7704A
Well-known member
Picked up to use as a mod platform, hence New Project Day.
Edit: (Poorly recorded and played) clips as promised:
Last edited:
Picked up to use as a mod platform, hence New Project Day.
Edit: (Poorly recorded and played) clips as promised:
Metalhex
Well-known member
Proud VK100 owner here 
.
Interested to see what you do with it and how it sounds. Take before and after sound clips if you can!
. Interested to see what you do with it and how it sounds. Take before and after sound clips if you can!
RaceU4her
Well-known member
first thing i said before i even opened the thread was "ive heard killer modded ones", curious to hear the results
7704A
Well-known member
That's the plan! Hopefully fairly fine-grained ones too. E.g., "Clip log: Changed resistor FOO to a BAR resistor, take BAZ." Would like to get some strong causal relationships worked out between things.
7704A
Well-known member
If you know where the schematics for said killer modded ones are, I'm all ears.
C
ClintN667
Well-known member
I could be wrong, but I think the rhythm guitarist for cattle decapitation was using one when I saw them last December. The other guitarist was using the hiwatt super hi 50 but they sounded fantastic. The rhythms during the lead parts sounded great too so not sure if it was modded or what he was using with it.
Metalhex
Well-known member
There's also the patch cable FX loop hack but I've never tried it.
T
TONEISTKRIEG
New member
The stage left guitarist uses a Peavey 3120 boosted with a Seymour Duncan 805. Stage right guitarist uses the Hiwatt SuperHi 50 straight into the head with no overdrives or boosts.
C
ClintN667
Well-known member
Ah ok I always get those two confused. I do like the cosmetics of the 3120 more than the JSX or XXX but it's not very memorable.
T
TONEISTKRIEG
New member
Yup. The 3120 seems like a “well we have all these XXX chassis laying around…”
311splawndude
Well-known member
Hah. Cool.
Peavey Valveking was my first tube amp. Coming from a Fender Frontman, it was quite the upgrade. But yes, it needed upgrades. I swapped out the tubes, did the FX loop patch trick and the dummy jack trick. Then, once I replaced the stock 'custom voice Valveking speaker' with an Eminence Man-O-War - I was in business. The amp went from this:
to this:
Edit. I also did the closed back mod
Peavey Valveking was my first tube amp. Coming from a Fender Frontman, it was quite the upgrade. But yes, it needed upgrades. I swapped out the tubes, did the FX loop patch trick and the dummy jack trick. Then, once I replaced the stock 'custom voice Valveking speaker' with an Eminence Man-O-War - I was in business. The amp went from this:
to this:
Edit. I also did the closed back mod
7704A
Well-known member
Cracked open the chassis to do a visual inspection of the board (the amp doesn't make sound, hence going for cheap) and found the through-hole high-voltage fuse was blown. Will replace, then continue troubleshooting from there.
7704A
Well-known member
New fuse funny business: I decided to check the mains fuse, which I know isn't blown since the amp turns on. On the back of the amp it's spec'd as a fast-acting 5A, 250V glass fuse. Opening the fuse holder, I find a fast-acting, 20A, 32V glass fuse. 
So I'll be replacing that fuse as well.
So I'll be replacing that fuse as well.
7704A
Well-known member
Got the needed fuses, plus a PCB mounted fuse holder so I don't have to pull the board whenever I change the HV fuse, just the chassis. Removing all the knobs, nuts, washers, screws, and connectors gets old quick. When desoldering the busted fuse, I noticed another part looking a little ill...
That'd be C201, placed across the high-voltage secondary terminals:
Aaaannnnd it's a dead short. So that could be why the fuse blew, or maybe it was collateral damage in the incident that caused the fuse to blow? Not certain how that would work. Maybe a nasty bit of line noise took the cap out? There is some filtering across the input though:
Hmm.... I think I have a pile of ceramic disc caps I picked up in a moving sale, gonna have a look through those. To be continued...
That'd be C201, placed across the high-voltage secondary terminals:
Aaaannnnd it's a dead short. So that could be why the fuse blew, or maybe it was collateral damage in the incident that caused the fuse to blow? Not certain how that would work. Maybe a nasty bit of line noise took the cap out? There is some filtering across the input though:
Hmm.... I think I have a pile of ceramic disc caps I picked up in a moving sale, gonna have a look through those. To be continued...
7704A
Well-known member
I found a cap close to, but not exactly the same specs. Bulk storage ceramic instead of MLCC, and probably only good up to 65°C instead of 85°C. Also, it's uncomfortably old so I'm unsure how it may have aged. After some discussion on another forum, I've decided to leave C201 out for now since it's not critical, possibly not doing much anyway, and I don't care to put another potential short circuit liability in the amp. I do have a higher-voltage rated replacement on order from digikey though if I want to put it back in.
That decided, I prepped the board then installed the fuse holder with the new fuse. Also removed the standby switch while I was in there since from my reading and research so far, I think it is likely not necessary in guitar amps ("low" plate voltages) and I have not heard any convincing arguments to the contrary yet. Though so if someone has an explanation of the physics behind cathode stripping/bombardment and why it's an issue for guitar amps, I'm all ears.
I also replaced the mains fuse (previously a 20A, 32V fast blow!!) with the 3A, 250V as spec'd on the PCB silk screen for 120V models. This conflicts with the chassis label and schematic, but after seeing that the factory-installed HV fuse matched the silkscreen and not the schematic, I'm going to trust the silkscreen for now for the mains fuse. Worst case it keeps blowing and I have to move from 3A to 5A.
Brought up on my variac and lightbulb limiter, and it works! The most authoritative low end I've felt so far too (small sample size though), pushing the volume and playing soft (it's late here) palm-muted low notes on the clean channel makes things in my workshop rattle and vibrate, and I can feel the percussion in my digestive track. Promising...
On the downside, the reverb and drive channel aren't that great at first glance. The reverb is useful, adds something nice to the sound, but is too piercing in the high-end. The drive sounds too thin and buzzy to me. I don't think playing it through EVM's are doing it any favors, nowhere to hide. But in the end, I got this amp to modify into something I think sounds good, so moving from non-functional to functional with a sound I don't like seems like a step forward. I think I want to try remaking the pre-amp into the London Power Standard pre-amp and see how that shakes down. Maybe after I'll try an Orange TH30 pre-amp. Got some noise-reduction/clarity-improving mods planned as well. For now though, I have other more pressing projects, and I'm just happy to have a working amp to play through.
That decided, I prepped the board then installed the fuse holder with the new fuse. Also removed the standby switch while I was in there since from my reading and research so far, I think it is likely not necessary in guitar amps ("low" plate voltages) and I have not heard any convincing arguments to the contrary yet. Though so if someone has an explanation of the physics behind cathode stripping/bombardment and why it's an issue for guitar amps, I'm all ears.
I also replaced the mains fuse (previously a 20A, 32V fast blow!!) with the 3A, 250V as spec'd on the PCB silk screen for 120V models. This conflicts with the chassis label and schematic, but after seeing that the factory-installed HV fuse matched the silkscreen and not the schematic, I'm going to trust the silkscreen for now for the mains fuse. Worst case it keeps blowing and I have to move from 3A to 5A.
Brought up on my variac and lightbulb limiter, and it works! The most authoritative low end I've felt so far too (small sample size though), pushing the volume and playing soft (it's late here) palm-muted low notes on the clean channel makes things in my workshop rattle and vibrate, and I can feel the percussion in my digestive track. Promising...
On the downside, the reverb and drive channel aren't that great at first glance. The reverb is useful, adds something nice to the sound, but is too piercing in the high-end. The drive sounds too thin and buzzy to me. I don't think playing it through EVM's are doing it any favors, nowhere to hide. But in the end, I got this amp to modify into something I think sounds good, so moving from non-functional to functional with a sound I don't like seems like a step forward. I think I want to try remaking the pre-amp into the London Power Standard pre-amp and see how that shakes down. Maybe after I'll try an Orange TH30 pre-amp. Got some noise-reduction/clarity-improving mods planned as well. For now though, I have other more pressing projects, and I'm just happy to have a working amp to play through.
Metalhex
Well-known member
Following!
7704A
Well-known member
I'll post some clips of crappy riffing when I get a chance. Tomorrow maybe?
midnightlaundry
Well-known member
Had a VK 112 Combo.
Quick story.. Some years ago I was walking in the woods, and I found a couple of old TV's someone just dumped.. They were old and had Tubes.. I managed to pluck a real Telefunken ECC83.. Score! Latter I put it in the VK and the Tube Sockets were so tight it ripped a pin off' the Telefunken..
Fuck that VK..LOL
Sold it and barely remember it. The only unique thing stuck in my mind about it and I had to refresh myself with a search on what it actually was, was the Texture Control on the back...
BUT, good luck with the tinker.. Seems like you have some skills.
Quick story.. Some years ago I was walking in the woods, and I found a couple of old TV's someone just dumped.. They were old and had Tubes.. I managed to pluck a real Telefunken ECC83.. Score! Latter I put it in the VK and the Tube Sockets were so tight it ripped a pin off' the Telefunken..
Fuck that VK..LOL
Sold it and barely remember it. The only unique thing stuck in my mind about it and I had to refresh myself with a search on what it actually was, was the Texture Control on the back...
BUT, good luck with the tinker.. Seems like you have some skills.
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7704A
Well-known member
I gotta find some local tone woods to walk in. Maybe I'll find a Crescendo!
Yikes, warning noted, thanks. I haven't had that issue yet (haven't had any old Telefunken tubes either though), but what has been annoying is how deep-set the preamp tubes are into the chassis. Makes it a real pain to pull them out. Probably easier if I just unscrew the base of the tube shield in the future so that I have more to grasp.
Yeah, that's kinda interesting. Messes with waveform symmetry I think. Not too sure how I like it, might replace it with something more useful.
Thanks! Gonna be a bit before I can tinker with it again, have a friend's amp I need to focus on now that I have something to play through myself. Feeling the air move is awesome, I can only imagine what a Wizard or Fryette feels like. Matching that could be a goal for future mods I guess: "concussion or bust!"
7704A
Well-known member
Oh, some tube porn:
