Questions about faulty Blues Jr

[dvkerner96]

Hello, I recently bought a used Blues Jr (early 2000's, USA made) and I have a few questions about what could be wrong with it. I bought it through Reverb.com, where the condition was listed as being excellent, but when I received it, it was (still is) very, very muddy, even at low volumes, and increases to being terribly muddy and distorted as the volume increases, it rattles excessively, a couple of the tubes are loose, and there is this high pitched squealing, shaking noise that comes out of the amp when playing high notes. What could be causing all of that? And is it worth it to try to repair it and possibly upgrade it, or should I just return it for a refund and buy a new Blues Jr iii or a Blues Jr NOS? Your insight into this matter would be greatly appreciated.

 

Danny

[onelife]

Look in the back of the amp as you play it and see if the two power tubes (the biggest tubes in the amp) light up evenly.

[dvkerner96]

Ok, I will do that now. Thank you for the suggestion!

[dvkerner96]

I checked the tubes, and yes, both the power tubes light up equally, and all three preamp tubes light up equally as well.

[WRGKMC]

Sounds like you have two issues. The squealing is likely tubes that have gone microphonic. Tubes can feedback like a microphone does when the elements get old or they are just poorly made, The sound from the speaker vibrates the tube and causes the elements inside to oscillate which makes the high pitch tones. It usually tales a couple of louder notes to set them off and then they just ring on their own.

 

You can usually detect which one it is by turning the amp up and lightly tapping on them with a pencil one at a time. That amp hasn't got many tubes so I'd just replace them all with some rugged tubes like JJ's.

 

After that you can decide if the sound quality has been improved enough. If it has you're good, if it hasn't, you probably want to try a different speaker. If the speakers stock it should produce a decent sound quality for most guitars. If it sounds muddy maybe someone swapped the speaker with something muddy sounding.

[dvkerner96]

Sounds like you have two issues. The squealing is likely tubes that have gone microphonic. Tubes can feedback like a microphone does when the elements get old or they are just poorly made, The sound from the speaker vibrates the tube and causes the elements inside to oscillate which makes the high pitch tones. It usually tales a couple of louder notes to set them off and then they just ring on their own.

 

You can usually detect which one it is by turning the amp up and lightly tapping on them with a pencil one at a time. That amp hasn't got many tubes so I'd just replace them all with some rugged tubes like JJ's.

 

After that you can decide if the sound quality has been improved enough. If it has you're good, if it hasn't, you probably want to try a different speaker. If the speakers stock it should produce a decent sound quality for most guitars. If it sounds muddy maybe someone swapped the speaker with something muddy sounding.

 

Ok, thank you! One of the preamp tubes and one or both of the power tubes are loose, so it could very well be something like you described. And how much difference does the tube type I use affect the tone of the amp? I am looking for a tone similar to what the amp has, just less muddy. And same thing with the speaker, I wouldn't want to change the tone completely, I just want it to be cleaner. As far as I know, the speakers in it now are stock speakers. And would it be worth it to just return it and get a newer version of the amp since I have to do work on this one that may or may not fix the problem?

[WRGKMC]

JJ's sound great in fenders. They are very durable and don't cost an arm an a leg. Tubes can vary tone but the differences aren't huge between them. Something like Sovtec can be a little darker sounding.

 

Electro Harmonix are great tubes too. They have a high output and decent response and are also decently priced.

Tung Sol have low microphonics and have a strong output as well. Haven't tried the Mullard Reissues yet but they have some great ratings.

 

There are two decent tube stores on line which deal exclusively in vacuum tubes. They seem to have the better prices then just about anyone out there. Other places can charge an additional 50~100% markup but you can also just Google the tube types and compare.

 

http://www.thetubestore.com/Tubes

 

https://www.tubedepot.com/?gclid=CJWEjJfqwccCFQ-IaQodYPMJ1w

[dvkerner96]

JJ's sound great in fenders. They are very durable and don't cost an arm an a leg. Tubes can vary tone but the differences aren't huge between them. Something like Sovtec can be a little darker sounding.

 

Electro Harmonix are great tubes too. They have a high output and decent response and are also decently priced.

Tung Sol have low microphonics and have a strong output as well. Haven't tried the Mullard Reissues yet but they have some great ratings.

 

There are two decent tube stores on line which deal exclusively in vacuum tubes. They seem to have the better prices then just about anyone out there. Other places can charge an additional 50~100% markup but you can also just Google the tube types and compare.

 

http://www.thetubestore.com/Tubes

 

https://www.tubedepot.com/?gclid=CJWEjJfqwccCFQ-IaQodYPMJ1w

 

I will check all those out, and I will check out the websites! Thank you for your help, I appreciate it! I'm sure I will be able to find the right tubes on one of those sites.

[dvkerner96]

Also, what do you think about groove tubes? Since I think that's what come stock in Blues Jr's

[WRGKMC]

I still have a set of 6L6 Groove tubes in my 67 Fender Bassman head. They've been in there over 10 years now and still sound good. They sound allot like the original RCA tubes that came with the head when I bought it new back in 1967. The company has been bought by Fender so I'm not sure how or if they've changed since I bought the last set. JJ's seem to produce a similar tone from my comparisons. I have changed out the 12AX7's about 5 years ago with Electroharmonix. The Grooves were loosing their mojo and the EH were a big improvement for that head.

 

I did a comparison between a dozen different preamp tubes when I was looking for a good replacement in my Marshall head. I used a Mic preamp to try out the tubes because it has no tone stack to color the tubes output. I tried all of the Sovtec versions, a couple of NOS I had, a JJ, an Electroharmonix, and a coupe of others. The EH out powered them all for clean tone and clean gain. I did wind up using a 5751 tube in the Marshall. Its a low gain 12AX7 variant which cooled down the Marshalls hot gain channels which were overly hot using 12AX7 tubes.

 

I may go with a set of EH power tubes on the Bassman soon too. I put a set in my Music Man head and they sound better then the JJ's that were in it.

 

Each amp can be different however. Circuits, tone stacks, speakers and even your instrument affects the tone. Finding the best tubes for a particular amp is a matter of experimentation because all those other factors are part of the chain and peoples tastes are different. My Bassman head is all about clean tones.

 

With a smaller amp like yours its all about getting the right balance between cleans and driven tones. I haven't heard the amp so I can only base my suggestions on your opinions. A guitar with vintage wound pickups plugged straight in you should get cleans with the volume cranked between 1/2 way up and 2/3. Beyond that you should be getting saturation. If you have hot would pickups, you may not get any cleans above 1/4 and it can sound like muted mud if the pickups are wound above 10K, even if the pickups are backed far from the strings. Those small amps were mainly designed for single coil pickups. Something bright like a Tele could make them scream. The amp adds the warmth to the single coil tone.

 

On larger fender amps you often need a drive pedal to get single coils to sound good. I've owned about a half dozen different Fenders, a Twin, Bandmaster, Black and silver faced Bassmans, Super Reverb, Champ, Princeton, M-80. On the bigger ones I'd usually put preamp tubes that broke up sooner and sounded warmer. On the small ones I used tubes that were brighter and didn't break up as easily so I'd have a wider clean range. This way if I used Humbuckers I could still get some cleans before it broke up. I used mostly Mini Humbuckers however which aren't as strong as full sized. I could nail that Dicky Betts Allman Brothers Tone from a Fender amp quite well without using gain pedals.

 

I like my Blackface Bassman to have cleaner tones because I run pedals before it and it essentially works like a clean tube power amp. The EH tubes get me that. Again, I'm not sure what might be best for yours, but you got to start some place. I'd likely err on the side of brighter and cleaner. You can always stick a tube screamer in front of it to get tube drive.

[Mikeo]

Hello, I recently bought a used Blues Jr (early 2000's, USA made) and I have a few questions about what could be wrong with it. I bought it through Reverb.com, where the condition was listed as being excellent, but when I received it, it was (still is) very, very muddy, even at low volumes, and increases to being terribly muddy and distorted as the volume increases, it rattles excessively, a couple of the tubes are loose, and there is this high pitched squealing, shaking noise that comes out of the amp when playing high notes. What could be causing all of that? And is it worth it to try to repair it and possibly upgrade it, or should I just return it for a refund and buy a new Blues Jr iii or a Blues Jr NOS? Your insight into this matter would be greatly appreciated.

 

Danny

 

The high pitch squeal probably comes for a bad pre amp tube(s). The muddiness comes from well worn power tubes.

 

I'd retube the whole thing at your fav shop with some JJ's.

 

The distortion is just ok, but push the front end with you fav OD box.

 

I have a NOS BJ and it's a decent grab and go amp.

 

You can change out the speaker too, or make it sound like a Vox with some BilM mods.

 

Check out BillM site, he's good at modding the BJ, and maybe one of the best. He's back in biz too, but still doing chemo treatments, I believe.

 

It's not a muddy sounding amp nor does it rattle and squeal. It has a cheapo transformer. I might order a new power Tranny for my PRRI. Tone is in the iron.

 

 

 

http://billmaudio.com/wp/

 

[dvkerner96]

I still have a set of 6L6 Groove tubes in my 67 Fender Bassman head. They've been in there over 10 years now and still sound good. They sound allot like the original RCA tubes that came with the head when I bought it new back in 1967. The company has been bought by Fender so I'm not sure how or if they've changed since I bought the last set. JJ's seem to produce a similar tone from my comparisons. I have changed out the 12AX7's about 5 years ago with Electroharmonix. The Grooves were loosing their mojo and the EH were a big improvement for that head.

 

I did a comparison between a dozen different preamp tubes when I was looking for a good replacement in my Marshall head. I used a Mic preamp to try out the tubes because it has no tone stack to color the tubes output. I tried all of the Sovtec versions, a couple of NOS I had, a JJ, an Electroharmonix, and a coupe of others. The EH out powered them all for clean tone and clean gain. I did wind up using a 5751 tube in the Marshall. Its a low gain 12AX7 variant which cooled down the Marshalls hot gain channels which were overly hot using 12AX7 tubes.

 

I may go with a set of EH power tubes on the Bassman soon too. I put a set in my Music Man head and they sound better then the JJ's that were in it.

 

Each amp can be different however. Circuits, tone stacks, speakers and even your instrument affects the tone. Finding the best tubes for a particular amp is a matter of experimentation because all those other factors are part of the chain and peoples tastes are different. My Bassman head is all about clean tones.

 

With a smaller amp like yours its all about getting the right balance between cleans and driven tones. I haven't heard the amp so I can only base my suggestions on your opinions. A guitar with vintage wound pickups plugged straight in you should get cleans with the volume cranked between 1/2 way up and 2/3. Beyond that you should be getting saturation. If you have hot would pickups, you may not get any cleans above 1/4 and it can sound like muted mud if the pickups are wound above 10K, even if the pickups are backed far from the strings. Those small amps were mainly designed for single coil pickups. Something bright like a Tele could make them scream. The amp adds the warmth to the single coil tone.

 

On larger fender amps you often need a drive pedal to get single coils to sound good. I've owned about a half dozen different Fenders, a Twin, Bandmaster, Black and silver faced Bassmans, Super Reverb, Champ, Princeton, M-80. On the bigger ones I'd usually put preamp tubes that broke up sooner and sounded warmer. On the small ones I used tubes that were brighter and didn't break up as easily so I'd have a wider clean range. This way if I used Humbuckers I could still get some cleans before it broke up. I used mostly Mini Humbuckers however which aren't as strong as full sized. I could nail that Dicky Betts Allman Brothers Tone from a Fender amp quite well without using gain pedals.

 

I like my Blackface Bassman to have cleaner tones because I run pedals before it and it essentially works like a clean tube power amp. The EH tubes get me that. Again, I'm not sure what might be best for yours, but you got to start some place. I'd likely err on the side of brighter and cleaner. You can always stick a tube screamer in front of it to get tube drive.

 

I've heard that since Groove Tubes were bought out, they just rebrand other manufacturers' tubes and don't actually make their own. The stock ones in the Blues Jr I bought say Groove Tubes, but if you look carefully at the tube you can see the original branding underneath, which is actually Sovtek. I have heard that Sovtek tubes are durable, but only decent when it comes to tone. I've heard of JJ's, though I'm not quite sure what to think about them, I've seen mixed opinions, some people like them, others don't care for them. I have looked into Electro Harmonix 12ax7's too, though I have been considering going with Tung Sol 12ax7's because I have heard that they are more sensitive and articulate (that may or may not be true, it is just what I have gathered from some research on the internet, I have no direct experience with either). Have you had any experience with Tung Sols? And if the EH outpowered the rest of those with clean and gain, that may be good for my amp. I am looking for tubes that will give me a better clean range with more headroom and more clean depth, that break up closer to 7 or 8 (mine now break up at 4-5), and that will add articulation and sensitivity, but still keep the warmth of the amp intact. A tiny bit brighter would be alright, too. How much does the power tube type affect tone? I've heard that the tubes that affect the tone most are the preamp ones, is that true? And yeah, I have been trying to look into which tubes go best in Blues Jr's for that reason, since the amp itself affects tone more than the tubes in it (as far I know). And I also have to factor in that my guitar uses humbuckers, which affects the tone a lot too, even more than the amp or the tubes. I realize that experimentation is probably the best way to find tubes suited to each individual's taste, but I am in a position now where it would be best if I was able to pick ones that I like right away, which requires some educated guessing. I am basically looking for tubes that will give me more clean headroom, a more articulate response, more depth and clarity, more dynamic control, and maybe just a pinch brighter, though that would be the least important of all the characteristics I mentioned. I played through a Bassman once, and I thought it had a great tone, though it was a little too warm for my taste (though I played through that one with a single coil guitar), but I also played through a Pro Jr (also with a single coil guitar) that had a Bassman speaker put into it and it was one the best sounding amps I've played through, although still a tiny bit warmer than what I'm looking for now. I agree that with a small amp like the one I have it is important to get the right balance between clean and driven tones, and I would ideally like to have it so that it doesn't start to break up until about 6.5-7.5 (the amp goes until 12). My guitar's pickups are Gibson 59 tribute humbuckers, so I don't think they are wound as hot as some of the others around. And since the amp I'm using was designed more for single coils, the tubes I use would need to help counteract some of the muddiness that pairing a Blues Jr with humbuckers could get. I have also noticed that with larger Fender amps, single coils can be a bit on the thin side, but when overdriven, they sound great. I have considered putting 6L6 tubes in place of the EL84's in the Blues Jr to help get more clean headroom, but I'm not sure if that's a good choice or not. I wouldn't be using any pedals, so it is important that whichever tubes I go with can give me a good driven tone once they reach a higher volume. I will consider the EH tubes since you say that they are very clean and add some brightness. How easily do those break up? Since I am looking for more clean headroom, but I do still want to have a good overdriven sound once I get past 6-7. Thank you for your help!

[WRGKMC]

Woah. Tubes are all different. There's a few that will work as substitutes without modding but the rest require different support circuitry.

 

EL84's are completely different low wattage tubes compared to 6L6 tubes. The sockets are different and the whole power amp would need to be reengineered with different power and output transformers. It would be cheaper to buy a whole a hole different amp then to try and mod it up.

[dvkerner96]

Ok, I will probably just put a couple new EL84's and some new 12ax7's into it then, that way I can still fix up the amp, but I'll be able to avoid all the hassle of modding (which I don't really want to do anyway). Thank you for your help and for your time, I appreciate it!

[dvkerner96]

 

The high pitch squeal probably comes for a bad pre amp tube(s). The muddiness comes from well worn power tubes.

 

I'd retube the whole thing at your fav shop with some JJ's.

 

The distortion is just ok, but push the front end with you fav OD box.

 

I have a NOS BJ and it's a decent grab and go amp.

 

You can change out the speaker too, or make it sound like a Vox with some BilM mods.

 

Check out BillM site, he's good at modding the BJ, and maybe one of the best. He's back in biz too, but still doing chemo treatments, I believe.

 

It's not a muddy sounding amp nor does it rattle and squeal. It has a cheapo transformer. I might order a new power Tranny for my PRRI. Tone is in the iron.

 

 

 

http://billmaudio.com/wp/

 

Ok, thank you! I will probably retube the amp, though I may go with Tung Sol preamp tubes and the tube store's "Preffered Series" power tubes, they are supposed to be older Russian tubes that are good. Have you had any experience with either? And I don't use any pedals, so I am looking for tubes that can push the amp into a good overdrive when loud enough, but other than that, I use mostly clean tone. And ok, thank you for the info on the NOS! I will probably change the speaker to one of the ones BillM recommends on his site. I'm not sure I'll do any modding, though. And I didn't know BillM got sick, that's a shame, I hope he's doing better. And yeah, I've played other Blues Jr's and none of them had these problems. I've heard about the power transformer too, but I will probably leave that alone unless changing the tubes and the speaker isn't enough. Hopefully just changing the tubes will be enough! But if not, then my next step is changing the speaker. After that, I'm not sure what would be next. I guess then it would be time to check the transformer. Thank you for your suggestions!

[onelife]

I checked the tubes' date=' and yes, both the power tubes light up equally, and all three preamp tubes light up equally as well.[/quote']

 

Do the tubes also light up equally when you are playing through the amp? They may have a bit of a blue glow as signal passes through them and the glow should be somewhat even.

 

The muddiness you describe could be caused by an uneven push pull output circuit.

[dvkerner96]

 

Do the tubes also light up equally when you are playing through the amp? They may have a bit of a blue glow as signal passes through them and the glow should be somewhat even.

 

The muddiness you describe could be caused by an uneven push pull output circuit.

 

Yes, they all light up equally even when I'm playing through it. And ok, I guess if retubing it doesn't fix the problem then I'll know that it must be something else. Thank you!

[r0bo01]

retubing is prolly your first best move...

if that doesn't do it, i wonder if substituting a 12at7 as the first preamp tube (v1) would help. this will cut back your preamp gain so that breakup started occurring further into your gain knob. overall volume would be less, however, so you might be back where you started if you try to go above a certain volume level...

a more efficient speaker might help also. especially paired with the 12at7. look for a higher db/watt rating (eg: 95db, 1 watt, 1 meter -> 105db, 1 w, 1 m).

i get that all this may run up into more than what you paid for the amp, so...

[dvkerner96]

retubing is prolly your first best move...

if that doesn't do it, i wonder if substituting a 12at7 as the first preamp tube (v1) would help. this will cut back your preamp gain so that breakup started occurring further into your gain knob. overall volume would be less, however, so you might be back where you started if you try to go above a certain volume level...

a more efficient speaker might help also. especially paired with the 12at7. look for a higher db/watt rating (eg: 95db, 1 watt, 1 meter -> 105db, 1 w, 1 m).

i get that all this may run up into more than what you paid for the amp, so...

 

If retubing doesn't work, I will consider trying that. My first move would probably be just looking for a better speaker, since it would get pretty expensive to keep retubing it. Hopefully retubing will work! Thank you for your suggestions!