$299 Gibson tube amp - Made in USA! - Page 27

rlowe · April 20th, 2008, 03:02 PM

I added the tap and hooked her up to a Mesa cab with a 12" Black Shadow speaker. I think these are celestions. Anyway, sounds much fuller with later breakup.

Guitarslinger1 · April 20th, 2008, 05:19 PM

Quote:

Originally Posted by rlowe

I added the tap and hooked her up to a Mesa cab with a 12" Black Shadow speaker. I think these are celestions. Anyway, sounds much fuller with later breakup.

Cool idea.

What's the current rating on the mini switch?

rlowe · April 20th, 2008, 07:12 PM

Quote:

Originally Posted by specialty guitars

Cool idea.

What's the current rating on the mini switch?

6 amps at 125. Any idea what the demand is on the output?

R

Guitarslinger1 · April 20th, 2008, 07:23 PM

Quote:

Originally Posted by rlowe

6 amps at 125. Any idea what the demand is on the output?

R

It should be fine.

I believe it's around 1 - 2 amps @ 5 volts or so.

Rob DiStefano · April 21st, 2008, 04:58 AM

Quote:

Originally Posted by TNO

I got my CVA8 yesterday. It's got smoother highs than the stock speaker and better bass but it's pretty loose in the low end. Probably get better once it's broken in. I emailed Mojo to see if they'd consider making 10" baffles for the GA-5.

I thoroughly investigated installing a 10" speaker, and even considering building a new baffle (which I did for a more robust 8") a 10" will NOT be a direct drop-in as there just isn't enough room between the lip of the 10" speaker and chassis - not to mention clearing the power tube. SO, besides creating a new baffle, some mods to the chassis and/or speaker will be in order. AND, the speaker will overlap and be blocked by a portion of the cab's TV front. IMO, not worth the effort for the small gain. Going to a 12" driver or multi speaker outboard cab makes a much bigger/better difference, IMO.

Read/view this ...

http://www.tdpri.com/forum/amp-centr...ml#post1141378

Guitarslinger1 · April 21st, 2008, 11:09 AM

It's important to keep in mind what the amp is. It's a 5 - 6 watt, class A amp, with an 8" speaker. It is what it is, and has its limitations. Do the mods you think are best for you, install the 8" you think is best for you, and you have a cool, very portable, rocking little amp.

If you want more from it than that, hook up to an extension cab as Rob is suggesting, and past that, you're going to have to move to a more powerful amp.

Blues Hurler · April 21st, 2008, 11:55 AM

Yeah, i think the 12" extension spkr may be the way to go for me, because, frankly, this thing sounds pretty darn good with the stock speaker, but it just doesn't move enough air in a band setting. I think with the right 12" this thing will be a bit of a monster.

po-boy · April 21st, 2008, 12:50 PM

has anyone contacted mojo about making a matching extension speaker cab, loaded with a 10 in or 12 in speaker ?

lots of guys out there with this little amp now, a mini-stack would sound and look great -

- i'm not a complete idiot, some parts are missing -

Blues Hurler · April 21st, 2008, 01:46 PM

If the price was reasonable, I'd sure buy one. Matching the look of the amp would be very cool.

Guitarslinger1 · April 22nd, 2008, 10:04 AM

Quote:

Originally Posted by Blues Hurler

If the price was reasonable, I'd sure buy one. Matching the look of the amp would be very cool.

Contact Mojo and find out which tolex they used, and ask for an extension cab done with it.

http://www.mojomusicalsupply.com/products.asp?id=45012

I'm guessing it's the Ivory Levant, but would want to hear it from them.

Blues Hurler · April 22nd, 2008, 11:43 AM

I'll contact them, thanks. Here's a thought: I've been thinking about having a 12" ext. cab, and when using the 12, disabling the 8" speaker that's in the amp. But what if I just created an ext. cab with an 8" and ran both speakers at the same time? Then I'd have 16" of speaker running instead of just 12". And I could separate them to spread out the sound. Does that make any sense at all? And if I did that, what ohm rating would I want for the ext. speaker? I admit I don't know anything about this ohm business.

zero2sixty · April 22nd, 2008, 10:58 PM

Has anyone hooked up a 4 ohm 8 " Weber blue pup ceramic? Any reviews?

androo · April 23rd, 2008, 08:17 AM

I'm pretty sure there are a couple heading towards their respective homes....I know specialty guitars has one en route....maybe Rob too?

droo

Rob DiStefano · April 23rd, 2008, 08:33 AM

Yeah, I got some Blue Pups coming - AlNiCo and ceramic ...

Jaybird · April 23rd, 2008, 09:38 AM

Quote:

Originally Posted by Jaybird

After playing my amp a while today, I decided that I like it better stock, so I reverted all the mods. I was never able to get that NFB resistor to function properly, The 25uf cap "leglift" just made the amp sound spotty and gargley, so now everything is stock except I left in the .1 coupling caps, I am really likeing the amp again. I sort of ABed it with my new 5F1 and they both are pretty sweet. I must say that I believe the 5F1 is a little richer sounding though. This is a great thread with some good ideas and timely responses.

Originally Posted by specialty guitars
"Yours is a unique one for sure. I can't imagine lifting that 25uF cap would make it sound "spotty and gargley", when all it does is reduce gain. NFB can be a tricky issue. I do wonder if the .1uF caps made it unstable. Yours is the only one that's had those problems (that we know of), and it's the only one with different value coupling caps. Amp circuits are kind of a "balancing act"."

Strange stuff. While switching from an 8 ohm speaker in the 8 ohm input, to a 4 ohm speaker into the RCA input, my amp developed a case of very low power and volume. I must have spent the better part of 2 days checking out what might be wrong. As it turned out, the 4 ohm tap on my OT appears to not work, while when I use the 8 ohm tap, the amp is as loud and clear as ever. Is that possible?
In the process, I discovered (after removing the board from the chassis) that the wire from pin #3 to the cathode resistor, was hooked up to the bypass cap, not the resistor. That is why when I tried the mod of lifting the bypass cap leg, my amp sounded like it was in a can. After looking at various pics from this thread, I confirmed my suspicion that the wire should be connected differently. I drilled a hole in the board , ran the wire through and connected it to its proper home on the cathode resistor. So while wired this way (by a human at the factory) the amp worked, after a modification as in this thread, the amp would not function. My guess is that it was misswired. Easy enough to wire to the wrong spot from the underside. On my amp the underwires are soldered to the turrets from below, not run through holes and wired from above, where mistakes are easier to spot. Possibly why they started drilling holes in the chassis for this purpose.
I am not sure if I am going to do the mods at this point. I have another project to do, and need to take a break from this amp and just play it a bit.

Blues Hurler · April 24th, 2008, 08:29 AM

Well, I emailed Mojo, with my questions from my previous post and here's what they had to say:

"Thank you for choosing Mojo for your musical needs! We can buildyou a custom extension cabinet for your GA5, however, your transformerwould need to be rewired for multiple taps if you want to use morethan one speaker or even a speaker that is larger and the 8" supplied.This can be very expensive, we do not believe the amps were designedto operate more than one speaker. Sorry for not having the parts thatyou need!"

I did get a fast response, but I guess they don't read the tdpri. So it's back to wiring up that 8 ohm tap.

Rob DiStefano · April 24th, 2008, 08:55 AM

Quote:

Originally Posted by Blues Hurler

Well, I emailed Mojo, with my questions from my previous post and here's what they had to say:

"Thank you for choosing Mojo for your musical needs! We can buildyou a custom extension cabinet for your GA5, however, your transformerwould need to be rewired for multiple taps if you want to use morethan one speaker or even a speaker that is larger and the 8" supplied.This can be very expensive, we do not believe the amps were designedto operate more than one speaker. Sorry for not having the parts thatyou need!"

I did get a fast response, but I guess they don't read the tdpri. So it's back to wiring up that 8 ohm tap.

Mojo's not thinking outta the box.

Add a Switchcraft 13E isloated switching jack, wire it to the green GA5 OT 8 ohm tap and wire the switch side to the yellow RCA 4 ohm tap, plug into any 8 ohm cab. Plugging into the new jack will turn off the 4 ohm internal speaker and activate the external 8 ohm speaker. Even amp dummies like me could figure that one out.

Guitarslinger1 · April 24th, 2008, 09:04 AM

Quote:

Originally Posted by Blues H

"Thank you for choosing Mojo for your musical needs! We can buildyou a custom extension cabinet for your GA5, however, your transformerwould need to be rewired for multiple taps if you want to use morethan one speaker or even a speaker that is larger and the 8" supplied.This can be very expensive, we do not believe the amps were designedto operate more than one speaker. Sorry for not having the parts thatyou need!"

What??!!

Gotta love customer service.

There is no reason why you can't run this amp into a 4 x 12" cab if you have the correct OT tap hooked up. And, it's not very expensive to rewire from one tap to the other on a speaker jack. Takes about 5 minutes to do it and re-assemble the amp.

Blues Hurler · April 24th, 2008, 09:56 AM

Quote:

Originally Posted by Rob DiStefano

Mojo's not thinking outta the box.

Add a Switchcraft 13E isloated switching jack, wire it to the green GA5 OT 8 ohm tap and wire the switch side to the yellow RCA 4 ohm tap, plug into any 8 ohm cab. Plugging into the new jack will turn off the 4 ohm internal speaker and activate the external 8 ohm speaker. Even amp dummies like me could figure that one out.

Rob, did you post a photo of this somewhere in this gigantic thread? Seems to me you did, but I can't find the freakin' thing. I've never done any amp work before, so I'd need to see it before I attempt it. Uhh, and I stay away from them blue things that can fry me, right?

Guitarslinger1 · April 24th, 2008, 10:22 AM

For kicks, I ran my GA-5 through a tweed Deluxe cab loaded with an 8 ohm Celestion Alnico Blue 12". While not the most economically viable possibility, it simply sounded wonderful.

I tried a Weber ceramic Blue Pup 8", and it was kind of dark. Not what I remember from these speakers. I'm almost wondering if this one isn't quite right. Tried a CVA 8" as well, and preferred it out of those two, but agree that serious bass response is not its strong point.

boris bubbanov · April 24th, 2008, 10:24 AM

Quote:

Originally Posted by Blues Hurler

"Thank you for choosing Mojo for your musical needs! We can build you a custom extension cabinet for your GA5, however, your transformer would need to be rewired for multiple taps if you want to use more than one speaker or even a speaker that is larger and the 8" supplied.This can be very expensive, we do not believe the amps were designed to operate more than one speaker. Sorry for not having the parts that you need!"

Sounds like the communication fell into the hands of someone in a hurry to respond to all of their messages.

Maybe we should try again later.

Guitarslinger1 · April 24th, 2008, 10:32 AM

Quote:

Originally Posted by boris bubbanov

Sounds like the communication fell into the hands of someone in a hurry to respond to all of their messages.

Maybe we should try again later.

The best thing to do with Mojo, is to call them, tell them what you want to do and let them tell you what it will cost.

In my experience, custom cabs with them can be expensive.

Rob DiStefano · April 24th, 2008, 11:41 AM

Quote:

Originally Posted by Blues Hurler

Rob, did you post a photo of this somewhere in this gigantic thread? Seems to me you did, but I can't find the freakin' thing. I've never done any amp work before, so I'd need to see it before I attempt it. Uhh, and I stay away from them blue things that can fry me, right?

It takes a special 1/4" Switchcraft jack ... 1/4" mono switching, normally closed, non-shorting contacts, Switchcraft 13E. When the external jack isn't used, the internal jack switch is closed to allow the 4 ohm load to the internal RCA jack. When ya plug in the 1/4" jack to turn on an external speaker cab, the jack's switch is opened and automatically disconnects the internal speaker ....

Not easy to find the 13E, but Allied Electronics carries it for $7.36 ...

http://www.alliedelec.com/Search/Pro... FCD80977E17F

April 20th, 2008, 03:02 PM	#1041 (permalink)
rlowe TDPRI Member Join Date: Nov 2006 Location: Austin, Texas Age: 38 Posts: 29	Added 8ohm tap on switch I added the tap and hooked her up to a Mesa cab with a 12" Black Shadow speaker. I think these are celestions. Anyway, sounds much fuller with later breakup.

April 21st, 2008, 11:55 AM	#1047 (permalink)
Blues Hurler Tele-Holic Join Date: Aug 2003 Location: Toronto, Canada Posts: 557 6 Photos	Yeah, i think the 12" extension spkr may be the way to go for me, because, frankly, this thing sounds pretty darn good with the stock speaker, but it just doesn't move enough air in a band setting. I think with the right 12" this thing will be a bit of a monster. __________________ The blues ain't about theory, they's about therapy.

April 21st, 2008, 12:50 PM	#1048 (permalink)
po-boy Tele-Meister Join Date: Oct 2007 Location: dees, alabama Posts: 155	re: gibson tube amp has anyone contacted mojo about making a matching extension speaker cab, loaded with a 10 in or 12 in speaker ? lots of guys out there with this little amp now, a mini-stack would sound and look great - - i'm not a complete idiot, some parts are missing -

April 21st, 2008, 01:46 PM	#1049 (permalink)
Blues Hurler Tele-Holic Join Date: Aug 2003 Location: Toronto, Canada Posts: 557 6 Photos	If the price was reasonable, I'd sure buy one. Matching the look of the amp would be very cool. __________________ The blues ain't about theory, they's about therapy.

April 22nd, 2008, 11:43 AM	#1051 (permalink)
Blues Hurler Tele-Holic Join Date: Aug 2003 Location: Toronto, Canada Posts: 557 6 Photos	I'll contact them, thanks. Here's a thought: I've been thinking about having a 12" ext. cab, and when using the 12, disabling the 8" speaker that's in the amp. But what if I just created an ext. cab with an 8" and ran both speakers at the same time? Then I'd have 16" of speaker running instead of just 12". And I could separate them to spread out the sound. Does that make any sense at all? And if I did that, what ohm rating would I want for the ext. speaker? I admit I don't know anything about this ohm business. __________________ The blues ain't about theory, they's about therapy.

April 21st, 2008, 11:09 AM	#1046 (permalink)
Guitarslinger1 Tele-Holic Join Date: May 2005 Posts: 951	It's important to keep in mind what the amp is. It's a 5 - 6 watt, class A amp, with an 8" speaker. It is what it is, and has its limitations. Do the mods you think are best for you, install the 8" you think is best for you, and you have a cool, very portable, rocking little amp. If you want more from it than that, hook up to an extension cab as Rob is suggesting, and past that, you're going to have to move to a more powerful amp.

April 22nd, 2008, 10:58 PM	#1052 (permalink)
zero2sixty TDPRI Member Join Date: Mar 2008 Location: CT Posts: 22	Has anyone hooked up a 4 ohm 8 " Weber blue pup ceramic? Any reviews?

April 23rd, 2008, 08:17 AM	#1053 (permalink)
androo TDPRI Member Join Date: Dec 2004 Location: Portland, Oregon Posts: 79	I'm pretty sure there are a couple heading towards their respective homes....I know specialty guitars has one en route....maybe Rob too? droo

April 23rd, 2008, 08:33 AM	#1054 (permalink)
Rob DiStefano Friend of Leo's Join Date: Mar 2003 Location: Park Ridge, NJ Age: 62 Posts: 4,514	Yeah, I got some Blue Pups coming - AlNiCo and ceramic ...

April 24th, 2008, 08:29 AM	#1056 (permalink)
Blues Hurler Tele-Holic Join Date: Aug 2003 Location: Toronto, Canada Posts: 557 6 Photos	Well, I emailed Mojo, with my questions from my previous post and here's what they had to say: "Thank you for choosing Mojo for your musical needs! We can buildyou a custom extension cabinet for your GA5, however, your transformerwould need to be rewired for multiple taps if you want to use morethan one speaker or even a speaker that is larger and the 8" supplied.This can be very expensive, we do not believe the amps were designedto operate more than one speaker. Sorry for not having the parts thatyou need!" I did get a fast response, but I guess they don't read the tdpri. So it's back to wiring up that 8 ohm tap. __________________ The blues ain't about theory, they's about therapy.

April 24th, 2008, 10:22 AM	#1060 (permalink)
Guitarslinger1 Tele-Holic Join Date: May 2005 Posts: 951	For kicks, I ran my GA-5 through a tweed Deluxe cab loaded with an 8 ohm Celestion Alnico Blue 12". While not the most economically viable possibility, it simply sounded wonderful. I tried a Weber ceramic Blue Pup 8", and it was kind of dark. Not what I remember from these speakers. I'm almost wondering if this one isn't quite right. Tried a CVA 8" as well, and preferred it out of those two, but agree that serious bass response is not its strong point.