got a Pro Jr. today ...

teledude66 · February 27th, 2005, 01:15 AM

i like it ...but i got it home and noticed one of the power tubes isn't glowing so i guess it's a good enough reason for a retube ...i'm embarrased to say i don't remember checking the tubes out when i played through it , it sounded fine playing it

...what will happen if i play it in this condition ....couldn't help it i had just sold my tele and GAS had a very strong hold on me

Caper · February 27th, 2005, 08:20 AM

Well if it sounds good now, it should sound even better when you replace the tube. So which tube was out?

teledude66 · February 27th, 2005, 09:07 AM

Quote:

Originally Posted by Caper

Well if it sounds good now, it should sound even better when you replace the tube. So which tube was out?

looking at it from the back it's the left power tube ...

Mik · February 27th, 2005, 11:40 AM

Are you sure the tube isn't glowing/working? I've had power tubes, including EL84's, that have had their glow obscured by the "paint" on the top of the tube.

Mik

teledude66 · February 27th, 2005, 09:50 PM

Quote:

Originally Posted by Mik

Are you sure the tube isn't glowing/working? I've had power tubes, including EL84's, that have had their glow obscured by the "paint" on the top of the tube.

Mik

when i read this i went to make sure so i plugged it in and looked, no glow ...so i picked it up and turned it over to get a good look and .......the freakin tube is broken there's a HOLE in it right at the bottom ...it had to have been there before i bought it cause no glass in the cab ...i feel sorta stupid now ...but it sounds good ....i'm still looking for someone to weigh in as to will it hurt the amp to play it like this, i'm not going to but i have played it some before i found this out

TexGoneNW · February 27th, 2005, 11:35 PM

I really like toting my PJ around and putting a mike in front of it when necessary. Guys on the sound board love me, and I like the tone.

Getchya some o' them JJ's that people brag about here. I got some NOS JAN Philips back when they were reasonable.

chet · February 28th, 2005, 11:08 AM

I got a pair of NOS EL84's that I'm going to put in mine. I'd go ahead and replace both of them if I were you. ;-)

tweedtone · February 28th, 2005, 05:14 PM

Just got the retube kit for my PJ via eurotubes.com - big thumbs up!

teledude66 · February 28th, 2005, 09:18 PM

Quote:

Originally Posted by tweedtone

Just got the retube kit for my PJ via eurotubes.com - big thumbs up!

yeah i'm gonna get some JJ's but what did you tell him you wanted out of them i'm thinking of telling him i want more clean volume ...just wondering what you asked for ...
i went ahead and got some Peavey brand Sovteks today just so i could play it (10.00$s) , it's nice it brings out the tone of my strat better than any amp i've played, i like how you can crank it and roll of the volume to clean it up and it keeps the volume up ( i have it mic'd and listen to it through my headphones through an Alesis mixer) one word huge

tweedtone · February 28th, 2005, 09:37 PM

Quote:

Originally Posted by teledude66

Quote:

Originally Posted by tweedtone

Just got the retube kit for my PJ via eurotubes.com - big thumbs up!

yeah i'm gonna get some JJ's but what did you tell him you wanted out of them i'm thinking of telling him i want more clean volume ...just wondering what you asked for ...

I said I wanted to tighten up the bottom end, so to speak, and it does that. Obviously, how much clean headroom you're gonna get out of the PJ circuit is in large part dependent on what's hitting the input, i.e. how hot your pickups are and any boost you're using. I've got Bardens so it starts to cream out nicely with the volume halfway up.

I've got his retube set for my Blues Junior on route as we speak ... er, type.

TexGoneNW · March 2nd, 2005, 03:49 AM

If you're looking for clean headroom, that's not really what the PJ does well, but you can tone down the preamp stage a little bit by replacing the preamp tube with a lower gain selection than the standard 12AX7.

Or just keep the pickups and/or volume knob down.

Cliff · March 2nd, 2005, 07:04 AM

When you guys replace the power tubes in your PJ, do you have to reset the bias? Just wondering. Thanks.

teledude66 · March 2nd, 2005, 08:41 AM

Quote:

Originally Posted by Cliff

When you guys replace the power tubes in your PJ, do you have to reset the bias? Just wondering. Thanks.

it's fixed ....

and i don't really want to clean mine up just bump up th spot where it does overdrive but the new tubes actually did that ...i may have said this before but i cranked it to 12 and used the guit's vol knob and it did just what i wanted ...sweet lil amp it's fun, and i really dig th space it doesn't use

Electric_Ripple · March 2nd, 2005, 11:19 AM

I found my Pro Jr. to be VERY sensitive to tubes. I played around with different tube combinations for days before settling on Tesla EL84's and a couple of RCA blackplate 12ax7's. Made a HUGE difference.

TexGoneNW · March 3rd, 2005, 03:10 AM

First time I changed tubes, I was nervous about messing something up, but (don't do this if you don't know how to do it safely) I referred to the schematic that came with the amp and checked out all the voltage reference points with a VOM, and everything, while different, was within tolerances stated on the specifications on the print.

Different tubes absolutely change the reference voltages, but in a relatively subtle way. How much of the difference is that subtle change and how much is the tube, I dunno.

Biggest difference, to me, was speaker. I like the stock blue frame, but don't care for the stock brown frame.

Daddy Elmis · March 3rd, 2005, 09:20 AM

Quote:

Originally Posted by Cliff

When you guys replace the power tubes in your PJ, do you have to reset the bias? Just wondering. Thanks.

The PJ has an non-adjustable, fixed bias. You could change resistors to adjust bias, or install a bias pot, but with EL84 tubes that's a lot of work for not a whole lot of benefit (IMHO, YMMV).

I think the PJ is very sensitive to its tubes because the tone stack and circuit are so simple -- there's not a lot of "stuff" affecting the tone of the tubes. This, to me, is the PJ's great strength.

teledude66 · March 3rd, 2005, 09:26 AM

just put it on near the end with my pedals going thru it ...everybody seemed impressed (usually i get the "not another piece of gear routine...lol) just for the sake of backup i think it'll be a live addition, with a mic of course...beats toting a 212 and a 410

Cliff · March 3rd, 2005, 10:39 AM

Daddy Elmis - Thanks for your reply. My wife bought me a Tweed PJ right when they came out, quite a few years ago, like '96? I'm not sure if I was on the TDP yet, but at the time I knew very little about rebiasing. I was aware of the benefits of retubing, though, and I switched out the stock ones for NOS. My tech at the time was sure that he had to change the resistor to correctly set up the amp, and he did. I'd always wondered about that. Seems like he knew something about what was going on, but not enough. That, or he was taking me for a ride.... What is the recommended bias current for that amp anyway?

Mik · March 3rd, 2005, 10:58 AM

I think Cliff's tech did the right thing, installing the correct resistor to properly bias the new power tubes. I've swapped out stock Sovtek EL84 tubes in 2 Pro Jrs for NOS 6BQ5's, installed NOS 12AX7s, and found no substantial differences in amp performance. (I admit I did not rebias). So the Sovteks went back in. I don't find the PJ "sensitive to tubes". :? My mileage varied!

Why would EL84 power tubes not need rebiasing, in a fixed bias circuit, as much as other tubes?

Mik

Daddy Elmis · March 3rd, 2005, 02:52 PM

Folks more knowledgable than me (and that's a hell of a lot of people) and several who, to me, are experts in the field of tubes and tube amps, have told me that EL84's are low powered and generally are not as sensitive to bias "mismatch." Not saying that a proper bias is not smart, won't improve performance, etc., just that (according to my info) you are generally ok to plug and play EL84s (more so than higher powered tube -- 6L6, EL34, etc.).

Now, if I had a bias pot I would rebias with EL84's myself. But to have a tech pull the chassis, cut and replace/resolder a resistor on the PCB, seems like a lot of trouble (and introduces the potential for damage) that, to me, isn't worth it.

Off topic, but one thing that strikes me as a really "nice to have" feature on Tone King amps -- they put the bias point and built in meters on the back of their amps so you can easily check and change bias.

As I always remind people, however, checking/adjusting bias is a relatively recent phenomenon. Back in "the day" everybody just plugged and played (except maybe touring pros that had amp techs traveling with them). Interestingly, this was also the "golden age" of tube amp tone from today's perspective (Hendrix, Cream, Butterfield, Who).

February 27th, 2005, 01:15 AM	#1 (permalink)
teledude66 Friend of Leo's Join Date: Oct 2004 Location: Lawndale,N.C. Age: 42 Posts: 2,752 20 Photos	got a Pro Jr. today ... i like it ...but i got it home and noticed one of the power tubes isn't glowing so i guess it's a good enough reason for a retube ...i'm embarrased to say i don't remember checking the tubes out when i played through it , it sounded fine playing it ...what will happen if i play it in this condition ....couldn't help it i had just sold my tele and GAS had a very strong hold on me __________________ The fact that no one understands you doesn't mean you're an artist.

February 27th, 2005, 11:40 AM	#4 (permalink)
Mik Tele-Afflicted Join Date: Mar 2003 Posts: 1,416	Are you sure the tube isn't glowing/working? I've had power tubes, including EL84's, that have had their glow obscured by the "paint" on the top of the tube. Mik __________________ a "motor-bike with a touch of blood in it is better than all the riding animals on earth, because of its logical extension of our faculties, and the hint, the provocations, to excess."-T.E. Lawrence

February 27th, 2005, 11:35 PM	#6 (permalink)
TexGoneNW Tele-Holic Join Date: Mar 2003 Location: Victoria, TX Posts: 917 4 Photos	Ya could do a lot worse I really like toting my PJ around and putting a mike in front of it when necessary. Guys on the sound board love me, and I like the tone. Getchya some o' them JJ's that people brag about here. I got some NOS JAN Philips back when they were reasonable.

March 2nd, 2005, 03:49 AM	#11 (permalink)
TexGoneNW Tele-Holic Join Date: Mar 2003 Location: Victoria, TX Posts: 917 4 Photos	Another $0.02 from me If you're looking for clean headroom, that's not really what the PJ does well, but you can tone down the preamp stage a little bit by replacing the preamp tube with a lower gain selection than the standard 12AX7. Or just keep the pickups and/or volume knob down.

March 2nd, 2005, 07:04 AM	#12 (permalink)
Cliff Tele-Meister Join Date: Mar 2003 Location: Left Coast Posts: 168 3 Photos	Re-tube When you guys replace the power tubes in your PJ, do you have to reset the bias? Just wondering. Thanks.

February 27th, 2005, 08:20 AM	#2 (permalink)
Caper Friend of Leo's Join Date: Mar 2003 Posts: 2,169 7 Photos	Well if it sounds good now, it should sound even better when you replace the tube. So which tube was out?

February 28th, 2005, 11:08 AM	#7 (permalink)
chet Poster Extraordinaire Join Date: Aug 2004 Location: The Jersey Shore Posts: 7,538	I got a pair of NOS EL84's that I'm going to put in mine. I'd go ahead and replace both of them if I were you. ;-)

February 28th, 2005, 05:14 PM	#8 (permalink)
tweedtone Tele-Holic Join Date: Dec 2004 Location: Tampa Bay, FL Age: 42 Posts: 684	Just got the retube kit for my PJ via eurotubes.com - big thumbs up!

March 2nd, 2005, 11:19 AM	#14 (permalink)
Electric_Ripple TDPRI Member Join Date: Nov 2003 Posts: 14	I found my Pro Jr. to be VERY sensitive to tubes. I played around with different tube combinations for days before settling on Tesla EL84's and a couple of RCA blackplate 12ax7's. Made a HUGE difference. __________________ My blood type?? AB763

March 3rd, 2005, 03:10 AM	#15 (permalink)
TexGoneNW Tele-Holic Join Date: Mar 2003 Location: Victoria, TX Posts: 917 4 Photos	Tube changes First time I changed tubes, I was nervous about messing something up, but (don't do this if you don't know how to do it safely) I referred to the schematic that came with the amp and checked out all the voltage reference points with a VOM, and everything, while different, was within tolerances stated on the specifications on the print. Different tubes absolutely change the reference voltages, but in a relatively subtle way. How much of the difference is that subtle change and how much is the tube, I dunno. Biggest difference, to me, was speaker. I like the stock blue frame, but don't care for the stock brown frame.

March 3rd, 2005, 09:26 AM	#17 (permalink)
teledude66 Friend of Leo's Join Date: Oct 2004 Location: Lawndale,N.C. Age: 42 Posts: 2,752 20 Photos	rehearsed last nite... just put it on near the end with my pedals going thru it ...everybody seemed impressed (usually i get the "not another piece of gear routine...lol) just for the sake of backup i think it'll be a live addition, with a mic of course...beats toting a 212 and a 410 __________________ The fact that no one understands you doesn't mean you're an artist.

March 3rd, 2005, 10:39 AM	#18 (permalink)
Cliff Tele-Meister Join Date: Mar 2003 Location: Left Coast Posts: 168 3 Photos	Thanks for the info Daddy Elmis - Thanks for your reply. My wife bought me a Tweed PJ right when they came out, quite a few years ago, like '96? I'm not sure if I was on the TDP yet, but at the time I knew very little about rebiasing. I was aware of the benefits of retubing, though, and I switched out the stock ones for NOS. My tech at the time was sure that he had to change the resistor to correctly set up the amp, and he did. I'd always wondered about that. Seems like he knew something about what was going on, but not enough. That, or he was taking me for a ride.... What is the recommended bias current for that amp anyway?

March 3rd, 2005, 10:58 AM	#19 (permalink)
Mik Tele-Afflicted Join Date: Mar 2003 Posts: 1,416	I think Cliff's tech did the right thing, installing the correct resistor to properly bias the new power tubes. I've swapped out stock Sovtek EL84 tubes in 2 Pro Jrs for NOS 6BQ5's, installed NOS 12AX7s, and found no substantial differences in amp performance. (I admit I did not rebias). So the Sovteks went back in. I don't find the PJ "sensitive to tubes". :? My mileage varied! Why would EL84 power tubes not need rebiasing, in a fixed bias circuit, as much as other tubes? Mik __________________ a "motor-bike with a touch of blood in it is better than all the riding animals on earth, because of its logical extension of our faculties, and the hint, the provocations, to excess."-T.E. Lawrence

March 3rd, 2005, 02:52 PM	#20 (permalink)
Daddy Elmis Tele-Holic Join Date: Jun 2004 Location: USA Posts: 961	Folks more knowledgable than me (and that's a hell of a lot of people) and several who, to me, are experts in the field of tubes and tube amps, have told me that EL84's are low powered and generally are not as sensitive to bias "mismatch." Not saying that a proper bias is not smart, won't improve performance, etc., just that (according to my info) you are generally ok to plug and play EL84s (more so than higher powered tube -- 6L6, EL34, etc.). Now, if I had a bias pot I would rebias with EL84's myself. But to have a tech pull the chassis, cut and replace/resolder a resistor on the PCB, seems like a lot of trouble (and introduces the potential for damage) that, to me, isn't worth it. Off topic, but one thing that strikes me as a really "nice to have" feature on Tone King amps -- they put the bias point and built in meters on the back of their amps so you can easily check and change bias. As I always remind people, however, checking/adjusting bias is a relatively recent phenomenon. Back in "the day" everybody just plugged and played (except maybe touring pros that had amp techs traveling with them). Interestingly, this was also the "golden age" of tube amp tone from today's perspective (Hendrix, Cream, Butterfield, Who).