Will 6550's work in in a MKIV ??

[Lights Out]

Hi
A friend of mine has excess to some NOS GE 6550's .
Im interested in checking them out but I cant remember anyone using them in a Boogie MKIV .

Basically im looking to get the fattest tone out of this amp without any external FX's/EQ's etc...

Does anyone know if they work with this amp if so ,
how do they sound ?

thanks

 

[fdesalvo]

Check to see how much current they draw. I am also curious about kt66s in there as well.

 

[Boogiebabies]

I would not use 6550's until I called Mesa to see if any mods need to be done to the bias range and screen grid resistors.

The KT66HP from Groove Tubes will work just fine in the 6L6 sockets.
If you use them in the EL34 sockets of a simul class amp they draw way to high of a bias. I use the GT KT66HP in a 5 and they draw 35ma in the 6L6 sockets and 78ma in the EL34 sockets. If you have a 60/100 you will be fine.

 

[jackieTHEjokeman]

It will blow up if you put them in.

 

[RR]

I would not use 6550's until I called Mesa to see if any mods need to be done to the bias range and screen grid resistors.

Yes.

It will blow up if you put them in.

yes, bias is not set for the powerful 6550s.

They're actual 'clean' tubes are more used for power amps and bass amps. I think the classic bass amp Ampeg SVT tube model. But by guitar amp standards, they're rather "sterile" sounding, too clean.

I think VHT used them on one of their models though.

 

[Boogiebabies]

The VHT UL used KT88's and also used 6550's. Why would the thought
of using 6550's in a Mesa MK IV seem appealing? I did not even like them in my Diezel VH4. It had to be so **** loud to sound decent it was insane.

 

[RussB]

I wonder if they would physically fit...the power tube sockets may be too close to each other...

 

[scottcrud]

I've got them in my bastardized .50 cal+, sounds pretty **** good to me and anyone else who's heard it.

 

[fdesalvo]

If you dig clean headroom and no pwertube coloration in your tone- you'll love 'em! Suuuuuper tight!

 

[RR]

If you dig clean headroom and no pwertube coloration in your tone- you'll love 'em! Suuuuuper tight!

That would be my impression. I even heard that those guitarists that like scouped over-saturated pre-amp drives (e.g. Pentera although doesn't he use Randall [solid state]?) likes 6550s.

 

[scottcrud]

Yep, big tight power. I for one play Boogies because of the preamp, not the power amp distortion. If you want power tube distortion, play a Marshall plexi at 10.

 

[fdesalvo]

^^^