This time around, I went about it differently than I would have a decade ago. Before breaking out the soldering iron, I chatted with Jelle Welagen and Tony Albany at length – thanks guys. I’d built my last amp exactly 10 years ago and it soon became apparent to me that there had been some developments that I hadn’t followed in the last decade. My last “ah ha!” moments 10-15 years ago had been getting access to a few amps, orienting plastic caps and setting the PI trimmer. It seems that since then, a great deal of effort has gone into finding the right parts for amps.
I currently have two amps, one of them is a low plate Skyliner, my 7th build, that I gig with and that has been my go-to amp since about 2007. The other is my 9th build, a 102 clone that’s been sitting in my living room for 10 years and that hardly ever gets gigged. Not that it matters too much, but I’ll add that both amps had undergone a lot of changes back in the day before ending up in their current configurations. I thought I’d experiment on the 102, since it’s the spare one. I built this amp in a Brandon Montgomery chassis and put Brandon’s Heyboer Fender Twin PT and OT in it. I used a mix of resistors that included a few old NTE MFs (the good ones), KOA Speer MFs, “reissue” Dales and a lot of older Xicon CFs. Plastic caps are all 6PS type through and through, and true to the original, the Treble cap is a silver mica, big cap that either Brandon or Gary Johnson had sent me 10 years ago – I sincerely forget who.
I called Jelle and we discussed what I could do to have a more refined sounding 102 amp, with a better singing quality, more sustain, etc., etc. He said he’d done a lot of research on resistors and that that was the ticket. He recommended I tried something other than the Dales on the plates, and that I replaced all of the CFs with LCA0414 Roederstein Draloric. After the makeover, the amp now has CFs throughout the preamp except for the V1 and V2 plates and cathodes and the 4.7K feedback resistor from the OT‘s secondary which is an old NTE. V1’s grid stoppers are also NTEs, V2’s are CF. For the record, I’d never used the CF resistors Jelle recommended. He explained that the LCA0414 Draloric share a lot of the old Q Line characteristics; those resistors as well as the old red Pihers were all over HAD’s older builds. Jelle has a large stock of the Dralorics and you can get them from him on eBay. The snob in me, back in the day, would have probably scoffed at what I’m about to say, but how about if most of the “tweaking” and customization Dumble did for his clients was selecting different parts to use in each build? I’ve come to think there’s definitely something to this. Anyway, a few days later I got a whole bunch of resistors from Jelle to put into my 102. He also suggested I tried a 715 instead of a 6PS Orange Drop for the Middle cap. Over the years, there has been a lot of discussion about using a different type of cap for the Middle slot, but I had never paid much attention to it.
Making the changes outlined above on an already built amp represented a lot of work, at least for someone as meticulous as me, so I knew I was not going to get this done in one pass. Instead, I chipped away at it and then stopped to listen, then continued to work some more. I was also able to gig the amp somewhere along the way. I’ll try to describe the changes and their effects in general terms so that they can serve as reference for anyone interested.
1. Resistors
The V1 and V2 plate resistors were easy to change and had some effect on the tone in OD, making the sound a little more even, for lack of a better description. The Dales were a bit more jagged sounding. The remaining resistor changes encompassed a very large group, so it’d be harder to say which one of them all had the biggest impact since I changed a few at a time. Common sense could suggest that resistors that are always in the signal path, like the OD output resistors, may have a larger impact than the resistor at the tail of the bass pot. But what I can sincerely say is this: every single change got me a little closer. I took a picture of the amp, attached here, while it still had Xicon CFs at V2’s grid stoppers and at the input jack. I had gigged the amp like that was it sounded great, but I went ahead and replaced those as well. It sounded better afterwards. At this point I’m willing to believe just about anything with regards an amp’s secret sauces. The collective effect of the resistors was in a way similar to what I’d heard the first time I had oriented the caps’ outer foils where they needed to go. The amp sounds purer after the change. The tone has more sustain than grind, both clean and OD are less spikey, the clean channel has a little more compression, etc. Basically, the amp sounds more musical. I was checking in with Jelle while I was making the changes, and at some point, he said “Now you have been able to hear what distortion coming from resistors sounds like.” He’s right. I can turn the preamp volume all the way up and the OD Level all the way up, dialing in all the gain the preamp will put out, and the sound is still musical. Before, it would get to a point where I would either have to change the tone control settings, or back off on the gain because the amp would start sounding like crap if the amount of gain was too large.
2. Midrange Cap
I changed the .01 uF Middle cap, replacing the 6PS with a 715. The difference was very noticeable to me as the 715 seems to focus the midrange more. If anyone feels their amp is bottom heavy, which is a common complaint about the Skyliner tone stack, the 715 cap will change that for the better. When I first installed it, the low-end response changed so much that it kind of freaked me out and I put the 6PS back in. The next day, I put the 715 back in and took the amp to the gig.
3. OD HF Taper
Through the years, I went back and forth on this a few times. Early on, I used it. After getting the caps’ outer foils orientation correct, I got rid of it. When I added a larger bright cap on the Master volume, because I liked what it did to the clean, I reinstalled it and it stayed there. I had also tried using a 180K OD output resistor, instead of 150K, but I didn’t like that it decreased the available OD volume somewhat. In the end, I had opted for staying with the 150K and using the HF trim. This time around, I disconnected the HF trim and used a 180K Draloric resistor from Jelle. I will put it this way: I found that the HF trim, which for me was a .001uF cap and the 1 M trimmer dialed in at about 350-400K to ground, has more of an effect on the OD volume than using the 180K output resistor. The overdrive is on the bright side but it is very musical at the same time.
After all the changes, my amp might as well be another amp all together. I’ve been having to rethink my settings as well, and I’ll give you and example. Before, I would have the bass turned up, otherwise the Middle control doesn’t do much, but I’d have to turn the Middle higher still because otherwise the bass would make the sound stiff. So that setting was, at the end of the day, a compromise. Now, I can turn the bass up and leave the Middle halfway up, for example, and the sound will be good. I can turn the Middle up a bit for a little more gain, for example, and the sound will be different, and also good. With the three tone controls are about halfway up, I can switch back and forth between the Lead and Rhythm pickups on a Gibson and get a good sound. For a fatter lead tone with more of that low-end roar, I can turn the Treble down a click or two and maybe the bass up also one click or two, and the sound is there. Turning the Middle up at that point will get more of honky sound and focus the low end more and get you further away from a RF type of tone. If this sounds subtle, it really is not.
Bottom line, I’ve had a lot of fun tweaking the 102 and I’m enthused about gigging it and getting to know it better. Had a gig last week halfway through the changes and I loved the results. I have another gig tomorrow and I can’t wait. So, for all TAG tweakers, I recommend you consider a similar resistor makeover if you feel you’d like to try to get more mileage out of your amp. If you’re happy with your amp, leave it alone and maybe don’t come hang out at TAG!
The parts I mentioned can be readily bought, at least for now, and will not set you back a significant amount. It will be a fair amount of work, though. The next chapter for me will be to do the same for the low plate Skyliner and see how I like that.Gil
