Jump to content
Faerwald

Spider Valve MkII HD100 tube issues - questions.

Recommended Posts

Hey everyone.

 

So this is my first tube amp, and it was working great so far.

However, Yesterday during band practise, after it had been on and working perfectly for two hours, the volume suddenly dropped. When I checked the amp to see what was going on, I noticed that one of the tubes (the one on the left) was way hotter than the others. when I turned down the volume, where was a small lightning inside the tube, and then no sound. From what I've gathered from the internet, the tubes weren't paired or biased properly. When the amp is on, the other tubes light up normally.

 

Anyway, when I bought the amp, the people at the store had only two tubes installed (the two in the center), to cut the output down and make it playable in the store.

 

I wanted to know if there is any specific manipulation to do in order to do that. (I have a gig in 4 days and I probably won't have neither time nor money enough to have the tubes changed and the amp biased before then). 

 

 

Share this post


Link to post
Share on other sites

As I recall, impedance doubles when you take two tubes out of a four tube push-pull power amp....Not recommended...

 

4 ohm output becomes 8 ohms nominal

8 ohm output becomes 16 ohms nominal

16 ohm output becomes 32 ohm nominal

 

If you do this, and 8 ohm load in the 4 ohm output is technically, the safer bet....Still not something I would do...

Share this post


Link to post
Share on other sites

It may be only that it's time for a tube change out and bias. Good idea to do that once every

12-18 months if you're a performing musician. Have it checked out at a Line 6 authorized service

center in your area, that knows tube amps.

 

Sales person should have never pulled two tubes out of it,...  much less the wrong two tubes. It

offset the push-pull symmetry. That and how long they've been in the amp is probably why the

one tube was hot.

 

Don't try to deal with it yourself, it hurts when you get zapped. Take it in to a service center, have

the right tubes put in and biased by a tech.

Share this post


Link to post
Share on other sites

I'm definitely getting a tube change and bias, I was just wondering if the "two tubes out" solution would work as a temporary solution in case I could not get it done before the upcoming gig.

 

I guess I'll just have to find a tech to do it tomorrow

 

Thank you for your answers!

Share this post


Link to post
Share on other sites

"I was just wondering if the "two tubes out" solution would work as a temporary

solution in case I could not get it done before the upcoming gig." ----

 

No!

Don't do that.

 

These aren't our grandfather's tube amps, these are mixed technology amps,

you can't get away with this sort of thing like we used to in the old days. They

are not designed to do that.

Share this post


Link to post
Share on other sites

And use the specified Sovtek 5881WXT, matched quartet tubes.

 

No JJ's, Mesa's or Groove Tubes,.... if they are biased the same

as the 5881WXT, there will be problems, the characteristic curves are

not matched close enough for use in this amp.

Share this post


Link to post
Share on other sites

Be sure to use the correct impedance output for the cabinet that you are using.

They have to be matched or the tubes and circuitry will get stressed,... and then

it will end up on a technician's bench. And that's no fun.

 

Keep your fingers out of the inside of the amp,... even with the power off, a capacitor

can discharge into your hand, and that hurts like hell.

Share this post


Link to post
Share on other sites

And use the specified Sovtek 5881WXT, matched quartet tubes.

 

No JJ's, Mesa's or Groove Tubes,.... if they are biased the same

as the 5881WXT, there will be problems, the characteristic curves are

not matched close enough for use in this amp.

 

This is a contradiction....You must be new...

 

http://line6.com/supportarchivenew/thread/74881/

Share this post


Link to post
Share on other sites

No, I'm not new,... the thread is out-of-date. I'll let Dave know, thanks.

I've been dealing with Spider Valve since the beginning, been dealing

with tubes and tube amps for more than four decades.

 

The characteristics curves of the JJ's, Mesa's and Groove Tubes

are not close enough. If those are biased the same to the

bias settings for the 5881WXT's,... then the amp ends up on

my bench with problems. Can't use the same bias settings on these

other tubes as with the 5881WXT.

 

I see too many come back because of the wrong tube and/or bias settings.

This is a mixed technology amp. You can't get away with the same

sort of things we used to get away with for Marshall amps with 6550's

in them.

 

These amps are not as forgiving as the tube amps of yesterday-years.

It's a Bogner hot-rod.

Share this post


Link to post
Share on other sites

New Sensor (Sovtek) 5881WXT is actually a 6Π3C-E and nothing like a real 5881....It's more like a 6L6 actually.....A JJ 5881 is actually a real one...23 watts and SV's plate voltage is too high for it...a mistake to put real 5881s in an SV....

 

The following branded tubes are the same 6Π3C-E bottle......

 

Fender 6L6 Precision Matched Tubes (5881WXT)

Fender GT-6L6B or 6L6R (5881WXT)
Groove Tubes GT-6L6B or GT-6L6R (5881WXT)
Marshall 5881 (5881/6L6 WGC)
Mesa Boogie STR425 (5881/6L6 WGC)
Ruby Tubes 6L6R (5881/6L6 WGC)
Sovtek 5881/6L6 WGC
Sovtek 5881WXT

Share this post


Link to post
Share on other sites

The Sovtek 5881WXT is what Rheinhold Bogner spec'd for this one (Spider Valve series).

The Sovtek 5881/6L6 WGC doesn't have the cup at the bottom which created problems with tube retainers

so we don't use those anymore.

 

People want the crunch of a Mesa tube, unfortunately too many with Mesa tubes come back with problems.

JJ's and GT's also come back to us with problems, and things like the bias being way off-spec.

 

The Sovtek 5881WXT is what Rheinhold Bogner spec'd for this one (Spider Valve series). There are interactions

between the digital portion and the tube portion, such that, it is not as forgiving as old 60's as 70's tube amps.

You can't get away with the same deviations with these as we used to with older tube amps.

 

 

We have our tubes go through some extra scrutiny.

Best to stick with the specified tubes,... less problems that way.

Share this post


Link to post
Share on other sites

I noticed that my SV HD100 had Sovtek 5881WGCs installed when I bought it. Since then it has undergone tube replacement. Besides the cup, is there any tonal difference in the Sovtek 5881WXT vs Sovtek 5881WGC?

 

How much of the tone actually comes from the power tubes vs the preamp tubes? I understand that there is a very specific set of rules for preamp tubes in the SV HD100 as well. Should you always have the same preamp tubes ion V1 and V2? I recently was informed by a Line 6 team member that I could really only safely use SHU GUANG 12AX7B, SOVTEK 12AX7LPS or electro-harmonix 12AX7EH.

 

This amp really impressed my when I played it in the store, but soon after I discovered that after about 20 minutes of playing the sound becomes less edgy with a loss of volume. I can adjust the knob and the volume returns, but the original clarity and bite are no longer present. Could this be a tube issue? As I said I had the tubes changed with a match quartet of Sovtek 5881WXTs and bias adjusted.

 

I would love to have the that original presence and crisp sound back.

Share this post


Link to post
Share on other sites

"Besides the cup, is there any tonal difference in the Sovtek 5881WXT vs Sovtek 5881WGC?"---- No, purely structural.

Early spring retainer pressure had a tendency to crack the tubes, bear trap retainers scratched and weakened the glass.

The base cup solved both problems.

 

Electro-Harmonix 12AX7EH are low microphonic and stable, as are LPS, and the China-B is good. I'm an EH fan myself. 

 

"... after about 20 minutes of playing the sound becomes less edgy with a loss of volume. I can adjust the knob and the volume returns, but the original clarity and bite are no longer present. Could this be a tube issue?"--- If the tubes have not been changed in two of years,... yes. Tone,... the digital section and the analog tube section talk to each other and balance each other out. And being that it's after 20-minutes,... it take about 20-30 minutes for a tube amp to fully warm up and level out. One of the reason we turn on the sound set-up  an hour before a concert and did sound checks a 15 to 30 minutes before the concert (back in the mid 1970's when I crewed for Iron Butterfly). Nature of the tube beast. 

 

Presence is a useful setting for the crispiness.

 

Share this post


Link to post
Share on other sites

I have a SV HD100 (not the MKII) and I am experiencing volume swings.  The volume will go low at times intermittently and any time I change a channel or preset the volume goes thru the roof. Is this a power tube or preamp tube issue or is it both?   I do need to change the tubes, any recommendations on what to use?

Share this post


Link to post
Share on other sites

Use the specified 12AX7 preamp and Sovtek 5881WXT matched set the power tubes. Do not use substitutes,

as these are not all analog tube amps.

 

 

And do it soon, don't continue using it at this point until the tubes are changed out.

Have it done at a Line 6 authorized service center, so they can do a thorough going

over to it. And they will have access to me in ways others don't, for further deep dive consulting if they wish it. 

 

 

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


×
×
  • Create New...