ADA Depot - A Forum To Support Users of ADA Amplification Gear
Miscellaneous => Discussions => Topic started by: rabidgerry on May 27, 2022, 03:19:02 AM
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Well I'm back!
Had so many things to bring up for discussion with you all but just hadn't the heart to talk about it until I felt like a musician again with a band. Weird right? Well I got a bass player now so he's playing with me and the drummer and things are starting to feel like a band again so here I am!!
Anyways I think I brought this up before but here I go again.
FEEDBACK!!
I have real issues with feedback. I'm now contemplating using two noise gates which to me seems really crazy considering I would be using what I would consider 80's hi gain. So I bet no one used two noise gates back then which is why it is crazy to me as one noise gate just doesn't seem to cut it for me.
That is unless there is something wrong with my rig.
However I don't think it is my pickups as they are potted. I don't think it's tubes (using a Peavey Classic 50/50 tube power amp and Peavey rockmaster) as it's not whistling feedback. Well to be honest the feedback sounds vary. The main way I would describe this is resonance from the guitar body. I also am guilty of standing facing my cabs. Yip that's right. Why? Because it sounds like shit if you turn your back. So if I shouldn't do this in the rehearsal room what is the best way to monitor without standing say 15ft from cabs and facing them?
To go a little deeper, the noise gate I use does work. It just seems to open to much from resonance and string noise. Like sometimes I can catch the strings and mute them and feedback will still happen unless I turn my back quickly as well. It's all a bit weird unless this is totally normal and I just shouldn't face my cabs. Then again I ask how do you guys monitor in rehearsal?
The noise gate I use tracks the guitar signal then has a loop to place into that the noisy device. In this case it's what ever preamp I am using. It's a rocktron Silencer pedal I use.
Here is one way I've hooked it all up before
(https://i.ibb.co/1QZ6s9K/my-rack-setup.png) (https://ibb.co/W5ntDcF)
and a similar way
(https://i.ibb.co/GHxKTk3/my-rack-setup-silencer-n-rockmaster-output.jpg) (https://ibb.co/XY2h8pk)
and here is another way but it's also in the loop of the rockmaster pre
(https://i.ibb.co/HXbkDVc/my-rack-setup-silencer-in-rockmaster-loop.png) (https://ibb.co/Yb1q735)
and also in the loop again but guitar goes to the GX700 first and then that unit send goes to the input of the silencer
(https://i.ibb.co/dPkNSGC/my-rack-setup-silencer-in-rockmaster-loop-2.jpg) (https://ibb.co/X7Fn9S0)
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I use in essence 2 noise gates, the decimator pro g rack which has 2 noise gates. The signal comes from the reciever into my rack wah and then goes into the first channel of the decimator, from there it's splits into my MP-1 and MP-2, the output of my MP-1 goes into the second channel of the decimator. For the MP-2 I use the internal noise gate a bit since I only use it for cleans it's not so noisy. The output of the second channel of the decimator then goes into my midi loop switcher, same as the MP2 output so I can switch between the mp-1 and mp-2.
Works perfect for me. Also the decimator is super fast. I found out that this works best, one gate before (which cleans up the guitar signal) and one after (which cleans up the preamp).
Maybe mixing a pedal with rack gear doesn't work so well, instrument vs line levels. The decimator can be switched between line and instrument level per channel, so my first channel is set to instrument level, second is set to line level.
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Hey RG great news about the bass player :whoohoo!: .
IMHO there's a couple of things going on. Facing your cabs is how you get feedback normally unless the volume is so low you don't and you have to put the guitar right on the speaker to get it. But I assume you know that, just watch a Hendrix live clip.... This sort of feedback is hard to gate out as there is lots of signal feeding back which opens the gate and higher gain + vol even more signal/feedback. But to gate resonance feedback, it's probably done best up front just after the guitar (like MJMP does with one channel of his gate, before the preamps add gain to it) so the guitar resonances are lowered and they don't have much gain at this point. But your gate works a bit differently to MJMPs, the silencer has the loop thing, so it's gating the loop return, not the (guitar) input and while it's ok with lower level line level signals (max 10dBu) it's more meant for a noisy distortion pedal with much lower output than the rockmaster.
(It's all a bit weird unless this is totally normal and I just shouldn't face my cabs :thumb-up: )
So monitoring with your back to the cabs will control it (well to a degree, depends how loud you are playing), as you said. So you need to work it such that you are ok with sound coming from behind or even the side (so you can turn away to stop the resonant feedback). I rehearse with one split stack behind me so the angled top means I don't have to get as far away for it to be ok. Maybe mic the guitar as well and put a bit in the PA or a monitor/wedge so you can face away from your cabs and get a ok sound.
The other sort of feedback is gain/circuit/electrical type squeals/noise which will happen when you get your guitar really close to the preamp/amp etc (when the gains cranked up, even if the guitar volume is off/0) or when there are gain issues with your signal chain. The way you run your rig is a bit unusual (albeit interesting and inventive and hey, works for you :thumb-up: ) and looking at the 4 patching options, they all have various degrees of (potential) gain structure issues. IIRC you use the GX700 as both preamp and FX and the rockmaster like a distortion pedal (albeit a line level one with lots of gain) in the GX700 loop. So straight up there is a (potential) gain structure miss match. The rockmaster input is inst level and its output is line. Obviously you have made this work ok but this is generally squeal city (and using the gate is helping control/accommodate the gain mismatch). If for example you had a early MP-1 top switch model (and no rear jack mod), you'd either use the MP-1 front in (inst level) and switch the MP-1 out to inst level, OR use MP-1 rear input (line level) and switch output to line level thus no gain mismatch in GX700 loop. With the various patch options, where the various loops are in the signal chain (within each unit and overall) and what control you have over their send and return levels makes a big difference also, but even if you can balance them up with a combination of controls (i.e. input/output vols, send level return level) so there's no clipping etc. any inst and line level mismatch will add noise and squeal.
So looking at the silencer, seems the input just passes through (tru bypass mode i.e. switched out/off) or when switched on, the input goes to the send (you said there's some sensing of that signal for noise reduction purposes ? for the Hush?) so whatever the input level is, (up to 10dBu or the input will clip) is what the send level is. The return signal goes through the gate to the output and also is "hushed" at whatever level comes in the return jack.
In your setup 2 gates make sense. One up front between the guitar and input to help control resonance feedback, and one in the GX700 loop to help control the gain mismatch squeal/noise from the rockmaster.
Anyway my 10 cents my friend, hope it helps :wave:
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@MJMP
I get what you are saying but from the manual it should be ok to take line level at the Silencer send/return and instrument level and the Silencer input. https://manualzz.com/doc/17278095/rocktron-guitar-silencer-pedal-manual--pdf- (https://manualzz.com/doc/17278095/rocktron-guitar-silencer-pedal-manual--pdf-)
I mean it is designed to go in the loop of an amp same as I have used it and same as Boss NS-2 or Decimator G-string pedal which all follow the same principal of tracking guitar signal, then send that into whatever device you are using etc etc. There could be something in what you are saying though which is why I was asking what is the best way for me to hook my gear up and posted the examples.
I think I'm leaning toward Guitar > Silencer Input > Silencer Send > GX700 Input > GX700 Send > Preamp Input > Preamp Send > Silencer Return > Silencer Output > Preamp Return > Preamp Output > GX 700 Return > GX700 OUTPUT > Power Amp Input
@Richard, that's what I thought you were going to say. I already knew this about feedback but I guess I was looking someone else to tell me as a sanity check.
Really standing with my back to cabs is such a stupid way to hear myself, but then so is facing the dam cabs. Yesterday I looked at the Boss GX700 again to see if some levels had changed that I wasn't aware off. I revised each thing again which I think helped. Basically I dialled the input for the guitar going into the GX700 input down a little and this seemed to help A LOT. However, I feel have lost some distortion now which I am disappointed at.
If I was to employ two gates I think I would put one on the end of the guitar by itself however I still really don't think I should have to do this.
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Hey RG, the issue is mixing inst level and line level. The silencer is either, not both at the same time. The silencer input is fed to its send, so if the input is inst level (your guitar), that's what will go out the send, if the silencer input is loop send (GX700 or rock rockmaster), that will be the silencer send level (line albeit dialed down via send level control). The manual diagram puts a noisy distortion pedal in the silencer loop which is inst level in and out. If you put the rockmaster in this loop instead, you create a (large) gain mismatch because it's inst level in and line level out, the rockmaster isn't designed to go in a loop or fx chain (e.g. pedal board) where the noisy pedal is. Obviously you can make it work by adjusting the various send and return levels etc. but it's like you have a gain volcano with a plug in it, so the potential gain is still there in the circuit i.e. squeal city. You can get some interesting/amazing sounds this way but they are always on the edge. One of the best guitar sounds I ever created (back when I was 14(ish)) was:
Guitar -> battery powered microphone preamp -> old 5w tube radiogram crystal input (before magnetic LP PU cartridges), 5w speaker out -> 100w amp input (it normally wants 1v (not 5w :metal: )), 100w out -> 2 x 20w twin cone hifi speakers. So massive gain mismatches all over the shop. Sounded absolutely awesome until I started blowing my dads hifi speakers :facepalm: (he was not impressed). Also squealed like a banshee but that's partly how I learned to play.
Another example more similar to your gain mismatch is when I used a Rockman for solo boost:
Guitar -> a/b a+b switch, a to Marshall 50 input, b to Rockman input, Rockman headphone outs, left to Marshall 50 bass ch input and right to Marshall 100w Artist input. I put resistors in the Rockman output leads to bring them back to inst level for the Marshall inputs. This sounded great but squealed uncontrollably when I stopped playing (because of the Rockman gain mismatch), so I had to be quick on the a/b switch to turn the Rockman input off at the end of songs, the singer called it the beast LoL. So even though I'd balanced the levels (resistors in the Rockman output leads), the potential gain in the Rockman just went off, same thing is happening with your rockmaster.
As we discussed ages ago, to use the 2 preamps, you could split the guitar signal so both preamps get inst level in and bring it all together with a small mixer. But then you don't get to load up/boost the rockmaster input from the GX700 preamp stage (which IIRC you like to) or get the GX700 fxs on the rockmaster. So since the way you do it gets the sound you want, you need to control the gain mismatch (squeal potential). So running the rockmaster in the silencer loop will (and does) help. A normal gate after the guitar will also help because the whole preamp setup wants to feedback. Also using more sophisticated gate(s) could assist as they give control over gate attack and release times, not just threshold.
I like to rehearse as similar to stage as I can, so cab(s) behind me. Unless I put the cabs up to ear(ish) level or get a fair way from them, I don't hear the top end as much as it all goes into my legs. Consequently my patches probably have too much top end.
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So which of my diagrams is the most suitable do you think?
Ok I totally get what you are saying now.
Does that mean the silencer can't cope with a line level being returned to it?
For all intents and purposes I know the loop in the Boss is supposed to be able to cope with a preamp or something like it in it's loop. And should there be issues levels can be adjusted either via the output of the rockmaster or the return level of the boss. The boss has metering for the every item in the chain so this can be checked as well to make sure what is coming back in the return isn't pushing anything to far.
I would never have imagined the was an issue with the silencer's loop though.
Like I mentioned earlier I did get things under control on Saturday by looking at the level of the guitar going into the boss but I can't help feel I've lost some distortion now.
PS I have another simple, single ended noise gate pedal that I bought as part as part of a flight rig, I could potentially use this as the second gate after the guitar. If I was to place this in my setup would where would you place it? On the send of the Boss? Or between the guitar and the boss?
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I would place that single ended gate directly after the guitar. That would work best IMO.
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Hey RG, I'm with MJMP, directly after the guitar and see if you can get the level into the Boss back up so you don't have the distortion loss. And of the patching methods, put the rockmaster in the Boss loop so Boss send -> silencer input, silencer send to rockmaster input, rockmaster output to silencer return, silencer output to Boss return. So basically like the silencer manual with rockmaster being noisy distortion pedal. There will be the gain mismatch but you can balance the various inputs and output (as you have been doing) so there is no clipping and tweak the silencer hush and gate thresholds to keep it as quiet as possible.
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Thanks as always guys, well that seems like the best way, so I shall try this out on Saturday.
I have also discovered this which I am keen to try.
Seems very good in my opinion and for the cash????? Holy :poop:
Have a question about what guys where using for noise suppression in the early 80's and even further back. Can anyone tell me?
http://www.youtube.com/watch?v=pLJVRBhka2I
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Well my first noise gate was a boss NF-1, still have it ::)
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But you don't use it though right? Not with the Decimator in your rig.
Like what would Judas Priest have used for example in like 1982? Or anyone else. Kinda fascinates me as I know toward the late 80s lots of bands where using Hush units. And I really really love the Hush IICX but I use this for for home use. Adapted a pedal into my rig as it is smaller.
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No don't use it anymore, it's quite old, I think I bought it new in '84. I just keep it because of the memorys I guess. I also have my old DS-1 and some other MIJ boss pedals.
From what I recall DOD and MXR also had noise gates around that area. Maybe some DBX gates were used before the hush, just guessing here.
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I just used my hands, never had or seemed to need a gate. When I included the Rockman I had to be quick on the a/b switch at the end of songs. When I went to the MP-1 rig I never had any issues. I have notice from teaching guitar to the occasional person(s) that I have developed various hand left/right techniques to shut the guitar up. I developed these due to necessity playing full bore (no master volume on amps back then). I don't think gates were invented way back then? and fx wise, I had a MXR phase 45 for a while, then a electro harmonics Memoryman delay for a bit. Later I got a tom shultz power soak which let me play the Marshall 50 at lower volumes and then a korg digital delay and digital chorus. Then moved on to MP-1, Quadverb, B200s, which was just heaven after the Marshall 50 and never had any need for a gate. I used the gated reverb in SPX90 for snare, mixing live bands. IIRC it also had a gate patch but I never used it.
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Yeah that's right MJMP a couple of other brands followed suit with the noise gate pedals. I believe a had the DOD one from the mid 80's but I got rid as it wasn't what I thought it was. It had a loop in it for whatever reason but not a side chain to guage the opening and closing of the gate like the Rocktron Silencer or ISP G-string or NS-2.
Well I can only assume Richard that your gain or distortion levels were never as high as some of the acts I'm talking about. Just at a guess. I get no where near as much noise from my Rockmaster pre when I'm on the crunch channel for example. But on the Ultra Gain channel with boost switch engaged I get feedback at the volume I'm playing at. Still might get feedback with lower distortion tones but I have to coax it out a little more, i.e find the right spot when facing the cabs. I think great deal of my feedback issues is down to resonance from the guitar and also from facing the cabs as I mentioned in the beginning. However as I'm 15fth away I can control it like you do by adjusting my technique. I noticed over the years so as not to lean on my locking trems I developed a really light palm mute which I am now having to adjust. I was always paranoid about pushing down on a floating trem and that gave me this light right hand muting technique. I'm now trying to adjust that these days to a more pressure applied to the strings approach to help catch the string noise. I also try and mute with the left hand as best I can too. The combination is good but still sometimes that "groan" resonance from the body can sneak through hence wanting to get the gates to help me a little more.
May could start to use my IEM's I bought a long time ago and never got to use thanks to Covid and then I wouldn't need to face the cabs.
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I spent a lot of time with noise gates and I was happy when I found the decimator. For me the dual gate setup is the best way, I did a lot of experimenting with different brands and the dual gate was always the best solution.
Don't think that the feedback is coming from the guitar itself but it can come from either the strings or the pickups.
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Hey RG, I suspect you are correct, with the Marshall my feedback was more volume related than gain, well a bit of both but the '73 Marshall input stage is not as high gain as some later amps and gadgets. I do need to use the MP-2 built in gate for its really high gain voices. The MP-2 gate gives you the option of fader release rather than hard gate which I prefer. Other gates I've used in live PA rigs (mostly for drums to improve separation and rings) are a bit more sophisticated and give you control of attack and release times etc. You can get rack versions of these with 4 (or more) gates, maybe an option to consider as these days allot of people are using digital consoles which have gates (and other goodies) built into to each channel (saves allot on patching as the gates are usually connected to channel insets) so there would be some on the 2nd hand market.
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I spent a lot of time with noise gates and I was happy when I found the decimator. For me the dual gate setup is the best way, I did a lot of experimenting with different brands and the dual gate was always the best solution.
Don't think that the feedback is coming from the guitar itself but it can come from either the strings or the pickups.
I just can't help feeling I shouldn't need two gates. I almost certainly have a ground loop as well which I think throws some horrible resonating frequencies into the mix and adds another feedback trigger.
But I'm going to employ the two gates technique and see how it goes.
Hey RG, I suspect you are correct, with the Marshall my feedback was more volume related than gain, well a bit of both but the '73 Marshall input stage is not as high gain as some later amps and gadgets. I do need to use the MP-2 built in gate for its really high gain voices. The MP-2 gate gives you the option of fader release rather than hard gate which I prefer. Other gates I've used in live PA rigs (mostly for drums to improve separation and rings) are a bit more sophisticated and give you control of attack and release times etc. You can get rack versions of these with 4 (or more) gates, maybe an option to consider as these days allot of people are using digital consoles which have gates (and other goodies) built into to each channel (saves allot on patching as the gates are usually connected to channel insets) so there would be some on the 2nd hand market.
Oh I'd love the luxury of adding a more sophisticated gate and another unit to my rack but unfortunately for me, the smaller the rig I have the easier it is. I'd love to be wheeling a "fridge" sized rack around with me with all my fav units included and wired up in a million different ways. Adding pedal gates into the chain was so they can get stuck in the back of my rack case. The GX700 has a built in noise gate but I think I'd get a purer signal without using it. I could also be paranoid :facepalm:
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Hey RG, if your rack has rear mounting rails, you could include a 1 RU multi gate rack unit from behind (typically they are not very deep units), once they are set you wouldn't need to touch them (from the front). Can you adjust where the GX700 gate sits in the signal chain? seems to me it would be worth a try but depends where it sits in the signal flow.
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I actually was using Boss NS-50 noise gates for a long time and I actually can't remember why I stopped that. I think I was having crazy feedback issues again but to do with the inputs on the NS-50 or something like that. So I just switched and thought it sounded a bit better.
Yes the loop is moveable on the GX-700.
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Tried the two gate approach and it nothing for me unfortunately. So I am inclined to think it isn't guitar resonance triggering the noise.
One thing I noticed when the Silencer gate doesn't close in time properly is a weird hum sneaks through. I kinda wonder is the ground loop making crazy noise and triggering the gate to stay open? I never ever did got rid of my ground loop issues. Well I did with my old setup way back, but since I went all rack I never got rid and just lived with it. Perhaps I need to fix this first. Also power supplies in the back of my rack cause may be another contributing factor to excessive noise or hum that is messing up the gate performing properly.
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As you say the hum wont be helping. Have you tried the 3 different ground switch positions on the back of the rockmaster ? may help :dunno:
I thought of another patch for you to try:
Guit > Boss input > Boss send > RM input > RM send > Silencer input > Silencer send > RM return > RM output > Silencer return > Silencer output > Boss return
Use the RM Common EFX Loop as it's used for all RM modes (but you could also try other EFX loops probably the higher gain ones?).
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Hi Richard,
the Rockmaster UK version has no ground switch unfortunately so can't utilize it.
So I traced one source of hum, basically the GX700 has a power supply in an inline format. I had it stuffed in the back of the amp rack case. So I realised that where it was situated was right next to the Peavey 50/50 transformers. So I dunno where I will locate this permanently, but I do know for the time being moving to out of the rack and lying somewhere out the back of the rig helped reduce the hum I was getting quite a bit. However some hum still remains. I'm convinced this is from the peavey rockmaster.
Today's practice was unbearable. So much feedback and very few positions for me to stand in where I could manage it. So another discovery occurred whilst trying to look for hum offenders. Basically the drums are setting the feedback off also. The drummer did one kick on the bass drum and whilst I had the gate off, and volume up the feedback occurred. So what the hell am I supposed to do with that? I mean where my amp and cabs are set are like a stage currently. So cab stack either side of the drummer. What am I supposed to do, ask him to stop playing drums? I have to get rid of this issue as I cannot play without feedback interference distracting me from rocking out.
I also swapped amp and it seemed like this helped, but in reality it was still the same.
So hum and feedback need to be eliminated and I do not know how.
I also tried the setup you suggested Richard with the send from the Boss GX700 feeding the silencer side chain. Again seemed to help for about 3 seconds. So in reality pretty much the same as feeding the silencer the pure guitar signal. Absolutely fed up.
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Hey RG, complete empathy for your exasperation :facepalm: . IIRC you have been running your rig the way you have it patched (minus the gates) for quite a while and never had all these problems ?? My inclination has always been make the patch rockmaster centric not GX700 as in use the GX700 for effects, so either put it in the rockmaster main loop (as it has 4 loop options) (but loose stereo) or use a small mixer and run the GX700 off a mixer Fx send so you can bring it back in stereo into 2 channels, mixer stereo out to power amp. This is a much better setup for gain structure.
For the kick drum to be setting your rig off (or any other really loud noise) implies tubes (and or PUs) being microphonic. There's no such thing as no microphonics in either tubes or PUs, just some less than others. At a certain volume (usually very loud) anything will feed back. Hums are a headache as lots of things can cause them, like having the GX700 PSU close to transformers. But also for some they find the various devices earthing to each other via the rack rails causes issues. I've never experienced this issue thankfully. Another exacerbator of hum (and noise) is old electrolytic caps which is the main thrust of the MP-1/2 noise mods.
Solutions include isolate in the rack (unit and mounting screws insulated from the rails)
New low microphonic tubes (generally short plate tubes are less susceptible)
Recap preamp and amp
Keep input and power leads well apart, if they have to cross, cross at right angle to lessen any induction
Keep everything away from transformers, particularly power amp transformers
Wax pot PUs (which you've done)
Ensure all good quality leads, the shield in leads can also break down over time but mostly for guitar leads as they are subject to physical ware
Keep rack away from vibrations, e.g. not on top of cabs
But you know most (if not all) of this.
When you play really high gain though, it's always on the edge, hence MJMP utilising 2 gates to control it. If I use the really high gain settings in my MP-2 I have to use its built in gate. At such high gain is also where tube microphonics (and hum/noise) are more pronounced.
If hum is from the rockmaster (and I agree that's likely) then it needs a retube and a recap. It's an old unit, the electrolytic caps will have hardened (as they have in MP-1/2 etc.) The 50/50 is also old and will have the same issue. Maybe use your Koch instead? It's much newer and solid state.
Have you considered building a rig around your MP-1?
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To be fair I have always had feedback issues. But there has been two years of very little band action as well and I hadn't long switched to all rack set up really before it all came to a stand still. It's just a lot worse now. I'm in a different practice room also. The last one I was in was for over 10 years and my rig was away from drums and facing them drummer. I've always suspected other vibrations from other sources (bass gear, drums) to be a contributing factor and have never quite been able to prove it. And now I know it has been which would explain why in some venues it was worse than others depending on where I was on stage.
As for solutions, I do know most of those things. Time to resolve them all though is in very short supply. I guess this is what I get for buying better, but much older equipment.
Yeah I know the rockmaster probably needs those power caps changed. Seem very accessible. I just need to get replacements and time t swap them out.
The GX700 I hate to admit, I believe might be microphonic also. I've had suspicions about the inputs for a while, but I really would not know how to fix this. I can't swap over to the Digitech GSP1101 just yet. It would take a while to get used to the unit and replicate similar patches I have on the GX700 on this unit and then work out all the mid stuff to for the FCB1010.
Ok another psu I use for powering the Silencer pedal was in the back of my rack too. This could well be a feedback contributor also from vibrations etc.
Yes I would consider building my rig around one of my MP1's but I feel It wont be a matter of just swapping it out with the rockmaster. Plus I need a boost in front of my MP1 (not the 3TM) and I just know that the addition of the boost is asking for more trouble.
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Do you use a boost in the boss to boost the peavy?
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No I don't use a boost with the peavey. However for different flavours I have wanted to boost using a variety of other pedals, mainly an EQ for a specific kind of tone but needless to say I can't enjoy anything like kind of thing unless I am at my home setup where I listen to it all with headphones.
The Peavey has a pull switch in the gain knob for both crunch and Ultra channels, this acts as a boost kinda built in for the Peavey. I play on about number 6 on the Peavey with the push/pull pot pulled out to engage the boost.
Really not sure the Peavey preamp tubes are microphonic, they aren't that old. There is the tap test right? How do I do this?
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Here is a video. Beware of the feedback though so as not to hurt your ears. So yo can hear the hum, which was worse remember until I moved the boss power supply away from the back of the Peavey Classic 50/50. So this is the hum that remained. And my amp is turned up very loud hear to demonstrate, also the gate is off.
http://www.youtube.com/watch?v=fqX2fvnYccA
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Hey RG, well that feedback sounded normal for when you're guitar is up close. Do you use a power conditioner? Has this got worse since you moved rehearsal space? There is always some hum & noise when you crank up, particularly with older gear (often caps :facepalm: ) but noisy power can be part of the issue? The only way to "really" fix that is to build/buy a proper balanced power setup which phase cancels all the noise from everyone else on your bit of the power grid. Although allegedly power conditioners do help.
Your silencer PSU shouldn't be microphonic but, like the GX700 PSU can be affected by inductance and RF from the other power transformers.
The tap test is to lightly tap each tube while powered up and gauge how loud you hear it. You could use the tip of a jack plug (gently). Generally with the gain up at your normal level, you will hear the tap, but if a tube is very microphonic it will be noticeably louder.
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That hum doesn't sound normal to me, it's way too loud. I'm sure this is from the rockmaster. I remember when I first bought that preamp someone had disconnected the ground inside the plug. I obviously reconnected it. But when I used the rockmaster in the loop of my GT5 before going full rack I remember having this hum and when I tested it I removed the ground of the rockmaster plug and turned it all on and the hum had gone. So that is when I employed the Art Clean Box II which is basically transformers in box to remove ground loops from setups etc. It worked for me, albeit at the cost of a few db in signal. But then I moved to rack. So there are many more possibilities now for these loops, casing, rack rails, etc so I'm going to need to get the multimixer out and go through my rack. But I think the hum is only one contributing factor to to this overall feedback issue as a mentioned in my post before the video.
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So I guess it's going to be a process of elimination.
I will start off with what I think is the easiest to re-cap (less caps). I'm going to re-cap the Rockmaster preamp. Are their premium caps you can buy that do not degrade? I could replace the three big power caps and see if this has any affect or not.
The GX700 on the other hand has a lot of caps. So I'm going to attempt this last.
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On the rockmaster, just replace C26,28 308.
C308 http://www.banzaimusic.com/F-T-22uF-450V-SKU20484.html
C26,28 http://www.banzaimusic.com/F-47uF-500V.html
Thes should work but check the dimensions.
What I would try is to get rid of the 4 cable method. I would go into the rockmaster first and hook up the boss after the rockmaster. So nothing in the loop of the GX700.
That should also quiet things down IMO.
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Hi Mjmp,
yes I've totally thought about this many times, but it leaves certain functions of the GX700 redundant then, like the compressor or wha wha for example. I have an Rocktron Replifex that would be perfect for running like this, but this unit doesn't get used as it doesn't have a harmoniser like GX700 does. Eventually the plan is to move over to a digitech GSP1101 and run that in 4 cable method also, again because it has harmonizer etc but this is a long way off.
However in the mean time, I might give your suggestion a try, just to see.
What way would you hook it up? The GX700 has a guitar input so if I plug the rockmaster output into this might there be some kind of mismatch as it isn't instrument level?
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I think you can try it out by starting at a low rockmaster volume, I saw in the manual it has a led meter so just make sure you levels are set correctly.
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I forgot to try this out. I will next week. I'm assuming you mean just plug the Rockmaster into the front end of the GX700.
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Yes I do. Let us know how that goes.
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So I went another direction (however I will re-cap my equipment). I removed the Rocktron Silencer altogether and decided to use the onboard noise reduction from the Boss Gx700. Well feedback seems to have been greatly reduced and more under control. I have even decided to mess about and add in EQ into the loop and act as boost in-front as opposed to the onboard Rockmaster boost for more distortion. The whole reason I used an external noise gate was simply as I thought it would be better quality and less signal degrading. Perhaps the GX700 just doesn't like that setup or I need to try a more suitable unit. I do have a Rocktron Hush X at home that I would still like to try. It should be more appropriate for this application than say a noise gate guitar pedal. I still don't think it should have mattered but may be as I say the Boss just didn't like it.
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Hey RG, well it's good that its improved.