I have an Ampeg SVT7 pro 4 Ohm and an Acoustic B410 8 ohm cab. I just thought about how this could be a serious problem. What I'm wondering now is what is the cheapest and most efficient way to fix it. I'd rather avoid stacking 2 cabs for live shows, considering how much a pain that'd be, and I really don't want to get a 4 ohm cab. Is there an easy way I can increase the resistance on my head? Thanks for reading, comments are greatly appreciated.
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Problem: what to do?
- Thread starter mcblahflooper94
- Start date
Why is it a problem? The amp is happy with an 8 ohm load, and still probably puts out more than enough power.
Really? Man I'm still trying to understand this thing. It keeps dying sometimes, the SVT 7, and I'm trying to understand the problem. Do you think it's just the fact that it's a 7 Pro, which are notorious for being glitchy?
On the top of the amp, is there a sticker that has some letters and numbers like C 00?
Some of the earlier revisions (A and B) had some problems. There are several threads here that give loads of info about these issues. I hope it works out!
Some of the earlier revisions (A and B) had some problems. There are several threads here that give loads of info about these issues. I hope it works out!
Can you explain what "keeps dying sometimes" means? Are the speakers farting? Not loud enough? The amp cuts out? How are your controls set?
Can you explain what "keeps dying sometimes" means? Are the speakers farting? Not loud enough? The amp cuts
out? How are your controls set?
Heads that use solid state (SS) power amplifiers will generally have a "minimum" impedence. This is usually either 2 ohms or 4 ohms (it will be listed in the manual and on the back of the amplifier). As you have noted, your amplifier is 4 ohm minimum, therefore, as long as the load is above 4 ohms, you are ok. But if you go below the minimum, that's bad.
Heads with a tube power section tend to be fussier and you'll have a selector switch on the back of the amplifier for specific impedances (ohms).
How new is your amp? Might be worth seeing what the service center says.
It'll start getting fuzzy and crackley as if the gain is on a lot, and then just kinda fade out to being extremely quiet.
If the brute has an effects loop you can try linking the send to return with an instrument cable to see if that helps the situation. Aside from that, I'd follow Mr B's advice.
Really? Are those symptoms of needing a new tube? I never thought about it, considering it's only 1. Makes sense though. Although, I've only had this amp for not even 6 months.
New Production tubes are no where near as reliable as days past. I personally would start there and I have been doing amp repair for better than 40 years. The symptoms just don't sound like a PWM power section problem. A bad solder joint is still possible but the tube is easy to change as a first and very possible last step. 
Are you running an active bass by any chance? If so, when was the last time you changed the battery?
That wouldn't surprise me if that was the problem. I gig/have band practice frequently, not to mention playing for about 2 hours every day for about a year without changing a battery wouldn't surprise me. Thank you all very much for helping!
I recently finally wore out the first battery on my Bartolini preamp, installed in May 2012. Even though it still worked fine with the EQ turned off, there was finally no output with the EQ on (I never use it, was just using it as an on-board battery tester 
I was quite surprised at the tone improvement, you'd think if it's not clipping it should be a clean signal - not so.
I was quite surprised at the tone improvement, you'd think if it's not clipping it should be a clean signal - not so.
