Marshall AVT50 Mods - Page 6

Fixr1984 · 09-10-2009, 09:51 PM

I signed up, now I just gotta remember to check in there along with the 4 other forums i use.

Johnfender · 09-10-2009, 09:59 PM

HI, I am new to the forum but maybe you can help me I purchased a used JCM 800 super lead 1959 model and I think I made a mistake, there is no way to control the volume on this beast...Have you heard or know of a Master volume Mod for this amp....

rockinr0ll · 09-11-2009, 09:46 AM

John this really isn't a good spot for the question you asked because not many people read this thread for mods on other amps besides the AVT. Try starting a new thread.

Fixr thanks for signing up. It could be a cool forum if people are interested.. Even though I made it, I don't really want it to be "my forum" I just made it because there is no sites dedicated to the AVT.

http://marshallavt.proboards.com/

wammi · 01-05-2010, 09:27 PM

You guys seems good with questions so if I may ask...

I have an atv50H head that has no reverb. Does the footswitch jack in the back turn it off and on assuming I had a footswitch? Maybe it came with a 2 button footswitch originally? Does anyone know? But I would think the reverb would get employed anyway when I turn the depth knob. Am I wrong?

Thanks for your help.
Wammi J.

Fixr1984 · 01-05-2010, 09:47 PM

The jack in the back is just for changing the channel. Unless the depth knob is all the way down the reverb is always on.
Have you had the head since new? If not check that reverb tank is still connected to the circuit board. Some people disconnect the tank as a mod to the amp.

wammi · 01-06-2010, 10:51 AM

Does anyone have a schematic? Also can anyone tell me (while looking at the back of the amp) which side the red reverb tank the rca is on (left or right), and what color wire is pin# 1 at the reverbs 4 pin plug on the board?
All seems tight, but I wonder if it is on correctly.

Fixr1984 · 01-06-2010, 09:42 PM

I can email you the schematic if you need it.
Here is a few pics to hopefully help you out.

simmons1989 · 02-26-2010, 01:57 PM

Quote:

Originally Posted by Peter

I came up with some great modifications for my AVT50 amp:
1. The obvious mod: add a second speaker jack.
2. Installed a clean channel midrange control.
3. Increased preamp tube gain by around 25% (switched).
4. Installed a 6 position mid shift switch on the Overdrive channel with the stock midrange frequency, and 5 others [a great mod in any amp].
5. I reinforced some key components in the amp with higher wattage and voltage components (cheap insurance).

The fatter tones from the mid shift switch along with the extra tube drive really really brought the amp to life. The amp sounds 100% way better, and I didn't even drive the tube nearly as hot as in other tube amps. The clean channel tube sound really rocks on full gain, and rolls off at lower gains. Very impressive improvements. I am also working on an optoelectronically controlled footswitch for Lead Boost and Scoop. Anybody out there interested in Kits? I am interested in producing them.

PETER THE TONE DOCTOR

Cool mods, just wondering if you have any mods for the AVT150h?
Thanks.

brassriot · 04-30-2010, 01:40 PM

So I've got a burned out R58 and I wanted to know whether I should just replace it with the stock 1/2W or will putting a 1W prevent it from over heating again? Plus I'd like to know what "cheap insurance" Peter was talking about. I've got this thing all taken apart so if there is something I can do to beef it up or help prevent its over heating that would be nice. Also I'd like to know how to get more gain out of this puppy. I play out of a full stack and I play this sucker loud, so I can imagine why it gets so hot.

Here are pictures of the burnt out R58 and the wear it made on the back of the PCB (which the discoloration is actually under R59 and R60 but the look fine themselves, maybe they might need to be changed as well?)

http://i80.photobucket.com/albums/j1...ot/burnout.jpg
http://i80.photobucket.com/albums/j1...ssriot/R58.jpg

Fixr1984 · 05-01-2010, 01:16 PM

My R58 has been changed out already and it gets pretty hot. Personally I would put in a higher wattage. I dont have a technical reason I would just feel better knowing that the stock one burned up and the replacement gets hot. "cheap insurance", I have no idea. Maybe higher wattage components or better quality caps? For more gain check out the AVT forum I have a quick write up there, or I can PM you more info.

brassriot · 05-11-2010, 04:09 PM

so I changed out R58 with a 1w 10ohm resistor and it got ungodly hot almost 400 degrees f!! Something went pop and now there's hardly any sound coming out of it (only when I play the guitar hard.) It's making a funny noise right when I turn it on too. It doesn't look like the tube is lighting up all the way (maybe blew the tube?) and the leds that tell you which channel its on aren't working anymore. The CD Jack still works. I changed out R58 for its stock value hoping it would work but its still boned

help!

Fixr1984 · 05-11-2010, 10:12 PM

Does the fan still work? My memory is slowly coming back to me: I'm thinking that the fan died in mine overheating the power chip and took R58 with it.

AVTMAN · 05-29-2010, 02:37 PM

Hi there avt fans ! I have been watching this avt50 forum to see if peter is going to give pricing for the diy mod kits. I recently made my avt slant cab stereo and am now looking for the next signifigant mod for my half stack avt. Anyone else out there with interest should post and make it worth his while to do kits.

Fixr1984 · 05-29-2010, 07:31 PM

I dont think Peter has been around in a while. Check back to page 3 I have some info and some pictures that might help you out.

brandoz28 · 05-29-2010, 10:26 PM

thanks for those pics man. hopefully the combo's are similar.

Peter · 06-03-2010, 09:53 AM

Hi, I started this thread, with the intention of producing kits for the AVT50. My amp is really great, but I came to the conclusion that doing the kits isn't worth it to me. Anyone wanting theirs modded in the Toronto area can contact me through my web site at ToneWerkz.com Musical Equipment Service, Mods, Repair, Kits, Forum Home Page , or at service@tonewerkz.com. Thanks.

Peter

The Tone Doctor

El Toro · 06-04-2010, 10:13 PM

Hey Peter. Saw your post and your surprised post that no one shouted back. So talk to me. I have a Valvestate 2000 AVT50 combo and I have tons of questions and would love to hear all about your mods. I'm an Industrial Electrician and was formally trained by the U.S.Navy in avionics so I should be able to follow you. I actually landed in this forum 'cause I was looking to find out what kind of preamp tube is used in the thing. Mine is marked simply with a 0041. Doesn't sound like an AX7 or EL84 so I was wondering what it is and does it cross. Thanks for the info,

Mike

brandoz28 · 06-07-2010, 02:53 AM

it should be a 12AX7......pretty sure that's all they used in those

glad to see you're back around Peter

prodanov · 06-11-2010, 09:07 PM

Hi everyone!

I have a problem with my AVT50X. Maybe you can help me.

Problem #1. When I increasing gain on clean or OD channel volume also grows up. So if I want to play with high gain I have to put down volume almost to zero or I become deaf =)

Problem #2. The Reverb acts really strange. It doesn't give nice spring reverb to my sound but only cuts high freqs.

Any solution?

jgearhart76 · 08-01-2010, 05:06 PM

Wow, I'm really bummed that Peter kinda dropped out on this. I joined the forum because of this thread.

I Have and AVT50H and was wondering how I could mod it. It has always sounded too bright in my opinion. Also the idea of a mid control on the clean chanel, and getting it to sound more like a tube amp intrigued me.

Does anyone else have any suggestions/mods of their own?

jgearhart76 · 08-01-2010, 05:23 PM

Quote:

Originally Posted by Fixr1984

I would also be interested in hearing what you changed in your amp as well. Was it a big improvement? Did it not help and thats why you sold it? My fan is making noise again so i have to open it up again so I wouldnt mind doing a few more mods.

My fan is having the same issue. Amp works great, but the fan has gotten noisy over time. is there a fix/treatment for this?

jgearhart76 · 08-01-2010, 05:31 PM

Quote:

Originally Posted by Fixr1984

Honestly this question will probably get a bunch of different answers based on prefrence. The Head is rated at 50 watts into 4 ohms, so if you are running a larger load on it you wont get the full power. I'm not sure how much is lost going to 8 and 16 ohm. Half? Personally I would like a 4 vs 4 ohm so I could get the full power out of the amp. I have the 4x12 AVT cab and its rated at 8 ohms so I guess if Marshall paired them up this way then its no big deal. Tube is another story, you have to match the ohms to the amp or you are looking for trouble but on solid state its not too much of a concern.

I used to run my head through an 8ohm 4x12 cab and got plenty of volume out of it. (though not quite enough to cover my bassist! lol)

Jigz-RigZ · 09-02-2010, 03:32 PM

hey Peter, fist post! i have the AVT 50 H i love it but i dont! hahaha, you were recommended to me by Rob Hull at TubeDepot.com, im totally interested in the mods man, do yo have one to add more tubes?

09-10-2009, 09:51 PM	#151 (permalink)
Fixr1984 Senior Member Join Date: Nov 2008 Posts: 113	Re: Marshall AVT50 Mods I signed up, now I just gotta remember to check in there along with the 4 other forums i use.

09-10-2009, 09:59 PM	#152 (permalink)
Johnfender Junior Member Join Date: Sep 2009 Location: Miami Posts: 1	Re: Marshall AVT50 Mods HI, I am new to the forum but maybe you can help me I purchased a used JCM 800 super lead 1959 model and I think I made a mistake, there is no way to control the volume on this beast...Have you heard or know of a Master volume Mod for this amp....

09-11-2009, 09:46 AM	#153 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,737	Re: Marshall AVT50 Mods John this really isn't a good spot for the question you asked because not many people read this thread for mods on other amps besides the AVT. Try starting a new thread. Fixr thanks for signing up. It could be a cool forum if people are interested.. Even though I made it, I don't really want it to be "my forum" I just made it because there is no sites dedicated to the AVT. http://marshallavt.proboards.com/ Last edited by rockinr0ll; 09-11-2009 at 06:40 PM.

01-05-2010, 09:27 PM	#154 (permalink)
wammi Junior Member Join Date: Dec 2009 Posts: 9	Re: Marshall AVT50 Mods You guys seems good with questions so if I may ask... I have an atv50H head that has no reverb. Does the footswitch jack in the back turn it off and on assuming I had a footswitch? Maybe it came with a 2 button footswitch originally? Does anyone know? But I would think the reverb would get employed anyway when I turn the depth knob. Am I wrong? Thanks for your help. Wammi J.

01-05-2010, 09:47 PM	#155 (permalink)
Fixr1984 Senior Member Join Date: Nov 2008 Posts: 113	Re: Marshall AVT50 Mods The jack in the back is just for changing the channel. Unless the depth knob is all the way down the reverb is always on. Have you had the head since new? If not check that reverb tank is still connected to the circuit board. Some people disconnect the tank as a mod to the amp.

Today
Marshall Amps	Sponsored Links __________________ This advertising will not be shown in this way to registered members. Register your free account today and become a member on Marshall Amp Forum

01-06-2010, 10:51 AM	#156 (permalink)
wammi Junior Member Join Date: Dec 2009 Posts: 9	Re: Marshall AVT50 Mods Does anyone have a schematic? Also can anyone tell me (while looking at the back of the amp) which side the red reverb tank the rca is on (left or right), and what color wire is pin# 1 at the reverbs 4 pin plug on the board? All seems tight, but I wonder if it is on correctly.

01-06-2010, 09:42 PM	#157 (permalink)
Fixr1984 Senior Member Join Date: Nov 2008 Posts: 113	Re: Marshall AVT50 Mods I can email you the schematic if you need it. Here is a few pics to hopefully help you out.

04-30-2010, 01:40 PM	#159 (permalink)
brassriot Junior Member Join Date: Apr 2010 Posts: 2	Re: Marshall AVT50 Mods So I've got a burned out R58 and I wanted to know whether I should just replace it with the stock 1/2W or will putting a 1W prevent it from over heating again? Plus I'd like to know what "cheap insurance" Peter was talking about. I've got this thing all taken apart so if there is something I can do to beef it up or help prevent its over heating that would be nice. Also I'd like to know how to get more gain out of this puppy. I play out of a full stack and I play this sucker loud, so I can imagine why it gets so hot. Here are pictures of the burnt out R58 and the wear it made on the back of the PCB (which the discoloration is actually under R59 and R60 but the look fine themselves, maybe they might need to be changed as well?) http://i80.photobucket.com/albums/j1...ot/burnout.jpg http://i80.photobucket.com/albums/j1...ssriot/R58.jpg

05-01-2010, 01:16 PM	#160 (permalink)
Fixr1984 Senior Member Join Date: Nov 2008 Posts: 113	Re: Marshall AVT50 Mods My R58 has been changed out already and it gets pretty hot. Personally I would put in a higher wattage. I dont have a technical reason I would just feel better knowing that the stock one burned up and the replacement gets hot. "cheap insurance", I have no idea. Maybe higher wattage components or better quality caps? For more gain check out the AVT forum I have a quick write up there, or I can PM you more info.

05-11-2010, 04:09 PM	#161 (permalink)
brassriot Junior Member Join Date: Apr 2010 Posts: 2	Re: Marshall AVT50 Mods so I changed out R58 with a 1w 10ohm resistor and it got ungodly hot almost 400 degrees f!! Something went pop and now there's hardly any sound coming out of it (only when I play the guitar hard.) It's making a funny noise right when I turn it on too. It doesn't look like the tube is lighting up all the way (maybe blew the tube?) and the leds that tell you which channel its on aren't working anymore. The CD Jack still works. I changed out R58 for its stock value hoping it would work but its still boned help!

05-11-2010, 10:12 PM	#162 (permalink)
Fixr1984 Senior Member Join Date: Nov 2008 Posts: 113	Re: Marshall AVT50 Mods Does the fan still work? My memory is slowly coming back to me: I'm thinking that the fan died in mine overheating the power chip and took R58 with it.

05-29-2010, 02:37 PM	#163 (permalink)
AVTMAN Junior Member Join Date: May 2010 Posts: 1	Re: Marshall AVT50 Mods Hi there avt fans ! I have been watching this avt50 forum to see if peter is going to give pricing for the diy mod kits. I recently made my avt slant cab stereo and am now looking for the next signifigant mod for my half stack avt. Anyone else out there with interest should post and make it worth his while to do kits.

05-29-2010, 07:31 PM	#164 (permalink)
Fixr1984 Senior Member Join Date: Nov 2008 Posts: 113	Re: Marshall AVT50 Mods I dont think Peter has been around in a while. Check back to page 3 I have some info and some pictures that might help you out.

05-29-2010, 10:26 PM	#165 (permalink)
brandoz28 Senior Member Join Date: May 2010 Posts: 106	Re: Marshall AVT50 Mods thanks for those pics man. hopefully the combo's are similar. __________________ Jackson JDR-94, Jackson PS-3T, Ibanez RG350DX.....and lots of other no-name stuff that's not as bad as you might think Lead 12 Head with MG15MSII straight cab, AVT50 1x12 combo building a new rig..............i got G.A.S. and i can't control it!

06-03-2010, 09:53 AM	#166 (permalink)
Peter Member Join Date: Mar 2008 Location: Toronto, ON, Canada Posts: 60	Re: Marshall AVT50 Mods Hi, I started this thread, with the intention of producing kits for the AVT50. My amp is really great, but I came to the conclusion that doing the kits isn't worth it to me. Anyone wanting theirs modded in the Toronto area can contact me through my web site at ToneWerkz.com Musical Equipment Service, Mods, Repair, Kits, Forum Home Page , or at service@tonewerkz.com. Thanks. Peter The Tone Doctor

06-04-2010, 10:13 PM	#167 (permalink)
El Toro Junior Member Join Date: Jun 2010 Location: Redding, Ca Posts: 1	Re: Marshall AVT50 Mods Hey Peter. Saw your post and your surprised post that no one shouted back. So talk to me. I have a Valvestate 2000 AVT50 combo and I have tons of questions and would love to hear all about your mods. I'm an Industrial Electrician and was formally trained by the U.S.Navy in avionics so I should be able to follow you. I actually landed in this forum 'cause I was looking to find out what kind of preamp tube is used in the thing. Mine is marked simply with a 0041. Doesn't sound like an AX7 or EL84 so I was wondering what it is and does it cross. Thanks for the info, Mike

06-07-2010, 02:53 AM	#168 (permalink)
brandoz28 Senior Member Join Date: May 2010 Posts: 106	Re: Marshall AVT50 Mods it should be a 12AX7......pretty sure that's all they used in those glad to see you're back around Peter __________________ Jackson JDR-94, Jackson PS-3T, Ibanez RG350DX.....and lots of other no-name stuff that's not as bad as you might think Lead 12 Head with MG15MSII straight cab, AVT50 1x12 combo building a new rig..............i got G.A.S. and i can't control it!

06-11-2010, 09:07 PM	#169 (permalink)
prodanov Junior Member Join Date: Jun 2010 Location: Russia Posts: 1	Re: Marshall AVT50 Mods Hi everyone! I have a problem with my AVT50X. Maybe you can help me. Problem #1. When I increasing gain on clean or OD channel volume also grows up. So if I want to play with high gain I have to put down volume almost to zero or I become deaf =) Problem #2. The Reverb acts really strange. It doesn't give nice spring reverb to my sound but only cuts high freqs. Any solution?

08-01-2010, 05:06 PM	#170 (permalink)
jgearhart76 Junior Member Join Date: Aug 2010 Location: San Jose, CA Posts: 3	Re: Marshall AVT50 Mods Wow, I'm really bummed that Peter kinda dropped out on this. I joined the forum because of this thread. I Have and AVT50H and was wondering how I could mod it. It has always sounded too bright in my opinion. Also the idea of a mid control on the clean chanel, and getting it to sound more like a tube amp intrigued me. Does anyone else have any suggestions/mods of their own?

09-02-2010, 03:32 PM	#173 (permalink)
Jigz-RigZ Junior Member Join Date: Sep 2010 Posts: 1	Re: Marshall AVT50 Mods hey Peter, fist post! i have the AVT 50 H i love it but i dont! hahaha, you were recommended to me by Rob Hull at TubeDepot.com, im totally interested in the mods man, do yo have one to add more tubes?

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode