Genz Benz Streamliner Tube Rolling

[erdosi3]

Hey,

I recently bought some new tubes and I wanted to test them in my Streamliner 900 also. A few pieces of Sovtek 12AX7LPS and Tung-Sol 12AX7. Both worked fine for a few minutes then they started to get more and more quiet until produced no sound at all. Switched off the amp, pulled the tubes out, reinstalled the previous set and like nothing happened, the amp works fine.

Ok, that means I have some bad ones, I thought. Then I tested them in a tube tester and installed them in my other amps, they test ok and work perfectly in other amps.

Also tried different pieces from the same type in the Streamliner and after a few hours they still work fine. Only 1 specific tube from both manufacturers do not work.

Any ideas what could be causing this?

 

[SeayBass]

I'm not sure I understand your issue- you have tubes that test good and work in other equipment that didn't work one time in your Streamliner. Is that correct?
Every other tube and every other Streamliner experience is fine, and the questionable new tubes work fine everywhere else?

Could it have been a one-time 'loose power cable in the back of the amp' type problem? Or a 'tubes installed loose' type problem?

 

[agedhorse]

Hey,

I recently bought some new tubes and I wanted to test them in my Streamliner 900 also. A few pieces of Sovtek 12AX7LPS and Tung-Sol 12AX7. Both worked fine for a few minutes then they started to get more and more quiet until produced no sound at all. Switched off the amp, pulled the tubes out, reinstalled the previous set and like nothing happened, the amp works fine.

Ok, that means I have some bad ones, I thought. Then I tested them in a tube tester and installed them in my other amps, they test ok and work perfectly in other amps.

Also tried different pieces from the same type in the Streamliner and after a few hours they still work fine. Only 1 specific tube from both manufacturers do not work.

Any ideas what could be causing this?

I don’t recommend replacing tubes unless there is a REAL problem with the original tubes. They are very high quality and screened for low noise and long life (between 7500 and 10000 hours)

It’s not at all uncommon to find defective new tubes, I see amps from guys who rolled tubes in for repairs with replacement tubes that became defective after only a short while.

The most likely cause is one of those tubes is defective. My suggestion is to leave the amp alone before you break something else by accident. (I often see this as well).

 

[erdosi3]

I'm not sure I understand your issue- you have tubes that test good and work in other equipment that didn't work one time in your Streamliner. Is that correct?
Every other tube and every other Streamliner experience is fine, and the questionable new tubes work fine everywhere else?

Could it have been a one-time 'loose power cable in the back of the amp' type problem? Or a 'tubes installed loose' type problem?

Yes, that is correct. New tubes, worked fine for a few minutes in the Streamliner then they got more and more quiet. Pulled them out, they test ok and works fine in other amps. The amp works great with other tubes, just not with these two. Never had any issues before. I though it might be some kind of protection in the amp if the tubes are faulty, but they test ok for both halves in a tube tester, that's why it's weird. The power cable is secure and the tube sockets are well maintained, so they have a good connection.

I don’t recommend replacing tubes unless there is a REAL problem with the original tubes. They are very high quality and screened for low noise and long life (between 7500 and 10000 hours)

It’s not at all uncommon to find defective new tubes, I see amps from guys who rolled tubes in for repairs with replacement tubes that became defective after only a short while.

The most likely cause is one of those tubes is defective. My suggestion is to leave the amp alone before you break something else by accident. (I often see this as well).

Thank you for your input!
I bought the amp second hand from Germany last year in nearly perfect condition, but I think it didn't have the original tubes already, there was JJ ECC83S in all 3 positions.
The tone was too bass heavy for my taste so I tested a lot of variations, ended up with 12AX7LPS in V1, JJ ECC81GP in V2 and Tungsram ECC83 in V3. With these the tone is more balanced (to my ears), have those mids and high mids which helps to cut through the mix. Used the amp for a few hundred hours with this set of tubes without any issues and I really like the tone I have now.

 

[agedhorse]

The JJ ECC83S will work fine in all positions. The native voicing of the amp is quite bass heavy, that's unrelated to the tubes themselves.

Tube testers do not test the tubes at the voltages and currents that they operate at in this amp. It's one reason that we at Mesa have our own custom built high voltage tube testing machine (two of them actually). We find a lot of questionable results at higher voltages and currents which result it screen-outs that go back to the manufacturer to presumably be sold to their other customers with different standards that we have. We did much the same thing at Genz Benz, screening tubes according to their application.

 

[erdosi3]

In your experience, what brand produces reliable quality nowadays? Or at least have a higher level of quality control so no defective tube leaves the factory?
As far as I know there are only a handful of working factories today (Russian, Chinese, Slovakian) and many more companies specialized in selecting, matching and rebranding tubes.

 

[agedhorse]

All brands can produce good tubes, and some produce good tubes of one type but not as good of another type. It really depends on where the good tubes go (and also where the poor quality tubes end up.

Also, just because a tube as bad for one application doesn't mean that it's bad for all applications, further muddying the waters. This is why the cork sniffer guides to each tube brand, model and version in excruciating detail can be so misleading, it depends on where a particular tube falls in a production lot and across production lots.

We have had the same model tube with yields above 90% and we have had another lot with yields below 50%. Every once in a while we get surprised when we schedule production and shipments then discover that a particular tube lot falls well below our average number and we end up short on tubes. When this happens, there are delays in shipping amps (that are really out of our control, other than always buying double what we need so that in the event that we get a low yielding batch we are covered, but that can run into an additional $50k sitting on the shelf of a particular model (and we use multiple models). We use a LOT of tubes in a typical month.

 

[BassBeginer64]

I have had a few Streamliner's - 3 of 600's - 1 of 900, few that @agedhorse has even worked on with his magic, and still working and sounding great !
I did not know much about tubes way back when, but with the knowledge over the years have worked well for my streamliners and have found to my liking to use low gain 12AX7's in the V1, not a fan of the 5751 due to the gain are in the 60-70's, but 12AX7 in the high 80' or low 90's seemed to be the sweet spot and can run the gain easily at 12 noon and the gain volume about the same.
I Have used Tung sol, EX , Genalex China made are are ok, the Russian ones seem better in the V1. as for the V2 and V3 the JJ's are fine, 100 on the triodes does not seem to cause any issue but you can also order them in the mid 90's on the triodes and they are very quiet, JJ makes a good tube.,
I also have used a few mesa tubes, and as @agedhorse said they are tested , very good tubes indeed.
I test my preamp tubes using a maxi preamp tester on all my preamp tubes, be surprised how much new made tubes are junk that are missed labeled and noisy !

 

[HowieD72]

Personally, I love my Streamliner 900 stock standard! After getting an Andy upgrade, it sounds phenomenal!! Like a totally new & upgraded Streamliner. Very impressed! I'm actually looking for another 900 now so I can get the Andy upgrade & hold it for a rainy day.

I've found with my active Warwick Fortress Masterman basses & active p-bass, I can get the meanest lows, mids & crisp highs without much effort at all.

My equation: Genz-Benz Streamliner 900 + Barefaced 410 (tweeter less) cab + Fortress Masterman = Sonic Perfection!

(All of the above is IMHO. YMMV)

 

[erdosi3]

Can you tell us more about this upgrade?

I also use my Streamliner with a Barefaced Two10S and it is just great!

 

[agedhorse]

Can you tell us more about this upgrade?

I also use my Streamliner with a Barefaced Two10S and it is just great!

He’s talking about factory updates, it depends on when in the production cycle the amp was built, and if the amp had been serviced under the factory service program.

If you message me, I will get you the service program information.

It’s more difficult in the EU, but there’s a shop in the UK that can handle the work.