohZmn_akjs&feature=em-upload_owner (https://www.youtube.com/watch?v=QohZmn_akjs&feature=em-upload_owner)

Title: Re: Cigar Box Guitar Amp
Post by: John on September 12, 2017, 06:15:33 am

Sounds great, and nice playing too!