Feel free to ask Myles

[myles_rose]

[Caevan O’Shite]

Hey, Myles-

 

Re: a driver tube V2 for my old Fuchs Lucky 7 head-

 

-do I need certain specs or qualities from V2A or V2B- as in, does it only use triode V2A or V2B- or do I need a "Balanced" and/or "Matched" Phase-Inverter/Driver?

[myles_rose]

Just use a good quality tube that meets specs in both locations.

[Caevan O’Shite]

Just use a good quality tube that meets specs in both locations.

 

Thanks. I'll name the first note I play through my freshly re-tubed Lucky 7 with my recently repaired Les Paul (broken headstock/fret-job/misc.etc.) after you, Myles!

 

[myles_rose]

Don't do that ..... unless it is a clunker note.

 

Name it after the girl you left that you still think of fondly

 

[Caevan O’Shite]

Don't do that ..... unless it is a clunker note.

 

Name it after the girl you left that you still think of fondly

 

There will be more than one note; perhaps dozens... I will name a thoughtful, wry one after you, Myles, and a squirrely, wild, devious, sweet one after Elizabeth; and... OH, ehr, eghmn, gee, uh, there are no other girls I'll be naming notes after!

 

 

(She knows better. And I know better than to name them other notes. )

[myles_rose]

 

[Caevan O’Shite]

OK, so I've been recommended a Sovtek 12AX7LPS for the driver, V2, in my Fuchs Lucky 7. Your thoughts, particularly as opposed to a NOS or "ANOS" tube, which I would have expected to have been suggested by the vendor/tester?

 

For my aforementioned needs (Dynamic play-the-amp/"touch", cranked Fuchs Lucky 7, want bold aggressive sound w/ more low-end, compressed lead tones w/ maxed guitar and amp volumes, while backing off guit-vol cleans up through nice shades of grind to clean), should I opt for "Matched Gain"? "Balanced Triodes Phase Inverter"? "High Gain"?

 

FWIW, I will be hitching the driver-tube to a vintage/NOS Tesla EL34, and also will likely get a vintage/NOS Siemens EL34.

 

Thanks once again for your time and effort!

 

"High gain, low noise, smooth sound. Great as a phase inverter.

 

The Sovtek 12AX7LPS is a long plated spiral filament dual triode. High gain, and low noise, is nicely balanced all around - not bright.

 

Players with combo amps or those who like to play on max volume may want to reconsider, as the 12AX7LPS can be prone to microphonics (due to the long plate).

 

The Sovtek 12AX7LPS is the same tube as the Groove Tubes 12AX7R2. The long plate makes it great in the phase inverter spot, a position which can impact the overall feel of your amp.

 

Avoid these in high voltage cathode follower(CF) spots, these cannot withstand prolonged high voltage. They also don't appear to light up because of the spiral filaments, please listen to your amp before emailing us about a DOA tube!"

 

http://www.dougstubes.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/s/o/sovtek12ax7lps.jpg

[myles_rose]

Doug is right on the money except ....

 

The reason the heater cannot be seen light most of the time is not because of the spiral heater, it is because the cathode tube encases the heater more fully than many other designs. The LP (which is supposed to be the non-spiral heater) is really the same tube. None of the heater filaments on any dual triode are straight, or spiral. They are just sort of generally sloppy but it does not matter much in the end as more hum and noise comes from other poor aspects of quality.

 

The LPS or LP is a good phase inverter but have Doug pick out one that meets spec.

 

[Caevan O’Shite]

Doug is right on the money except ....

 

The reason the heater cannot be seen light most of the time is not because of the spiral heater, it is because the cathode tube encases the heater more fully than many other designs. The LP (which is supposed to be the non-spiral heater) is really the same tube. None of the heater filaments on any dual triode are straight, or spiral. They are just sort of generally sloppy but it does not matter much in the end as more hum and noise comes from other poor aspects of quality.

 

The LPS or LP is a good phase inverter but have Doug pick out one that meets spec.

 

Thanks.

 

Your thoughts on the options of

 

"Matched Gain",

 

"Balanced Triodes Phase Inverter", and

 

"High Gain"

 

for my needs?

[myles_rose]

Personal taste and preference.

[Caevan O’Shite]

Personal taste and preference.

 

I was thinking/hoping that a higher-gain driver-tube (that also tested for having at least 1.0mA of plate current output) would drive the NOS Tesla EL34, OT, and speaker that much harder for more overdrive/distortion/compression for leads when both the amp and the guitar's volume-controls are cranked.

 

Would that be the case, or will a higher-gain 12AX7 driver either be wasted, or even hurt my dynamic "play the amp" touch-sensitivity?

 

THANKS AGAIN, AGAIN, for your time and effort, Myles- I just really want to get this RIGHT!

[myles_rose]

With only a single output tube your driver will have no problem pushing the output tube. It is not the gain of the driver tube you are concerned about, it is the plate current. They are different things.

 

The touch sensitivity of these single ended class A amps is what they are prized for, pretty much regardless of tube selection.

[Caevan O’Shite]

With only a single output tube your driver will have no problem pushing the output tube. It is not the gain of the driver tube you are concerned about, it is the plate current. They are different things.

 

The touch sensitivity of these single ended class A amps is what they are prized for, pretty much regardless of tube selection.

 

Thanks!

 

It's gonna rock and my blues will (almost) blow a fuse.

 

[Caevan O’Shite]

So, I carefully swapped out the JJ EL34 at V3 in my Fuchs Lucky 7 for a NOS Tesla EL34 (from KCA NOS), and replaced the stock Ruby 7025 driver at V2 with a brand-new Sovtek 12AX7LPS.

 

I let it warm up.

 

I adjust the bias as per the manufacturer's instructions.

 

Smells a little hot- seems to be the NOS Tesla EL34, but no red-plating or anything unusual.

 

Double-check the bias.

 

Plug in a guitar, roll the controls on the amp up, lightly, tentatively hit a chord, and...

 

Horrible, crappy sounding crackling blatz results from playing.

 

I power down, carefully change the output-tube/V3 back to the JJ. Problem remains.

 

I power down, carefully change the driver-tube/V2 back to the Ruby. PROBLEM REMAINS. (With all original tubes.)

 

I swapped instrument-cables and checked the speaker and speaker-connection. I swapped-out the tube at V1. Problem remains.

 

 

The amp was working fine a few days ago, playing at 'band/gig levels', with a band at a gig, with the amp connected to an AC outlet that I'd tested, which was fine...

 

 

I'm so p!ss3d frustrated right now- practice tomorrow night, and gigs (albeit for peanuts) next Friday AND Saturday... !?

[myles_rose]

Did you also replace the new power tube with whatever you had in before?

 

Never mind. I did not read the post slowly enough.

 

I am not sure what to check but if there is a 1.5K 5 watt resistor on the output tube socket check it. It is the grid resistor and may be blown. If it is a 470 ohm of less wattage let me know.

 

 

 

 

[Caevan O’Shite]

Did you also replace the new power tube with whatever you had in before?

 

Never mind. I did not read the post slowly enough.

 

I am not sure what to check but if there is a 1.5K 5 watt resistor on the output tube socket check it. It is the grid resistor and may be blown. If it is a 470 ohm of less wattage let me know.

 

 

 

 

Will do! THANKS! I'll let you know.

 

Most "normal" people just do not understand what it means for me to be able to play, to have an amp or guitar go down like this, to be worried that I won't be able to afford repairs, parts, replacements after I already laid out a $h!tload of money for my guitar and gear... on top of having to get a cracked neck/headstock... Thank you for all your help.

[Caevan O’Shite]

UPDATE: Maybe I'm just not so sharp- maybe I'm reading the bias wrong or something? 'Cause if I adjust the bias "by ear", keeping an eye on the stock JJ EL34 for red-plating or anything odd, the crackle goes away, hum goes away, and it sounds a LOT stronger... I'm going to try it with the NOS Tesla...

[myles_rose]

If you can adjust by ear and it sounds good and there is no red plating you are in business and good to go.

[haywired2]

Good afternoon Myles,

 

In order to reduce power in a four EL84 amp , Peavey Classic 30, can you remove 1 or more of the tubes to obtain this without hurting anything? I've heard of being done, but have never tried it.

 

Thanks

Scott

[myles_rose]

Good afternoon Myles,

 

In order to reduce power in a four EL84 amp , Peavey Classic 30, can you remove 1 or more of the tubes to obtain this without hurting anything? I've heard of being done, but have never tried it.

 

Thanks

Scott

 

NO. You cannot do that. You will destroy the output transformer and what you are talking about is even worse in a cathode biased amp as the bias supply network expects four tubes to be in the circuit.

 

In a grid biased amp you can remove one pair in a quad (generally the inner or outer tubes) and then plug into the jack or set the amp for half the impedance of the speaker cab. You can do that but it is not a good idea for many reasons. I talk about this on my GAB website.

 

BUT ... to repeat ... you cannot NOT do this on your Classic 30 and NEVER remove only one tube in any amp. Ever.

 

Anybody that ever actually has done this ended up with a big expensive repair on a Classic 30.

 

[haywired2]

Good enough. Thanks.

[CouchBed]

Who want's to cut power anyway? Turn it up!

[haywired2]

Who want's to cut power anyway? Turn it up!

 

 

LOL!!!!!!!!!!!!!!!!!!!!

Nothings ever too loud for me, even after all these years, but some of the places I play are pretty small sometimes.

[CouchBed]

I hear ya'.

Not much is too loud for me.

On the other hand, I'm still living at home, and there are a lot of things that are too loud for my mother.

[davidm]

Hi Myles,

 

The midrange controls on channel 1 and channel 2 are greatly increasing the volume level when I increase their levels on my Quiana Reverb. Channel 2 is also cutting in and out and distorting. Channel 1 doesn't seem to be as affected, aside from the midrange issue. The amp was serviced a couple of months ago. My tech replaced and biased the power tubes with matched JJ 6l6GCs. He also replaced a microphonic V4 preamp tube with a JJ as well. The amp has been sounding terrific since then. Do you think this is a preamp tube issue? If so, which one do you think might be the most likely culprit?

 

Dave

[myles_rose]

Hi Myles,

 

The midrange controls on channel 1 and channel 2 are greatly increasing the volume level when I increase their levels on my Quiana Reverb. Channel 2 is also cutting in and out and distorting. Channel 1 doesn't seem to be as affected, aside from the midrange issue. The amp was serviced a couple of months ago. My tech replaced and biased the power tubes with matched JJ 6l6GCs. He also replaced a microphonic V4 preamp tube with a JJ as well. The amp has been sounding terrific since then. Do you think this is a preamp tube issue? If so, which one do you think might be the most likely culprit?

 

Dave

 

Take a known good 12AX7 and start at V1. Replace each preamp tube one at a time. It could also be a power tube issue in regard to the amp cutting in and out. Just because tubes are new it does not mean they are good.

 

If this was not an issue before you took your amp to the tech take it back and make him fix it. If he does not fix it please post his name and contact info.

 

Side note .... The Quiana is a wonderful amp that can have a great vintage tone. This will be compromised with JJ 6L6S tubes which are edgy and gritty. These are better suited to a Mesa Recto, 5150 or SLO100 type amp. Get some nice 6L6s for that amp and some nice NOS medium plates in V1 and V2.

 

[davidm]

Thanks Myles, I'll try swapping preamp tubes tonight. I agree, the Quiana is a really nice amp.

[myles_rose]

Thanks Myles, I'll try swapping preamp tubes tonight. I agree, the Quiana is a really nice amp.

 

The Quiana is one of my favorite amps on the planet. My friends that play them love channel 2 (or seem to use that channel the most) but I love Channel 1, the clean channel, with the master turned all the way up (get it out of the circuit) and then just play. The way Paul Rivera utilizes the first tube in the first gain/tone stage is somewhat unique so he gets more current drive and less squashing and compression when cranked up. It also means that pedals with high output level settings don't overload the front end as quickly so the amp is very pedal friendly. In the end it is an amp that you will have for decades as even if you want something different than the higher gain channel all you do is grab a new pedal and use channel 1 and you are in business with a new amp in a manner of speaking. Some amps are great foundations and this is one of them.

[Fred_C]

Hey Myles,

 

If you read the forum posts, you are probably aware that I just scored an Ampeg GVT15-112.

 

Like most players, I seek the "Jazz Holy Grail of Tone". I want a tone that is:

 

1. CLEAN!!!

2. Smooth

3. Liquid

4. Mellow

 

The tubes in the amp are as follows:

 

2-6V6

2-12AX7

 

Could you make any recommendations regarding tube substitutions that would contribute to achieving that tone?

 

Thanks for your help.

 

_________________________

If you play cool, you are cool.