Triple Rec running on 4 tubes

[Damjan]

Hi everybody!

I read through some previous posts, where discussion was about running Dual Rec on half power. My question concerms my Triple Rec head.

Here is the question: recently, my 3 rectifier and one of my 6L6 power tubes got damaged in transport. I ordered new tubes and are currently waiting for them, but it will take 2 more weeks. I can still use my amp, I removed outer pair of tubes and I'm using silicon diode rectification. Amp is working perfectly.

I just wanted to know, what happens to the impendance of the Triple speaker outputs? I understand that on Dual Rec, it is possible to remove outer tubes, thus limiting Dual to 50W (halving the power - doubling the impendance). In that case speaker outputs have double impendance (what was 4 ohm is now 8 ohm). But how does that apply to Triple Rec? 100W is not half the 150W, and I'm not sure how are speaker outputs working in this configuration? My 2x12" 300W cabinet is handmade and has very much options for connectivity, it can work in 4ohm mono, 16 ohm mono, 8 ohm stereo and 8ohm single speaker configurations.

Basically, I'd like to know - when outer pair of 6L6 tubes is removed, how should I connect triple to my cabinet?

Thank you

Damjan

 

[ibanez4life SZ!]

Because of this very fact, Mesa says NOT to run your triple like this.

Whether is will cause any permanent damage or not, I don't know, but because of these changes, it is usually not done on the triple.

 

[RoCk4souls]

I contacted Mesa once about this and the tech told me that in fact you could remove a set of power tubes from the triple rec. He said if you are normally running 8 ohm, to change it to 4ohm. I don't know if that is halfing or doubling. I think it's doubling the impedance.

But anyways I've read all kinds of conflicting reports about this with the triple.

I ran my triple with a set of power tubes (outside pair) removed at 4ohms into a mesa 8ohm 4x12 cab with no problems. I ran it about a week in this set up and decided I didn't like so I changed it back.

 

[Reese Bobby]

when i use my triple with my orange 2x12 i take it down 50 watts by removing the two outer tubes and one recto. when i asked mesa about this they said to run the speaker outputs as i normally would. i've heard numerous conflicting statements about this subject but i can honestly say i've been running my amp like this for six months with no probs and the two mesa reps i spoke to knew exactly what i was doing and what impedence my cab was.

 

[Damjan]

Thanks for trying to clarify this issue for me. Here is the answer I got from my amp tech: "If you remove one pair of tubes, be sure to run your cabinet connected like this: 8ohm output on your Triple to 16ohm input on your cabinet".

I'll try to find out what happens when you pull out ANOTHER set of tubes, reducing Triple to mere 50 Watts.... Maybe 4ohm output on Triple becomes 16ohm output...?

 

[disassembled]

The CORRECT info is to half the impedance(16 to 8 or 8 to 4). You can get away with a mismatch of 1 value (run a 16 ohm speaker in the 8 ohm jack) but mismatching 2 values (4 ohm speaker to 16 ohm is almost never recommended and usually results in something getting damaged eventually). My 20/20 only has 4 and 8 ohm taps but the manual says I can run 16 ohm speakers without a problem it's just the output will be a teeny bit less than if I used an 8 ohm cab.

I am sorry but your amp tech was mistaken when he told you to double the impedance you must HALVE the impedance. This has nothing to do with heresay but mere mathematics and electronic theory.

There is too much confusion on this topic. I believe it's because the amp will work in just about any configuration and then people are extremely happy so they believe it to be true. Bottom line, it will work pretty no matter how you hook it up but to have it right you should run it like this: 4 power tubes (16 ohm cab in the 8 ohm jack, 8 ohm cab in the 4 ohm jack), 2 power tubes (16 ohm cab in the 4 ohm jack).

 

[C.O.A.]

okay so which tubes do i remove to make it 100 watts?

 

[Damjan]

but to have it right you should run it like this: 4 power tubes (16 ohm cab in the 8 ohm jack, 8 ohm cab in the 4 ohm jack), 2 power tubes (16 ohm cab in the 4 ohm jack).

Isn't that exactly what I wrote? Read again my post please, I think we are talking about same thing

 

[disassembled]

but to have it right you should run it like this: 4 power tubes (16 ohm cab in the 8 ohm jack, 8 ohm cab in the 4 ohm jack), 2 power tubes (16 ohm cab in the 4 ohm jack).

Isn't that exactly what I wrote? Read again my post please, I think we are talking about same thing

I am sorry, you are absolutely right. I was just...uh..reiterating what you said, yeah that's it! I must've mixed your post up with the others. Anyway good luck.

To the other guy:

You have to remove the tubes in pairs (either the far outer pair, next inner pair, and then finally the second inner pair). So it's 1 and 6, 2 and 5, 3 and 4.

 

[jbird]

What is the point? Removing tubes: It is barely negligable to your ear, and it will sound worse!

 

[Damjan]

What is the point? Removing tubes: It is barely negligable to your ear, and it will sound worse!

I agree, but I have specific case. Read again:

recently, my 3 rectifier and one of my 6L6 power tubes got damaged in transport. I ordered new tubes and are currently waiting for them, but it will take 2 more weeks

 

[disassembled]

What is the point? Removing tubes: It is barely negligable to your ear, and it will sound worse!

Sounding worse is a moot point. If someone wants to do it they should know how. It's up for THEM to decide to keep it that way. Besides, there is going to be a great difference between 6 tubes working together vs 2.

 

[Damjan]

Hm, here is an answer directly from Mesa, it basically underlines what we said here, except for the detail that Triple has much more resistance to these experiments than Dual

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Hey there,

With a Triple Rectifier you basically have a choice of either 4 or 8 ohms
depending on your preference when your cab is set to 8 ohms.  A dual must be
switched to 4 ohms however.  Hope that helps.
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