uses for 12BH7A tubes?

[phsyconoodler]

Do 12BH7A tubes have uses in a guitar amp?Got some NOS ones and the data sheets are bit hard for me to figure out.Just wondering if anyone uses or has used them.

Cheers!

[SoundmasterG]

Ampeg used them in the SVT among other things. They are sort of like a super 12AU7, so not a ton of voltage gain, but good current drive, and they sound good.

Greg

[phsyconoodler]

Thanks a bunch!

[LooseChange]

Blackstar uses one as a power tube in their not so tube powered HT-5

[phsyconoodler]

I tried it in V1 of my jam amp and it was microphonic so I tried it in the PI position.Very nice!
  It still has plenty of volume but it isn't as dirty.Sweet sounding cleans.
I'd use it in the PI position anytime.
  Hmm.....happy with the results!

[HotBluePlates]

The 12BH7 is like a 12AU7, but has higher power handling capability.

I'd recommend selling it to someone with a McIntosh tube amp, an SVT or a headphone amp that uses them as output tubes. In the first two cases, the 12BH7 is the only tube that'll do the job, so it seems to me it would find a better home with folks who can't sub something in its place.

I say that as a guy with a pair of McIntosh MC-30's, which use this tube.

[drgonzonm]

Could the tube be used in phase inverter duty, or as the amp feeding a tone circuit similar to the Fender approach? 

How about using the tube in a cathodyne application? 

Just thoughts, no experience. 

[HotBluePlates]

Sure, you could do that, and that's how they're commonly used.

But for typical guitar amps, you don't make use of the 3.5w per plate dissipation rating. So it's kinda like using a sledgehammer to drive a nail.

So my thinking is that other circuits that might actually need more of that power capability are probably a better use for the tube.

That's one reason I brought up the headphone amp idea. Seems I recall folks using 12BH7's as final outputs to drive 32 ohm headphones.

[Dave]

I use them as reverb driver tubes in fender circuits. I think they make a much lusher and mellower reverb. I don't even consider 12at7's anymore.

Dave

[rzenc]

Do 12BH7A tubes have uses in a guitar amp?

FX loop driver, set as AC CF.

Best Regards
R.

[RicharD]

12BH7 makes a great cathode follower.  Hammond used one in push pull to drive the reverb tank in the PR20 tone cabinet.  They're fantastic in low gain applications.

[tubenit]

like this?

[drgonzonm]

Sledge hammers to drive nails.  
I worked in the mining industry where you measured with micrometer, marked with lumber crayon (eyes had to be closed), and cut with a number 12 oxy-actyl. tip using number 11 filters in the cutting lenses.  

Thanks for the info

[jojokeo]

This is my fav tube for self-split output tube ala Gerald Weber's Solo-7 and even in a Firefly-type amp. Way better than a 12au7. Certain plate types are better than others in most cases, YMMV.

[Tone Junkie]

In the firefly would you use it in place of the 12au7, or would you have to change some component values to make it work

[kagliostro]

John Chambers used it (like in Tubenit example) as phase splitter on his 1000W guitar amp (4 x 813 tube)

http://www.chambonino.com/construct/constwire2.html



Kagliostro

[sluckey]

kagliostro, that's just a couple cathode followers. Phase inverter is back in the preamp.

[jojokeo]

In the firefly would you use it in place of the 12au7, or would you have to change some component values to make it work

Simply just plug and play! (and enjoy) the tone, headroom, vol, etc. is a lot better. You probably won't want to change back to the 12au7 after doing this. For even more you can also use JJ's ECC99 tube. With this one you can get by w/ plug and play but will need to lower Rk to maximize Pdiss for "peak performance".

[drgonzonm]

20 turn preset pots,  
are the rest of the resistors also this precise?

[kagliostro]

kagliostro, that's just a couple cathode followers. Phase inverter is back in the preamp.

Many Thanks for the advice, this last days I'm near to be "out of service" 

20 turn preset pots

Chambers ordinary uses 20 turn pots for bias, I think he has a BIG stock 

Kagliostro

[Tone Junkie]

Thanks jojokeo i will have to give that a try.
Bill