Triple Rectifier: Removing Tubes?

[ResearchTriangle]

I'm looking to tweak my Triple Recto (3 Channel) a bit. I've heard of removing two power tubes to tighten up the sound. Anyone have any specifics about this mod (techniques, opinions on sound, etc.)?

 

[Elpelotero]

that can only be done on a dual rectifier. not the triple. it doesn't really tighten up the sound either on a dual anyways. it's basically to allow you to crank more so you get power tubes more involved.

 

[Platypus]

As elpelotero said, this does NOT work with the TR's.

The only reason it is done is to get more gain at lower volumes... ie less wattage = earlier breakup.

If you wish to tighten up your sound, start with the easy stuff like switching to the diode rectifier and using the bold power variac. If these don't help consider retubing.. TONS of options out there.

 

[MesaENGR412]

Could you please explain this thread then?! and clear up my questions as well?

http://forum.grailtone.com/viewtopic.php?p=33595&highlight=#33595
(you have to kinda scroll down, but it's a conversation between Mike and me)

Thanks guys!

-AJH

 

[Platypus]

Could you please explain this thread then?! and clear up my questions as well?

http://forum.grailtone.com/viewtopic.php?p=33595&highlight=#33595
(you have to kinda scroll down, but it's a conversation between Mike and me)

Thanks guys!

-AJH

I'm not saying it's impossible Mesa told him how to do this, but according to their own manual...

"NOTE: On the Dual Solo Head it is possible to run two 6L6 or EL34 tubes pulling the two center tubes, leaving far left and far right
tubes intact. This proceedure reduces the power by approximately 50%. Remove one of the Rectifier tubes if you are using the
TUBE RECTIFIER setting to assure a correct match."

Makes no mention of Triple and it's the same manual

 

[tele_jas]

I was told you could do it, but they didn't recommend it since it was an impedance issue and would eventually harm the amp. For short periods it would be fine, but I was told that they didn't recommend it for long term use. He mentioned maybe to record a part for a song or if I blew a tube and needed to get through the night at a show, but not much longer than that is safe for the amp.

If someone else was told something else, then I'm in the dark about it and you would probably need to call Boogie yourself and see what they tell you.

Let us know what you find out (but I think we already know the answer, but we may be surprised)?

 

[MesaENGR412]

I was told you could do it, but they didn't recommend it since it was an impedance issue and would eventually harm the amp. For short periods it would be fine, but I was told that they didn't recommend it for long term use. He mentioned maybe to record a part for a song or if I blew a tube and needed to get through the night at a show, but not much longer than that is safe for the amp.

If someone else was told something else, then I'm in the dark about it and you would probably need to call Boogie yourself and see what they tell you.

Let us know what you find out (but I think we already know the answer, but we may be surprised)?

Since it sounds like it will harm the amp, That's all i need to know, lol. I'm not even going to try it. Any "harm to my amp" doesn't sound good at all! Besides, someone else put on here a while back that the difference between 50w/100w was not very much, and that some amp companies don't advise you to take out the tubes b/c it doesn't help the tone.

Thanks for your help guys, man I love this site!

-AJH

 

[cbsmith]

I was told on the phone yesterday with Mesa Boogie that you could take the last two power amp tubes out of the rig BUT you need to also take one of the Rectifier tubes out as well if you do this!! It doesn't matter which Rectifier tube but one has to come out. As for the power amp tubes spots 1 & 6 are together and 2 & 5, then 3 & 4. So you would take out spots 1 & 6 if you wanted to do this.

later on,

I was told you could do it, but they didn't recommend it since it was an impedance issue and would eventually harm the amp. For short periods it would be fine, but I was told that they didn't recommend it for long term use. He mentioned maybe to record a part for a song or if I blew a tube and needed to get through the night at a show, but not much longer than that is safe for the amp.

If someone else was told something else, then I'm in the dark about it and you would probably need to call Boogie yourself and see what they tell you.

Let us know what you find out (but I think we already know the answer, but we may be surprised)?

Since it sounds like it will harm the amp, That's all i need to know, lol. I'm not even going to try it. Any "harm to my amp" doesn't sound good at all! Besides, someone else put on here a while back that the difference between 50w/100w was not very much, and that some amp companies don't advise you to take out the tubes b/c it doesn't help the tone.

Thanks for your help guys, man I love this site!

-AJH

 

[RR]

I was told on the phone yesterday with Mesa Boogie that you could take the last two power amp tubes out of the rig BUT you need to also take one of the Rectifier tubes out as well if you do this!! It doesn't matter which Rectifier tube but one has to come out. As for the power amp tubes spots 1 & 6 are together and 2 & 5, then 3 & 4. So you would take out spots 1 & 6 if you wanted to do this.

later on,

O-kay, but did they tell you what happens to the impedance? In a Dual Rectifier, you take two power stage tubes (the proper ones) and a rectifier tube, the output transformer impedance double. What was once the 8 ohms speaker output jack is actually now the 16 ohms, etc ....

Now what happens with a TriRectifier? That's the questions.

Besides, just because you lower the wattage and could drive the remaining power stage tubes, the output transformer is still "150 watter or whatever" and is not being "saturated" as though its a lower wattage amps as stated in the "50watt / 100watt" post.

So although possible, majority of us say its not "recommended".

 

[tele_jas]

The difference in 150 and 100 wts is only about 3-5 db and 150 to 50 is only going to be about 10 db, the main thing you get is you have more headroom with 150 wts which means that your cleans will stay cleaner at extremely loud volumes, and you'll not get in to power tube distortion. If you run at 50 wts, it's still going to have to be cranked pretty hard to reach the power tube saturation, you may notice a bit more compression on the clean channel but only at high volume. You're not going to be able to tell much, if any, difference at lower volume levels.

Story time:

One night I was running my Tremoverb head at 50wts and in between the 2nd and 3rd set I put the extra tubes back in to make it 100wts because I was hearing some rattle/buzz that I didn't like (I thought it was extra breakup I didn't want).... I told the soundman to be prepared for a volume increase, when we started - I couldn't tell ANY difference in volume or tone at all at the volume I was playing at.... The rattle/buzz ended up being all my "junk" sitting on top of the cab vibrating (capo, finer-ease, cell phone, spare picks, ect...).

Going from 150 to 100 or even 50 wts isn't going to be that big of a change in volume, just a loss of head room......which isn't going to mean a whole lot unless you crank your amp pretty hard.

 

[Dale B.]

I was told you could do it, but they didn't recommend it since it was an impedance issue and would eventually harm the amp. For short periods it would be fine, but I was told that they didn't recommend it for long term use. He mentioned maybe to record a part for a song or if I blew a tube and needed to get through the night at a show, but not much longer than that is safe for the amp.

If someone else was told something else, then I'm in the dark about it and you would probably need to call Boogie yourself and see what they tell you.

Let us know what you find out (but I think we already know the answer, but we may be surprised)?

I don't see how it would harm the amp itself. The only thing that can harm the amp in that situation is if you don't change your fuse rating, but I'm not going to get into all of that stuff.

The Output Transformer is on vacation when power tubes are pulled. It won't be seeing any extra current. The Impendence will be off, but the only thing you're compensating for is the extra load that will be placed on the power tubes, which is corrected once the Impendence is matched back up. Taking all of that into account and the fact that the Dual and Triple Rectos are biased on the cold side of things, you're probably not going to be doing much damage to the power tubes if the Impendence isn't corrected.

The Power Transformer will also be running cooler because it's going to have either 1.8 amps or 3.0 amps less heater current to supply to the power tubes that were pulled and I forgot to add the Rectifier tube into the equation.

If you're pulling tubes in a Triple Rectifier, you're going to want to use 2/3 of the normal Impendence if a pair is pulled. You do the math just like you do when you're making the adjustment with a Dual Recto, but it doesn't equal out in whole numbers. I've mentioned this before and I will gladly do it again... It will be safe, but you may experience excess hum due to the Impendence being off in weird amounts. Some amps will hum if you're running an 8 ohm speaker cab out of their 4 ohm speaker out. Just imagine if it's 5.33 ohms off...

Again, it won't hurt the amp if the power tubes are pulled. You're just opening the amp up to some other issues that "could" arise.

G'Day



Dale

 

[phantomlord2oo]

I had a pair of tubes pulled since I got the amp. Gigged with it, practiced with my band with it and recorded with it. I never had a problem. Mesa didn't say anything about a impedence mismatch or to take any of the rectifier tubes out. I did this for a LONG time and never had any problems what so ever. I always had the amp set at 8ohms to match my cab.

+Mike+

 

[ResearchTriangle]

I think I'll just call MESA direct and ask. I value all of your opinions, and I know you are all knowledgable with amps, but there's a lot of conflicting info here, and I'm sure MESA is the most legitimate source for the info :wink: .