Quick question about my 2000s

[xavieronasis]

Hey there,

I just bought a 2000s off of ebay and must say I was pretty stoked about it until I took it into my amp tech who then gave me the bad news - a fair amount of the circuitry (resistors, I believe) was fried to a crisp.  He's charging me over 200 bucks to replace them and the power cable which is a bit frazzled.  Sigh.  At least the tubes were ok and the rest can be repaired, right?  (Sad to have to lose the original parts, tho.  Grumble grumble...)

This particular 2000s has an 8 ohm and a 16 ohm output jack, but I've only got two 410h that are both rated at 4 ohms each.  So, here are my questions:

1.  I plugged both of those cabs into it and played on this guy for a couple of hours after receiving it and have this sinking feeling that this is what fried it, despite being told by a couple of amp guys who said that it wouldn't.  It sounded ok during the jam, but towards the end I noticed that my bass tone was a bit distorted (thus the trip to the repair guy). 

2.  Is using those 2 cabs is a no-no b/c of the mis-match in resistance?  I guess what confuses me is the fact that I saw a 2000s bass cab on ebay the other day and it was rated at 4 ohms and thought to myself, gee if the original cab that came with it was 4 ohms, then maybe it's ok?

As you can tell, I'm no electrical engineer, but I love the hell outta my Sunn gear and want to take the best care of it that I can (uhm, going forward .

THANKS!

xo

[JoeArthur]

I have to agree with you - the two 4 ohm cabs are probably primarily responsible for frying the amp.  Used together that would only be 2 ohms total.

If this amp only has two jacks one 8 and one 16, then it sounds like it is set up for a lowest nominal of 8 ohms.  While some tube amps might tolerate a 100% mismatch, 2 ohms seems well out of that ball park.  *some* 2000s amps do have 4 ohm capability, but it sounds like yours isn't one of them - and I would hesitate to run a 2 ohm load with a 4 ohm output.

It would be much safer to run your 4 ohm cabs in series and use only the 8 ohm jack.

[Soundmasterg]

The 2000S should have a 4 ohm tap, an 8 ohm tap, and a 16 ohm tap off the output transformer. The feedback loop will be hooked to one of them, and two of them will be hooked to the jacks on the back of the amp with the third soldered to a dummy terminal inside the amp. It is a simple matter to figure out which taps you want hooked to the jacks on the back of the amp, and unsolder the one inside and hook it up to the back. Knowing of course that what is written on the back would no longer be correct.

Greg

[lowtones]

I have a '69 1000S and my good friend (an amp expert) was able to do exactly that. He installed 2 toggle switches on the back panel, one of which goes between 4 and 8 ohms. The other goes between "neutral" and 16 ohms, overriding the other switch when engaged. Right now it's one of my spares (I'm a bass player) because it's just too much for me to haul around, but the flexibility of those switches lets me loan it to my guitar player without any headaches.