Feel free to ask Myles

[mjmclane]

Myles - I replaced the V1 in my Hot Rod Deluxe as you suggested. I originally tried an Electro Harmonix 12AX7 and noted an improvment. However, on the clean channel I go from "0" to full volume at 3 or 4, then increasing levels of OD. I contacted your friends at kcanostubes.com and went w/ a Mullard 4024 (12AT7) for less gain as I am looking for a very clean sound in this channel, but I still go into OD very quickly. Could there be a taper issue with the volume pot? Also, do you know what benefits would be derived from replacing V2 and V3? I'd like to make the OD channel more useful, but I don't which tube(s) it uses to generate its gain (I'm guessing V3 is an inverter tube)?

[johndara]

Myles, A question about attenuators. I have a 1959SLP 100w Marshall. I bought it back in 1976 with a straight and a slant cab. I decided to have installed a master volume knob figuring this would save my hearing some. Since it was done way back when, i feel its not that great of a sound and now am considering buying a attenuator. A couple of recomendations have been the Power Soak and a Marshall Power Break. My question (finally) is could I use a atteunator on my amp even though there is a master volume on it? Also, I have heard from one person that the Power Break actually blew out the tubes in his amp,,now I'm wondering if these are safe units...and seeing that you crank your amp in order for the attenuator to work properly, will the be alot of hiss or noise? Thanks in advance for your input. John

[myles_rose]

Originally posted by mjmclane:

Myles - I replaced the V1 in my Hot Rod Deluxe as you suggested. I originally tried an Electro Harmonix 12AX7 and noted an improvment. However, on the clean channel I go from "0" to full volume at 3 or 4, then increasing levels of OD. I contacted your friends at kcanostubes.com and went w/ a Mullard 4024 (12AT7) for less gain as I am looking for a very clean sound in this channel, but I still go into OD very quickly. Could there be a taper issue with the volume pot? Also, do you know what benefits would be derived from replacing V2 and V3? I'd like to make the OD channel more useful, but I don't which tube(s) it uses to generate its gain (I'm guessing V3 is an inverter tube)?

mjmclane ...

 

The EH is much nicer in V1 than the stock Sovtek 12AX7WA for most folks tastes.

 

The volume will not change that much over 4, but the distortion sure will. This is one of the great aspect of this amp and many lower powered amps. Go play through a vintage Fender tweed Deluxe, and you will see the same thing.

 

It is not a taper issue, that is how the amp works. If you want more clean headroom, a 12AT7 in V3, the phase inverter slot, and a set of properly biased output tube in a higher rating, say #8's, will do the trick. If you want more clean headroom than that, then it's time to think about a more efficient speaker (such as a Jensen C12N), and of that is not enough, a more powerful amp.

[myles_rose]

Originally posted by johndara:

Myles, A question about attenuators. I have a 1959SLP 100w Marshall. I bought it back in 1976 with a straight and a slant cab. I decided to have installed a master volume knob figuring this would save my hearing some. Since it was done way back when, i feel its not that great of a sound and now am considering buying a attenuator. A couple of recomendations have been the Power Soak and a Marshall Power Break. My question (finally) is could I use a atteunator on my amp even though there is a master volume on it? Also, I have heard from one person that the Power Break actually blew out the tubes in his amp,,now I'm wondering if these are safe units...and seeing that you crank your amp in order for the attenuator to work properly, will the be alot of hiss or noise? Thanks in advance for your input. John

johndara .......

 

Installing a master volume is not something I like to do in these amps. All these do is limit the drive to the phase inverter.

 

It may save your hearing, but makes the amp have no output distortion, and just a high percentage of preamp tube distortion, which is very different. For some folks, this is what they want, while for others, it is not.

 

The Marshall Power Brake is an older product, and the GT SE II is much advanced if you want to drop the power and have other functions, such as an effects loop, EQ, and the ability to drop power to the cab 50% and 25% levels, while having a speaker emulated feeds to the board, house system or recording equipment: http://www.groovetubes.com/product.cfm?Product_ID=1604

 

The THD Hot Plate is another option, but does not have the EQ, effects loop, or emulator aspects, and is limited to being a load to drop level to the speaker cab.

 

None of these units will hurt the amp, unless the amp was in bad enough shape where running them flat out without a box would have hurt the amp in the same way. Using one of these boxes allows the amp to run flat out, just as running the amp flat out without the box. The tubes will burn out much faster, the same in either case, and the load on weak output transformers will be very high in either case.

 

The noise will be the same in either case, you will be running your amp at over 100 watts, and the preamp section will be cranked too, thus more background noise due to more gain.

[johndara]

Thanks again Myles for straightening me out on attenuators. I've decided against them but I'm open to suggestions from you and others as to what I can use to overdrive my amp, remembering that I do have a crappy master volume already installed. I do get a fairly decent rhythm sound, but for soloing it needs something more. Would a regular overdrive pedal do it and would it interfer with the master volume? I've used a comptortion from Tech 21 which is great running on a clean channel on my solid state amp, but on the marshall its too muddy sounding and im assuming its because of the master volume> Help...

[TieDyedDevil]

Myles --

 

Thanks for your help over on HC regarding my search for a new non-MV amp to supplement the Blue Angel.

 

You've already weighed in with your opinions on some of my early candidates, and I found that very helpful.

 

I found one more candidate, a Fender Vibro-King, - played it, love the sound - and would appreciate your advice regarding potential service issues (if you've had experience with the amp).

 

Thanks again!

[myles_rose]

Originally posted by johndara:

Thanks again Myles for straightening me out on attenuators. I've decided against them but I'm open to suggestions from you and others as to what I can use to overdrive my amp, remembering that I do have a crappy master volume already installed. I do get a fairly decent rhythm sound, but for soloing it needs something more. Would a regular overdrive pedal do it and would it interfer with the master volume? I've used a comptortion from Tech 21 which is great running on a clean channel on my solid state amp, but on the marshall its too muddy sounding and im assuming its because of the master volume> Help...

johndara ...........

 

I think at this point, its probably the overdrive pedal route. In this areana, I am at a loss. There are a ton of them out there, more new ones every day. Maybe post something here such as a poll, asking which is felt is best out of a batch of them.

 

OD pedals and master volumes turned down with the preamp amp turned up, won't really get you that output stage distortion, but it is a sound that a lot of folks love.

[myles_rose]

Originally posted by TieDyedDevil:

Myles --

 

Thanks for your help over on HC regarding my search for a new non-MV amp to supplement the Blue Angel.

 

You've already weighed in with your opinions on some of my early candidates, and I found that very helpful.

 

I found one more candidate, a Fender Vibro-King, - played it, love the sound - and would appreciate your advice regarding potential service issues (if you've had experience with the amp).

 

Thanks again!

TieDyedDevil ..........

 

Lots of experience with these. I support at least 15 of them.

 

There is one complaint on these amps, from a number of folks. That is that they are too clean. The reason for this, is that they are LOUD amps, and put out about 60 watts.

 

The way I resolve this is to use a set of low rated #2-3 tubes in them, and then the amp will start to break earlier, at "4" or so.

 

Reliability wise, they are terrific. These amps are from the Fender Custom Shop, and hand wired in the way the original black face and earlier amps were done. They use very high grade components and the workmanship is terrific. Amps with this same construction have been out there working for decades, and this amp will too.

 

Steer clear of used ones that were earlier, and used an EL-84 in the reverb circuit. The 6V6 driven reverb driven circuit is preferred. Fender switched to the 6V6 pretty early into their run. If you do have an EL-84 based amp, just get rid of the Sovtek stock EL-84 and replace it with an EL-84S in a #4 rating, and things will be fine and dandy.

 

There were 85 of these amps in the Fender NAMM booth recently. They were all done in custom cabinet colors, or hardwood cabs. They ranged from price from may $4000 and up, and 85% of them were sold in the first three hours of the first day of the show.

 

When Clapton played with Knopfler, he used a Vibro King. There are tons of them today in Nashville, doing everything from rock to blues to jazz to country.

 

Bottom line is, they are amazing amps. If you get a used one cheap, and don't like it, call me, as I will probably be interested in buying it for myself.

[myles_rose]

Originally posted by TieDyedDevil:

Originally posted by myles111:

[qb]

Originally posted by TieDyedDevil:

[qb]Myles --

 

I wonder whether I'm looking at a couple of the amps from NAMM. There's one in turquoise tolex and another in tooled leather. The dealer says they list for about $3,500. If the run is truly that limited, one of those might make a nice long-term investment (not to mention being a great-sounding amp). Were there any other distinguishing marks on the NAMM amps - special badging, perhaps?

 

It's funny, someone on one of the guitar mailing lists I subscribed to pushed me into looking at the VK. I was resistant because I've never found a Fender amp that hits the sweet spot in terms of volume - they're always too clean at high volumes or they'll get dirty at a decent volumen but then don't have any clean headroom. I didn't even want to look at the VK at first... 60W of Fender clean? My ears cringed at the very thought.

 

I plugged a Les Paul DC into the VK and started playing with tones all set at 4 and volume at about 3 (the sales guy's starting point). That was just high enough to get some breakup with heavy chording, but still clean enough to ease off on pick attack and get some beautiful shimmer. The sales guy left for a few minutes then rushed back in to the amp room, suggesting that I try another amp (an 85 watter - I forget which one) if the VK was too quiet.

 

I did a bit of research last night and found mixed opinions - some people feel like the VK doesn't have enough clean headroom, others that it's too loud. For me, it hits that in-between sweet spot perfectly. The VK doesn't seem any louder than my Blue Angel (of course, I haven't been able to do a side-by-side comparison yet), but it does seem warmer with less of an edge on the attack and more of a 3D sound on the decay.

 

I found references to the EL-84 reverb driver problem. There's an interview with Ritchie Fliegler online at the Tone Quest Report in which he acknowledges the problem, says that the fix was to ad a grid stopper to the EL-84, and mentions that an EL-84 is more "squirrely" than a 6V6.

 

I did find a used VK - one of the older ones with the blonde tolex and EL-84 reverb driver. The former owner was a chicken-picker who couldn't get his sound from the amp. In trying to "fix" the amp, he replaced the speakers with some Fane ceramic-mag speakers. Those Fanes, I think, killed the vibe of the amp. There was less compression, and the breakup was not as smooth.

 

If I do buy a VK (and my leaning is very much in that direction), I'd really love to get the amp blueprinted right off the bat. Do you know anyone in Oregon who does that, or am I looking at a road trip to LA?

TD.........

 

If the VKs are in custom colors then they are from NAMM.

 

$3500 is a pretty fair price, considering there were only 85 of them, and the base amp is $2999 list, and they can be hard to get. The custom ones sold at NAMM very very fast.

 

Nothing different other than the covering or cabinets, some were in exotic hardwoods.

 

The 85 watt amp the sales guy was perhaps referring to was a Twin Reverb reissue. The VK can be almost as loud, and if you drop down in rating to 2-3, then your turn it up to 5-6, and it is quite memorable.

 

The difference in feelings .... too loud ... not enough clean headroom, can be said for just about any amp out there. Just like any amp out there, it needs to be set up to the player, just like a guitar.

 

The VK is quite a bit louder and has much more lows and mids than the BA. It is also more defined, being class A/B, the the BA's class A.

 

The only folks I know that tune amps directly to the player, and have the equipment such as curve tracers, to do it as far as we seem to do it, is myself and Alexander Dumble. In regard to Dumble amps, no two are alike. Each is set up and tuned for the player. If you ever hear somebody say they arn't that special, or worth the bucks, before you buy into that, play one. If you don't like it, play another. You will see they are different. Then take into account, that the amp was voiced and tuned specifically for an individuals taste.

 

As far as me blueprinting, I have my current client base, and have about an eight month backlog at this time. My next appointment opening is at the end of this summer.

[TieDyedDevil]

Myles --

 

Have you had problems with failure of the stock speakers on any of the Vibro-Kings you support?

[myles_rose]

Originally posted by TieDyedDevil:

Myles --

 

Have you had problems with failure of the stock speakers on any of the Vibro-Kings you support?

TieDyedDevil .........

 

Yes.

 

The stock P10R speakers are 25 watters, and the amp can bench 60+ in some cases, and transients can go above this when pushed hard.

 

Using a Rickenbacker 360-12 and playing hard rhythm guitar can tax these speakers. The percussive nature of the Ricky is hard on speakers as it can cause some pretty dynamic transients.

 

The 10" JENSEN VINTAGE, CERAMIC MAGNET, 35 W, 8 OHM has ten watt higher capacity, and is also a bit louder. I use this in a few of the amps.

 

The P-A-V10-40-8 SPEAKER, 10" CELESTION SILVER SERIES, 40 W, 8 OHM is used by the majority of the folks. 10", 8 ohms, 40/80 RMS/Peak watts, 95-5.5K response. It is pretty nicely priced too at about $37.95 my cost, I am not sure what the retail is.

[TieDyedDevil]

Originally posted by myles111:

Originally posted by TieDyedDevil:

Myles --

 

Have you had problems with failure of the stock speakers on any of the Vibro-Kings you support?

TieDyedDevil .........

 

Yes.

 

The stock P10R speakers are 25 watters, and the amp can bench 60+ in some cases, and transients can go above this when pushed hard.

 

Using a Rickenbacker 360-12 and playing hard rhythm guitar can tax these speakers. The percussive nature of the Ricky is hard on speakers as it can cause some pretty dynamic transients.

 

The 10" JENSEN VINTAGE, CERAMIC MAGNET, 35 W, 8 OHM has ten watt higher capacity, and is also a bit louder. I use this in a few of the amps.

 

The P-A-V10-40-8 SPEAKER, 10" CELESTION SILVER SERIES, 40 W, 8 OHM is used by the majority of the folks. 10", 8 ohms, 40/80 RMS/Peak watts, 95-5.5K response. It is pretty nicely priced too at about $37.95 my cost, I am not sure what the retail is.

Thanks, Myles. That's good to know.

 

Just curious: Is there any reason to prefer the Jensen vintage w/ ceramic magnet rather than the alnico-mag P10Q? My intuition says that the P10Q would preserve more of the amp's character.

[myles_rose]

Originally posted by TieDyedDevil:

Originally posted by myles111:

Originally posted by TieDyedDevil:

Myles --

 

Have you had problems with failure of the stock speakers on any of the Vibro-Kings you support?

TieDyedDevil .........

 

Yes.

 

The stock P10R speakers are 25 watters, and the amp can bench 60+ in some cases, and transients can go above this when pushed hard.

 

Using a Rickenbacker 360-12 and playing hard rhythm guitar can tax these speakers. The percussive nature of the Ricky is hard on speakers as it can cause some pretty dynamic transients.

 

The 10" JENSEN VINTAGE, CERAMIC MAGNET, 35 W, 8 OHM has ten watt higher capacity, and is also a bit louder. I use this in a few of the amps.

 

The P-A-V10-40-8 SPEAKER, 10" CELESTION SILVER SERIES, 40 W, 8 OHM is used by the majority of the folks. 10", 8 ohms, 40/80 RMS/Peak watts, 95-5.5K response. It is pretty nicely priced too at about $37.95 my cost, I am not sure what the retail is.

Thanks, Myles. That's good to know.

 

Just curious: Is there any reason to prefer the Jensen vintage w/ ceramic magnet rather than the alnico-mag P10Q? My intuition says that the P10Q would preserve more of the amp's character.

TD ............

 

The R seems to be more versitile in the amp for most folks.

[TieDyedDevil]

Originally posted by myles111:

Originally posted by TieDyedDevil:

Originally posted by myles111:

quote:

---

Originally posted by TieDyedDevil:

Myles --

 

Have you had problems with failure of the stock speakers on any of the Vibro-Kings you support?

TieDyedDevil .........

 

Yes.

 

The stock P10R speakers are 25 watters, and the amp can bench 60+ in some cases, and transients can go above this when pushed hard.

 

Using a Rickenbacker 360-12 and playing hard rhythm guitar can tax these speakers. The percussive nature of the Ricky is hard on speakers as it can cause some pretty dynamic transients.

 

The 10" JENSEN VINTAGE, CERAMIC MAGNET, 35 W, 8 OHM has ten watt higher capacity, and is also a bit louder. I use this in a few of the amps.

 

The P-A-V10-40-8 SPEAKER, 10" CELESTION SILVER SERIES, 40 W, 8 OHM is used by the majority of the folks. 10", 8 ohms, 40/80 RMS/Peak watts, 95-5.5K response. It is pretty nicely priced too at about $37.95 my cost, I am not sure what the retail is.

Thanks, Myles. That's good to know.

 

Just curious: Is there any reason to prefer the Jensen vintage w/ ceramic magnet rather than the alnico-mag P10Q? My intuition says that the P10Q would preserve more of the amp's character.

TD ............

 

The R seems to be more versitile in the amp for most folks.

---

I think something got lost in the translation here...

 

The P10R is the stock speaker, right?

 

You said that you've put 10" JENSEN VINTAGE, CERAMIC MAGNET, 35 W, 8 OHM speakers into a few amps.

 

I was just wondering why you might prefer those, rather than the Jensen P10Q which is also a 35W speaker and would (I assume) preserve more of the amp's original vibe, compared to the ceramic-magnet Jensen that you've mentioned.

[myles_rose]

As usual, Myles, thanks for all your help. It's wonderful to have a knowledgeable (and patient) source for this kind of info.[/QB]

TD ...

 

You are more than welcome

[Timmy2000]

Hi Myles,

 

I'm a real beginner when it comes to guitars and amps but I was wondering if you could help me anyway.

I've had an old Carlsbro 50 watt tube head for about a year now which I love. Yesterday though it started making loud shorting type noises through the cab when adjusting the volume on either channel (it's got 2 clean channels and 2 inputs on each channel). The power bulb would also fade out for a second when it happened.

 

I've been planning on taking it in for a service and a retube for a while now anyway but I was wondering if you could give me any idea as to what might be wrong with it.

 

Many Thanks

Tim

[myles_rose]

Originally posted by Timmy2000:

Hi Myles,

 

I'm a real beginner when it comes to guitars and amps but I was wondering if you could help me anyway.

I've had an old Carlsbro 50 watt tube head for about a year now which I love. Yesterday though it started making loud shorting type noises through the cab when adjusting the volume on either channel (it's got 2 clean channels and 2 inputs on each channel). The power bulb would also fade out for a second when it happened.

 

I've been planning on taking it in for a service and a retube for a while now anyway but I was wondering if you could give me any idea as to what might be wrong with it.

 

Many Thanks

Tim

Tim,

 

It sounds like it's time to tear it down, clean and lube the pots and jacks, maybe check the filter caps, clean - lube - retension all tube sockets, and retube and rebias.

 

That is the start.

 

Then let me know how it works.

[teleboy 59]

Hey Myles,

 

I was wondering where I could find a rating for the tubes I have?NOS Phillips JAN 6L6 WGB Power tubes.I just put them in a early silverface Twin that has been balckfaced.It has been modded,you can unplug one speaker and switch to low power(takes out two tubes) but still very loud.All the talk about rating tubes has me wondering if I should look for something different (tubes).I am also thinking about an attenuater what do you think?Also,any recomendations for preamp tubes I have a JJ in V1,an RCA? in v2,JJ in v4 and phase inverter.Appreciate all of your great advice.I am seriously contemplating picking up a Dr. Z maz Jr or a Fargen Epic 30 if I can't get the twin to work for me.Are you familiar with Ben Fargen's work?

[jeangeniemusic]

Hello Myles:

After our exchange of posts I bought a Univalve with a THD cab to use as a recording amp for my home studio. I love the tone, the versatility.

However mine seems to have a buzz/hum problem. I changed tubes, got a set of different power and preamp tubes from Bob at Eurotubes ( nice guy, very helpful).

I switched all these around, changed the speaker cord, My strat has kinman noiseless pickups and is shielded. Plugging in the amp doesn't add any noise whatsoever. The noise is part of the amp, is very noticeable and really frustrates me. I can forget about making clean recording with low level clean tones. The noise canceling feature helps but it alters the tone too much. Not in a good way.

Nothing else hums in my studio. everything is noiseless. Que pasa?

Beside this problem (!!!). I really love this amp.

Thanks in advance

Jeangeniemusic

[TieDyedDevil]

Hi, Myles --

 

Now that I have the Vibro-King (wonderful amp!), I'd like to lay in a stock of spare tubes. It came with GT-labelled Sovtek 5881WXTs. I don't see these on the GT web site or in Fender's price list for spare parts.

 

What do you recommend as spares? I'd like to preserve the tone of the stock tubes without going any higher in power. An earlier breakup would be OK, too.

 

Thanks!

[Chip McDonald]

Myles:

 

Just skimmed your tube essay/dissertation... fantastic work! I need to find the time to sit dow n with it an really absorb, great detail, very interesting...

[myles_rose]

Originally posted by teleboy 59:

Hey Myles,

 

I was wondering where I could find a rating for the tubes I have?NOS Phillips JAN 6L6 WGB Power tubes.I just put them in a early silverface Twin that has been balckfaced.It has been modded,you can unplug one speaker and switch to low power(takes out two tubes) but still very loud.All the talk about rating tubes has me wondering if I should look for something different (tubes).I am also thinking about an attenuater what do you think?Also,any recomendations for preamp tubes I have a JJ in V1,an RCA? in v2,JJ in v4 and phase inverter.Appreciate all of your great advice.I am seriously contemplating picking up a Dr. Z maz Jr or a Fargen Epic 30 if I can't get the twin to work for me.Are you familiar with Ben Fargen's work?

teleboy 59........

 

The JAN Philips WGBs are more from the 5881 side of the 6L6 family, with very robust internal construction and a shorter bottle than mnay 6L6s.

 

The bottom line on these, is that they are really terrific, and last a long time. They are still not too pricy, and really great tubes. I currently use these in a lot of Fender amps, and also a duet is currently in use in my S45 that is on loan.

 

On preamp tubes, it all boils down to personal taste. I like the RCAs, GEs, and Sylvanias a lot in the first gain stages of Fender amps, more than the JJ, but again, that is my personal preference.

 

The Dr. Z MAZ is a really nice amp. They sound great and are built very well. The Epic 30 is also a nice amp, so it is going to boil down to price and features, and of course, the tone you are looking for. They are both different than Fender tones, so this will compliment the Fender amp really nicely.

[myles_rose]

Originally posted by jeangeniemusic:

Hello Myles:

After our exchange of posts I bought a Univalve with a THD cab to use as a recording amp for my home studio. I love the tone, the versatility.

However mine seems to have a buzz/hum problem. I changed tubes, got a set of different power and preamp tubes from Bob at Eurotubes ( nice guy, very helpful).

I switched all these around, changed the speaker cord, My strat has kinman noiseless pickups and is shielded. Plugging in the amp doesn't add any noise whatsoever. The noise is part of the amp, is very noticeable and really frustrates me. I can forget about making clean recording with low level clean tones. The noise canceling feature helps but it alters the tone too much. Not in a good way.

Nothing else hums in my studio. everything is noiseless. Que pasa?

Beside this problem (!!!). I really love this amp.

Thanks in advance

Jeangeniemusic

jeangeniemusic........

 

On your Univalve, if you bought a older used one, there may be a cap that later on they stuck on one of the preamp tube sockets that was not there on earlier models. This was not much of an issue, just with some 12AT7s maybe, a bit of instability could occur rarely.

 

The first thing I would do is change V1 and V2. If the amp still has noise, give a call up to THD and talk to Andy or Ed.

 

Is the Univalve new? These are normally quiet amps.

[myles_rose]

Originally posted by TieDyedDevil:

Hi, Myles --

 

Now that I have the Vibro-King (wonderful amp!), I'd like to lay in a stock of spare tubes. It came with GT-labelled Sovtek 5881WXTs. I don't see these on the GT web site or in Fender's price list for spare parts.

 

What do you recommend as spares? I'd like to preserve the tone of the stock tubes without going any higher in power. An earlier breakup would be OK, too.

 

Thanks!

TieDyedDevil.........

 

The stock tubes "were" the GT 6L6B, now called the 6L6R, which is the Fender 6L6GC, and also the Sovtek 5881 WXT. These, by the way, are the "6L6" tubes that Fender uses in most of their amps. I say "were", as in all their custom shop amps such as the Vibroking and Vibroverb, they now use the GT-6L6GE tube. This is a substantial upgrade in tone, and this is what I would suggest, in a #5 rating, for best all around use.

 

Either of these tubes is on the GT website.

 

Just keep the same distortion rating, and you will be fine. For earlier breakup, go the 3's or 4's.

 

Be sure to rebias.

[myles_rose]

Originally posted by Chip McDonald:

Myles:

 

Just skimmed your tube essay/dissertation... fantastic work! I need to find the time to sit dow n with it an really absorb, great detail, very interesting...

Chip,

 

Thanks.

[TieDyedDevil]

Originally posted by myles111:

Originally posted by TieDyedDevil:

Hi, Myles --

 

Now that I have the Vibro-King (wonderful amp!), I'd like to lay in a stock of spare tubes. It came with GT-labelled Sovtek 5881WXTs. I don't see these on the GT web site or in Fender's price list for spare parts.

 

What do you recommend as spares? I'd like to preserve the tone of the stock tubes without going any higher in power. An earlier breakup would be OK, too.

 

Thanks!

TieDyedDevil.........

 

The stock tubes "were" the GT 6L6B, now called the 6L6R, which is the Fender 6L6GC, and also the Sovtek 5881 WXT. These, by the way, are the "6L6" tubes that Fender uses in most of their amps. I say "were", as in all their custom shop amps such as the Vibroking and Vibroverb, they now use the GT-6L6GE tube. This is a substantial upgrade in tone, and this is what I would suggest, in a #5 rating, for best all around use.

 

Either of these tubes is on the GT website.

 

Just keep the same distortion rating, and you will be fine. For earlier breakup, go the 3's or 4's.

 

Be sure to rebias.

Got it. Thank you!

[TieDyedDevil]

Myles --

 

Man, this Vibro-King is tough on tubes! I'm having a hard time finding a 12AX7 that can survive the vibration in V2 - the reverb recovery slot. The original GT-labelled Sovtek 12AX7WA and a new Svetlana 12AX7 both went microphonic within a matter of hours.

 

I'm thinking that a JAN 5751 might be a bit more rugged. What do you think? Is there anything else I should try?

[myles_rose]

Originally posted by TieDyedDevil:

Myles --

 

Man, this Vibro-King is tough on tubes! I'm having a hard time finding a 12AX7 that can survive the vibration in V2 - the reverb recovery slot. The original GT-labelled Sovtek 12AX7WA and a new Svetlana 12AX7 both went microphonic within a matter of hours.

 

I'm thinking that a JAN 5751 might be a bit more rugged. What do you think? Is there anything else I should try?

TieDyedDevil ...........

 

There is something wrong here, as this is normally not a problem.

 

Is your amp one that uses a 6V6 or EL-84 in the reverb circuit?

 

If it is an EL-84, loose the stock tube and replace it with an EL-84S in a #4 or #5 rating.

 

The Svetlana 12AX7 is perhaps, the most unreliable 12AX7 made today, in any part of any circuit, so the stock tube may have had a problem initially, but the Svet surely added it's own problem.

 

Another 12AX7 of any type, if tested well, will work fine. That is one reason alone to try something like a GT 12AX7C, which works great in this area and is guaranteed to be microphonic free for six months.

[TieDyedDevil]

Originally posted by myles111:

Originally posted by TieDyedDevil:

Myles --

 

Man, this Vibro-King is tough on tubes! I'm having a hard time finding a 12AX7 that can survive the vibration in V2 - the reverb recovery slot. The original GT-labelled Sovtek 12AX7WA and a new Svetlana 12AX7 both went microphonic within a matter of hours.

 

I'm thinking that a JAN 5751 might be a bit more rugged. What do you think? Is there anything else I should try?

TieDyedDevil ...........

 

There is something wrong here, as this is normally not a problem.

 

Is your amp one that uses a 6V6 or EL-84 in the reverb circuit?

 

If it is an EL-84, loose the stock tube and replace it with an EL-84S in a #4 or #5 rating.

 

The Svetlana 12AX7 is perhaps, the most unreliable 12AX7 made today, in any part of any circuit, so the stock tube may have had a problem initially, but the Svet surely added it's own problem.

 

Another 12AX7 of any type, if tested well, will work fine. That is one reason alone to try something like a GT 12AX7C, which works great in this area and is guaranteed to be microphonic free for six months.

OK, I'll lose the Svet and see whether I can get a warranty replacement for the Fender GT 12AX7 that came with the amp. And I'll pick up a spare 12AX7C to keep in the gig bag.

 

This is a new Vibro-King, so it uses the 6V6 reverb driver. The stock driver tube seems reasonably quiet, but I suppose it wouldn't hurt to keep a spare for that one, too.

[Blue Note]

Myles,

 

I finally am getting around to retubing my Marshall, it is a dual channel with reverb JCM 800 model 2210. I would like your preferences on both the pre-amp and power tubes. This amp came from Marshall with 6550's which I had converted to EL-34's back in 1991 at a amp shop in New Jersey. Even though the amp tech disagreed I insisted on using Groove Tube pre-amp GT-12AX7's and GT El-34 power tubes and also using only two power tubes instead of four to lower the overdrive volume of the power tubes. The only new tubes I have is some sovtek EL-34WXT's that I bought about six years ago and the guy sold them to me then at a discount because he said they had them forever. I don't know exactly how old they are but the box they are in is turning yellow and even though I don't have it with me right now I think they both had a sticker on the box with 370 wrote on it so I assume they are a somewhat matched pair. I know this is not a lot of info but do you think these tubes are any good. Also I noticed the "GT-12AX7" is not available any more I think its only GT-12AX7R, or GT-12AX7C. The GT-12AX7's really have not been played a whole lot and thought these may still be better than any new ones available today. But then again these tubes may have not been tested to be a matched Driver tube. The reason I think the amp needs retubed is evidently the amp tech in New Jersey had the amp very much under biased because the GT label paint is burned to the point it has even flaked off and I think this means they have been running to hot. Also I think I remember you suggesting to get a true Marshall sound the amp needs to have just a hint of crossover notch still on the scope. Do I remember correctly?

 

Thank's again for your help and expertise,

 

Blue Note.