Mini Rec Tube "Rules"

[soundchaser59]

Not looking for tone qualitites in tube suggestions, but rather looking for "rules of thumb" regarding which tubes NOT to use in which slots in a Mini Rec.

For example, I've read some things about not using just any old 12AX7 in the "cathode follower" position, or the P.I. position. The wrong tube in that position will have short life and "burn out" prematurely. That's what they say.....

What does it mean, Obi Wan Kanobi? And which tubes should NOT be put in those slots? Which ones will last longest in those slots? What is the right question to ask the tube guy when I buy?

(I don't have the amp yet, it will be here in a couple of days.....but I always retube when I get them)

Thanks!

 

[domct203]

If the Mini Recto is true to it's Rectifier heritage, the Tone Stack Driver (V3) & FX Loop Buffer (V5) will be Cathode Follower positions. You should avoid all New Sensor Corp. tubes in those positions as they have been proven to fail in Cathode Follower use. New Sensor brands include Tung-Sol reissue, Mullard reissue, Sovtek & Electro Harmonix.

So far the only current production tubes that will remain reliable in those positions are the Shuguang/Penta Chinese & JJ 12AX7 (ECC83).

Just about any NOS 12AX7 should be fine as well.

As far as Mesa branded 12AX7's are concerned only the Mesa "Chinese" and current Mesa "Russian" (JJ) are reliable in those positions. Avoid the Mesa "Russian-1" (Sovtek) and Mesa "Russian-2" (Electro Harmonix) 12AX7.

This does not effect the PI tube.

You can read more about it here.

http://forum.grailtone.com/viewtopic.php?f=4&t=25102&hilit=Memo&start=19

Dom

 

[soundchaser59]

A couple of things, after speaking with Mark at Mesa Boogie today......

The cord should be minimum 16 gauge, not 18, although the Mini Rec is not a huge current draw like other amps can be.

The Mini Rec does not really follow the pattern of other "big boy" rectifiers, the PI or driver tube is not considered a cathode follower, so there is no need to worry about using special 12AX7 tubes in that position. Any good quality 12AX7's will work fine in all positions. The concern with 12AX7's in the "cathode follower" position is intended for dual rec's and above. He did say they prefer not to use Russian tubes in the positions that do have that concern.

Currently the Mesa tubes are (if I understood him correctly) rebranded JJ's. He said, "We are using JJ's." Maybe (cross our fingers) that is one step they took to cut the incidence of Mesa tubes failing prematurely?

If my hum (it's a 60hz hum) goes away when the guitar is unplugged, he said that points to the possibility of a weak preamp tube, assuming the guitar is properly shileded, grounded circuits, etc....assuming everything else in the room and the signal path is ok. Suggestion was to swap out preamp tubes one by one with a known new tube known good tube and see if the hum can be removed that way. He seemed to suggest that a hum that stays after the guitar is unplugged would point more toward a weak power tube.

I'm no expert, so call them if unsure about any of this, I'm just regurgitating what I think I was told. Hope this makes sense.

 

[domct203]

A couple of things, after speaking with Mark at Mesa Boogie today......

The Mini Rec does not really follow the pattern of other "big boy" rectifiers, the PI or driver tube is not considered a cathode follower, so there is no need to worry about using special 12AX7 tubes in that position. Any good quality 12AX7's will work fine in all positions. The concern with 12AX7's in the "cathode follower" position is intended for dual rec's and above. He did say they prefer not to use Russian tubes in the positions that do have that concern.

Currently the Mesa tubes are (if I understood him correctly) rebranded JJ's. He said, "We are using JJ's." Maybe (cross our fingers) that is one step they took to cut the incidence of Mesa tubes failing prematurely?

As far as I know the PI tube of any Mesa amp IS NOT a Cathode Follower. I believe that cathode follower usage only applies to tone shaping stages of the preamp.

I'm suprised that at the least the Tone Stack driver is not a cathode follower. I thought that was a key part of the tone stack, and how the EQ functions in the amp.

http://www.freewebs.com/valvewizard1/dccf.htm

Dom

 

[soundchaser59]

I wouldn't know that kind of detail. Just relaying what he tried to explain to me, and he could probably tell that I'm not an amp tech. Mainly he said it's not a huge concern in the Mini Rec, not like it would be with "the big rectifiers." Any good quality 12AX7's should work fine and have normal life in any of the 5 positions.

 

[GibsonV05]

current Mesa "Russian" (JJ) are reliable in those positions.

JJ's are not made in Russia, never have been.

 

[Cadavre]

Not looking for tone qualitites in tube suggestions, but rather looking for "rules of thumb" regarding which tubes NOT to use in which slots in a Mini Rec.

How does the mini sound - almost got one - then ran into a desperation sell I couldn't refuse that was comparable to the mini. GC was offering them for 799$ - now they price above 1k$ - do they cost more to make - or - as most suspect - the USD has been QE'd to it's current TP FX status?

Been a while, but if the tube pin outs don't match the panel's pin in's, they won't fit. If the match, and only recall this for power tubes, there may be something else called "bias". Some amps have a pot - some don't. If you go to Mesa's site, they have area listings for their certified "craftsmen". I called two in different towns and they will share their expertise regarding those issues.

So whats the rule for "burned out" tubes these days - is there a "glow hue" rule of thumb.

Been told the best tubes are Russian. Sveltlana (Sovtek) tubes are lauded as "phat sick bad a*s". Sveltana 12xA7. Sveltana EL34. Sveltana 6L6. Sveltana EL84. Shop and you'll get a better price - US can order directly from Sveltana.

 

[Cadavre]

.. not like it would be with "the big rectifiers."

Play it through a phat speaker cab and it sounds pretty darn good. They're phat enough for club venues. If it be a big hall, then it will sound great cranked to the top and mic'ed through a phat PA (little all tube champs cranked to their limit sound great. It has the big rec power tube, just don't have as many. 12AX7's are usually pre-amp tubes (and usually one per hard waired channel). My TA has 5, but [only] the one associated with the active channel is the only one being used (i think) :roll:

Next time you're at a marquis virtuoso's show, check his / her gear. He may have a wall of Orange or Marshals (those guys get paid to place but don't necessarily play em. Look around. Somewhere back there you'll see a little inconspicuous raggedy as*ed old open cab combo with a mic shove up it's speaker "grill". That's the amp you be hearing.

 

[domct203]

current Mesa "Russian" (JJ) are reliable in those positions.

JJ's are not made in Russia, never have been.

That is correct, but that is what Mesa called them when I spoke with them. They are not labeled Russian though, sorry if I confused anyone.

Dom

 

[Adambomb]

.. not like it would be with "the big rectifiers."

Play it through a phat speaker cab and it sounds pretty darn good. They're phat enough for club venues. If it be a big hall, then it will sound great cranked to the top and mic'ed through a phat PA (little all tube champs cranked to their limit sound great. It has the big rec power tube, just don't have as many. 12AX7's are usually pre-amp tubes (and usually one per hard waired channel). My TA has 5, but [only] the one associated with the active channel is the only one being used (i think) :roll:

Next time you're at a marquis virtuoso's show, check his / her gear. He may have a wall of Orange or Marshals (those guys get paid to place but don't necessarily play em. Look around. Somewhere back there you'll see a little inconspicuous raggedy as*ed old open cab combo with a mic shove up it's speaker "grill". That's the amp you be hearing.

OMG you guys must have stronger ears than me. I wouldn't ever even imagine micing the Mini recto especially through a 4x12. This is NO LOW VOLUME AMP. They seriously probably shouldn't even have made it this loud. But no really it rocks in ever way possible. Some really good blues tones on neck pickup on ch1 in pushed mode, and ch2 covers about ever single gain application you could imagine.

 

[ken361]

10 watt mode works great for low playing

 

[soundchaser59]

10 watt mode works great for low playing

Just judging by flipping the switch without changing any knobs, it's not really softer to my ears, it just seems to take the edge and bite out of the sound. I need to experiment with cranked 10 watt settings.

 

[ken361]

bed room playing I mean, 25 is a bit raspy on the modern mode