Feel free to ask Myles

[myles_rose]

Thanks Myles!

 

(And thanks again for the trace-matching you did on the "Marshall Hi-Gain Kit w/ MPI" for me then!)

 

You are more than welcome.

 

When I left GT I took all of my tube test gear with me so I can continue to do that sort of thing in the future and a lot more.

 

 

[MILLO]

Hey Myles:

 

Do you know if that trick of connecting a cd player to an amp, and run it really loud does work for "breaking in" a speaker? Should I put the amp/cab in a closet w/ blankets? ...is there danger of having the speaker not be able to breath? You know, will it not have its own waves whipping back at it?

 

It's specifically for a 1x12 open-back combo.

Thanks in advance...

 

PS: Just ordered some JJ 803s and EL84's from Doug, specifically thinking of this combo. I'll let you know how things sound.

[myles_rose]

Hey Myles:

 

Do you know if that trick of connecting a cd player to an amp, and run it really loud does work for "breaking in" a speaker? Should I put the amp/cab in a closet w/ blankets? ...is there danger of having the speaker not be able to breath? You know, will it not have its own waves whipping back at it?

 

It's specifically for a 1x12 open-back combo.

Thanks in advance...

 

PS: Just ordered some JJ 803s and EL84's from Doug, specifically thinking of this combo. I'll let you know how things sound.

 

Just plug into the input jack.

[Junior 1]

Hi Myles,

Happy Monday! I use a EH Holy Stain for my Verbs and Tremolo. It's EH's multi FX pedal. The last knob on the top of the pedal is a Clean/Fuzz/OD selector. I would like that to be a stomp switch. Could I install a 3 position heavy duty switch in it's place? I could tap that sucka with my size 9's easy.

Thanks

Anthony

[myles_rose]

Hi Myles,

Happy Monday! I use a EH Holy Stain for my Verbs and Tremolo. It's EH's multi FX pedal. The last knob on the top of the pedal is a Clean/Fuzz/OD selector. I would like that to be a stomp switch. Could I install a 3 position heavy duty switch in it's place? I could tap that sucka with my size 9's easy.

Thanks

Anthony

 

Any good tech should be able to do that with ease and without a high cost.

 

[Junior 1]

Thanks Myles

[myles_rose]

Thanks Myles

 

You are quite welcome.

 

 

[Bluesape]

Hey Myles,

 

The rectifier tube in my old 6V6 Lifco Cobra Mark 2 has something rattling around inside it, so I wanna replace it. There are no legible numbers left on it, and it could very well be the original tube from the 60's/70's. One reviewer thinks it has the AB763A circuit, like an old Princeton(?). Another says his has 7025's. Mine has 12AT7's. Is a 5U4GB gonna be the right recto tube?

 

My local store has a 5AR4, but doesn't know if it's an appropriate substitute.

 

[myles_rose]

Hey Myles,

 

The rectifier tube in my old 6V6 Lifco Cobra Mark 2 has something rattling around inside it, so I wanna replace it. There are no legible numbers left on it, and it could very well be the original tube from the 60's/70's. One reviewer thinks it has the AB763A circuit, like an old Princeton(?). Another says his has 7025's. Mine has 12AT7's. Is a 5U4GB gonna be the right recto tube?

 

My local store has a 5AR4, but doesn't know if it's an appropriate substitute.

 

A 5AR4 and 5U4 are NOT the same. Use the proper rectifer.

 

If you have 12AT7 tubes in the front end gain where a 12AX7/7025 tube goes the amp will sound awful. Replace any tube in V1 especially if it is a 12AT7 where it should be a 12AX7. In the "old days" a 7025 was a 12AX7 that was selected for low noise but today anything marked 7025 is just a 12AX7 and those are fine.

 

[Bluesape]

A while back ya said use a 12AT7 in V1. I did that, and it improved the sound over the 12AX7. I didn't know a 12AX7 and 7025 were the same.

 

Again, would you think the 5U4GB is the right rectifier?

[myles_rose]

A while back ya said use a 12AT7 in V1. I did that, and it improved the sound over the 12AX7. I didn't know a 12AX7 and 7025 were the same.

 

Again, would you think the 5U4GB is the right rectifier?

 

I may have said to try a 5751 in V1 which has the same gain as a 12AT7 but I don't think I would ever suggest a 12AT7 in a tone/gain position unless I was drunk.

 

I do not know about the rectifier as it is not a production amp or an amp that I have seen.

 

 

[Bluesape]

Well, I wouldn't know about that - the being drunk part , but if we dredge up the post, I believe it'll say just that.....

[myles_rose]

Well, I wouldn't know about that - the being drunk part , but if we dredge up the post, I believe it'll say just that.....

 

Well ... in any case, a 5751 is a better choice than a 12AT7.

 

[miroslav]

Yeah...I tried a 5751 in my 5E3 Tweed amp...and I like it the most...more than a 12AT7 or 12AX7.

So now I have a couple dozen 5751 tubes and I will be trying them in my other amps.

(It's just that they are not not cheap $$ compared to the 12Axx family.)

 

 

Myles

 

I know you've parted ways with Groove Tubes...but I was wondering if you could point me in the right direction.

I have some GT Electronics tube mics that utilize the miniature 5840 tube (I'm told some GT mics came with the 6502 - same difference).

 

Anyway...I was curious about the life-span of those tubes in these microphone applications with mild/medium use.

IOW...should I expect to have to ever replace these tubes?

 

[myles_rose]

Yeah...I tried a 5751 in my 5E3 Tweed amp...and I like it the most...more than a 12AT7 or 12AX7.

So now I have a couple dozen 5751 tubes and I will be trying them in my other amps.

(It's just that they are not not cheap $$ compared to the 12Axx family.)

 

 

Myles

 

I know you've parted ways with Groove Tubes...but I was wondering if you could point me in the right direction.

I have some GT Electronics tube mics that utilize the miniature 5840 tube (I'm told some GT mics came with the 6502 - same difference).

 

Anyway...I was curious about the life-span of those tubes in these microphone applications with mild/medium use.

IOW...should I expect to have to ever replace these tubes?

 

 

The lifespan can be a decade or a year or less depending on handling etc.

 

They are both tubes that are very easy to get and not pricy.

 

 

 

[Powerage]

Hi Myles,

I have just purchased a new Fender supersonic combo and am about to totally revalve it, both pre-amp and power valves. Can I replace the 6L6 with reissue TUNG SOL 5881 valves without doing any long term damage to the amp?

If it is possible to run the TUNG SOLS what bias rating would you recommend?

Thanks

Powerage

[myles_rose]

Hi Myles,

I have just purchased a new Fender supersonic combo and am about to totally revalve it, both pre-amp and power valves. Can I replace the 6L6 with reissue TUNG SOL 5881 valves without doing any long term damage to the amp?

If it is possible to run the TUNG SOLS what bias rating would you recommend?

Thanks

Powerage

 

The 5881s are actually just 6L6's.

 

You can replace with no damage of any type. Just bias at 30-32mA per tube.

 

 

[Zephyr]

Hey Myles, I have an interesting question in regards to mixing different power tubes in a cathode-biased amp (ie a KT66 and an EL34). I have a Fargen Mini-Plex, so it is possible to do so in this amp.

 

Anyway, is there a method to "match" a KT66 and an EL34 for the sake of tone? They're both built to different specs I know, but generally speaking should I look for a 66 and a 34 that have a similar current?

[myles_rose]

Hey Myles, I have an interesting question in regards to mixing different power tubes in a cathode-biased amp (ie a KT66 and an EL34). I have a Fargen Mini-Plex, so it is possible to do so in this amp.

 

Anyway, is there a method to "match" a KT66 and an EL34 for the sake of tone? They're both built to different specs I know, but generally speaking should I look for a 66 and a 34 that have a similar current?

 

These two tubes are not similar in any aspect.

 

 

[Zephyr]

Hey Myles, I have an interesting question in regards to mixing different power tubes in a cathode-biased amp (ie a KT66 and an EL34). I have a Fargen Mini-Plex, so it is possible to do so in this amp.

 

Anyway, is there a method to "match" a KT66 and an EL34 for the sake of tone? They're both built to different specs I know, but generally speaking should I look for a 66 and a 34 that have a similar current?

 

These two tubes are not similar in any aspect.

 

 

Hmm, so I don't need to look for specs, just plug and play?

[myles_rose]

Hey Myles, I have an interesting question in regards to mixing different power tubes in a cathode-biased amp (ie a KT66 and an EL34). I have a Fargen Mini-Plex, so it is possible to do so in this amp.

 

Anyway, is there a method to "match" a KT66 and an EL34 for the sake of tone? They're both built to different specs I know, but generally speaking should I look for a 66 and a 34 that have a similar current?

 

These two tubes are not similar in any aspect.

 

 

Hmm, so I don't need to look for specs, just plug and play?

 

If the amp was designed for dissimilar tubes you are fine IF it is cathode biased.

 

 

[Zephyr]

Yep it is and it sounds great, thanks Myles

[steve f]

Myles, I understand the Electro-Harmonix big bottle 6CA7 is supposed to be modeled after the original Sylvania big bottle 6CA7. What is your opinion on the EH 6CA7? Is it close to the Sylvania in sound?

[myles_rose]

Myles, I understand the Electro-Harmonix big bottle 6CA7 is supposed to be modeled after the original Sylvania big bottle 6CA7. What is your opinion on the EH 6CA7? Is it close to the Sylvania in sound?

 

It is not close to the Sylvania as it does not have crossing grid 1 and grid 2 design. It sounds different than a Sylvania or GE both of which sound much bigger and are much stronger.

 

 

 

 

[steve f]

Myles, I understand the Electro-Harmonix big bottle 6CA7 is supposed to be modeled after the original Sylvania big bottle 6CA7. What is your opinion on the EH 6CA7? Is it close to the Sylvania in sound?

 

It is not close to the Sylvania as it does not have crossing grid 1 and grid 2 design. It sounds different than a Sylvania or GE both of which sound much bigger and are much stronger.

 

Myles, thanks for the heads up on the EH 6CA7.

 

Another question. I'm going to be retubing a friend's Marshall DSL50. She doesn't do any type of regular maintenance on her amps, and it's hard to get them away from her to check them out. Basically she waits until one or more of the tubes wears out before replacing them.

 

I read your piece on the phase inverter being the hardest working tube in an amp, and was wondering what you think of putting a NOS 12AT7 as the PI in a DSL50. I know someone with an old Mullard ECC81/12AT7 that is new in the original box that I can get pretty cheap. My friend likes the sound of her DSL50 a lot, and I don't want to do anything that would affect it too much, so, would a 12AT7 be appropriate for a DSL50 in your opinion? I'd like to put something in there that would last as long as possible.

[myles_rose]

Myles, I understand the Electro-Harmonix big bottle 6CA7 is supposed to be modeled after the original Sylvania big bottle 6CA7. What is your opinion on the EH 6CA7? Is it close to the Sylvania in sound?

 

It is not close to the Sylvania as it does not have crossing grid 1 and grid 2 design. It sounds different than a Sylvania or GE both of which sound much bigger and are much stronger.

 

 

 

Myles, thanks for the heads up on the EH 6CA7.

 

Another question. I'm going to be retubing a friend's Marshall DSL50. She doesn't do any type of regular maintenance on her amps, and it's hard to get them away from her to check them out. Basically she waits until one or more of the tubes wears out before replacing them.

 

I read your piece on the phase inverter being the hardest working tube in an amp, and was wondering what you think of putting a NOS 12AT7 as the PI in a DSL50. I know someone with an old Mullard ECC81/12AT7 that is new in the original box that I can get pretty cheap. My friend likes the sound of her DSL50 a lot, and I don't want to do anything that would affect it too much, so, would a 12AT7 be appropriate for a DSL50 in your opinion? I'd like to put something in there that would last as long as possible.

 

On the 12AT7 ... it is really user taste and preference. If you try it and like it then it's a great thing to do.

 

As far as tube replacement ... waiting until something fails is pretty lame thinking to me ... that means that for what may be years you are living with substandard tone and performance out of your amp and the reliability factor of the amp is substantially reduced. In the case of waiting for output tubes to fail, when they do fail they can cause other damage such as blowing fuses or in some amps they can cause damage to the output transformer.

 

[Caevan O’Shite]

If I may chime in, no matter what type of tube you're using for a phase-inverter, I think it's WELL worth it to pay the little extra for a "Matched Phase Inverter" (it was Myles who turned me on to these), or paying the mark-up/service-charge for tubes tested for balance and gain (basically the same thing) for an M.P.I. tube.

 

Groove Tubes USED to have these, and Doug's Tubes offers testing for balance and gain on many models, as I'm sure some others also do. I can speak from experience with GT (in the past) and Doug's Tubes (recently/currently) that it makes a wonderful difference! It really helps you get the most out of matched output-tubes, too.

 

That is, as long as the amp you're re-tubing uses a design where this is relevant. (I think it's safe to say that most are, but check if you're not certain.) Even so, it wouldn't hurt if it wasn't, it'd just be somewhat wasted on an amp that didn't need it.

 

And replacing it along with the output-tubes should be a matter of course every time.

[myles_rose]

If I may chime in, no matter what type of tube you're using for a phase-inverter, I think it's WELL worth it to pay the little extra for a "Matched Phase Inverter" (it was Myles who turned me on to these), or paying the mark-up/service-charge for tubes tested for balance and gain (basically the same thing) for an M.P.I. tube.

 

Both Groove Tubes and Doug's Tubes offer these, as I'm sure many others also do. I can speak from experience with GT and Doug's that it makes a wonderful difference! It really helps you get the most out of matched output-tubes, too.

 

That is, as long as the amp you're re-tubing uses a design where this is relevant. (I think it's safe to say that most are, but check if you're not certain.) Even so, it wouldn't hurt if it wasn't, it'd just be somewhat wasted on an amp that didn't need it.

 

And replacing it along with the output-tubes should be a matter of course every time.

 

These are no longer available from GT no matter what they say since their sale to Fender. I was the one who picked these on MY own equipment and when GT was sold to Fender I left and took my stuff with me.

 

But .... you can get these at www.dougstubes.com and www.kcanostubes.com

 

 

[Caevan O’Shite]

Thank-you for that very interesting information, Myles! Good to know. I will edit my previous post to reflect that...

 

I got some very nice tubes (and great, speedy service) from Doug's Tubes, including a particularly excellent JJ ECC83S that was tested for balance and high-gain, which I popped into a Laney head mated to a Marshall 4x12. It made an obvious improvement, with better presence, clarity, definition, strength, and all-around good tone. Other people who were non-musicians commented on the sudden improvement!

[myles_rose]

Thank-you for that very interesting information, Myles! Good to know. I will edit my previous post to reflect that...

 

I got some very nice tubes (and great, speedy service) from Doug's Tubes, including a particularly excellent JJ ECC83S that was tested for balance and high-gain, which I popped into a Laney head mated to a Marshall 4x12. It made an obvious improvement, with better presence, clarity, definition, strength, and all-around good tone. Other people who were non-musicians commented on the sudden improvement!

 

Doug Preston is an ultra cool fellow and does great work.