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Discussion Starter #1
I was reading a post on here about 5150 mods done in Vancouver, well does Dr. Ho , I believe his name was, do any of the mods that are offered by FJA or Voodoo?
 

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Discussion Starter #3
Nothing is wrong with it, I just like to try new things. For example when I had the Mercury Magnetic output transformer and choke put in, it was just to see if I liked it. Man what an improvement in my opinion! It's like I fell in love with the amp all over again. It's so tight and very articulate. Each note comes through perfectly clear... also swapping the Sheffields out of my 5150 cab to Celestion G12T-100 X Veteran 30's (V30 Clones) made the world of difference, once broken in.

Basically I like to try new things and see what other sounds I can get. Every step seems to get me closer to that "perfect tone" to my ears.

I could take the steps and maybe consider buying another amp to join with the 5150 but meh I like running one head, which is why I'm trying to sell my backup head.... but I must wait till I get 5 posts before I post it in the for sale section.
 

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Ho's Electronics,ive never delt with him yet,but i hear he does
some really nice work,plus he build some guitar amp gear,not
sure what they all are,i do know one thing is a antenuator
for your speaker cab,and heard of a few urban myths,about
some of his other creations,and then again they my not be myths
never delt with the guy
 

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Discussion Starter #6
Umm are you asking if I'm Steve? Nope sorry.

I really like my amp tech I go to but as far as modifying an amp thats where he hasn't ventured. Well at least with 5150's. He was the one that installed my transformer and choke; he did a great job I might add. Also helped me correct a supid problem regarding a speaker cab miswiring. Really should have taken my time at that project.
 

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Umm are you asking if I'm Steve? Nope sorry.

I really like my amp tech I go to but as far as modifying an amp thats where he hasn't ventured. Well at least with 5150's. He was the one that installed my transformer and choke; he did a great job I might add. Also helped me correct a supid problem regarding a speaker cab miswiring. Really should have taken my time at that project.
Just had a guy bring me a 6505/5150, brand new with less than 10 hours on it.

Among other mods, he wanted me to install an adjustable bias control and bias the tubes warmer. When I went to do the bias adjusting I immediately found that one output tube wasn't working!

This unbalances everything. This kind of amp works with an even number of tubes on each side of the output tranny wiring. A dead tube means more distortion (harsh, not nice) and big current swings in the now unbalanced transformer, which is NOT good for it!

Turned out to be an open screen resistor. Looked just as pretty as the day it was made. No signs of burning - just wide open inside! This would leave the tube lit up but nobody at work.

There's no way the tube could have pulled enough current through that resistor to burn it out. Peavey must have gotten a bad batch on the production line.

This is easy to miss! This amp when it leaves the factory has no bias adjustment so they'd just stick the tubes in and try it out! They wouldn't have a meter on it to see the lack of current from one tube. With 3 tubes working the amp would still be loud and the extra distortion would not necessarily be obvious to the ear of the "tester".

It's a good thing he got me to do the bias-adjust mod. Makes me think that the idea of not having one at the factory may not always be a good idea...

:food-smiley-004:
 

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Discussion Starter #9
My mistake. I know a guy in Abby with much the same gear lineup.
:sport-smiley-002: I sense a challenge! Time for a guitar off! :rockon2: Who ever looses must sell all their equipment and buy a completely different line up.....





Maybe not a good idea.... I like my stuff
 

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Discussion Starter #10
Just had a guy bring me a 6505/5150, brand new with less than 10 hours on it.

Among other mods, he wanted me to install an adjustable bias control and bias the tubes warmer. When I went to do the bias adjusting I immediately found that one output tube wasn't working!

This unbalances everything. This kind of amp works with an even number of tubes on each side of the output tranny wiring. A dead tube means more distortion (harsh, not nice) and big current swings in the now unbalanced transformer, which is NOT good for it!

Turned out to be an open screen resistor. Looked just as pretty as the day it was made. No signs of burning - just wide open inside! This would leave the tube lit up but nobody at work.

There's no way the tube could have pulled enough current through that resistor to burn it out. Peavey must have gotten a bad batch on the production line.

This is easy to miss! This amp when it leaves the factory has no bias adjustment so they'd just stick the tubes in and try it out! They wouldn't have a meter on it to see the lack of current from one tube. With 3 tubes working the amp would still be loud and the extra distortion would not necessarily be obvious to the ear of the "tester".

It's a good thing he got me to do the bias-adjust mod. Makes me think that the idea of not having one at the factory may not always be a good idea...

:food-smiley-004:
That seems to be a big problem with the 5150's/6505's. A bad tube coming from factory resulting in a blown or wide open SGR. I think thats why a lot of the 5150's have gotten a bad rap for being too buzzy of "sounding like a can of bees". I might have noticed that problem when playing at a volume of .5-1.5, but a nice sweet spot and still tolerable for the ears is a volume of 3. It only gets better the louder you go.

I've never bothered with the bias mod as in adding an adjustable trimpot to change the bias. Each time I've taken it to my tech I've always just had the fixed bias adjusted, I guess it would be swapping the resistors to match the tubes to the amp.... I'm really not too sure as I've never taken apart the amp, so just a flat out assumption. I prefer piecing together pedals.

BYOC all the way!!
 

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Discussion Starter #11
AWESOME!!! POST COUNT OF FIVE!!! FOR SALE SECTION HERE I COME!!!!:rockon2:

meh nevemind.... still can't post there
 

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5150's IMO are notoriuos for blowing screen resistors. I've had a few over the past year with this problem...they also wind up blowing the neg. bias feed resistors on occasion too.
 

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:sport-smiley-002: I sense a challenge! Time for a guitar off! :rockon2: Who ever looses must sell all their equipment and buy a completely different line up.....





Maybe not a good idea.... I like my stuff
LOL!!! Could've been fun to watch :D
 

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5150's IMO are notoriuos for blowing screen resistors. I've had a few over the past year with this problem...they also wind up blowing the neg. bias feed resistors on occasion too.
Blowing the resistors? That's hard for me to believe, NR!

It's just straight Ohm's Law. A 5 watt 100 ohm resistor by formula can safely carry 224 ma. of current. How the hell can a screen draw enough current to blow such a resistor? And leave absolutely no sign on the resistor of excessive heating?

I mean, the resistor I changed looked like it had never seen any power at all!

If a bad tube had a shorted screen it might then draw such current. Still, no fuse blew? And even if the fuse decided not to blow, wouldn't such current be enough to fry a circuit board trace?

Besides, I tested the tube. Not a damn thing wrong with it.

Unless somebody can explain the math better, I just can't accept the resistor was blown. It fits the facts much better that Peavey has been getting bad resistors.

Probably made in China! :smile:

:food-smiley-004:
 
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