Author Topic: pix of Custom built guitar amps/cabs  (Read 391639 times)

stallik

Re: pix of Custom built guitar amps/cabs
« Reply #720 on: February 19, 2018, 08:35:59 AM »
Dunno. He refers to different voltage transformers so I presume some must go as far as the States. Drop him a mail
Insanity: doing the same thing over and over again and expecting different results. Albert Einstein

roseblood11

Re: pix of Custom built guitar amps/cabs
« Reply #721 on: February 19, 2018, 08:55:11 AM »
This is my mini AC-30, with normal and top boost channels into push-pull power amp based on an ECC99. It has a 10“ Elac speaker from 1965.


http://musikding.rocks/index.php/Image/447-Mini-AC-30/

stallik

Re: pix of Custom built guitar amps/cabs
« Reply #722 on: February 19, 2018, 11:20:49 AM »
That looks very nice
Insanity: doing the same thing over and over again and expecting different results. Albert Einstein

thomasha

Re: pix of Custom built guitar amps/cabs
« Reply #723 on: February 19, 2018, 12:52:14 PM »
That coke bottle looks awesome!
I always thought those tubes were power holes, some old radios used some that had hungry heaters.
Are there any low wattage NOS options too?
I found the 6G6G as power tube. Just need a double triode or even pentode to make an all coke bottle amp!

roseblood11 that cab looks like a projector amp/speaker box. Have you refinished it or have you made the box from scratch?

rankot

Re: pix of Custom built guitar amps/cabs
« Reply #724 on: February 19, 2018, 02:16:19 PM »
The circuit started with the circuit from Doug: http://www.dougcircuits.com/neon.html
Unfortunately the AC4 build page is down.
I used in mine an OPAMP LFO, cause the Neon light wasn't working in a periodic way, it was more like a random tremolo.

The imput has 4 configurations, EF86, 12ax7, both in series, both in parallel, which gives some nice different tones, from clean to mean.


Could you share schematic for this in some better resolution?
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Ben N

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Re: This is silly.
« Reply #725 on: February 20, 2018, 08:27:11 AM »
Got the four 4 1/2" full range speakers from Parts Express for cheap.  Sounds exactly like what one would expect from little speakers, thin, no bottom end, but it's hilarious.
Have you thought about porting the cab to get more bass out of it?

thomasha

Re: pix of Custom built guitar amps/cabs
« Reply #726 on: February 20, 2018, 02:28:24 PM »

rankot

Re: pix of Custom built guitar amps/cabs
« Reply #727 on: February 20, 2018, 03:12:28 PM »
Thanks a lot! I presume V1 is 12AX7, V2 is EF86 and V3 is EL84?
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thomasha

Re: pix of Custom built guitar amps/cabs
« Reply #728 on: February 20, 2018, 05:25:17 PM »
yes, haven't seen that...

mth5044

Re: pix of Custom built guitar amps/cabs
« Reply #729 on: February 21, 2018, 01:05:15 AM »
This is my mini AC-30, with normal and top boost channels into push-pull power amp based on an ECC99. It has a 10“ Elac speaker from 1965.

http://musikding.rocks/index.php/Image/447-Mini-AC-30/

That’s really cool!! You wouldn’t happen to have the schematic for it?

stallik

Re: pix of Custom built guitar amps/cabs
« Reply #730 on: April 01, 2018, 05:00:48 PM »
Spent much of today putting together a test cab for a vintage 30 to go with my new champ clone. Wanted as small a box as possible. Did a nice job of it and it sounds good clean but with distortion is really boxy. Bummer. Start again
Insanity: doing the same thing over and over again and expecting different results. Albert Einstein

thermionix

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Re: pix of Custom built guitar amps/cabs
« Reply #731 on: April 01, 2018, 07:00:55 PM »
Spent much of today putting together a test cab for a vintage 30 to go with my new champ clone. Wanted as small a box as possible. Did a nice job of it and it sounds good clean but with distortion is really boxy. Bummer. Start again

Is the V30 brand new or broken in?

vigilante397

Re: pix of Custom built guitar amps/cabs
« Reply #732 on: April 02, 2018, 01:11:11 AM »
Is the V30 brand new or broken in?

That can be a huge deal. I bought a 2x12 with vintage 30's brand new and I hated the sound. So I let a friend borrow the cab for a few weeks and when he brought it back it sounded AMAZING.
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stallik

Re: pix of Custom built guitar amps/cabs
« Reply #733 on: April 02, 2018, 04:07:16 AM »
It's  used. eBay job, apparently the seller decided he wanted a hybrid 2x12 and this is the one left over.
Insanity: doing the same thing over and over again and expecting different results. Albert Einstein

stallik

Re: pix of Custom built guitar amps/cabs
« Reply #734 on: April 02, 2018, 02:17:26 PM »
My speaker cab sounds a lot better with a closed back but still not right. Did some guesstimations on some the internal volumes of some commercial cabs based on their external size less what I think is the thickness of the wood and most are in the ballpark of .45m2
Mine was much less so I knocked up an extension to the existing cab and it worked much better.
I'm going to end up with a cab far larger than I wanted >:( I think the volume is the critical bit so I'll play with the dimensions a bit so I don't end up with a cube. There's obviously a reason why good 1x12's are either wide or deep
Insanity: doing the same thing over and over again and expecting different results. Albert Einstein

Govmnt_Lacky

JCM800 2204 build
« Reply #735 on: May 14, 2018, 04:04:56 PM »
JCM800 2204 head built into an old Marshall 8340 amp cabinet. Custom bent chassis for the head.

Some highlights:

- Used Sozo caps in all the right places
- Used metal film 1% 1W resistors in place of the 1/2 watt. In the power sections I used the recommended 2 or 3W versions. 5W on the power tubes
- Used Mullard tubes throughout. EL34s (matched) and 12AX7s
- I wanted to maintain a black and silver theme to the build. The fuse holders are not going to stay. Replacing with black ones.
- Added external tube bias test points and external bias pot for, you guessed it... easy external biasing  ;)
- Getting a custom name plate 3D printed to put in place of the old Marshall plate. Hope to get that on very soon. Also going to get some name plates for controls done at a local trophy shop sometime in the near future.

The cabinet was a re-use from a Marshall 8240. Had to get a chassis bent to fit the space. The speakers are hand-me-downs that came with the cabinet. They are not impedence matched (one is 8ohm, the other is 16 ohm) but they sound good for now until I can get a pair of Celestions.

I do think that I need to look into this amp a bit more. The tone stack sounds very flat to me AND, I am not getting any break-up even when the Master and Pre-amp controls are dimed. I initially thought that I would get something but, I may be wrong. Maybe one of you with experience on the JCM800s can elaborate.

Anyways, here are some pics.







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Kipper4

Re: pix of Custom built guitar amps/cabs
« Reply #736 on: May 14, 2018, 04:33:16 PM »
Neat :) Jelous......
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otherwise, you might end-up with SOIC or gullwings, for surface mounts."


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vigilante397

Re: pix of Custom built guitar amps/cabs
« Reply #737 on: May 14, 2018, 05:06:44 PM »
In all seriousness I love the Celestion Rocket 50. It's a super cheap speaker made by Celestion for Nady (not sure what they went in) but I put one in an amp project and LOVED the way it sounded.

Great looking build. I know you've been working on it a while and I've been looking forward to seeing it. It was worth the wait 8)
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thermionix

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Re: pix of Custom built guitar amps/cabs
« Reply #738 on: May 14, 2018, 08:20:01 PM »
Quote
I am not getting any break-up even when the Master and Pre-amp controls are dimed

Well that doesn't sound right.  Maybe a weak preamp tube?  Those "reissue" Mullards can be hit or miss.  Do you get much dirt with the gain up but master low?  It shouldn't be JCM900 levels, but some at least.  How hot are your power tubes biased?


Nice, neat build BTW.  Where did you get the chassis custom bent?

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.
« Last Edit: May 14, 2018, 08:33:22 PM by thermionix »

thermionix

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Re: pix of Custom built guitar amps/cabs
« Reply #739 on: May 14, 2018, 08:31:58 PM »
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