Single recto question ...

[-BOOGIE_MAN-]

Guys,
I was just surfing the mesa/boogie address and went into the single recto page. They said 'Fixed Bias for Consistent, Maintenance Free Performance'; and what does it mean??

Does it mean, if i wanna change the tubes to el34 i can just plug and play??

What about the preamp tubes??

No bias requirements?? i dont think there is any bias adjuster on the recto.

 

[andershoeg]

There is a switch on the single recto that you can toggle between 6L6 or EL34 tubes.
b.r. andershoeg

 

[6L6C]

There is a switch on the single recto that you can toggle between 6L6 or EL34 tubes.
b.r. andershoeg

As anderhoeg said there is a switch to change between 6L6 & EL34 but other things to keep in mind.
Preamp tubes do not need to be biased so get whatever you like.
Bias is fixed for the power tubes(mesa specs). So when you purchase power tubes from a vendor need to tell them the amp you have so they can select a set of tubes within the range of the Mesa specs.
Other vendors besides Mesa themselves are www.eurotubes.com/ and www.dougstubes.com/ there are others but these two pop up allot on the board. Personally I’m a Doug person.
Beware of the local guy that has the wrap “just put these tubes in Mesa does not have to be biased” or one I overheard a while back was “you don’t have to bias tubes with a Mesa they self bias”

 

[-BOOGIE_MAN-]

There is a switch on the single recto that you can toggle between 6L6 or EL34 tubes.
b.r. andershoeg

As anderhoeg said there is a switch to change between 6L6 & EL34 but other things to keep in mind.
Preamp tubes do not need to be biased so get whatever you like.
Bias is fixed for the power tubes(mesa specs). So when you purchase power tubes from a vendor need to tell them the amp you have so they can select a set of tubes within the range of the Mesa specs.
Other vendors besides Mesa themselves are www.eurotubes.com/ and www.dougstubes.com/ there are others but these two pop up allot on the board. Personally I’m a Doug person.
Beware of the local guy that has the wrap “just put these tubes in Mesa does not have to be biased” or one I overheard a while back was “you don’t have to bias tubes with a Mesa they self bias”

Hello,
Do you think the eurotubes (doug) can be trusted?? i haven't with him yet, i just emailed him a couple of times and he is really quick on replying the emails

THere are whole of collection of full retube kit on their website, u think if pick any one of them i can just plug it in without having to go to technician??

 

[domct203]

Hello, Do you think the eurotubes (doug) can be trusted?? i haven't with him yet, i just emailed him a couple of times and he is really quick on replying the emails

THere are whole of collection of full retube kit on their website, u think if pick any one of them i can just plug it in without having to go to technician??

EuroTubes and Doug'sTubes are two different vendors. Bob at Eurotubes.com is strictly a JJ tubes dealer. Doug at dougstubes.com handles many different brands of tubes, including JJ's. Both can get you set up with tubes to meet the specs of your amp.

I have bought from both, but deal mostly now with dougstubes.com for the variety. For example, the SED =C= 6L6's he recommended blow away the JJ 6L6 IMHO.

Also, educate yourself in regards to tube bias. Mesa's are non-adjustable fixed bias, meaning that the bias circuit is at a fixed value throughout the normal operation of the amp, and is not adjustable. This is why you need to specify the type of amp you are using so the vendors can give you the correct range tubes.

Then it's just 'plug and play'. No tech needed.

There are bias measuring devices available, and the're inexpensive and easy to use. Just because you can't adjust the bias doesn't mean you should'nt check the bias when trying different tubes. It's good insurance IMO. A blown power tube can reak havoc on the amp.

Dom

 

[6L6C]

Do you think the eurotubes (doug) can be trusted?? i haven't with him yet, i just emailed him a couple of times and he is really quick on replying the emails

Yes these guys do allot of business and both have pretty loyal people, like I said I’m a Doug guy.
www.dougstubes.com
I got a set of tubes from him last year and I was hooked my amp never sounded that good just took the amp to a different level. (Used Boogie tubes before this) Doug likes to use different brands of tubes in the preamp section and it just made every channel in my Mark IV shine.
V1 Tung-Sol reissue 12AX7
V2 high gain JJ ECC83S
V3 Penta Labs/Shuguang 12AX7C
V4 Unlabled/Shuguang 12AX7C
V5 balanced Sovtek 12AX7LPS
(4) SED 6L6GC WINGED =C=

THere are whole of collection of full retube kit on their website, u think if pick any one of them i can just plug it in without having to go to technician??

No problem! That’s what these guys do. They burn in new tubes match tubes and are well aware of the Mesa spec and other companies that have a fixed bias.
You never need a tech for there is nothing to adjust.

 

[clutch71]

If your looking to buy new the 6L6/EL34 switch is there. The older Series one did not have it BTW. Keep that in mind if you are looking on the used market.

 

[Tubegear Junkie]

Guys,
I was just surfing the mesa/boogie address and went into the single recto page. They said 'Fixed Bias for Consistent, Maintenance Free Performance'; and what does it mean??
Does it mean, if i wanna change the tubes to el34 i can just plug and play??
What about the preamp tubes??
No bias requirements?? i dont think there is any bias adjuster on the recto.

I would like to explain that the Single Recto uses EL34 sockets that can run 6L6's as long as the circuit runs at 500 volts or less, then any of the "6L6 style tubes" can be ran in an EL34 socket. This is why the tube selector switch on the back of the amp is most important.

this might help...I have noticed alot of poeple sort of get "Fixed Bias" and "Cathode Bias" mixed up.

Fixed Bias: a fixed negative voltage is imposed on the grids of the output tubes. The cathode is grounded, so the tubes sees the grid as being negative with respect to the cathode. This causes the tube to idle somewhere between cutoff & saturation, and is the bias point or operating center.

Usually but not always, higher-powered amps are designed as "fixed bias" and lower powered amps are "cathode biased".

Cathode Bias: a resistor is placed between the cathode and ground. The grid is operated at ground potential using only a high impedance load resistor. The cathode is pulling current through the cathode resistor, a positive voltage develops on the cathode. The tube sees this the same as the grid being negative with respect to the cathode. A more negative grid would cut the flow of current down, causing balance in terms of the operating level of the tube.
Preamp tubes all use this design and therefore never need biasing.

hope this helps...

Tubegear Junkie