5150 mods... revealed w/ pictures

[lolzgreg]

There is a lot less banter than the Sneap forum... and much less POD here.

 

[C_F_H_13]

There is a lot less banter than the Sneap forum... and much less POD here.

Thank god.

If I hear another POD/SD2.0 mix I might just give up.

 

[C_F_H_13]

ok and some real questions now ( TOTAL NOOB SORRY!)

What's the wattage on these resistors for the bias and R9 mod? like 1/4 watt or something?

What's the voltage on the cap? 500 volts?

Excuse the noobishness

 

[droptrd]

Are you sure the cap should be between 7 and 8? 10pF would have a negligible effect between grid and cathode as the tube's Miller capacitance will be far greater than that.

Between 6 & 7 makes sense as that will give a little high-frequency feedback thereby rolling off the highs.

And, for the life of me I can't find C15 anywhere on this schematic. It's probably right in front of me but I can't find it.

Between 6 and 7 is going to have a greater effect than on 7 and 8. I prefer between 7 and 8...it gets rid of most fizz, but not all of it. The last little bit is "hair" in my opinion. Between 6 and 7 was too dark for my taste.

could you do both???

Yes you could. You could also use a switch to go between 6 & 7 or 7 & 8. Mark and I discussed it.

Oooh snap that would be sweet.

I dont need my 5150 any darker than it is. Mine is pretty dark. I like how the 10pf mod made the upper mids in my amp a little more present and clear. It would be cool to put 6&7 on a switch maybe....a dark switch

I am having a problem however. I dont think the 2 are related but now all of a sudden my amp is having switching problems.

 

[JerryP]

You don't want pin 6 of the tube connected right to a switch, there's high voltage there. Put the cap off pin 6 and then connect the cap to the switch. Any cap you use on pin 6 should be at least a 400 volt cap.
Jerry

 

[Jimmie]

You don't want pin 6 of the tube connected right to a switch, there's high voltage there. Put the cap off pin 6 and then connect the cap to the switch. Any cap you use on pin 6 should be at least a 400 volt cap.
Jerry

Safety First. Still lots of residual voltage left in these amps after the power is turned off that cause serious harm to someone. When in doubt, arc to a known ground. Thanks for this Jerry.

Jimmie

 

[madrigal77]

*bump*. Anyone else try this? Liking the results? Just wondering if it's worth the trouble...

 

[yngzaklynch]

*bump*. Anyone else try this? Liking the results? Just wondering if it's worth the trouble...

I love it. I have played my 5150 non-stop for the last week.

Considering whatelse you own thats quite a statement. This video has my attention bigtime

 

[ericsabbath]

R9 mod is actually a gain cut
will work on most oversaturated amps between first and second in parallel with the gain pot, or second and third stages like on this mod
the less processed sound tends to be clearer, more open and tighter
high values won't make much difference, but anything below 100k is VERY noticeable

in some amps, those resistors are attached to switches, wired as reverse gain boosts, like Bogner usually calls it, or "gears", like Scott Splawn calls
on the Quickrod, there are two "R9 mods", one being the OD1/OD2 switching, the other being the 1st/2nd gear (3rd gear is a true midrange/gain boost on the third stage)

in the 5150, I'd also bypass the R22 (68k v1 grid resistor)
lower input resistance will improve dynamics and make the picking response a lot clearer

reducing the two first coupling caps would be interesting too

 

[Giga]

in some amps, those resistors are attached to switches, wired as reverse gain boosts, like Bogner usually calls it, or "gears", like Scott Splawn calls
on the Quickrod

Same in my H&K Duotone. And sure enough, it get's boomy with the boost engaged which is the exact opposite of what the goal was with the 5150.

in the 5150, I'd also bypass the R22 (68k v1 grid resistor)
lower input resistance will improve dynamics and make the picking response a lot clearer

Really ? as in going to 0 ohms ?

reducing the two first coupling caps would be interesting too

That's what I've done to my VTM60 (amongst others). Works really well to my ears. Stock, the amp tends to get boomy and the smaller couplingcaps prevent that by letting through less of the frequencies responsible for boominess.

Giga

 

[droptrd]

R9 mod is actually a gain cut
will work on most oversaturated amps between first and second in parallel with the gain pot, or second and third stages like on this mod
the less processed sound tends to be clearer, more open and tighter
high values won't make much difference, but anything below 100k is VERY noticeable

in some amps, those resistors are attached to switches, wired as reverse gain boosts, like Bogner usually calls it, or "gears", like Scott Splawn calls
on the Quickrod, there are two "R9 mods", one being the OD1/OD2 switching, the other being the 1st/2nd gear (3rd gear is a true midrange/gain boost on the third stage)

in the 5150, I'd also bypass the R22 (68k v1 grid resistor)
lower input resistance will improve dynamics and make the picking response a lot clearer

reducing the two first coupling caps would be interesting too

maybe ill try the R9. Ive done the 10pf and like it. One of my complaints about the 5150 is the gain range. My amp is like full on high gain or nothing. very hard to get nice low gain crunch. Not that im going for that but something in the middle. I run my amp thru the normal gain input with the gain around 9:30 on the lead ch.

I should probably do a bias mod too.

 

[Greazygeo]

maybe ill try the R9. Ive done the 10pf and like it. One of my complaints about the 5150 is the gain range. My amp is like full on high gain or nothing. very hard to get nice low gain crunch. Not that im going for that but something in the middle. I run my amp thru the normal gain input with the gain around 9:30 on the lead ch.

I should probably do a bias mod too.

Have you tried the rhythm channel with crunch and bright engaged, normal input and cranked? It gets a great crunch tone that way.

 

[droptrd]

maybe ill try the R9. Ive done the 10pf and like it. One of my complaints about the 5150 is the gain range. My amp is like full on high gain or nothing. very hard to get nice low gain crunch. Not that im going for that but something in the middle. I run my amp thru the normal gain input with the gain around 9:30 on the lead ch.

I should probably do a bias mod too.

Have you tried the rhythm channel with crunch and bright engaged, normal input and cranked? It gets a great crunch tone that way.

Oh yeah. I actually prefer the crunch ch. But For live i need a clean ch so I have to use the lead for crunch tones. I tried using the lead for a clean tone but it wasnt good enuff for what I wanted. Basically Id like to have a greater range of gain on the lead ch. I still like the brutal high gain it puts out and I use it with my newly formed metal band. But I also need low gain and crunch tones for my other bands out of the lead ch.

in a perfect world.....

 

[Greazygeo]

maybe ill try the R9. Ive done the 10pf and like it. One of my complaints about the 5150 is the gain range. My amp is like full on high gain or nothing. very hard to get nice low gain crunch. Not that im going for that but something in the middle. I run my amp thru the normal gain input with the gain around 9:30 on the lead ch.

I should probably do a bias mod too.

Have you tried the rhythm channel with crunch and bright engaged, normal input and cranked? It gets a great crunch tone that way.

Oh yeah. I actually prefer the crunch ch. But For live i need a clean ch so I have to use the lead for crunch tones. I tried using the lead for a clean tone but it wasnt good enuff for what I wanted. Basically Id like to have a greater range of gain on the lead ch. I still like the brutal high gain it puts out and I use it with my newly formed metal band. But I also need low gain and crunch tones for my other bands out of the lead ch.

in a perfect world.....

I used to use a JC120 for clean and a/b for dirty. It was nice, but way too much to carry around. I'm too used staying on one channel and rolling down for clean.

R9 does drop alot of gain, I'd drop even more though....way too much gain in that amp.

 

[Jimmie]

in the 5150, I'd also bypass the R22 (68k v1 grid resistor)
lower input resistance will improve dynamics and make the picking response a lot clearer

This is a cool mod as well. I find that if you go lower than 22k the signal tends to be too much and the bottom end tends to run away and become boomy. I have not tinkered with R22 in the 5150, but it is easy enough to do.... Thanks for the idea.

Hey Dave, do you intend to give it a try or leave well enough alone? I've been watching your results and considering picking one up. Thanks for the great thread.

 

[Rushtallica]

There's a 5150 mod thread that's been going on at the Ultimate Metal forum I meant to link back to here the other day: http://www.ultimatemetal.com/forum/equi ... hread.html

 

[lolzgreg]

My 5150 is cutting in and out of volume. Someone mentioned it may be dirty contacts in the effects loop. Does this sound right to anyone?

 

[ericsabbath]

in the 5150, I'd also bypass the R22 (68k v1 grid resistor)
lower input resistance will improve dynamics and make the picking response a lot clearer

This is a cool mod as well. I find that if you go lower than 22k the signal tends to be too much and the bottom end tends to run away and become boomy. I have not tinkered with R22 in the 5150, but it is easy enough to do.... Thanks for the idea.

yeah, some amps (like a stock mesa rectifier) can get boomy cause it's almost like using a clean booster in front of the amp
the raw signal gets into the first stage without being too tamed (79k is a lot of resistance)
but with a lower coupling cap for the first stage or some kind of bass filtering with mixer resistors/bright caps, it wouldn't be a problem
the 5150 already has one 22k for each input (in parallel, so it's 11k for the hi input)
I usually like 10k or 22k for most amps
for some reason, they become slightly less noisy too (I think I've read some explanation posted by Larry on metroamp forum)

in the 5150, I'd also bypass the R22 (68k v1 grid resistor)
lower input resistance will improve dynamics and make the picking response a lot clearer

Really ? as in going to 0 ohms ?

reducing the two first coupling caps would be interesting too

That's what I've done to my VTM60 (amongst others). Works really well to my ears. Stock, the amp tends to get boomy and the smaller couplingcaps prevent that by letting through less of the frequencies responsible for boominess.

yeah, complete bypass
but leaving the input resistors

the VTM is a great amp for mods
it already has a stock variation of the Jose master diode clipping on a switch (comp switch, I think)
my tech/bandmate Zambelli modded a VTM120 for a friend and it sounds killer
I think the specs he used were similar to a Bogner Shiva (which is right between a Jose and a Soldano), but it's tighter and more aggressive
http://bareknucklepickups.co.uk/forum/i ... ic=22446.0
funny thing is that the VTM120 has really small transformers (almost like a pedal supply) but it's punchy as f***

 

[Giga]

in the 5150, I'd also bypass the R22 (68k v1 grid resistor)
lower input resistance will improve dynamics and make the picking response a lot clearer

This is a cool mod as well. I find that if you go lower than 22k the signal tends to be too much and the bottom end tends to run away and become boomy. I have not tinkered with R22 in the 5150, but it is easy enough to do.... Thanks for the idea.

yeah, some amps (like a stock mesa rectifier) can get boomy cause it's almost like using a clean booster in front of the amp
the raw signal gets into the first stage without being too tamed (79k is a lot of resistance)
but with a lower coupling cap for the first stage or some kind of bass filtering with mixer resistors/bright caps, it wouldn't be a problem
the 5150 already has one 22k for each input (in parallel, so it's 11k for the hi input)
I usually like 10k or 22k for most amps
for some reason, they become slightly less noisy too (I think I've read some explanation posted by Larry on metroamp forum)

in the 5150, I'd also bypass the R22 (68k v1 grid resistor)
lower input resistance will improve dynamics and make the picking response a lot clearer

Really ? as in going to 0 ohms ?

reducing the two first coupling caps would be interesting too

That's what I've done to my VTM60 (amongst others). Works really well to my ears. Stock, the amp tends to get boomy and the smaller couplingcaps prevent that by letting through less of the frequencies responsible for boominess.

yeah, complete bypass
but leaving the input resistors

the VTM is a great amp for mods
it already has a stock variation of the Jose master diode clipping on a switch (comp switch, I think)
my tech/bandmate Zambelli modded a VTM120 for a friend and it sounds killer
I think the specs he used were similar to a Bogner Shiva (which is right between a Jose and a Soldano), but it's tighter and more aggressive
http://bareknucklepickups.co.uk/forum/i ... ic=22446.0
funny thing is that the VTM120 has really small transformers (almost like a pedal supply) but it's punchy as f***

Yeah, they are smallish but mine are big now because my 120 runs EL34's with a matching MM OT now.

I've tried the different inputresistor and opted for 10k. I have one of those rotating thingies with different values resistors in it for experimenting so it was easy to listen what happened. Indeed, the smaller the value, the less noise. I've heard Olaf about that too in the past.

I don't like that "comp" setting one bit, the amp looses a lot of punch and there seems to be some nasty artificial sounds coming through with that diodes engaged.
This may also have to do with the fact that I'm not into metal (with the appropriate gainlevels) at all.

Giga

 

[Nigel Tufnel]

My 5150 is cutting in and out of volume. Someone mentioned it may be dirty contacts in the effects loop. Does this sound right to anyone?

That is a pretty common thing with 5150's, it's cheap and easy to fix if it's the problem. A can of contact cleaner and a 1/4 inch cable can clean them right up. It could be any number of things but that is something you can try yourself.