Rev Blue Bias Question

misterspockyall

misterspockyall

Member
Checking Bias on my stock 2016 Rev Blue because it's cold outside an why not. From left to right I'm getting readings of:
23.9mV
23.8mV
29.3mV
19mV

Are these tubes horribly matched? If so, what could I expect from getting a properly matched set in there?
 
For some reason or other, I always had one that was like 4mA off.

And your bias is really cold. Needs to be 28mA at least.
 
If it were just 1 tube, I wouldn't worry, its the 19 to 29mV swing I'm worried about between V9 and V10. Am I right in thinking a new set is in order so I can bias higher without one of them spiking?
 
Definitely order a new matched quad from a reputable dealer. And the bias should be up higher like 35-38 ma depending on your plate voltage.

Your bias is cold and skewed right now. Not good for the sound.
 
Oddly enough, this is what I was hoping to be the case. I feel like my head has always sounded a bit fuzzy or saggy, so I opened it up in hopes that it was biased cold and could use more push. It was indeed cold. And not only that, after reading this thread ( viewtopic.php?f=59&t=175368 ) this gives me the chance to splurge on some cooler KT88s :yes: ...I think.

If I want a tighter sound for my high gain channel, would I be better off with a cool KT88, or something like an EL34L that I could run hot?
 
misterspockyall":vp0jqzae said:
Oddly enough, this is what I was hoping to be the case. I feel like my head has always sounded a bit fuzzy or saggy, so I opened it up in hopes that it was biased cold and could use more push. It was indeed cold. And not only that, after reading this thread ( viewtopic.php?f=59&t=175368 ) this gives me the chance to splurge on some cooler KT88s :yes: ...I think.

If I want a tighter sound for my high gain channel, would I be better off with a cool KT88, or something like an EL34L that I could run hot?
Click to expand...

Not huge difference with the KT88s as the amp was designed for EL34s. You get a slightly more scooped mid-range and sharper high-end, slightly tighter bottom... but you really, really need to crank the amp 12:00 or more on the masters to hear it... and at the volume, it's pretty much a moot point. 4 KT88s really eat up volume before they do anything. I've had several amps with them, and mostly what you hear is the preamp. KT88s are used to avoid power amp coloration (i.e. why they are also often used in high-end tube audio amps McIntosh etc).

A boost pedal up front and eq in the loop, (parametric, rack multi-band) will do more for you. Guitar and pups will also play a big part.
 
Yeah, I have a Maxon 808 for up front and MXR 6 band in loop. Always tinkering, and toying with the idea of playing into the amp without pedals/effects, I like the boost/eq for some things, but it sounds somewhat artificial compared to running straight in.

With the power tubes being so off on bias, I'm gonna get a new set regardless so I can get the bias hotter, or run KT's just because I'm already buying, so why not.

Would preamp tubes help control fizz/add grind? It currently has Ruby 12AX7ACZ HG throughout.
 
misterspockyall":3pys2l1w said:
Yeah, I have a Maxon 808 for up front and MXR 6 band in loop. Always tinkering, and toying with the idea of playing into the amp without pedals/effects, I like the boost/eq for some things, but it sounds somewhat artificial compared to running straight in.

With the power tubes being so off on bias, I'm gonna get a new set regardless so I can get the bias hotter, or run KT's just because I'm already buying, so why not.

Would preamp tubes help control fizz/add grind? It currently has Ruby 12AX7ACZ HG throughout.
Click to expand...

You might try some JJECC83S's as they will cut down on the fizz or at least put 1 in the V1 slot. I have the Ruby preamp tubes in mine mixed with some JJs. Lower output pickups help as well.
 
So, the age old question. Since I'm getting new power tubes so I can get an even bias, el34L or kt77? I'd like as aggressive and grindy a tone as possible.
 
misterspockyall":svn1qt32 said:
Yeah, I have a Maxon 808 for up front and MXR 6 band in loop. Always tinkering, and toying with the idea of playing into the amp without pedals/effects, I like the boost/eq for some things, but it sounds somewhat artificial compared to running straight in.

With the power tubes being so off on bias, I'm gonna get a new set regardless so I can get the bias hotter, or run KT's just because I'm already buying, so why not.

Would preamp tubes help control fizz/add grind? It currently has Ruby 12AX7ACZ HG throughout.
Click to expand...


What do you mean by fizz? Like harsh fizz on the treble frequencies? If that's the case try sucking out the 8 KHz and 16 KHz frequencies if you have that option on the MXR your running in the loop. Not sure if the 6 band has those frequency sliders or not. I use the 10 band mxr and completely suck those two frequencies out and my amps sound so much better; Zero fizz now. To add grind, I boost the hell out of the 2 KHz and 4 KHz frequencies.

I've had great results with either a tungsol or TAD 7025 in V1 FWIW. Finding I'm not such a big fan of JJ 12ax7s, at least for V1. I've run them in a bunch of different amps and always like the Penta 12ax7s or Ruby 12ax7s better in the V1 slot. Not a huge difference at all between any of them to my ear but more so in response IMO.
 
misterspockyall":16cju04u said:
So, the age old question. Since I'm getting new power tubes so I can get an even bias, el34L or kt77? I'd like as aggressive and grindy a tone as possible.
Click to expand...

I actually prefer a good set of SED =C= over both of those. But if I had to pick, JJ E34Ls would be it. KT77s aren't my favorite power tube. Reliable, maybe... sounds great, debatable.
 
I also know Lasse Lammert prefers an EH 6CA7 in his Rev 2 and has used KT88s in the past.

I currently have KT88s in mine and love it.
 
Lasse's Uber clips sound so nice. His vids are what made me want one to begin with. Going with the E34Ls for now. Have a Fryette Power Station on the way as well to hopefully squeak out some nice tones.
 
MetalHeadMike":u4cvjke2 said:
What do you mean by fizz? Like harsh fizz on the treble frequencies? If that's the case try sucking out the 8 KHz and 16 KHz frequencies if you have that option on the MXR your running in the loop. Not sure if the 6 band has those frequency sliders or not. I use the 10 band mxr and completely suck those two frequencies out and my amps sound so much better; Zero fizz now. To add grind, I boost the hell out of the 2 KHz and 4 KHz frequencies.

I've had great results with either a tungsol or TAD 7025 in V1 FWIW. Finding I'm not such a big fan of JJ 12ax7s, at least for V1. I've run them in a bunch of different amps and always like the Penta 12ax7s or Ruby 12ax7s better in the V1 slot. Not a huge difference at all between any of them to my ear but more so in response IMO.
Click to expand...

Don't quite remember what freq's I have up high on the 6 band. Been running it less, but it does help. I have a Tung Sol on order to try in V1 for sh**s and giggles. It's cold in the Midwest, so it's tinker time.
 
Yep. Its nice right now but hot as holy hell May>>>Sept/Oct.

I'll be back in coldsville in 6 months. Moving to Montana come end of May.
 
Just an update, put E34Ls in it, biased to 32mV. Wasn't a night and day difference, but it is a bit more together sounding and some more low end.
 
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