820R on V1 pin 2 reduce hum?

[donzoid]

Thanks Ken and Richie.

I will try that bit with moving my (so far preferred) GE long plate to V2 and then roll again. Is there a good source / price out there as far as dealers on the 5751 that won't clean my clock?

I noticed that V1 is "so" sensitive, that any chassis vibration transfers through it, even though it hasn't really given me grief yet. Makes me wonder what one of those shock mount sockets would do but I think at this point what I am dealing with is just plain guitar ground issues that this amp seems far more sensitive to (compared to the other amps I use). Of course it's always noisier with single coils. I am going to go to a lower output Alnico 5 in one of my Paul clones and see how much (noise) difference that makes because I usually run pretty hot pickups and I don't think they are needed for this amp.

[donzoid]

I just looked through my "oddball" tube stash, and found a 12aT7 GE which by the spec is only a little bit less gain than the 5751 (65% vs 70%). I'll try that tonight. I also saw on other threads where people are putting these into the PI. I might try that too...but more interested in how it behaves in V1 at this point.

[Ken Moon]

I use eBay a lot for stuff like this and I've gotten mixed results.

For example, I would watch this one, then bid 32.76 at the last minute if there are still no bidders. This knocks out those who bid $30 or $30.01.

Takes some patience

http://www.ebay.com/itm/Quad-4-Sylvania ... 338af1a2b1

[JazzGuitarGimp]

Yup, that's the way I bod too. In my opinion, placing a bid a few days before the close of auction only serves to artificially pump the bid up. So I ask myself, what's the maximum I am willing to spend on the item, then I add 10% to 50% to that, depending on how badly I want the item. Then I place my bid in the last 5 seconds of the auction.

[donzoid]

I tried the 12aT7 last night and I think I can see why you guys are recommending the 5751. The whole amp character changed...but there are a LOT of good aspects and since this tube is 60% (about) and the 5751 is 70% I can sense a sweet spot in that extra 10% I can't quite get (in terms of the flat-out roar I get with the 12ax7's for instance) I am going to try to pick up one or two 5751's for more trial.

Very interesting to note: the gain is far more controllable over the sweep of the guitar vol. knob and the tone is "smoother" to my ears. I was for the first time, rolling the vol. knob on the amp ALL the way up (and its pretty good there). It just doesn't quite have the roaring bite at the full-up level, but it does have all the singing sustain.

Getting back though to the OP topic, oddly...the hum level is virtually unchanged even with humbuckers. Next time I open the chassis, I am going to re-route the IEC ground away from the same star point as the PT center taps. And take a closer look at all ground busses.

[passfan]

Have you pulled the guitar cable out of the input jack and actually listened to the amp noise. This allows you to actually hear what is the amp and what is the guitar and possibly a bad cable

[donzoid]

Yes, pass I did that at the last gig and it was very quiet without the guitar cable plugged in. I know the cables aren't bad (tried more than one and I don't use disposables....so to speak). I've been through the LP clone I use once re-soldering grounds and since I am about to put in a pull switch on the volume pot to cut to one coil I'm going to go through it again. This amp is just plain more sensitive than my JMP's to...everything. If I need to I have some copper foil sheeting....I can line the cavities. At this point I don't think the amp is all of the problem. I had to open it up right before the gig last weekend, so I already relocated the IEC ground since I was in there. Didn't make a bit of difference but since Merlin recommends it, I did it.

[rooster]

Here's another thought, considering the fact that the amp is quiet with the guitar unplugged from the amp at the gig.....

Do you use a VooDoo Labs power supply on your pedalboard?

On second thought, I went to your Facebook page and see a recent photo with a few wall warts plugged into at least two pedals (TC Nova?) and something else, and then a white and black box plus a Whine-o-Wah. Your pedalboard is not a pedalboard, it's a grab bag of efx with multiple power supplies put on the floor - a menu for noise.

[geetarpicker]

You mention the amp is quiet without the guitar cable plugged in and I'm assuming that is with the amp volume up some?

That said is the amp still relatively quiet with the guitar plugged IN, the amp turned up to playing level, but with the guitar volume knob totally OFF?

[donzoid]

Thanks guys, Yes Glen the amp volume was turned up quite a bit.
Rooster, Yes its a mixed bag. But there are a few reasons. One pedal requires 18v so I use a computer power supply (its regulated better). One is a Vocalist Live and it requires 12v AC thus it has its own dedicated supply. I use a dedicated supply for the butler tube drive. The rest of them (9v) run a supply rail I built and stuffed underneath which I capped across to smooth some ripple. That supply is a 1.2 amp that puts out almost 12v but that doesn't account for the sag across 5 or 6 pedals including the wah. All that said, I certainly have toyed with the idea of a power brick (as long as it includes an 18v tap). I don't use fuzz so I don't really care about a tap I can "starve". I appreciate you going out and looking! It might look hokey but it gives me little trouble gig after gig.

There are only 4 pedals in the primary chain and the rest are looped through noise reduction. And its almost as much noise when I use only one pedal like I did yesterday, on battery supply at a jam session. Sure, its homemade (out of a cabinet door even) But because of the varying voltage requirements, I can't get away from at least three adapters. I still think its likely the guitars are the source and the amp being more sensitive to them than my jmp50. I dunno.

[donzoid]

Sorry Glen I had to re-read the question...yes the noise level goes down as the volume pot is turned down to off. Of course with this beast, clean tones are at about 1.5 on my vol. dials, so the noise comes in commensurately. Its actually a LOT less noticeable at higher gain, its as though the noise floor raises at clean levels.

I was digging in the parts bins to sort more, and found a ground tab (the ring type that mounts in front of a jack inside the panel.) Do you think installing that and taking the input jack off the ground bus (across all the front pots) would help? 'Cause that's where it is now....tied to those.

Btw, this amp sounds bitchin' with a pair of old stock 6v6. Nice! Still can't believe how much volume I'm getting from 28 watts.

[geetarpicker]

If the noise goes up and down with your guitar volume pot the noise source is probably not the amp at all. However the high gain nature of these amps makes them very unforgiving of any noise the pickups and/or pedals might pick up.

It is one of the reasons these amps are mostly run without pedals, though there are exceptions. First I'd remove any and all boosts, overdrives, distortions, fuzzes, and EQs from the front of the amp period as they tend to be the noisiest of effects. You can make up for all this by turning the amp up and working the guitar knobs. 2nd I'd figure out a way to place any ambience type pedals POST amplifier, via a wet/dry rig or perhaps a Badcat unleash with it's post amplifier loop. That should leave only a handful of pedals left at the most, and with those you can make sure they are all true bypass, have clean power to them, and are wired with good quality cable and an attention to detail in pedal board layout to minimize hum pickup. For example sometimes pedals can simply get too noisy by be placed too close to the power supplies.

IMHO to get the most out of these amps you need to approach them quite differently than other amp rigs. Personally for playing live I prefer to play my Express with a wet/dry rig with just reverb/delay/chorus and no reamping of the dry signal only the wet. In the studio, my preference is to plug straight into the amp (short of maybe a wah wah perhaps) and add any needed ambience or chorus type effects during the final mix down.

[donzoid]

Thanks Glen...that's a lot to consider for my current band. I've admittedly never run a pedal board before...now, it seems it could be my "bane". I have a lot of tones to try to replicate here. But the first and foremost item in the chain is the buffer pedal. It's prevented "tone suck" since I built it. Maybe with this beast I don't need it. I have never felt like I needed to get even close to full vol. on this thing (quite a contrast to a JMP which was good at abt 3/4 up). This thing is just over half so I could see using it without the buffer. It certainly isn't lacking in high end bite. I'll try that at our gig this weekend. Thanks!

[donzoid]

btw, the single only pedal I run in jams is a voodoo labs sparkle drive, with only a little gain, but a lot of boost...and that is only for solo's if that makes any sense. I think the way this amp behaves is so different because of the vol. controls that I haven't really got a feel for it yet. I'm not used to having my vol. at 6 all the time. Even though that sings like the fat lady...