REVISED: I made a mistake. My testing was flawed. I wasn't engaging the NR when I thought I was, it was engaging one of the tube effects. Ooops. What I did find was the NR at low to moderate levels was somewhat effective at reducing the hiss, especially at lower gain and power levels, but with the NR anywhere beyond half way and the notes started getting all warbally, almost a vibe effect. In the end, I found that as long as I don't run the Gain, Master, and Power knobs at 12:00 or higher (all together at one time) I can nearly eliminate the hiss. I can exceed the 12 o'clock position on any 1 knob as long as I compensate by lowering one of the other knobs to 9 or so. For example, I can run the Gain at 10, the Master at 10, and the Power at 3 o'clock and I'm fine. Or I can turn up the Gain to 1 or 2 as long as I keep the Master and Power around 9 or 10. It's possible my amp always had this issue but I never turn it up that loud to notice.

I need to find another 40+ at a local store and see if I can duplicate my findings. I had a chrome front VT15 that I sold to buy the 40+. Now I'm wishing I'd kept it. Might be time to visit Craigslist and say goodby to the 40+.

What's really interesting is that I have a Boss FA-1 FET pre-amplifier pedal (clone) that can boost volume significantly. It can be used to really slam the tube. I expected that using that would cause my clean amp settings to start hissing when the volume or drive was driven up with the pedal. I set the amp with gain, master, and power settings that gave no hiss, then I engaged the FA-1 pedal and started turning up the volume. Still no hiss, or if there were any, it was barely noticeable, but I was getting a lot more volume and a bit of crunchy drive.

That's very interesting. I have a VT20+ and a VT30. The hiss is much more obnoxious on the VT20+. On low gain clean amp models, I don't find that the NR does anything except ruin the sustain, so I keep it turned off. The vast majority of the hiss comes from the power amp section, so Gain and Volume don't contribute much unless you crank them way up.

Adding a pre-amp in front of the Gain control, though, would be the same as turning up the Gain wouldn't it? If you increase the gain using a preamp into the input, don't you then have to turn the Gain knob down to keep it clean, just as you would if you used a higher output guitar pickup?

I have a Boosta Grande so I'll try this out when I have a chance, but it's hard for me to see how it would be any different.

BTW, the AC30TB model is noisier than any of the other clean models - I found it useful in the earlier Valvetronix amps, don't like it on the VT+.

The other issue I have with your advice is that with all Valvetronix amps, the tone takes a hit if you lower the PL and MV controls. The sweet spot for MV is around 1:30-3:00 as it drives the tube nicely. The PL, in spite of what Vox would have us believe, is nowhere close to transparent and always sounds better turned up to 1:30 or so, higher on the earlier ones. This was not a problem in the AD series or the VT series as the hiss only becomes audible in the last 1/4 turn of the PL knob, and MV had little effect on hiss. Unfortunately, in the VT+, I have to put up with hiss to get decent tone, even with those controls lower than I would like.

I would never recommend using the VT+ to record, at least not the 20+ or the 40+. The higher priced ones may, according to posts by some of their owners, have less hiss due to higher quality power amp parts, and so may be more useful for recording. OTOH, my VT30 is stellar in both high and low volume situations.

Thanks for the info voxman and cosmicrepairdude. I did misunderstand. I thought I was pushing the tube with the FA-1. Hitting the digital pre-amp with the FA-1, adjusting the FA-1 volume level does give me everything from a clean boost with a bit of thickness on up to a decent amount of clipping, kind of a mild Tube Screamer sound. I thought this was somewhat the sound benefit I was looking for from the FA-1. It's definitely different that what I could get with my TS9 or TS808 on light settings.

Speaking of external pedals, are they detrimental to an amp like this, especially the FA-1 which sends boosted volume into the amp?? I have a Joe Webb effects loop kit that I have not yet installed.

I just started getting this snare noise in the last few weeks and I feel sick to my stomach about it. I just completed the expensive cleaning process with Deoxit and disassembly of every friction contact point inside, including the tube. No change. The AC30TB is the worst and being a U2 fan, is the model I almost always need. I suppose I could try and get by with the AC15 model but I bought this amp for its AC30TB capability. Until recently, I don't recall ever having a problem with it.

Can either of you explain why I don't seem to have a snare problem when using headphones? Even the AC30TB sounds pretty good and seems to be void of the snare when using headphones.

So I did some more testing. I can run the MV up at 1:30 to 3:00 but I have to leave the PL at 9:00 or below. I also have to make sure the gain is somewhere left of 12:00. These settings make the snare noise nearly inaudible with all other knobs straight up. If I bump the volume or treble past 12, snare creeps in. But if what you tell me is true, I'm robbing myself of tone with the PL that low. I think my ears would be bleeding if I turned up the PL to 1:30 with the ML at 3:00....and the snare hiss would be off the chart.

Adding the FA-1 lets me maybe get a bit more volume out of it but as you suggested, I have to back off the gain unless I'm looking for that grit. So I'm no expert but is using the FA-1 that pushes a higher volume signal into the amp really just doing exactly the same as turning up the gain a bit? I hope I didn't spend a lot of money and time to build a pedal that just substitutes the gain knob. It seems like there would have to be a slight difference in sound, aside from the ability to EQ using the bass and treble knobs on the pedal.

As I mentioned, I used to have an AD15VT and a VT15 prior to this. I actually liked the AD15VT better than the VT15 tone wise. Never tried the VT30. GC's got a used VT30 for $150. Maybe it's time to throw in the towel and put this 40+ up on Craigslist. Is the VT30 a reliable quality sounding unit in AC30TB mode? My VT15 sounded a bit thin but probably due to the speaker size. I also didn't like the restriction of using only one effect at a time but I don't use internal effects anymore.

No, your ears wouldn't be bleeding because you should be using the Volume control to turn down the loudness. Leave the Treble at 12 or below.

Regarding bass and treble: do those knobs on the FA-1 have a different effect than the same knobs on the amp itself or do they do pretty much the same thing? If the latter, then your FA-1 is just duplicating things you could be doing on your amp.

I already told you what I think of the AC30TB model - I think it sounded much better on both my original AD15VT and my VT30, but that's just my opinion. BTW, my rave reviews on the VT30 are dependent on having added acoustic insulation to the cabinet. There are threads on that, which I can direct you to, if you're interested.

And as I have pointed out on the snare noise thread, people who have the problem can't get rid of it by turning knobs or changing models, as far as I can tell. Some models are noisier than others (like the AC30TB) but that's not snare noise. As I also said there, you have to test for it with Noise Reduction (noise gate) off.

One more question regarding the hiss/noise issue you raised here: are you using single coil or humbucking pickups?

In my view, the tube is one of many areas where the anti-oxidant coating can screw things up.
http://www.voxamps.com/forum/topic.php?id=3716&page=20
About half way down the page:
The procedure mentioned lower down that page [19] involving the tube pins and speaker connectors won't necessarily do the trick for everyone because several people earlier on in this thread replaced the tube with a brand new one and it didn't help, and others have reported that they hear the snare noise through headphones which would eliminate speaker connections (and the tube) as the problem.
I believe that the problem can come from any of several connections which is why I think all connections should be cleaned, not just 2.

BTW, further testing this morning with the FA-1... it seemed like the sound it adds is slightly different than what the Gain control adds and in some ways, gave me a bit more volume and gain to work with to compensate for my need to keep the amp's gain and PL lower to avoid the snare. The amp's Gain is smoother and more refined than what the FA-1 provides. Turning the gain down a bit and bumping up the volume on the FA-1 gives a slightly thicker sound with some grit. I'm not familiar with a Boosta Grande but I'd be curious what results you have with it going into a Valvetronix digital pre-amp. Like with the tone knob on a TS9, the bass and treble knobs on the FA-1 sort of determine the color of the FA-1 tone rather than just doing the same as the bass and treble on the amp. Granted, it all sort of works together and in some ways, there is more than one way to get to the same end result. In general though, there is something different about the sound I get when using the FA-1. Maybe I'll post a clip. What I really need to do is take my FA-1 into a shop and test it with a real AC30 to hear for myself how the sound compares to what I get on my amp. Then I'll know if it's adding any value to my overall sound.

Nothing worse than a flaccid wobbly connection. I hate when that happens. LOL! Thanks for the explanation of the various components and their order in the chain.

The shop I bought this one from does not have another. I have a Guitar Center in town that used to have one on their demo floor. I've got another shop in town that caries Vox but they didn't have one either last time I checked.

The shipping I referred to was directly to Korg USA when my first one died. I had dropped the dead one off at the local authorized dealer for service. After waiting in cue for 3 weeks they informed me that Korg does not repair this line of Valvetronix. It was somewhat "disposable" and considered a "non-serviceable" item. My only option was to, at my expense, ship it to Korg. It was expensive but as I said, once they got it, they shipped me a brand new unit in a couple of days with brand new warranty. If I find one locally to compare it to, I may be doing this again. At that point, I may just sell the replacement as "NEW" and buy a used VT30.

If I can find one, I'll take my guitar, amp, and cable to the shop. I'll document the settings as well. I do computer and systems troubleshooting for a living so know the importance of methodical elimination and setting variables consistently.

As others have posted, I sure wish I could just open this thing up and find something obvious like a bulging capacitor or loose connection. In my case, not so much.

Yes, my local dealer used the word disposable, then corrected themselves with the official phrase of "non-field serviceable" even though my amp tech could probably build it from scratch. The last time they serviced my old AD15VT and had no issues doing so. Must be a change in Korg policy with the new line. He wasn't really even allowed to look at it, or at least, Korg wasn't willing to pay him to do a level 1 assessment, even to determine if it was something as simple as a blown fuse.

I think what the Vox dealers might be referring to is what might be better described as 'beyond economical repair'.

If you take a VT20+ for example, Vox has squeezed a load of technology/options/tone into a very compact and very competitively priced unit. Because this is a 'mass market' product, and Vox are trying to be as competitive as possible, there probably isn't a huge mark-up. Now that's good news for consumers, and at £120 or so, a VT20+ represents stonking bang for your buck! Remember, these are made in China to benefit from lower manufacturing costs (eg labour) compared to US/UK.

But if anything breaks down, unless it's easy to identify and fix, the chances are that home country labour costs (which will be way higher than those for production costs in China) will be way more. I'm guessing that a qualified electrical engineer probably costs circa £40 an hour - so if (for example) the real net manufacturing cost of the VT20+ before marketing, distribution, retail profit, etc is say £60 (purely an example - I have no inside pricing knowledge) it's probably cheaper for Vox (& faster for the customer) just to replace the amp under warranty.

The Valvetronix is arguably as much computer as it is guitar amp, and it's exactly the same with modern day IT gear - nowadays if your graphics card or hard drive goes, its cheaper to replace than try & repair. So, we are now living in an ever more disposable world - when I bought my DVD player it was £165. I can now buy a DVD player for £25 with better spec or a more up-to-date Blue Ray player for £65!! Repair just doesn't make sense anymore for a lot of goods and it is ever-increasingly just a fact of life now.

Rich