# More amp problems



## guitarman2 (Aug 25, 2006)

So my 67 Pro Reverb came back from repair and service and for a few days was fine. Sounded great. Then I noticed it didn't sound quite as loud. And it wasn't quite as clean. Today I came home from lunch and fired it up and it was definitely dirty sounding on 3. So I cranked it up to about 5. It was not near as loud as it should be and was driving pretty good. Actually sounded kind of nice except that I knew this wasn't natural. So I look in the back of the amp and sure enough one of the 6L6 tubes was not lit. So its running on one. So I turn the amp off and attempt to pull the tube out. The glass breaks in half in my hand. So I figure the tube blew. So I dig out a spare 6L6 I have laying around and plug it in. Success the amps sounds great again.
I had ordered a rectifier and a pair of 6L6 tubes from the tube store. The rectifier was bad out of the box. And now a 6L6 tube done. I bought the perferred series thinking I'd maybe get a better tube but not too much luck so far. I'll have to request a replacement. In the meantime I'll run the amp with the spare tube and give it a work out to make sure it isn't something in the amp thats doing this. As Rich from Amps Plus had just serviced this and gave it a clean bill of health I would expect that it was probably the tube but you never know.
One question, does anyone think there is a problem running the other spare tube with out a bias? The amp certainly sounds good. Just be a pain to half to haul it back to Rich. His hours are only 10 to 5 and I have to schedule time from work for drop off and pickup.
Sometimes I really hate tubes.


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## isoneedacoffee (Oct 31, 2014)

I don't really have any advice, but wanted to say that pretty much the exact same thing happened to me with my YBA1 MOD1. Low volume. Checked and saw that a tube was dead. Upon removing it, the tube shattered in my hand... and it was a "preferred series" matched EL34 pair from the tube store as well. Throughout the pandemic, I've been playing my Katana 50 much more than my tube amp. And I have the Katana head on the way. I hope that the Katana head will be good enough to cover rehearsals, and maybe even gigging duties because I too am tired of the maintenance and costs required with tubes.


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## Budda (May 29, 2007)

Those preferred EL34's arent so good, to the point my amp tech wont use them (last retube was the jcm800).

OP if your tech is a haul, i would probably use another amp til your replacement tube comes in.


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## isoneedacoffee (Oct 31, 2014)

Budda said:


> Those preferred EL34's arent so good, to the point my amp tech wont use them (last retube was the jcm800).


That's good to know. I'll definitely keep this in mind the next time I order tubes.


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## guitarman2 (Aug 25, 2006)

Budda said:


> Those preferred EL34's arent so good, to the point my amp tech wont use them (last retube was the jcm800).
> 
> OP if your tech is a haul, i would probably use another amp til your replacement tube comes in.



He's not really a haul just his hours are only the hours that I work so its a bit of a pain to schedule drop off and pickup as I have to be away from work a little longer than I like.
I'd like to leave the JJ tube I have in there to test and see if its the amp that may be causing the tubes to blow up before I put a new replacement in there. I ran it for about 15 minutes successfully over lunch so I'm pretty confident it was the tube. Confident enough to ask Jon for a replacement today.


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## guitarman2 (Aug 25, 2006)

isoneedacoffee said:


> I don't really have any advice, but wanted to say that pretty much the exact same thing happened to me with my YBA1 MOD1. Low volume. Checked and saw that a tube was dead. Upon removing it, the tube shattered in my hand... and it was a "preferred series" matched EL34 pair from the tube store as well. Throughout the pandemic, I've been playing my Katana 50 much more than my tube amp. And I have the Katana head on the way. I hope that the Katana head will be good enough to cover rehearsals, and maybe even gigging duties because I too am tired of the maintenance and costs required with tubes.


I'll probably never get rid of my Pro reverb but I'm seriously considering a purchase of the tonemaster twin. From what I hear and read about them is they're dam close. I've been putting it off thinking maybe one day they'll be dead on.


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## DaddyDog (Apr 21, 2017)

Although I'm no amp tech, I think you'll be fine without checking the bias until the next tech visit.

Regarding tubes for a vintage Pro Reverb: did you check the recommendations from The Tube Store? Yours is here:




__





 Fender Pro Reverb Amp - Tube Replacement Sets


Re-tube your Fender Pro Reverb Amp with our pre-selected audio tube kits. Our tube replacement kits are designed for your amp and come in different option levels.




www.thetubestore.com





Note it depends on which circuit you have. It should be on the tube label inside.

I once had amp issues, and discovered the rectifier tube I purchased blindly did not suit the specs of the amp at all!


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## guitarman2 (Aug 25, 2006)

DaddyDog said:


> Although I'm no amp tech, I think you'll be fine without checking the bias until the next tech visit.
> 
> Regarding tubes for a vintage Pro Reverb: did you check the recommendations from The Tube Store? Yours is here:
> 
> ...



The Premium package is recommending the Preferred series. Which has been a bit of bad luck for me so far. Rich from Amps plus is recommending Tung Sol GC-STR so I may order a pair of those and keep the preferred series as backups. He says the Tung Sol sound great in Fender amps.


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## jb welder (Sep 14, 2010)

You are fine to use the spare old tube til you get your new pair.
Back when these amps were 'current' there was no such thing as even buying pairs. You had a bad power tube, you replaced that one.
To a certain extent, the whole 'matching' thing was due to modern tubes being so loose in their tolerance. That and being able to sell tubes that didn't meet spec.


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## nonreverb (Sep 19, 2006)

Here's my 2 cents for what it's worth. I'm not a lover of the Preferred Series. I've installed some of the 6L6's/EL34's at the customer's request and yes, they're decent...but not worth the extra money IMHO. (No offence to the good folks at The Tube Store...they're just trying to make a living like the rest of us). That said, they have just as many failures and become just as rattly...maybe even more so than JJ's or Russian (pick whichever Mike Matthews sub brand here).


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## Davestp1 (Apr 25, 2006)

While I have no doubt the tubestores tubes are ok, power tubes should always be gripped on the base and not the glass to remove.....You should also seek out a good used set of RCA blackplates if possible for that Fender. The used set from the mid 60's that I bought over 20 years ago and now in my BFVR have been going strong in that amp since 2006......


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## guitarman2 (Aug 25, 2006)

nonreverb said:


> Here's my 2 cents for what it's worth. I'm not a lover of the Preferred Series. I've installed some of the 6L6's/EL34's at the customer's request and yes, they're decent...but not worth the extra money IMHO. (No offence to the good folks at The Tube Store...they're just trying to make a living like the rest of us). That said, they have just as many failures and become just as rattly...maybe even more so than JJ's or Russian (pick whichever Mike Matthews sub brand here).


This is basically what Rich from Amps Plus says, that he doesn't have a lot of luck with the preferred series.
When I talked to Jon about a replacement he said that its rare he gets a return for the preferred series.


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## guitarman2 (Aug 25, 2006)

Davestp1 said:


> While I have no doubt the tubestores tubes are ok, power tubes should always be gripped on the base and not the glass to remove.....You should also seek out a good used set of RCA blackplates if possible for that Fender. The used set from the mid 60's that I bought over 20 years ago and now in my BFVR have been going strong in that amp since 2006......


Easier said than done. And when I do see a pair I never have the hundreds of dollars the seller seems to want.


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## NashvilleDeluxe (Feb 7, 2018)

I've had good luck with the Preferred 6V6's and 6L6's from the Tube store for the Tremolux and Sky King, and they sound great. Tubes are just finicky, period.


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## guitarman2 (Aug 25, 2006)

NashvilleDeluxe said:


> Tubes are just finicky, period.



Yeah thats what I figure. I'm just going through a rough patch. I can play tube amps for years with out an issue. Than I'll get a cluster of issues all at once.


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## Latole (Aug 11, 2020)

guitarman2 said:


> One question, does anyone think there is a problem running the other spare tube with out a bias? The amp certainly sounds good. Just be a pain to half to haul it back to Rich. His hours are only 10 to 5 and I have to schedule time from work for drop off and pickup.
> Sometimes I really hate tubes.


New tubes with out bias ?
I'll never do that.

You'll never know if tubes's life will be shortened. Or worse you can damaged your amp if fuse don't blow first.
Be sure you have the right fuse.

IMO the tech may don't do the right bias about your tubes issue


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## nonreverb (Sep 19, 2006)

Latole said:


> New tubes with out bias ?
> I'll never do that.
> 
> You'll never know if tubes's life will be shortened. Or worse you can damaged your amp if fuse don't blow first.
> ...


That's not what he's asking Latole. He wants to run the existing power tube alone with the bias it was set to before he removed it's failed mate.


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## guitarman2 (Aug 25, 2006)

Latole said:


> New tubes with out bias ?
> I'll never do that.
> 
> You'll never know if tubes's life will be shortened. Or worse you can damaged your amp if fuse don't blow first.
> ...


I trust the tech I used. He said as long as I order the new tubes with the same number as what he biased that I could put them in and run them without a rebias. I've been playing tube amps for close to 40 years. There was a time I'd change these tubes with out rebiasing. As someone said earlier, if one went bad you simply replaced that tube. Back in the 80's, 90's I never had any trouble and I used to tour and run these amps 6-7 nights a week every week. 
Nowadays I turn my amp on 3 or 4 nights a week for maybe an hour at a time. I spend most of my time with my acoustics.


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## guitarman2 (Aug 25, 2006)

nonreverb said:


> That's not what he's asking Latole. He wants to run the existing power tube alone with the bias it was set to before he removed it's failed mate.


No, I'm not running the existing tube alone. I placed a spare JJ 6L6 I had where the failed tube was. I'm running that with the other tube that didn't fail. I put it in to test and make sure that the amp was still fine. I had a 6V6 tube in a tone king that blew up once and took a resistor with it. Just wanted to make sure that something similar didn't happen. Tonight I'll test a little more to see how the tubes hold up to make sure the integrity of the amp is fine before I put new power tubes in. I'll be getting a warranty replacement for preferred series that died. And I'll be ordering a pair of Tung Sol 6L6 (on Rich's recommendation) and likely I'll put the preferred series away for spares. Rich said as long as I get the same number I can put what ever tubes in with out rebiasing.


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## Latole (Aug 11, 2020)

nonreverb said:


> That's not what he's asking Latole. He wants to run the existing power tube alone with the bias it was set to before he removed it's failed mate.



Sorry my bad english speaking.


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## Latole (Aug 11, 2020)

guitarman2 said:


> I trust the tech I used. He said as long as I order the new tubes with the same number as what he biased that I could put them in and run them without a rebias.


To keep same bias you must buy not only tubes with the same number but most important : *the same brand.*
Another brand may need new bias, you never know before.

Bias on Pro Reverb is very easy to do for anybody with a bias probe and few hints


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## Davestp1 (Apr 25, 2006)

guitarman2 said:


> Easier said than done. And when I do see a pair I never have the hundreds of dollars the seller seems to want.


I guess there is a reason for that. FWIW someone from Calgary (GCF member LIX) contacted me out of the blue through a PM here about 3 months ago looking for a set. I sold him one of my spare sets, good strong used RCA blackplates for 135 plus shipping. With the preferred series of 6L6GC being 100 dollars Canadian plus tax plus shipping....I think the RCA's, although used, are a far, far better deal and will outlast those preferred series tubes by a long shot. The used pair in my BFVR have been going strong for years.


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## guitarman2 (Aug 25, 2006)

Latole said:


> To keep same bias you must buy not only tubes with the same number but most important : *the same brand.*
> Another brand may need new bias, you never know before.
> 
> Bias on Pro Reverb is very easy to do for anybody with a bias probe and few hints


I've been told that I'm fine regardless of brand if the numbers match by a tech I trust. I'm not going to worry about it too much. Like I said with close to 40 years of playing tube amps I've never worried as much (nor any other player I knew) as players seem to worry now a days. 
As for biasing an amp. I used bias the amps when I had a couple Allen amps as you didn't need to go inside. Everything was on the outside of the amp. I don't crack open the insides to do anything.


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## guitarman2 (Aug 25, 2006)

Davestp1 said:


> I guess there is a reason for that. FWIW someone from Calgary (GCF member LIX) contacted me out of the blue through a PM here about 3 months ago looking for a set. I sold him one of my spare sets, good strong used RCA blackplates for 135 plus shipping. With the preferred series of 6L6GC being 100 dollars Canadian plus tax plus shipping....I think the RCA's, although used, are a far, far better deal and will outlast those preferred series tubes by a long shot. The used pair in my BFVR have been going strong for years.


I'm mixed on how I feel about NOS tubes. Although I've not had any power tube failures I've had 2 rectifiers go prematurely, both Mullards. One I bought from KCA that lasted about 8 months and one I bought from you that lasted about 2 months. Usually when I invest in expensive NOS power tubes for some reason I sell the amp. Nothing to do with the tubes it just works out that way. Although I'm pretty much done with selling gear for the most part.
I don't feel I'm hard on tube amps anymore as it never moves from the spot in my office\music room and it mostly doesn't go over 3 on the volume knob except when I'm recording where I try to isolate it and push it around 6 or 7 but thats hardly ever. And the amount of time I have it on, once I get a decent set a tubes in there it should give me some good miles.
I guess if I run in to a decent deal on RCA 6L6 I might jump at them if they're reasonable. I had a pair in a mint 65 bassman head I picked up a couple years ago. They were original. The amp along with the matching piggyback 2X12 cabinet had been stored in a closet since 1980. When I got it, it was dusty as hell but cleaned up like a museum piece. When I sold it I should have pulled the RCA tubes but stupidly didn't.


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## Paul Running (Apr 12, 2020)

Maybe owner's of tube amps should start a mass protest..."Good tubes matter".


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## nonreverb (Sep 19, 2006)

Latole said:


> Sorry my bad english speaking.


Actually, it appears I misread the post. My apologies Latole. To your point, in rare cases it can be problematic installing an unknown tube without a rebias. That said, most often it can be done without trouble as long as it's not in there for a while. Unlike the "good old days" when folks would just throw another tube in and be on their way, new tubes seem to be a wee bit more susceptible to under bias conditions.


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## nonreverb (Sep 19, 2006)

guitarman2 said:


> No, I'm not running the existing tube alone. I placed a spare JJ 6L6 I had where the failed tube was. I'm running that with the other tube that didn't fail. I put it in to test and make sure that the amp was still fine. I had a 6V6 tube in a tone king that blew up once and took a resistor with it. Just wanted to make sure that something similar didn't happen. Tonight I'll test a little more to see how the tubes hold up to make sure the integrity of the amp is fine before I put new power tubes in. I'll be getting a warranty replacement for preferred series that died. And I'll be ordering a pair of Tung Sol 6L6 (on Rich's recommendation) and likely I'll put the preferred series away for spares. Rich said as long as I get the same number I can put what ever tubes in with out rebiasing.


Duly noted! I misunderstood the original post.


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## Latole (Aug 11, 2020)

guitarman2 said:


> I
> As for biasing an amp. I used bias the amps when I had a couple Allen amps as you didn't need to go inside. Everything was on the outside of the amp. I don't crack open the insides to do anything.



I ti s same for the Pro Reveb, no need to go inside for bias


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## guitarman2 (Aug 25, 2006)

Latole said:


> I ti s same for the Pro Reveb, no need to go inside for bias



Do you have instructions for the pro reverb? I still have my multi meter for when I biased my allen amps.


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## Paul Running (Apr 12, 2020)

guitarman2 said:


> I'm seriously considering a purchase of the tonemaster twin.


That would be a wise choice.


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## Davestp1 (Apr 25, 2006)

_I'm mixed on how I feel about NOS tubes. Although I've not had any power tube failures I've had 2 rectifiers go prematurely, both Mullards. One I bought from KCA that lasted about 8 months and one I bought from you that lasted about 2 months._

Luck of the draw I'd say. As I mentioned when you posted a while back, you should have gotten a hold of me. I've sold probably 50 GZ34 Mullards over the years, all used and only that one had an issue. But that is one more than should have been. But they were not NOS tubes and I never sold them as such. KCA's might have been NOS but not mine. My BFVR and 62 Tremolux both have early 60's used Mullard GZ34's. Both still going strong for years.


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## guitarman2 (Aug 25, 2006)

Davestp1 said:


> _I'm mixed on how I feel about NOS tubes. Although I've not had any power tube failures I've had 2 rectifiers go prematurely, both Mullards. One I bought from KCA that lasted about 8 months and one I bought from you that lasted about 2 months._
> 
> Luck of the draw I'd say. As I mentioned when you posted a while back, you should have gotten a hold of me. I've sold probably 50 GZ34 Mullards over the years, all used and only that one had an issue. But that is one more than should have been. But they were not NOS tubes and I never sold them as such. KCA's might have been NOS but not mine. My BFVR and 62 Tremolux both have early 60's used Mullard GZ34's. Both still going strong for years.



Yeah sometimes I just have bad luck with tubes. I bought a Tone King Metropolitan some years back when Mark owned the company. I had the amp for less than a month when one of the 6v6 tubes (EH) blew on me taking a resistor with it.


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## NashvilleDeluxe (Feb 7, 2018)

I hope Mark Bartel made it right with you. The nice thing about Tone King amps is that they're cathode-biased; just stick in new tubes, and away you go.


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## guitarman2 (Aug 25, 2006)

NashvilleDeluxe said:


> I hope Mark Bartel made it right with you. The nice thing about Tone King amps is that they're cathode-biased; just stick in new tubes, and away you go.


Mark was fantastic. He sent me out replacement tubes right away. He directed me to find an amp tech which at the time I went to someone in Burlington that Scott from axeandyoushallreceive recommended (I bought the amp from Scott) and Mark got on the phone while the tech did the repair to offer any assistance needed. This was at night, as the amp tech had an engineering day job and Mark made him self available. I had fantastic support from Scott, Mark and the tech that performed the repair.
I don't think you'll get that kind of attention from Tone King now.


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## jb welder (Sep 14, 2010)

And a reminder that there are tons of tube amps out there that don't even have a bias adjustment.
And not cathode biased, fixed bias. Mesa Boogie made a point of not having it.
Just 'plug 'n play'. 
If the fixed bias is set conservatively, it's no big deal. PV 5150 is a good example of this.


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## Latole (Aug 11, 2020)

nonreverb said:


> Unlike the "good old days" when folks would just throw another tube in and be on their way, new tubes seem to be a wee bit more susceptible to under bias conditions.


In the "good olds day" , Fender and Marshall amps, to name a few, have bais adjustments pot.
Today, there are still people who do the same thing.
The need for bias has always existed.


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## Latole (Aug 11, 2020)

jb welder said:


> And a reminder that there are tons of tube amps out there that don't even have a bias adjustment.
> And not cathode biased, fixed bias. Mesa Boogie made a point of not having it.
> Just 'plug 'n play'.
> If the fixed bias is set conservatively, it's no big deal. PV 5150 is a good example of this.


To avoid mixing and distracting Guitarman2 I prefer to stick to the Pro Reverb and because this amp have a easy ajustable bias pot.


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## Latole (Aug 11, 2020)

guitarman2 said:


> Do you have instructions for the pro reverb? I still have my multi meter for when I biased my allen amps.


As I wrote, you need a bias probe. Best one can also read plate voltage and milliamp.
Allen amps have a kind of bias probe inside their amps. With that you only need tests points for your meter

You need a bias probe like this one; I don't know this product, mine look close, was made by Amp-head Inc, not available anymore.









Vintage DC Current Voltage Tester - Cornwell Allied KL-787 - Ohio-Works Perfect | eBay


Find many great new & used options and get the best deals for Vintage DC Current Voltage Tester - Cornwell Allied KL-787 - Ohio-Works Perfect at the best online prices at eBay! Free shipping for many products!



www.ebay.ca












Plate voltage and cathode current


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## DaddyDog (Apr 21, 2017)

guitarman2 said:


> Yeah sometimes I just have bad luck with tubes. I bought a Tone King Metropolitan some years back when Mark owned the company. I had the amp for less than a month when one of the 6v6 tubes (EH) blew on me taking a resistor with it.


Funny, I had pretty much the same experience. Fortunately the new Tone King people were very helpful, responsive, and provided my amp tech with the needed info. Love my Metropolitan!


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## NashvilleDeluxe (Feb 7, 2018)

jb welder said:


> And a reminder that there are tons of tube amps out there that don't even have a bias adjustment.
> And not cathode biased, fixed bias. Mesa Boogie made a point of not having it.
> Just 'plug 'n play'.
> If the fixed bias is set conservatively, it's no big deal. PV 5150 is a good example of this.


Interesting about Mesa Boogie. I could NOT get this Studio 22 to behave, even after a full re-tube. Amps aren't really my thang, though. I sent the customer along to someone unafraid of getting cooked.
Will, at @la grange guitar workshop


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## nonreverb (Sep 19, 2006)

jb welder said:


> And a reminder that there are tons of tube amps out there that don't even have a bias adjustment.
> And not cathode biased, fixed bias. Mesa Boogie made a point of not having it.
> Just 'plug 'n play'.
> If the fixed bias is set conservatively, it's no big deal. PV 5150 is a good example of this.


That said, I have been known to install bias pots on customer Mesa units that are out of warranty.


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## loudtubeamps (Feb 2, 2012)

@guitarman2 ...just reading through this post.
I have I believe,2 matched pair of used RCA 6L6 blackplates. 
Very clean ,quiet, and stable current draw in a practical application.
150.00 plus shipping for a pair.
Pm me if interested.
Cheers.


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## guitarman2 (Aug 25, 2006)

I called the tubestore for a replacement tube for the preferred series that blew. And I decided to order all new preamp tubes and a spare set of Tung Sol power tubes. All the tubes are matched numbers and according to the tubestore and my amp tech I should be fine with out a rebias.


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## loudtubeamps (Feb 2, 2012)

guitarman2 said:


> I called the tubestore for a replacement tube for the preferred series that blew. And I decided to order all new preamp tubes and a spare set of Tung Sol power tubes. All the tubes are matched numbers and according to the tubestore and my amp tech I should be fine with out a rebias.


@guitarman2
FWIW....it takes about 10 minutes to pull the chassis far enough out to put a set of probes on the output section to check current draw on the tubes, set bias and pop the chassis back in and reinstall the chassis bolts.
Well worth the time and little bit extra $$, just to be sure everything is good...under the hood .IMHO


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