Author Topic: pix of Custom built guitar amps/cabs  (Read 450887 times)

Rob Strand

Re: pix of Custom built guitar amps/cabs
« Reply #740 on: May 14, 2018, 08:42:07 PM »
Quote
JCM800 2204 head built into an old Marshall 8340 amp cabinet. Custom bent chassis for the head.
That's a great job.   
Send:     . .- .-. - .... / - --- / --. --- .-. -

diydave

Re: JCM800 2204 build
« Reply #741 on: May 15, 2018, 03:10:44 AM »
JCM800 2204 head built into an old Marshall 8340 amp cabinet. Custom bent chassis for the head.

Those are nice projects.  ;D
Build me a Super Champ (with a 6l6 instead of a 6v6) a few years back, in a solid state combo which just sat there.
Used the original chassis though. It's my main gig-amp for small venues.




stallik

Re: pix of Custom built guitar amps/cabs
« Reply #742 on: May 15, 2018, 03:59:02 AM »
Really nice job Lackey. The chassis looks like it came off the Bismark :)
Knobs look a little small to my eyes but then, I shove chicken heads on everything ::)
Insanity: doing the same thing over and over again and expecting different results. Albert Einstein

Govmnt_Lacky

Re: pix of Custom built guitar amps/cabs
« Reply #743 on: May 15, 2018, 09:28:14 AM »
Hold on, I think I found it.  You have no bypass cap on V1A cathode.  Stock value is 330u, but anything from 25u up will probably sound about the same.  BIG boost in gain and dynamics.

https://drtube.com/schematics/marshall/2204u.gif

Lol. Turns out it was my stupidity. I was plugging exclusively into the Low sensitivity input. When I finally plugged into the High.... it was MAGIC!!  :icon_lol:

Also, the original prints do not call for a bypass cap on V1a. It does have one for V1b (680n)

EDIT: I see what you are talking about now with the bypass cap. The build I did was based off the 50W Mk2. No bypass cap on V1a
« Last Edit: May 15, 2018, 10:45:21 AM by Govmnt_Lacky »
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Govmnt_Lacky

Re: pix of Custom built guitar amps/cabs
« Reply #744 on: May 15, 2018, 09:31:13 AM »
Nice, neat build BTW.  Where did you get the chassis custom bent?

It was done by a guy in Maine. He was referred to me by a member from another forum.

Quote
Here's something you don't want to hear, or bother with, but would be easy with eyelets...there would be some real benefit to reversing all of your coupling caps.  Lower noise (and maybe better tone) with the banded ends toward the plates.

These are not polarized caps. Why would their orientation make any difference?  :icon_confused:
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Govmnt_Lacky

Re: pix of Custom built guitar amps/cabs
« Reply #745 on: May 15, 2018, 09:32:53 AM »
Really nice job Lackey. The chassis looks like it came off the Bismark :)
Knobs look a little small to my eyes but then, I shove chicken heads on everything ::)

Knobs were chosen that way because I am still toying with the idea of getting custom faceplates done. If the knobs were too big then it would limit what I can do.
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
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thermionix

  • Guest
Re: pix of Custom built guitar amps/cabs
« Reply #746 on: May 15, 2018, 06:07:54 PM »
These are not polarized caps. Why would their orientation make any difference?  :icon_confused:

Outside foil.  The Sozos are properly marked (the band).  They work either way, had they been polarized caps they would have been destroyed.  There's a thread about it here with some links to good vids.

thermionix

  • Guest
Re: pix of Custom built guitar amps/cabs
« Reply #747 on: May 15, 2018, 06:12:03 PM »
The build I did was based off the 50W Mk2. No bypass cap on V1a

You could throw one on a switch and have both.  Might pop loudly so best to switch in standby.

davent

Re: pix of Custom built guitar amps/cabs
« Reply #748 on: May 15, 2018, 06:36:12 PM »
The build I did was based off the 50W Mk2. No bypass cap on V1a

You could throw one on a switch and have both.  Might pop loudly so best to switch in standby.

Put ~100k resistor between the cap and ground, use the switch to short out the resistor, should solve the pop.
dave
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Phoenix

Re: pix of Custom built guitar amps/cabs
« Reply #749 on: May 29, 2018, 04:37:13 PM »
I just added a thread on my new build here, but here's a sample photo:


amptramp

Re: pix of Custom built guitar amps/cabs
« Reply #750 on: May 29, 2018, 09:49:36 PM »
^^^
Tuning eye tube in the middle - nice!  Is it in the circuit as an amplifier or is it just used as an indicator?

Phoenix

Re: pix of Custom built guitar amps/cabs
« Reply #751 on: May 29, 2018, 09:53:01 PM »
Thanks Ron!
It's hooked up as a VU meter, so responds to your playing, but isn't in the signal path. There's a video linked in my other thread that shows it off.

thomasha

Re: pix of Custom built guitar amps/cabs
« Reply #752 on: May 30, 2018, 02:06:21 PM »
Just finished another one!

this time it's a JCM800 preamp pushing two ECL82 in PP.
The cab is made of mahogany, that's why it's so thin. Only used 1/2" planks! It's OK since it only has a 10" speaker...
Good thing is that it's not as heavy as expected, I can carry it around the house without a problem! Can't say the same thing from another amp that has a tube tremolo, tube reverb and 2x10"...









Cheers!

rankot

Re: pix of Custom built guitar amps/cabs
« Reply #753 on: May 30, 2018, 03:01:29 PM »
How many watts you can get from two ECL82 in PP?
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Govmnt_Lacky

Re: pix of Custom built guitar amps/cabs
« Reply #754 on: May 30, 2018, 03:40:30 PM »
Thomas,

Are you creating your own plates or are you using pre-drilled chassis with pre-printed labeling plates?

I would LOVE to get some made for my latest amp build but, I have no idea where or how to get some done for the custom design.
A Veteran is someone who, at one point in his or her life, wrote a blank check made payable to The United States of America
for an amount of ‘up to and including my life.’

davent

Re: pix of Custom built guitar amps/cabs
« Reply #755 on: May 30, 2018, 04:22:10 PM »
That face plate could be waterslide decals on the back of 1/16" polycarbonate or acrylic then sealed in with gold paint.

dave
"If you always do what you always did- you always get what you always got." - Unknown
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thomasha

Re: pix of Custom built guitar amps/cabs
« Reply #756 on: May 30, 2018, 04:39:18 PM »
the waterslide idea is a good one, but I used a transparency. Just printed it mirrored and used some clear coat over the print.
Then I drilled the chassis and painted it gold. When the chassis was dry I glued the transparency to the chassis.
You can also add the acrylic plate over it to protect the transparency. The pots and jacks hold the plate in position.
« Last Edit: May 30, 2018, 04:48:31 PM by thomasha »

stallik

Re: pix of Custom built guitar amps/cabs
« Reply #757 on: May 30, 2018, 06:12:58 PM »
Lovely build
Insanity: doing the same thing over and over again and expecting different results. Albert Einstein

Joncaster

Re: pix of Custom built guitar amps/cabs
« Reply #758 on: May 31, 2018, 08:29:06 AM »
Really lovely. That mahogany is a great choice with the gold.
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amptramp

Re: pix of Custom built guitar amps/cabs
« Reply #759 on: May 31, 2018, 06:35:24 PM »
How many watts you can get from two ECL82 in PP?

This tube is the same as the 6BM8 and should be good for 8 watts in push-pull.