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GB Shuttle 6.0 Tube Swap - done it/do it?

#41
I replaced mine with a Penta Labs tube from dougstubes.com. It's basically a select Shuguang (chinese) tube. I used to really like the Sovteks, but I found I liked these even better. Anyway I was surprised to find that the Shuttle ships with a Ruby tube. My experience was that it made an improvement, but not to the same degree that I've experienced with replacing the Groove tubes in SWR amps.

Ralf
 
#43
Okay, guys. swapping out the stock Ruby Chinese tube with a better one DOES make a difference. You can tell that the preamp circuit WAS designed for the sound of the preamp tube, as Agedhorse has noted.

I used a premium balanced 12AX7LPS. It is excellent. It has really smoothed out the tone, and the head is very responsive to playing nuance. There's more sustain and power.

The input moves into tube clipping more gradually, and the overdriven sound is very pleasant.

Although testing for balance is supposed to only be important for certain 12AX7 applications, it probably makes a difference for well-designed bass preamp section use as well. All notes seem to have more power. Higher notes on the D and G strings have more low frequency content and punch.

I've played the Shuttle into most of my current cabs in the house. It sounded great with both the Bag End S15's. With the M-Line Wizzy, there was a lot of midrange push that I had to dial out. I've currently got it hooked up to the Dr.Bass BL1260, which sounds terrific. I've haven't played into the Carvin LS1503LF, that's today.
 
#44
Earlier I described the marked improvement by replacing the Ruby tube wtih a JJ ECC83 S. I found a Telefunken 12AX7 ECC83 Smooth Plate tube on eBay and decided to try that given its reputation and other statements on this thread.

WOW! The difference in aural quality was as marked as when I moved from my Eden WT330 to the Shuttle 6.0. The Telefunken is hotter so the signal is louder. Even creamier, warmer, and much greater nuance is apparent in tones, especially with my wooden Steinberger modified to sound like an upright. Another byproduct is EQing requires more subtle nudges to the knobs. Everything is running more toward the flat position than with the JJ, which in turn required less EQing than the Ruby.

I felt no indecision or need for trial on this one the instant I powered up the new configuration. The Telefunken is an amazing tube for the Shuttle 6.0. Mine cost $55 plus shipping. I'm surprised at the huge difference in tone and am happy I proceed with the switch. Happy?--estatic is a better word. WOW!
 
#46
5StringPocket said:
I looked for Telefunken 12AX7 ECC83 tubes and found short/long plate and 14/17 mm sizes. Is 17 mm the size and does long plate make any difference?
Click to expand...

Can't say what the size is in mm as it's installed and out of sight. Wouldn't be sure what to measure! The tube is a few millimeters shorter than the JJ and Ruby tubes. It has two plates inside, unlike the JJ and Ruby which have multiple plates.
 
#47
MichaelVee said:
Agedhorse, please fess up about this. You knew that the preamp circuit was designed for the sound of the preamp tube, and it WAS.
Click to expand...

My guess would be that when you consider the large volume of tubes that Genz has to buy to put in their amps that they put it out to bid.

They have a certain spec they want to see in their front ends and the tube manufacture's submit quotes and usually the lowest price wins. Which doesn't necessarily mean you would end up with a not so good tube. BTW my GBE1200 also uses the Ruby.

Half the fun of owning a tube amp is swapping out tubes to see what you like. Another thing is always having spares available. My experience is that tubes usually crap out at the worst time. Preamp tubes are less prone to failure but they will go bad. I carry a Groove tube 12AX7 gold series as a backup just in case.
 
#48
Interesting thread! I've got a couple JJ's here... one ECC 83S, and one ECC803S. I noticed in the post above with all the tube reviews that the 803S is a "hotter" tube. Could that potentially mean more clean headroom? I'm a complete tube noob, and won't have a chance to try it out till Thursday night. Anyone else try these 2 tubes?
 
#49
alembic5 said:
Interesting thread! I've got a couple JJ's here... one ECC 83S, and one ECC803S. I noticed in the post above with all the tube reviews that the 803S is a "hotter" tube. Could that potentially mean more clean headroom? I'm a complete tube noob, and won't have a chance to try it out till Thursday night. Anyone else try these 2 tubes?
Click to expand...

Yeah I did tried both the ECC83S and ECC803S. The 803 is the "high gain" tube. The result was that this one (803) distort very easily and seemed better suited for guitar use than for bass. It sounds thin compared to the ECC83S.

I made a tube shootout page on my website if you're interested in hearing the clips I made to compare them. That was made a long time ago but should make you hear the differences.

http://www.martinletendre.com/preamp_tubes.html

Let me know what you think.
 
#50
1kinal said:
I made a tube shootout page on my website if you're interested in hearing the clips I made to compare them. That was made a long time ago but should make you hear the differences.

http://www.martinletendre.com/preamp_tubes.html

Let me know what you think.
Click to expand...

Very cool of you to share with us! They all sound very different but none of them particularly bad. Although the Sovtek does seem a bit noisy/gritty where the JJ's are clear.
 
#51
60bass said:
My guess would be that when you consider the large volume of tubes that Genz has to buy to put in their amps that they put it out to bid.

They have a certain spec they want to see in their front ends and the tube manufacture's submit quotes and usually the lowest price wins. Which doesn't necessarily mean you would end up with a not so good tube. BTW my GBE1200 also uses the Ruby.

Half the fun of owning a tube amp is swapping out tubes to see what you like. Another thing is always having spares available. My experience is that tubes usually crap out at the worst time. Preamp tubes are less prone to failure but they will go bad. I carry a Groove tube 12AX7 gold series as a backup just in case.
Click to expand...


Has absolutely NOTHING to do with the cost of the tube. It has to do with the overall average quality of sound to the design team's ears with a large sample of tubes from a typical production lot.

It has to do with availability... notice how many out of stock "premium MARKETED" tubes there are. If they are not available, then they may as well be made of unobtanium.

It has to do with reliability and consistency from tube to tube in a production batch.

It has to do with mechanical stability, the ability to refrain from microphonics in a bass amp used as a combo, subjected to high vibrations which can cause ghost notes as the grid vibrates with the note and modulates the electron stream unintentionally.

It has to do with long term reliability, we like to see an expected lifespan of around 10-12 years for the average user even though the tube itself has a more limited warranty. Our selection process and product history show this to be a reasonable expectation. I also have some tubes that have been running off and on for almost 30 years and still perform just fine.

It has to do with an optimum transfer curve and plate current curve for the specific circuit the tube is used in. This leads to reliable and stable long term performance.

It has to do with the noise floor that the tube generates, a noisy tube, no matter how "fancy" is still a noisy tube.

There are plenty of absolutely awful NOS tubes out there, I have a box FULL of fancy NOS tubes (probably many thousands of dollars worth when valued at "collector's prices" and there are a good many dogs in there that collector oggle over. Just because you pay $100 for a tube of unknown specifications doesn't mean it's really a $100 tube.

With regards specifically to the 12AX7LPS, we found that without special screening there was WAY to wide of a variation of several parameters that adversely affected the performance and reliability in some of the preamp circuits I have designed for bass products (in general). While a fine tube for some circuits/applications, I can not recommend this for use in the NeoPak, GBE and Shuttle preamps. What makes it good for one application makes it a poor choice for another.

Use your ears when deciding if the the tube swap really makes as much difference as expected/hoped for. Be sure you aren't hearing somethingthat isn't there. As a development engineer, one of the best pieces of advice I ever learned was from an old timer back when I was starting out who always warned me to be sure I was listening to what was really happening not for what I hoped was happening. He switched some things around without my knowing on a listening test and I made enough of a fool of myself to remember that lesson today... long since he passed away. He was indeed a smart old man. ;)
 
#52
agedhorse said:
With regards specifically to the 12AX7LPS, we found that without special screening there was WAY to wide of a variation of several parameters that adversely affected the performance and reliability in some of the preamp circuits I have designed for bass products (in general). While a fine tube for some circuits/applications, I can not recommend this for use in the NeoPak, GBE and Shuttle preamps. What makes it good for one application makes it a poor choice for another.
Click to expand...

Aged, that was a very well written post. Thanks for sharing the tube selection criteria. It's always good to get your input as the GB design engineer when we players start our desultory dissections of the Genz heads!

I've rewritten my original post above to tone it down a lot and also to share some information about what I heard when I started playing through the LPS tube.

Obviously, Genz is going to use the tube that generally works the best, is most reliable, and will sound good to the majority of purchasers. This makes a lot of sense both from a business as well as a sonic standpoint. I have said previously that I liked the sound of my Shuttle a lot, right out of the box. Doug, from dougstubes.com, also said the Chinese Ruby tubes are a good sounding, solid tube.

The fact that Alembic has used them in the F-1X and F-2B preamps says a lot as well.

So, I do validate and agree with what Aged, Doug, and others have said. I also know that this particular, select, Sovtek 12AX7LPS made a big difference in the tone. I played the amp before and after the tube swap, same bass, same cab, same volume level. It's not the "anticipation" or "snake oil" effect.. as a musician, I heard the difference. The instrument sings- a lot more flow in the sound.

Is there a fair amount of quality control and material variation in modern tube manufacturing? Is there a luck factor involved in getting a really good tube out of a batch of 10 average ones?

As end users, there are lots of things we don't know. The magic of tubes.

The Shuttle preamp is designed for tube coloration of the sound, so a really good tube is going to be audibly better. From a number of other posts in this thread so far, players are finding this to be true.

I love the way my Shuttle sounds with this new tube. It's the sound I've been looking for in a small amp head instead of the preamp/amp rack.
 
#53
The other thing I was going to mention in the previous post before it got so long is the interaction of all parts of the bass signal chain prior to the tube also has a lot of impact on the variables of tube sound.

It could certainly be that someone might sit down at my Shuttle 6/Dr.Bass setup, and plug in a high-power MTD 535 and the sound would not agree with them. On the other hand, we might all be blown away!

This current signal chain is my passive XZ-25 with stock EMGs, the HAS Sound Varitone harness, roundwounds, and a Bayou Cables Neutrik/Canare cable. I'm also experimenting with adding in the Seymour Duncan SFX-01 pickup booster pedal. Previously, I really couldn't hear a lot of difference in the 1 and 2 settings on the SFX-01, but now I can. The SFX-01 is a very nice, hi-fi preamp pedal, especially with a fresh 9V!

The Dr.Bass BL1260 has an Eminence Deltalite 12" neo swapped in. The new tube is causing the Shuttle to produce enough additional bass that I'm having to roll off the Shuttle low control, which is a new experience.

The new tube is a strong component in the signal chain. If all the signal is passing through it, then this explains what I'm hearing.
 
#54
All of the signal passes through the tube.

The variation within some brands/models of tube are so great that you can end up with one great one, a couple ok ones, some not so good ones and some terrible ones. That's part of why we use the tubes we do. We use (some) different tubes for the guitar amps, especially in the V1 position. Different tubes make more of a difference (in general) in a guitar amp (more gain designed into the circuit) as well as that different circuit designs are employed because low frequency microphonics are not as big of a deal.

When changing tubes in a Shuttle, be sure to tighten the bracket so that it remains perpendicular to the tubes longitudinal axis and the vibration damper is in firm contact with the tube body.

When changing tubes on the NeoPak and GBE's, be sure to hold the standoff when loosening the tube retainer. The standoff must be tigntened to the PCB before tightening the retainer screw.
 
#55
agedhorse said:
When changing tubes in a Shuttle, be sure to tighten the bracket so that it remains perpendicular to the tubes longitudinal axis and the vibration damper is in firm contact with the tube body.
Click to expand...
Ummm.... tighten the bracket? I, er, um, just kind of bent it a tiny bit to get to old tube out and bent it back again with the new tube. Am I doomed now? :rollno:

This was actually a troubleshooting exercise to determine why the output was dropping out. Turned out to be a little oxidation in one of the jacks. Ultimately solved with a bit of contact cleaner on a Q-tip, with one of the GB guys on the phone. (Thanks for that, guys!) I didn't notice any tone difference after the tube swap though. Now I'm curious, and I still have the original tube. Experimentation required!
 
#56
Fretster, the retaining bracket is secured with a hex nut. I used a hex socket from my computer toolkit to loosen it, I rotated the bracket, then tightened the nut back in with the socket tool after I replaced the tube.

Aged- thanks for clarifying that all the signal passes through the tube. It's obvious that the tube circuit in the Shuttle is not a gimmick!

Does a certified balanced tube make a difference in the Shuttle preamp design, then?
 
#57
MichaelVee said:
Does a certified balanced tube make a difference in the Shuttle preamp design, then?
Click to expand...

No difference at all, it's not used as a phase inverter, or differential amp/long tailed pair.

Certified balanced... at what current? The curves aren't all that linear so you end up matching parameters at some point on the curve. Not knowing where on the curves the maching takes place, it's pretty useless IMO. (jus tthe engineer in me talking... pretty good marketing idea though ;) )
 
#60
as the person that has final sign off on product, I can tell you that price has nothing to do with tube choice- I know Andy covered that in his post too.

Reliability is HUGE. Then, tone over a large sampling. I can roll tubes all day long between brands and find variances in tone. Also, I can roll them all day long with only one brand and find variances.

As of recently, I now manage all distribution for Groove Tubes in North America. If you want to get an education in tubes......man. :eek:
 

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