What is wrong with my Rectoverb II?? ***Problem solved!!!***

[tele_jas]

I've spent the last 2 days thinking my speaker was blown (or going out) and looking for a new speaker, I finally talked the wife in to putting a Celestion V-30 on the credit card and took it home and installed it....... The same **** thing happened, the speaker sounded fine at lower volume, but when I put any juice behind it it sounded like it was going to explode through the grill.... Thats the exact same sound it made Saturday night when I thought the speaker was blown. I then went and got that Peavey Scorpion from my buddy and put it in and the same thing happened...... I'm not a loud player either, here is that setting so you can see I'm not a volume nut or low end nut:
* channel 2 - Vintage
* Gain 3:30
* Treb 11:00-12:00
* mids 11:00
* Bass 9:30-10:00
* Pres 11:00
channel volume 10:00
main output 11:00
Guitar used: Peavey Wolfgang

I'm calling tech support tomorrow, but I was hoping to find out if this setting makes anyone elses rectoverb combo "fart out"??

I've replaced all the tubes with new mesa tubes (power and preamp) and it sounded fine with a 2x12 extension cabinet, but the stock speaker (and the other 2 speakers I tried) sounds like total a$$ - What do you think is wrong with it? Or am I just totally nuts and it's supposed to break up like that??

When I got it last week, the guy gave me some extra tubes for backup tubes and they weren't 6L6' or EL34's, they were 7581's... Could this guy have had these tubes in the amp and screwed it up?

 

[WillShred4Food]

I didn't re-read the other thread, so I hope I'm not missing something.

When I got it last week, the guy gave me some extra tubes for backup tubes and they weren't 6L6' or EL34's, they were 7581's... Could this guy have had these tubes in the amp and screwed it up?

I've never heard of 7581's until now but this is what it says on http://www.vacuumtube.com/FAQ.htm

7581, 7581A--beam power tube, uprated version of 6L6GC and sometimes given as replacement for KT66. Out of production. Original 7581 made by GE is rare and expensive. It can easily be recognized by its flesh-colored base. There is a 1980s military-surplus version made by Philips/Sylvania which is currently available from distributors.

It sounds similar to problems I've had with worn out powertubes, but that wouldn't explain why it sounded fine through the 2X12 cab. But this might:

Back before I got a closed back cab, my DR always had a nasty, metal-zone-through-a-bass-combo break up. I didn't realize that this was just a symptom of open back design. Now I don't get too surprised when my laney 1x12 or my boogie 3/4 back cab doesn't get a real tight sound at high volume.

Good luck.
WillShred

 

[tele_jas]

Well, this morning I got up early and played around with it and put the original speaker back in it and then I got out my Triple Recto and plugged the speaker from the combo in to my triple and it sounded amazing with a very nice tone on the distortion, even at high volume and the clean was very warm and clean..... I then dialed in the exact same settings on the ROV and tried it and it still sounded bad?!?!? The distortion had no low end with any volume behind it and the cleans sounded more like a fender deluxe with the volume on 11 due to it being such a broken up sound. I swear that the speaker was going to jump out and pop me upside the head when using the ROV.... I even tried the triple again at a VERY high volume and it still sounded good and crisp with plenty of bottom end too. And as you can tell from my settings it isn't too bottom heavy or even that loud. The ROV sounds good at a low volume, but once it gets anywhere near gig level, it starts "farting out".

I've got a call in to tech support and hopefully they'll call me back later today.

 

[tele_jas]

Tech support just called me back and they weren't really any help, and I can understand that trying to describe a problem over the phone. He said to swap out all my preamp tubes with the ones in my triple rectifier since I know all those are good and try that. If that doesn't work, then it may just be that extra overhead the triple has over the ROV that I'm used to hearing, but I find that hard to believe.

Does anyone have a ROV II combo they can try my settings on and use a guitar with pretty hot humbuckers and see where it starts sounding bad on them?

 

[WillShred4Food]

This may be a little patronizing, but did you run the 7581 business by the tech support guy?

 

[tele_jas]

I found this:

This is the infamous Sylvania 6L6GC USA tube (Philips ECG). The tube picutred above is actually a 7581A which is the same tube, but has a higher military spec. and can take a higher voltage. It sounds the same, and is the same size, etc. These can still be purchased NOS for about $120 for a quad which is really quite a good deal for tubes of this quality. These tubes were used in many Fender and Mesa amps in the 70's and 80's. In particular, the original Mesa Boogie 60/100w amp (now known as the Mark I) was designed around these tubes. If you own a Mark I and don't have these, get some. I was shocked at the tone improvement when I changed them out. Amazing tone!!

here:

http://www.cathedralstone.net/Pages/Syl6L6GC.htm

 

[tele_jas]

Well, my ROV is FIXED!!! One of the preamp tubes had a bent pin and wasn't in all the way and when I swapped it out last night she purred like a kitten (more like a tiger). I don't know how I missed that before?? I swapped every tube out one at a time and I may have skipped that one (since it was 3am when I was doing that and I had to be up in 3 hours to go to work and I was getting in a hurry).

I'm back in bidnesssss.... Thanks for all the help, TJ

Now back to the easy stuff from now on.