My Sig:X is down too!

[Loudness250]

Hey nice site here. Ok, down to biznazz. I bought the sig:x about a month ago. When I first checked the bias it was fine, 70%. Immediately swapped tubes. I had 2 sets of kt88's. I put winged C in first. Blew the ht fuse in about 5 minutes. Ok, so I put the sovteks back in and check the bias. "going by memory", 530volts at 65mv for each tube on HP mode. So Im saying to myself holy shit! that is pretty close to the limit of the max wattage of a kt88 at Idle! So long story short I take it down to like 45mv on HP mode.I understand that vht biases them at 70% and that's what mine was originally but I think the tubes drifted up. Im sorry but I dont trust new production kt88's to even be biased as a 40 watt tube even though I admit that they do put out alot of power. it sounded fine this way. So I put some Shuguang power tubes in it "which give it Waayyyy more thump". Swap in NOS preamp tubes in all 5 sockets, and this thing is sounding Ssweeet! Play 2 gigs with it and finally Im super happy with it.

So then the next time I go to fire it up and it sounds good, I keep playing and I start hearing this pffft pffft sound on lead channel as Im playing. So the sound starts getting pretty pronounced and the volume drops Im like getting pissed that I have to keep fu**ing with this thing but I figure I got a preamp tube going out. So I swap one of the chinese pre's that came with it , one by ones replacing every one of em and firing it up and repeating. Nothing helped, it stayed that way, both the rythem and lead channel's volume is very low, like you can talk over it at half vol on the master. So I put the original tubes all back in and took it and tried it and it still is broken and I took it back to the store. I'm pissed and I know it's nothing I did the amp just pooped out. If any of you had this happen to your sig:X and were able to fix it let me know. I can go get it out from the store and try whatever you did to solve it. I really dont want to wait for 2 months or something to get this handled, It doesnt seem like a huge problem but maybe Im wrong. BTW the clean channel still works perfect.

 

[bravedude2]

 

[messenger]

WTF. Guess they didn't work out all the bugs before the release.

 

[Loudness250]

When I first got mine it had a weird low frequency thump after every phrase or line I would play. It was annoying but Dave at VHT had me run some tests and was a great help in diagnosing the problem over the phone and it turned out to be the V3 preamp tube. The amp did not work out for me but I have no doubt VHT can help you get the amp running correct.

cool, well it's at the store now and the store is gonna call VHT and see how they want to handle it or whatever and meanwhile I have emailed support so if they give me something to try then it's fine if I go down to the store and try what vht suggests. Mine has quiet lead and rythem channels and it actually has a low frequency bump after palm muted chords too. Before that though it was fine. I personally dont like my kt88's biased high, my amp was not handling being played loud and brutalized with the mutes, it was noticeably crumbling and that's why I lowered the bias it was much better after that and it's biased cooler and it doesnt sound cold or shrill. It's biased at more like 60% .

 

[Loudness250]

WTF. Guess they didn't work out all the bugs before the release.

Well, preamp tubes do go out on ya, we'll see.

 

[philb]

It happened to me as well. From what I gather from VHT, in my amp VHT shorted out and took a resisitor along for the ride.
I was able to change the resistor and the amp is back to full operation. I swapped out the preamp tubes as well.

I used it with the band since twice and it works great.