Genz Neo Pak 3.5 problem. Help!

[leftymike]

So I purchased a used Neo Pak a few weeks ago. It was working great up until last week when I plugged my bass in and got no sound out of the amp. Through some knob twisting I figured out the only way I can get any sound out of the amp is if I crank the Tube Gain and Tube Volume to 10. Then its a very low farting noise. Before I take it in I was hoping someone could give me a clue on what may be causing this?

Thanks!!

[Gintaras]

I have a Neopak that acted up and I had bought it used. I called GenzBenz and thou I was the second owner and it was out of warranty. They said that it was a known issue. I sent it back and expected to pay for the repair but it came back 2 weeks later without a bill!!! Not sure if you are in the same boat but you might want to call GenzBenz first. I have heard such good things about GenzBenz service that I would send it there anyway even if you do have to pay for it.

[agedhorse]

There are a couple of things to check, but frankly it's not a known issue nor are there any known issues.

The first thing to check is that there's not an intermittent connection in the effects loop. There is an internal switvh that may not seat exactly right and could cause this problem. Cycle the effects loop return jack a few times or use a short 1/4" patch cord to bypass the loop switch. This can be an issue on ANY amp by any manufacturer that uses an effects loop.

The other thing to check is for a bad tube. If the tube happens to fail, the symptoms will be the same. Replace the tube and if the problem goes away you know waht the cause was.

You can always give Scott a call at the factory, he's the resident expert on these amps. He will help you get things sorted out. I 'm also assuming you have done the obvious like checking for a bad battery in an active bass, and bad cables and such.

[leftymike]

agedhorse, didn't have a patch cable but blew HARD (ok, I know the jokes are coming) in the effects loops a few times, plugged in the bass, presto, sweet tone! So I'm assuming this was this the issue. Thanks, I knew you (or someone else on talkbass) would be able to shed some light on this. ROCK!!!!

(FYI, I used a passive bass and the same cables through another amp with no issues)

[agedhorse]

Go ahead and cycle the jack a few times, that should take care of it. This sort of problem is generally independant of which manufacturer made the product, and should be filed away in your "troubleshooting for bass players" toolkit.

[leftymike]

Thanks!!!

[ErnieD]

GB CS Rox!

I too use a Neopak, 2 ohm modded, regularly. Is this an issue due to non-use of the effects loop? Because what, dust, a little corrosion build up or what typically causes this in any amp?

I did the 1/4" cable, IN-OUT (could be jokes here too) fix, in a older GK1001 awhile back. So whats the typical cause of this?

**Hey leftymike, I recently bought 3 different brand 12AX7 pre-amp tubes from a TBer to try each one in my Neopak and just to have a backup in case it ever failed. I need to get my lazy butt around to trying them out and see which one I'll leave in or just keep as backup. If you want to buy one of these pre-tubes from me to have as a backup, PM me, I could mail you one out. ( I read here GB says no real big changes will come about installing different pre-tubes) but still be nice to have a backup one. I dont think I'll need 3 backups as they seem to last so long. COOL? Sorry if I did a sale-derail but seems OP got his issue fixed.