THE INFAMOUS AMPEG VL SERIES
The Problem & Unit's History:
VL Mods: My amp appears to have developed this volume fluctuation before April 2015, when Chuck had sent it to Lee Jackson (the amp's designer) to have the standard VL-502/VL-1002 mods done to it.
Chuck said Lee then also cleaned and biased the amplifier before signing it, which he did upon Chuck's request. After a few sessions, Chuck swore the volume fluctuation was still present. It then seems the problem progressively worsened, becoming slightly more obvious and possibly occurring quicker as time went on. He contacted Lee in August 2016. Back then, Lee had never had one fail after the mods were completed. Lee suggested the problem could be in the Marshall-style impedance selector or a bad output transformer. Chuck put the repair on the backburner until May 2017, when he took it to a local repair shop. The techs failed to reproduce the issue in 2017 and 2018, running a radio signal through the amp during business hours. Tubes were replaced and they made a bias adjustment, but Chuck could still hear the intermittent problem, so he let it sit a year.
In 2019, Chuck fired the amp up and found that the volume issue seemed to have vanished! After a few months of occasional play without a hiccup, he listed it on Craigslist - I actually remember seeing it, but it disappeared. Someone had driven a few hours, demo'd it without an issue, returned home, and heard the problem. Embarrassed, Chuck refunded the money and put the amp back on his studio shelf. In 2020, he played it again and didn't notice the problem - the amp was starting to drive Chuck nuts. Confused, he put it back on Craigslist. I didn't let it get away this time. I spent almost one and half hours at his place demo'ing the amp and checking out his studio ...I never felt he was trying to pull a fast one on me.
When I told him about the volume issue, he was again embarrassed, but also frustrated. He offered to refund my money just so he could be the guy to toss the fucking thing in a dumpster. I really liked the amp ...and my girlfriend loved it, too. He shared all of his emails with Lee, the receipt from the tech shop, and any detail he could remember. COVID started to get crazy, so I didn't ask for a refund - I simply decided I was going to save it. I found the correct AFP-2 footswitch for $45.
I watched YouTube videos on tube amp repair for about a month and got a list of equipment I would need. I then started to focus almost entirely on bass playing, so the VL-502 took a backseat to everything else in my life. Every once in a while, I would fire it up, only to find the problem getting worse and happening quicker. It would start to fluctuate, or even fall flat on its face, after ten minutes of play. I decided it was too risky to keep playing it with the problem, and let it sit for a couple months. At the end of November 2020, I decided to clear out the gear I didn't use. This included two heads (the VL and a 1992 Peavey Ultra 120), plus fourteen effects pedals that I had bought in my two year quest to mimic Peter Steele's tone.
The VL went on Craigslist for $250 and Reverb for $270 in December 2020, local pickup only. I was very explicit in explaining the volume issue at the top of the ad. I continue to be shocked by people who want to buy something, but can't be bothered to read about condition. "Does it have any issues?" I also had several requests to ship it, but they apparently thought I would ship 50lbs+ of delicate electronics on my own dime. Fed up, I decided to finally open the amplifier up a week later to see if I could find a problem.
Then I noticed two factory joints that appeared to be cold, like the wire was either dirty or didn't warm up enough. These were connected to each tube's #7 pin at the board. These are JW1 and JW2. I fixed those and took it back to the bedroom for testing. It failed in about five minutes, just like it had been. I decided to clean up the mains by removing a mountain of solder, scraping off the crud with my fingernail, and cutting the nasty ends off the wires. Exposing the ends, I noticed some very light corrosion disperse from the strands. That's not good! I clipped an additional inch off and they appeared to be better. I reattached the leads, and play-tested it with the pre and post gain maxed. Again, it failed before I hit five minutes.
Time to get serious. I removed the power transformer and cut all but three inches off of the mains. I had some yellow marine-grade 16AWG wire on hand, which was perfect. I soldered the new wire to the old wire, remounted the transformer, and resoldered the leads to the power tube board. Back to testing, this time with a TS9 to occasionally push the suspect circuit even harder. At least twenty minutes went by and I never noticed anything other than perfectly consistent volume output! The corrosion makes sense as to why the problem worsened as the years went on. Whether or not I got all of the bad wire out or not, remains to be heard. I may try to replace the entire run of wire from the transformer. Otherwise, Mercury Magnetics has replacements for these if it acts up again.
Now, Lee mentions in his mod video that these main/heater wires are either green or yellow. Mine were green with a white stripe and it is an earlier unit. I was wondering if there was a manufacturing defect, and the update brought in transformers that have yellow wires? However, Lee had stated in 2016 that it could have been the output transformer and never said anything about the power transformer. I initially blamed the dirty wire jacket melting into the joints, but the issue predates the modifications.
If you have one, I have read a few forum posts by Voodoo Amps in NY. It sounds like they specialize in VL repair and they swear the amps are reliable once Lee's modifications are done. You might want to contact them if you're closer to them than Lee in Texas.
The VL and Stealth Series:
Unfortunately, Ampeg was pigeon-holed as a bass company and the marketing failed. Even with Zakk Wylde and Paul Gilbert using them, shops had VLs sitting on shelves long after the guitar lines were discontinued. From my understanding, Russ Parrish (Satchel of Steel Panther) used a VL-502 for every song on Fight's 1992 album, War of Words. I guess I should also mention that Tom DeLonge used them on tour. No one cares? Moving on... The VL-501, VL-502, VL-1001, and VL-1002 heads were notoriously problematic, but supposedly didn't hold a candle to the nightmarish VL-503 combo. SLM and Lee also released a somewhat similar, but seemingly even more troubled (cheaper components), version of the VL under the Crate name. These were the Stealth GT-50 and GT-100. The guy I bought my VH-140C from had a Stealth 50 that was flawless and it was one of his all-time favorite amps - coincidently, it was also his girlfriend's favorite. I've read of a few people owning both, and the Stealth might be the slightly more-preferred model. The VLs and Stealths seem to have all but vanished, though. Is it because they've been tossed into dumpsters out of frustration, or because anyone who has one refuses to let the unicorn go? I wager it's both since once I fixed mine, I immediately could not bring myself to sell the infamous rarity ...but I ultimately did a month later since I was more into bass. When I first posted what is a Holy Grail to some collectors on Reverb, it had 100+ views within fifteen minutes. Players are obviously still looking for them. I sold it the second time around for $625 within ten days (January 2021).
Bias selector set at 6550: 6550, 6L6, KT88
A common complaint among VL owners a weak clean channel, which many attribute to the EL34 tubes. I can attest that the clean channel on my VL-502 with EL34s is very lackluster. I have read owners saying the 6550 tubes produce a better bottom end, giving the amp a much improved clean channel along with a more modern type of distortion. Users describe the EL34 as producing a style of gain typical for the 1980s, being very mids-minded like a Marshall. I felt my EL34-loaded VL would sound much better to me when I cut the mids with an EQ pedal on both channels. I play metal, so purchased a pair of matched Svetlana 6550C tubes for $100 to try after the repair. After five minutes, I was pretty certain I preferred the 6550s for both channels, even though I'm not getting as much break up. I don't think I gained any volume, though the 6550s actually might have made the treble a little less harsh, allowing me to turn it up a bit before killing my ears. I have read a comment by Tim Stanley (appears to be a VL guru on YouTube) that mixing 12AX7 preamp tubes is the key to a livelier and thicker gain. He recommends a setup of long plate Mullards in V1, V2, V3, and V7. Then some Tung Sol reissues in V4, V5, and V6. He advises that generic Chinese tubes can make a VL sound dull and bland. He goes on to say that with his preamp tube combination, along with 6550s, it should give the amp the exact same sound as Zakk Wylde's Metaltronix on the No Rest For The Wicked album.
According to Lee's emails from 2016, a single pair of KT88 tubes are only useable in the 100watt heads. He says to use the outer sockets, due to their larger diameter. However, I ran across a picture on Reverb showing a pair from Groove Tubes installed in a VL-502. I then searched and found a few people that have managed this without mention of any issue. Looking at mine with 6550 tubes installed, there appears to be enough room between them. From my understanding, the KT88 tubes are more likely to require an adjustment to the internal bias pot.
Noise Gate Notes:
CrankyGypsy (established 2001)