24V guitar amp

[iccaros]

Here is my Amp I have been working on. It runs on 24 volts and is not a plate staved design.  I wanted some input and not take up anothers thread.
I am changing the bypass caps on the pentodes, but still playing with values.


For this first version I used 2 12k5 in parallel (I did not have a PP transformer at the time)
and 2 12u7 as pre-amp
Here is the design missing the first 12u7 (you can substitute a 12Au7 as they are the same tube, with the 12u7 certified for 12v operation) , I am still working on that part.


here is a sample, build on bread board, so I get some noise..

[iccaros]

My build out so far

My first Chassis, I got a break @ harbor Freight
Still learning



After base Paint

[zambo]

I am loving that chassis! I need to get a break as well. I intend to build on of these amps soon. 

[iccaros]

I am loving that chassis! I need to get a break as well. I intend to build on of these amps soon. 

got the 30" http://www.harborfreight.com/30-inch-bending-brake-67240.html

Had a 20% off coupon

Next is a drill press... And learning to paint..

[petemoore]

  This seems to be prime example of "Just barely enough, none more approach removes the artifacts associated with higher intensity".
   Excellent soundclips, thank you for sharing amp build reports.
  I used to repulse listeners with high intensity amplification devices.
   This clip reminds me of when We used to have 'hot-westinghouse' jamms with tennis shoes and live-grounds. The featherweight speakers sitting on kitchen table would play all night, attracting rave reviews, no complaints.   

[petemoore]

  Less often as time goes by, a review puts new order to the list I've been attempting to make a low priority.
   Thank you for sharing the amplifier build reports !
  I noticed there seemed to be an absence of artifacts which I associate with high intensity amplification devices.

[iccaros]

Thanks... Glad someone liked my fumbling..  Will have the completed build done this weekend I hope..

I am working next on the 1 watt version.. I do not see it being much louder..  But will be push Pull and I am looking for a tube Rectifier for sag...  There are some 7 pin car version..

[iccaros]

Build with graphics...




I will update schematic and add video - sound tonight

[iccaros]

video

[bluesman1218]

Very nice!

[iccaros]

@all, the whole board

I want to add a line out or use this strait in for recording.. How would I do that.. Thanks

[bluesman1218]

Here's your Direct Out


Here's a really cool, and simple, mod. A Bright, Fat Full switch. You'll never want to play an amp without one, after you try it!


For a photo essay of my Silvertone 1482 rebuild, check out my photo album at http://www.facebook.com/pages/VintageToneUSA/201522306547361?sk=photos

[iccaros]

to review.. I am slow..

R2 and R1 come off my the speaker jack to a new jack yes

and for the fat/boost/bright
If I put a pot on the end of the switch to ground, would that be like a presence mod?

Thanks

[bluesman1218]

to review.. I am slow..

R2 and R1 come off my the speaker jack to a new jack yes  YES

and for the fat/boost/bright
If I put a pot on the end of the switch to ground, would that be like a presence mod?   don't know, I'd have to look it up - been a long while since I did this.

Thanks

[iccaros]

Thank you.. Will repost when I add the line out..

I am also trying to clean up the mids, may just go to the PP design for that..

[El Heisenberg]

Ive built this too. At first is was just the sopht amp version, but iccaros did the parallel 12K5 and gave me the tubes to try it out.

I have to fix my heater wiring. The 12AE7 is wired in series with the 12K5s which are wired parallel.

[iccaros]

Ive built this too. At first is was just the sopht amp version, but iccaros did the parallel 12K5 and gave me the tubes to try it out.

I have to fix my heater wiring. The 12AE7 is wired in series with the 12K5s which are wired parallel.

once that is done.. Any clips?

[El Heisenberg]

I have the cheapest mic radioshack sells. A 1/4 inch jack. Only way to do it is plug that directly into my 2001 compaq presario laptop and record with audacity.

[iccaros]

I use my cheap cam corder ( >$60).. and my phone.. so who am I to judge...

[El Heisenberg]

Ok but lemme work some things out.

Last nite i measured B+ and it was 16.8v. Heaters were at 10v!!! The 24v ct transformer wasnt enough. I bought a 24v ct 2A from radio shack and B+ was still too low. I lowered my RC resisor to 22 ohm 2 watt and now B+ is 24.5v . Heaters are at 12.6 tho.





In the sopht amp design i started with the rc resistor was 62 ohms.