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Replacing Power Tubes in a solo 150w head

Posted: Thu Dec 27, 2018 11:51 am
by TNTRoy
Hello new to the solo 150w triple head. do you replace the power tubes in sets of two or do they make a complete set? couldnt find anything on Mesa website...

Re: Replacing Power Tubes in a solo 150w head

Posted: Thu Dec 27, 2018 11:17 pm
by silentbob
As long as they are replaced in pairs (2,4,6) you shouldn't have any issues. If you buy Mesa tubes in the same color code, you don't even really have to worry about keeping them paired. I have never tried mixing color codes on Mesa amps, but even their most extreme mismatch is still closer than the "matched pairs" you will get from some vendors.

Re: Replacing Power Tubes in a solo 150w head

Posted: Fri Dec 28, 2018 9:26 am
by TNTRoy
silentbob wrote:As long as they are replaced in pairs (2,4,6) you shouldn't have any issues. If you buy Mesa tubes in the same color code, you don't even really have to worry about keeping them paired. I have never tried mixing color codes on Mesa amps, but even their most extreme mismatch is still closer than the "matched pairs" you will get from some vendors.
I have looked on Mesa website and can not find a set of six tubes for my amp head.. All I can find is sets of two..... how would I go about getting the same color code? I have never had a amp head with this many tubes... All the amps I have had have only had two power tubes.. I loved my Rectoverb 50 v2 combo so much I had to get a Triple Rectifier head..... I love the tone and the ability to play any style of music thru them... and the build quality is far superior than any thing else I have ever owned...

Re: Replacing Power Tubes in a solo 150w head

Posted: Sat Dec 29, 2018 12:20 pm
by silentbob
TNTRoy wrote:
silentbob wrote:As long as they are replaced in pairs (2,4,6) you shouldn't have any issues. If you buy Mesa tubes in the same color code, you don't even really have to worry about keeping them paired. I have never tried mixing color codes on Mesa amps, but even their most extreme mismatch is still closer than the "matched pairs" you will get from some vendors.
I have looked on Mesa website and can not find a set of six tubes for my amp head.. All I can find is sets of two..... how would I go about getting the same color code? I have never had a amp head with this many tubes... All the amps I have had have only had two power tubes.. I loved my Rectoverb 50 v2 combo so much I had to get a Triple Rectifier head..... I love the tone and the ability to play any style of music thru them... and the build quality is far superior than any thing else I have ever owned...
Just buy three duets. If any of the duets has a different color code, just make sure they are placed in the same pair when you install the tubes. It won't make much, if any, difference but I'm anal about my tubes.

Re: Replacing Power Tubes in a solo 150w head

Posted: Tue Jan 22, 2019 10:07 am
by tbonesullivan
You may be able to request that the three duets are all the same color code in the special requests field. As others have said, just remember that if they are different colors, put those as a pair. They should be arranged 3 2 1 1 2 3 , so the 1s are a pair, the 2s are a pair, and the 3s are a pair.

Re: Replacing Power Tubes in a solo 150w head

Posted: Mon Jan 28, 2019 11:07 pm
by woodbutcher65
Actually by the way things are actually wired in the amp, there is nothing in the power stage that either knows or cares if you arrange your power tubes in symmetrical pairs or not.

Let's say your power tubes are three pairs color coded red, green, and blue. One pair of each color.


Traditionally you'd think that you'd arrange them, as seen from the back, in red green blue blue green red

but actually it makes no difference at all if you instead were to choose to arrange them as red green blue red green blue

or red green blue green red blue

since all three output tubes on EITHER side of the output transformer are wired in true parallel.


Now, if I am ordering tubes from Mesa, I do specifically request that multiple pairs be in the same color range. When I retubed a D180 I refurbished recently, I put in six green range tubes.



You just want to be sure that you have matching number of tube colors on each side. You would be advised against, for example, a layout of red red red blue blue blue as that would dramatically unbalance the current levels in the output transformer.


If you choose to run less than six power tubes (yes, you can do that) then you can run two, four, or six. And as long as you have the same number (and color range) of tubes on each side of the transformer, again, specific tube sockets don't matter.

I run only two power tubes. Why would a bedroom commando need 150 watts? As long as one is in socket 1,2, or 3, and the other is in socket 4, 5, or 6, it's fine.

Excess current draw is what kills transformers. With fewer power tubes installed, current draw must be less than with a full complement of tubes installed. Yes, it's safe to run less than 6 power tubes.

Re: Replacing Power Tubes in a solo 150w head

Posted: Wed Feb 20, 2019 9:58 am
by domct203
Gross impedance mismatch is also not good for an output transformer, I don’t recommend running less than 2-pair (4) of tubes in a Triple Recto due to the large impedance change at both the primary and secondary side of the OT. .

I owned and gigged a Triple Recto for years, there is not much of a difference between volume with 4 power tubes vs 6 power tubes. The real difference is in available headroom. I tried running my Triple with only 2-pairs of power tubes and found it lost too much punch and dynamics, I went right back to the full set.

Re: Replacing Power Tubes in a solo 150w head

Posted: Wed Feb 20, 2019 12:06 pm
by Authorized Boogie
woodbutcher65 wrote:
Mon Jan 28, 2019 11:07 pm
Actually by the way things are actually wired in the amp, there is nothing in the power stage that either knows or cares if you arrange your power tubes in symmetrical pairs or not.

Let's say your power tubes are three pairs color coded red, green, and blue. One pair of each color.


Traditionally you'd think that you'd arrange them, as seen from the back, in red green blue blue green red

but actually it makes no difference at all if you instead were to choose to arrange them as red green blue red green blue

or red green blue green red blue

since all three output tubes on EITHER side of the output transformer are wired in true parallel.


Now, if I am ordering tubes from Mesa, I do specifically request that multiple pairs be in the same color range. When I retubed a D180 I refurbished recently, I put in six green range tubes.



You just want to be sure that you have matching number of tube colors on each side. You would be advised against, for example, a layout of red red red blue blue blue as that would dramatically unbalance the current levels in the output transformer.


If you choose to run less than six power tubes (yes, you can do that) then you can run two, four, or six. And as long as you have the same number (and color range) of tubes on each side of the transformer, again, specific tube sockets don't matter.

I run only two power tubes. Why would a bedroom commando need 150 watts? As long as one is in socket 1,2, or 3, and the other is in socket 4, 5, or 6, it's fine.

Excess current draw is what kills transformers. With fewer power tubes installed, current draw must be less than with a full complement of tubes installed. Yes, it's safe to run less than 6 power tubes.
I would disregard this information and go with what our engineers and technicians have stated. Thanks

Re: Replacing Power Tubes in a solo 150w head

Posted: Wed Feb 20, 2019 8:41 pm
by woodbutcher65
There is absolutely nothing that differentiates the tube sockets on one side of the transformer from each other in any electrical parameter.

Thus it makes no difference whatsoever WHICH sockets you put the tubes in as long as one goes into one of the left three power tubes sockets and one goes into the right three power tube sockets.

They're COMPLETELY in parallel. There's NO difference between sockets 1, 2, and 3. There's no difference between sockets 4, 5, and 6.

Now, there's no reason NOT to arrange them in a mirror configuration. It's good practice to arrange them in a mirror configuration.

But it's neither necessary nor unsafe.

I've been in electronics for 40 years in one capacity or another. Today I work in avionics. Don't tell me or anybody that my advice is bad when anybody who knows electronics and the way a Trip is constructed knows I'm speaking pure truth.

Parallel is parallel. A socket =B socket =C socket (on one given side of the OT) and that's that.

We're not talking about an amp where one set of output tubes is wired up differently than another pair. This isn't an amp that has simulclass or pentode/triode or even 60/100 switching.

Re: Replacing Power Tubes in a solo 150w head

Posted: Tue Apr 02, 2019 2:41 pm
by lamejohn
woodbutcher65 wrote:
Wed Feb 20, 2019 8:41 pm
There is absolutely nothing that differentiates the tube sockets on one side of the transformer from each other in any electrical parameter.

Thus it makes no difference whatsoever WHICH sockets you put the tubes in as long as one goes into one of the left three power tubes sockets and one goes into the right three power tube sockets.

They're COMPLETELY in parallel. There's NO difference between sockets 1, 2, and 3. There's no difference between sockets 4, 5, and 6.
The rectifier tubes are in parallel as well correct? I have a rev G triple recto, and I've seen some pretty good prices on nos rectifier tubes (sometimes cheaper than modern production), but I'm unsure of how close they should be 'matched', if at all, or what problems could arise from them being too far mismatched, or whether that's a big concern with rectifier tubes.

Re: Replacing Power Tubes in a solo 150w head

Posted: Wed Apr 03, 2019 10:08 pm
by woodbutcher65
Matching rectifier tubes is mostly a matter of ensuring that they all deliver a fair share of the load. You probably don't have to worry about it much as there's no bias consideration in play with the rectifier tubes. At worst, you'll have some that just don't deliver as much current as others which can limit your amp's total output.

I really would not worry about that much. If you think you need new rectifier tubes, you'll be just fine to order a set of them at once from your preferred source. (Mesa is my recommendation. I've never had any issues with Mesa sourced tubes.)