Can I run different tubes in my amp?

[Agileguy_101]

So my 1968 Bassman is long overdue for new tubes. I run it hard pretty often and I don't think I've changed the power tubes in about two years. As long as I need some new tubes anyway, I was wondering whether or not I could run something besides 6L6's, perhaps something with more headroom. Will my amp work with tubes that are not 6L6's? Perhaps a pair of KT66's. More to the point, will it actually make a difference in headroom or is that one of those common misconceptions that's commonly purported in guitar forums?

 

[trevorus]

Re: Can I run different tubes in my amp?

They're close in specs, but you really need to be concerned with the heaters in those tubes. The KT66's draw 1.27 amps per tube, whereas the 6L6GC's draw only 0.9 amps. Some 7581's would be a safer interchange, and those are supposed to have a bit more clean headroom. If you are overdue for tubes, you might be surprised how much of a difference a fresh set of 6L6GC's would bring your amp to life, without changing tube type. Be sure to get it biased properly as well.

 

[Agileguy_101]

Re: Can I run different tubes in my amp?

You're probably right , I should just go for a new set of 6L6's and maybe try a new tube type at a later point when I have a fresh set of tubes to compare to.

I'm curious about the Winged C 6L6's are they worth paying almost twice the price of other brands?

 

[SongsForTheDeaf]

Re: Can I run different tubes in my amp?

I hear ALOT of good reviews about the winged C 6L6s FWIW

 

[jeremy]

Re: Can I run different tubes in my amp?

kt66 (real ones) wont have any more headroom than a 6l6gc and they do draw more current like trev said

 

[Lake Placid Blues]

Re: Can I run different tubes in my amp?

+ 1 on 7581s. No side effects and more head room than any other alternative for that amp. If thats what you want.

 

[King IzzO)))]

Re: Can I run different tubes in my amp?

I've been wanting to try the New Sensor Tung-Sol 7581 but there's hardly any trustworthy commentary on them yet. You could be our guinnea pig.

 

[glassman]

Re: Can I run different tubes in my amp?

My two cents...

People change out tubes WAY too often. A nicely broken in set of tubes can sound a lot smoother than a new set in a Fender. I have one amp that probably has over 10,000 on the cheap Chinese 6L6s in it.

Headroom in your amp is limited before the power tubes so no matter what you put in there, it's gonna for the most part be the same as it is now. You can bias it cooler though; this will raise all of the voltages in the entire amp a bit and give you a little more headroom.

 

[beaubrummels]

Re: Can I run different tubes in my amp?

If you want more clean headroom, I would try a lower gain factor pre tube in the V1 position, like a 5751 or 12AT7.

 

[Jolly_Rancher]

Re: Can I run different tubes in my amp?

You just need higher rated 6L6's. Groove Tubes 6-10 on their old scale, Mesa Blue or White (which are both a 6 on the old GT scale). Personally I would just try to call around and find someone that has Mesa White STR 440s since GT is no longer a good company. You can also call up Doug Preston and ask him if he has any of the other brand of 6L6's in a higher rated test for more headroom.

As for the 5751, yes, but a 12AT7 in V1 might not be smart; it's too different from a 12AX7.

 

[Agileguy_101]

Re: Can I run different tubes in my amp?

I've been wanting to try the New Sensor Tung-Sol 7581 but there's hardly any trustworthy commentary on them yet. You could be our guinnea pig.

I'm actually considering doing just that.

They're 30W tubes though - does that mean anything for me in terms of being able to use them with my amp?

 

[trevorus]

Re: Can I run different tubes in my amp?

That 30 watts is maximum plate dissipation. Bias usually aims for 70% or so of that. This will still be limited by the amount of signal put out by the preamp, and the power supply. You're not really changing wattage so much as you are shifting where the power tubes will start to distort.

Sent from my SCH-I535 using Tapatalk 2

 

[GuitarStv]

Re: Can I run different tubes in my amp?

Speaker efficiency can also play a huge role in headroom. A very efficient speaker can make your amp seem twice as loud as an older one . . .

 

[Boogie Bill]

Re: Can I run different tubes in my amp?

Stay with the 6L6. I've had really good luck with the Winged C tubes in my Mesas. I also like their EL34.

Bill

 

[zzmoore]

Re: Can I run different tubes in my amp?

http://www.dougstubes.com/power-tubes/6l6-5881-kt66/tad-6l6wgc-str.html

Some good suggestions already...including the heater draw on the KT66...I will just toss these into the mix.
I have heard them in a few different amps...have had good results with them.
You really never know until you buy a pair (of any brand/type) and try them yourself.
good luck