Marshall AVT50 Mods - Page 5

Fixr1984 · 06-13-2009, 10:02 PM

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.

Hawk · 06-17-2009, 02:18 PM

Quote:

Originally Posted by Fixr1984

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.

You sure about that? My understanding is that on any amp if you connect speakers in parallel you reduce the total resistance the amp sees, and the current through the amp increases. Take it far enough and you will fry something. key formuale are 1/Rtotal=1/R1+1/R2+1/R3.... and P=RxI^2

So if your amp is rated for 4 ohms and has a 4 ohm speaker, and is a 100 watt amp, max current would be sqrt(100/4)= 5 amps. Add a second 4ohm speaker and your total resistance drops to 2 ohms (1/R=1/4+1/4=1/2, so R=2ohms) and I=sqrt(100/2)=7 amps, nearly a 50% increase in current.

Correct me if I'm wrong, but that's my understanding of it.

rockinr0ll · 06-17-2009, 02:39 PM

The AVT cab is rated 8 ohms so that paired with another AVT cab (full stack) that would equal 4 ohms.

tgifntx · 06-28-2009, 10:18 PM

Here's what it states in the manual,
WARNING:
Always provide the AVT50H with a load
equal to, or greater than, 4 Ohms. Using the
two loudspeaker outputs, with cabinets rated at
8 Ohms each, the full 50W of the specially
designed AVT power amplifier will be
unleashed.

What I've done is, Using only one of the avt50h speaker outs
going into an 4x12 cab rated at max input 280W RMS/16 Ohms.
Am I in essence choking the amp or maybe the amp and cab?
Would I be better off to;
A. Rewire the cab to an 8 Ohm config
B. Rewire the cab to an 8 Ohm config and add an additional
spkr jack out to use both spkr outs, (L&R), so to speak from the avt
50h to "unleash" the avt50h...
I did check the Ohms on both the cab and the avt50h. The cab shows
16 Ohms, (single spkr out) and each of the speaker outs from the head
show 19 Ohms..?
Sorry to bird dog you guys... Just want to make sure I'm not matching
this stuf up all wrong.
Thanks again!

rockinr0ll · 06-29-2009, 10:05 PM

You have the matching AVT cab right? Then you are fine if it is.

tgifntx · 06-30-2009, 03:55 AM

No sir, Just an Eminence loaded cab unfortunately...

dsiar · 07-15-2009, 01:30 PM

You ARE the AVT50 man, I see, so do you know if a volume attenuator work with the AVT50? I realize that these devices are meant for tube amps but since the AVT50 has a preamp tube, I was wondering. Thanks, Dave

ddaypunk06 · 08-09-2009, 11:04 PM

Hey guys,

Just finished reading all the posts in this thread.

Lots of info! Let me tell you lol.

I would love to eventually mod my AVT50Combo. I was wondering if Peter ever posted his website or anything involving the kits.

I just bought it less than a month ago. The guy I got it from on eBay spent 40 bucks shipping it and when it got to me it has a diagonal dent running through the two jacks on the right side of the unit. You can definitely see that the fron panel doesn't line up right. However I had to guitar buddies play on it and said it sounded great. The only other concern I had was that tonight after practicing a bit and writting...I noticed I could hear the fan when I turned it on. Being a sort of computer tech, I know buzzing fans ins't a good thing. I'm hoping that is an easy fix.

Some guys and I just got a band together and I am trying to see how easy it would be to mod this to get some more out of this amp.

Currently I play a squire strat (stock) on it (looking to get an Epi LP Standard Plus soon) and an older Gretch Electromatic. My amp before this was a 10W crate...sounded like crap. Thought it was my squire, but was definitely the crappy amp. Sounds great on the Marshall.

My buddy is going to revamp the wiring and pickups on my strat, and then I will also pick up the Epi LP.

Anyways, back to the topic.

I just want to get the true marshall tone with a bit more crunch in it. The mid mods sounded enticing as well. Possibly upgrade the speaker down the line too.

jjvh66 · 08-11-2009, 12:53 AM

WOW nice mod on the AVT50. Is there a mod to make the clean channel CLEANER? I'm not quite using the gain as much nowa dayz.

rockinr0ll · 08-14-2009, 08:10 PM

Quote:

Originally Posted by dsiar

You ARE the AVT50 man, I see, so do you know if a volume attenuator work with the AVT50? I realize that these devices are meant for tube amps but since the AVT50 has a preamp tube, I was wondering. Thanks, Dave

You are not suppose to use attenuators with Solid State or Hybrid amps.

rockinr0ll · 08-14-2009, 08:12 PM

Quote:

Originally Posted by jjvh66

WOW nice mod on the AVT50. Is there a mod to make the clean channel CLEANER? I'm not quite using the gain as much nowa dayz.

The only way I have found is to lay off the gain and boost the volume as much as possible. I can get a decent clean sound but like you said not as clean as I would like. You kinda have to sacrifice low gain with lower volume or crunch and a louder volume setting.

tgifntx · 08-16-2009, 04:22 AM

Woohoo!!
Gents...
I finally got the matching cab for my AVT50H.
No more goofin' around, On the money. Picked
up this AVT412B cab yesterday evening...

rockinr0ll · 08-20-2009, 03:37 AM

very nice

rockinr0ll · 08-20-2009, 04:00 AM

Question.

I have never went inside the AVT50HX. I'm planning on buying a new tube to replace with the old one. To change the tube I would have to open the back and then unscrew the chassis right? Can anyone give me any safety tips? I have done with before with tube amps but these hybrids seem a little more difficult to break into.

Fixr1984 · 08-20-2009, 11:40 PM

Just unscrew the back, no need to take the chassis out. Pop off the wire hold down and pull the tube out. I wouldnt worry as long as you have the power disconnected there shouldnt be any hazzards for you.

rockinr0ll · 08-21-2009, 12:32 AM

What's the wire for?

Fixr1984 · 08-21-2009, 09:23 PM

You can see in the picture, there is a stiff wire bent around the tube to hold it in place. Just slide that off and the tube can be removed.

rockinr0ll · 08-21-2009, 11:32 PM

Thanks for the help! I'll let you know how my experience turns out.

rockinr0ll · 08-23-2009, 07:18 PM

So my new tube is expected to arrive Tuesday. A few moments ago I decided I would open the baby up to take out the old tube and check out the internals. Lucky I had a good screw driver which made opening the back really easy. Pulled the wire out like you said and pulled the tube out, no problem what so ever. Put one of the screws back on and am just now waiting the arrival of the new tube. Thanks!

Fixr1984 · 08-23-2009, 08:41 PM

While you wait you can unplug the reverb and see if you like the change it makes.

rockinr0ll · 08-23-2009, 08:59 PM

I'll try it out when I get the new tube. Too late to play right now.

e1: The reason I will most likely keep it disconnected is because most rack units are meant to be used before reverb, so keeping it on would not work.

e2: 12 hours from now I should have it, expect a follow up of my findings!

e3: It's here!!

rockinr0ll · 08-25-2009, 03:09 PM

It arrived around a hour ago. The NOS JAN Phillips 5751 preamp tube made a world of change for my AVT50HX. Not only does it now have almost zero noise, it also has some added quality too. The reverb when switched off sounds great. It has a tone pot effect that when you turn it up the high frequencies increase. This is now how I have it set up. The amp sounds like a new amp!

Fixr1984 · 08-25-2009, 05:03 PM

Sweet, where did you get the tube from? Price? Did you notice a change on both channels or more one than the other.

rockinr0ll · 08-25-2009, 05:40 PM

Got it Here, I paid the extra $4 to make sure I got a low noise and microphonics tested tube.

U.S. Made JAN Philips 5751

rockinr0ll · 08-25-2009, 05:41 PM

The overdrive is less noisy. It went from really loud to almost dead silent.

ki6up · 09-07-2009, 04:26 AM

Quote:

Originally Posted by jfox00

Can anyone post a way to add a mid eq control for the clean channel of a Marshall AVT50H? Thanks.

Hey - I got a behringer eq-700 and ran it through the effects loop - what a differance. Other then a plastic body - it is as good as I have seen - you can adjust the clean perfectly

ki6up · 09-07-2009, 04:26 AM

Quote:

Originally Posted by jfox00

Can anyone post a way to add a mid eq control for the clean channel of a Marshall AVT50H? Thanks.

Hey - I got a behringer eq-700 and ran it through the effects loop - what a difference. Other then a plastic body - it is as good as I have seen - you can adjust the clean perfectly

rockinr0ll · 09-07-2009, 08:35 PM

I do the same ki6up!

rockinr0ll · 09-08-2009, 05:58 PM

Came across this today:

YouTube - Marshall AVT Trick

Kinda cool..

rockinr0ll · 09-10-2009, 09:10 PM

If anyone is interested I started a message board for the Marshall AVT.

Here is the link if you guys want to try to get a following...

Message Board - Home

06-13-2009, 10:02 PM	#121 (permalink)
Fixr1984 Member Join Date: Nov 2008 Posts: 77	Re: Marshall AVT50 Mods 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.

06-17-2009, 02:39 PM	#123 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods The AVT cab is rated 8 ohms so that paired with another AVT cab (full stack) that would equal 4 ohms.

06-28-2009, 10:18 PM	#124 (permalink)
tgifntx Junior Member Join Date: Jun 2009 Posts: 12	Re: Marshall AVT50 Mods Here's what it states in the manual, WARNING: Always provide the AVT50H with a load equal to, or greater than, 4 Ohms. Using the two loudspeaker outputs, with cabinets rated at 8 Ohms each, the full 50W of the specially designed AVT power amplifier will be unleashed. What I've done is, Using only one of the avt50h speaker outs going into an 4x12 cab rated at max input 280W RMS/16 Ohms. Am I in essence choking the amp or maybe the amp and cab? Would I be better off to; A. Rewire the cab to an 8 Ohm config B. Rewire the cab to an 8 Ohm config and add an additional spkr jack out to use both spkr outs, (L&R), so to speak from the avt 50h to "unleash" the avt50h... I did check the Ohms on both the cab and the avt50h. The cab shows 16 Ohms, (single spkr out) and each of the speaker outs from the head show 19 Ohms..? Sorry to bird dog you guys... Just want to make sure I'm not matching this stuf up all wrong. Thanks again! __________________ Epi LP Custom Ltd Edtn/Dimarzio d Activators Epi LP Stdrd plus top/490r 498t Epi '65 RI SG G-400 Maestro Custom Shop Epi SG '66 reissue Custom Shop (Stock) Epi SG Custom Ltd Edtn/Dimarzio Tone zone/Air norton Marshall AVT50h/AVT412B Peavey XXL/XXL4X12 Peavey Classic 50/50 Peavey Classic 30 Boss GT-6 Digitech GSP21L

06-29-2009, 10:05 PM	#125 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods You have the matching AVT cab right? Then you are fine if it is.

06-30-2009, 03:55 AM	#126 (permalink)
tgifntx Junior Member Join Date: Jun 2009 Posts: 12	Re: Marshall AVT50 Mods No sir, Just an Eminence loaded cab unfortunately... __________________ Epi LP Custom Ltd Edtn/Dimarzio d Activators Epi LP Stdrd plus top/490r 498t Epi '65 RI SG G-400 Maestro Custom Shop Epi SG '66 reissue Custom Shop (Stock) Epi SG Custom Ltd Edtn/Dimarzio Tone zone/Air norton Marshall AVT50h/AVT412B Peavey XXL/XXL4X12 Peavey Classic 50/50 Peavey Classic 30 Boss GT-6 Digitech GSP21L

07-15-2009, 01:30 PM	#127 (permalink)
dsiar Junior Member Join Date: Jun 2009 Posts: 1	Re: Marshall AVT50 Mods You ARE the AVT50 man, I see, so do you know if a volume attenuator work with the AVT50? I realize that these devices are meant for tube amps but since the AVT50 has a preamp tube, I was wondering. Thanks, Dave

08-09-2009, 11:04 PM	#128 (permalink)
ddaypunk06 Junior Member Join Date: Aug 2009 Posts: 1	Re: Marshall AVT50 Mods Hey guys, Just finished reading all the posts in this thread. Lots of info! Let me tell you lol. I would love to eventually mod my AVT50Combo. I was wondering if Peter ever posted his website or anything involving the kits. I just bought it less than a month ago. The guy I got it from on eBay spent 40 bucks shipping it and when it got to me it has a diagonal dent running through the two jacks on the right side of the unit. You can definitely see that the fron panel doesn't line up right. However I had to guitar buddies play on it and said it sounded great. The only other concern I had was that tonight after practicing a bit and writting...I noticed I could hear the fan when I turned it on. Being a sort of computer tech, I know buzzing fans ins't a good thing. I'm hoping that is an easy fix. Some guys and I just got a band together and I am trying to see how easy it would be to mod this to get some more out of this amp. Currently I play a squire strat (stock) on it (looking to get an Epi LP Standard Plus soon) and an older Gretch Electromatic. My amp before this was a 10W crate...sounded like crap. Thought it was my squire, but was definitely the crappy amp. Sounds great on the Marshall. My buddy is going to revamp the wiring and pickups on my strat, and then I will also pick up the Epi LP. Anyways, back to the topic. I just want to get the true marshall tone with a bit more crunch in it. The mid mods sounded enticing as well. Possibly upgrade the speaker down the line too.

08-11-2009, 12:53 AM	#129 (permalink)
jjvh66 Junior Member Join Date: Aug 2009 Posts: 1	Re: Marshall AVT50 Mods WOW nice mod on the AVT50. Is there a mod to make the clean channel CLEANER? I'm not quite using the gain as much nowa dayz.

08-20-2009, 03:37 AM	#133 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods very nice

08-20-2009, 04:00 AM	#134 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods Question. I have never went inside the AVT50HX. I'm planning on buying a new tube to replace with the old one. To change the tube I would have to open the back and then unscrew the chassis right? Can anyone give me any safety tips? I have done with before with tube amps but these hybrids seem a little more difficult to break into.

08-20-2009, 11:40 PM	#135 (permalink)
Fixr1984 Member Join Date: Nov 2008 Posts: 77	Re: Marshall AVT50 Mods Just unscrew the back, no need to take the chassis out. Pop off the wire hold down and pull the tube out. I wouldnt worry as long as you have the power disconnected there shouldnt be any hazzards for you.

08-21-2009, 12:32 AM	#136 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods What's the wire for?

08-21-2009, 09:23 PM	#137 (permalink)
Fixr1984 Member Join Date: Nov 2008 Posts: 77	Re: Marshall AVT50 Mods You can see in the picture, there is a stiff wire bent around the tube to hold it in place. Just slide that off and the tube can be removed.

08-21-2009, 11:32 PM	#138 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods Thanks for the help! I'll let you know how my experience turns out.

08-23-2009, 07:18 PM	#139 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods So my new tube is expected to arrive Tuesday. A few moments ago I decided I would open the baby up to take out the old tube and check out the internals. Lucky I had a good screw driver which made opening the back really easy. Pulled the wire out like you said and pulled the tube out, no problem what so ever. Put one of the screws back on and am just now waiting the arrival of the new tube. Thanks!

08-23-2009, 08:41 PM	#140 (permalink)
Fixr1984 Member Join Date: Nov 2008 Posts: 77	Re: Marshall AVT50 Mods While you wait you can unplug the reverb and see if you like the change it makes.

08-23-2009, 08:59 PM	#141 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods I'll try it out when I get the new tube. Too late to play right now. e1: The reason I will most likely keep it disconnected is because most rack units are meant to be used before reverb, so keeping it on would not work. e2: 12 hours from now I should have it, expect a follow up of my findings! e3: It's here!! Last edited by rockinr0ll; 08-25-2009 at 03:06 PM.

08-25-2009, 03:09 PM	#142 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods It arrived around a hour ago. The NOS JAN Phillips 5751 preamp tube made a world of change for my AVT50HX. Not only does it now have almost zero noise, it also has some added quality too. The reverb when switched off sounds great. It has a tone pot effect that when you turn it up the high frequencies increase. This is now how I have it set up. The amp sounds like a new amp!

08-25-2009, 05:03 PM	#143 (permalink)
Fixr1984 Member Join Date: Nov 2008 Posts: 77	Re: Marshall AVT50 Mods Sweet, where did you get the tube from? Price? Did you notice a change on both channels or more one than the other.

08-25-2009, 05:40 PM	#144 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods Got it Here, I paid the extra $4 to make sure I got a low noise and microphonics tested tube. U.S. Made JAN Philips 5751

08-25-2009, 05:41 PM	#145 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods The overdrive is less noisy. It went from really loud to almost dead silent.

09-07-2009, 08:35 PM	#148 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods I do the same ki6up!

09-10-2009, 09:10 PM	#150 (permalink)
rockinr0ll Senior Member Join Date: Feb 2009 Posts: 1,340	Re: Marshall AVT50 Mods If anyone is interested I started a message board for the Marshall AVT. Here is the link if you guys want to try to get a following... Message Board - Home

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