Le Lead crackling sounds when performing palm mute

DrV

Member
Hi guys! :) Using Hot Fusion mode on Le Lead I've faced one significant problem - crackling sounds when doing palm mutes. Lowering gain on channel A doesn't help, moreover, crackle gets even more highlighted when the knob is on 12 o'clock. Lowering gain even more isn't practical as the structure of gain completely breaks apart. On the other hand lowering gain on channel B significantly changes the tone. I have gain controls on channel A all the way up and on channel B at 3 o'clock. Fusion knob is all the way up too. I'm for fuzz tones that's why settings are extreme a bit. :rock: I use active pickups (Seymour Duncan AHB-3) maybe they produce such artifacts, don't know. :confused: Maybe I need to rebias input buffer on preamp itself or rebuild guitar output circuitry or just use another pickups... Any help appreciated, thanks :)
 
Hi DrV,

in Le Lead in hot Fusion we allow to boost way more over the specs of the output, just in case someone uses a low level pickup on his guitar.

So, you should try to lower the FUSION knob up to the point the crackling is not there anymore, that should work, you'll get a little less gain though. But there will be already plenty.
 
Thanks, Guillaume :thumbsup: Actually I tried to lower the Fusion knob too, but figured out that: 1). Crackles stop around 2/3 position approximately. 2). In this position the sustain tends to be lesser than on Channel B with maxed out gain so it makes for me the very point of boosting useless. 3) In this position the tone loses pleasant saturation and becomes more flat and dull compared to maximum value of Fusion. At maximum it sounds like liquid fuzz, very dynamic, full of life, despite the fact the poor waveform should be decapitated and compressed to death :) But with crackles :( Tone controls and EQ correction in Torpedo C.A.B. doesn't help because the distortion character changes. That's how it is :confused: External booster is not an option too because I want to have Le Preamps chain and switch between them by MIDI, nothing in the middle, only modulation effects in fx loop.
 
Oh, maybe it's worth trying to change the tube? 12ax7 Tung-Sol or Sovtek LPS for example?
 
Output knob (on channel B, as that one on channel A isn't used in Hot Fusion mode) is on 12 o'clock. Torpedo's input is not clipping (-9...-6 db/peak). Audio interface's input (Tascam 2x2) is ok too. Input and output on Torpedo are set to Line, input on audio interface is set to mic/line. So it's definitely not analog or digital clipping on inputs/outputs if that's what you mean.
1). So, let's make it clear, as we're dealing with hybrid system and have single 12ax7 that is a dual triode: when Le Lead operates in Hot Fusion mode, signal from guitar goes to amplifying transistor circuit (or you use opamps, I don't know) then to first triode on channel A. Then amplified signal goes to different transistor circuit and then to second triode on channel B. If I push the transistor part of circuit on channel B too hard with signal from channel A, then that transistor overloads and clips and after that second triode amplifies this clipping with the rest of signal. Is it right? If it is then of course I need to lower Fusion knob in order to avoid hard clipping and crackling that occurs in the input transistors of channel B.
2). Speaking of changing a tube. If I want to have the Fusion knob lower and leave the gain amount at the desired level, I have to swap for the tube with greater mu coefficient than existing Ruby 12AX7AC5 HG. It's well known that theoretically every 12ax7 should have mu=100, but in reality it's not that simple. Mu changes from model to model and from unit to unit. Ruby 12AX7AC5 HG appears to be relabeled 9th generation Chinese tube (maybe Shuguang, but I'm not sure). If it is, it has rather high amplification factor. Now, the main question: what can I replace it with that have even more gain? :confused:
3). Since we have only one triode per channel, which is it in order? I mean, should I consider it as V1 or V2 (Vn,etc.) or is there a different approach? I'm new to hybrid systems and it's unclear for me a bit :confused:
4). I would like to have some professional opinion from you, Guillaume, as nobody knows your circuits as well as you and your crew. What exact tube can be a good replacement for the stock one? Something that doesn't change the tone quality much (as I like its structure), but has more gain. Since JJ, Electro-Harmonix and other common preamp tubes have approximately the same gain factor as a stock Ruby (even less actually), I personally search around Sovtek LPS (maybe it's a phase inverter tube but whatever :D ), Genalex Gold Lion and Tung-Sol with golden pins. Maybe there're better options that I don't know about. What tube would you install by yourself in my case? Thanks for help :)
 
Hi DrV,

I listened to the video on youtube, I see what you mean. This is indeed the gain structure breaking apart, just because at this point, there is just too much gain. Le Lead was not voiced to be played this extreme.

If you're after fuzz tones, there might be something you can try : keep the gain not that extreme, but push the bass on Channel A. This will drive Channel B way harder.

Regarding your technical questions : hybrid circuits are not that different from all tube circuits, it's all just gain stages. Changing the tube will change the tone and gain structure, but only up to a certain point. The 12AX7 is already a high-gain tube, so I'm not sure there is much to be gained here. But you can try, any standard dual triode should work.
 
Thanks, Basstyra :thumbsup: I tried to push a bass on channel A, but ,alas, the tone loses its edge and becomes not so expressive as before. Actually I tried EVERYTHING since I posted the first message. Everything except changing a tube, changing the plate resistor or adding extra gain stage mini-circuit right into the preamp. Oh, it seems to me it's gotta be hell of a weekend with a soldering iron in the end of a day :aww: Anyway, I like this little red beast (Le Lead), it'll not go anywhere from me, just need to tailor it to my taste a bit :D Awesome work, Two Notes, keep it up! Maybe one day we'll see a real 4- or even 6-stage all tube floor preamp from you! :m17:
 
Made it! After trying few hundreds of combinations I finally found the tone I was after. Bass all the way up on channel A, mids at 9 o'clock on channel B, Fusion just a hair above a half, everything else on 12 o'clock, gain on max (Ch.A and Ch.B). As always it was a cabinet matter and Alichino 1x12 made just perfect, much better than 2x12 or 4x12 british cabs I usually used :doh: And poweramp simulation in Triode mode instead of common Pentode. Perfect tone, great dynamics, awesome! :rock: Guillaume, Basstyra, thank you very much for help and responsiveness! :thumbsup:
 
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