New Dual Rectifier Roadster Troubleshooting- No Power

[Coleo]

Hi Everyone- I took the plunge and purchased a dual rectifier roadster off ebay that was apparently new and when it arrived there were a few things:

1 of the 6L6 tubes (#3) tubes was rattling
When I turned it on, there was some fizzing across all channels

Today I went and picked up a 12AX7 to see if there was an issue in the first pre-amp tube like on my previous DR and to my dismay there is virtually NO POWER! Like all the gain, master and output on all the channels had to be near full to get anything out of the amp! All the tubes were glowing but nothing from the guitar was coming through. I went direct from guitar to amp, swapped cables, swapped power outlets, etc. and nothing. I switched from spongy to bold, 50-100W and same same.

Any clues as to what this could be? I obviously want to play this thing but I guess have a warranty issue now which scares me.

thanks!!

 

[Addictedtokaos]

Is your speaker cable connected to the proper jacks for both amp and cab?

If you loop is active on all channels make sure the send level is not set too low.

Also, make sure the tuner mute is not on.

If all that checks out I would suspect the power tubes next. They are matched pairs. I believe with the roadster they are paired outters and inners.

Dont mix them up, and with the amp off (unplugged to be safe), take one set out (two outside power tubes) and put them to the side.

Next take the remaining two out of their sockets and put them into the outer sockets.

Put the first two you pulled out into inner sockets.

Set it to 50w and power the amp up, check for sound. If you get sound you know you have a issues with one of your sets. If this is the case i would guess it would be the set that is now in the inner pairing.

Check out https://www.youtube.com/watch?v=wSl-l9aWDHw#t=89. I recommend watching the entire video if you are new to tube amps. 7:20 it starts about power tubes.

 

[Coleo]

Well the speaker cable was not removed from the cabinet as all I did was take out the old dual rectifier and put the new roadster on, into the same impedance, so I feel that is not the issue.

I tried disconnecting the footswitch as well so I don't think it's tuner mute. The send and receive are at midway.

Yes correct they are outer and inner pair matched.

So here is a question, if one of the tubes in a pair or both tubes in a pair are fried/faulty, will the amp have some power/volume or no power/volume or does it depend on which 50w/100w setting I choose?

Thanks for your input.

 

[Addictedtokaos]

Before we go any further. I think I skipped the obvious. Before you swapped preamp tubes or v1 was the amp fine just a little hissy? take the new V1 out and replace it your old v1. Its possible you got a bad new 12ax7.

If putting the old V1 and/or old 12ax7s back in still results to no sound then continue with the power tubes.

So here is a question, if one of the tubes in a pair or both tubes in a pair are fried/faulty, will the amp have some power/volume or no power/volume or does it depend on which 50w/100w setting I choose?

If you set the amp to 50w, only the outer (V9 and V10) are being used by the amp. IN 100w all 4 power tubes are used.
http://www.mesaboogie.com/manuals/Roadster_130613.pdf see page 36 of the manual.

So by switching the sets and only using 50w mode you can eliminate if one set has an faulty tube. Because you said the issue is in both 50w and 100w the current outer set were already tested. . There is always a possibility that 3 or more tubes are faulty and why its a good idea to have a least 1 set of matched tubes you know are working for backups and troubleshooting.

 

[Coleo]

Yes it was working normally but just a little fuzzy on all channels. I used 2 other 12AX7s from the other dual rectifier that was working fine with no change, so think I've ruled out the faulty new 12AX7.

Thanks for clarification on which tubes are working on which setting. I am going to test this out tonight. So if I am using the 50W setting and V9 and V10 are powering the amp, if one of those tubes is bad, would that cause the problem?

 

[Addictedtokaos]

Im assuming it was shipped. It could have been damaged during shipping or is just burnt out from use. Tubes are similar to light bulbs where you go to turn them on or off one time and they're done or after hours and hours of use they barely produce any light, or in this case sound.

Is this your first tube amp? are you letting the amp warm up in standby for approx 30 seconds? Have you taken the time to read the manual?

 

[Coleo]

Yes I have owned a half dozen tube amps or so but have never really had to trouble shoot before. I am very conscious of warming up for at least a few mins if not more.

So what I thought was a new amp purchased last month was originally shipped in Jan 2011 to a guitar center, so the tubes are over 3 years old. It is possible it was a floor model sold last month, but the tubes are definitely not brand new, unused. I spoke with Mesa this morning and they gave me some good trouble shooting tips, so I will try those tonight I guess and see if I can further pin point it. :evil: :shock:

 

[jbird]

The thing that gets me is shipping with the tubes in it? Have you asked the dealer for new tubes, or reimbursement for replacements?

 

[Coleo]

Test 1: replaced V2 with a newish groove tube 12AX7 that was newest in previous rectifier and switched the loop to hard bypass per Mesa customer service this morning and voila! All 4 channels have Sound! Once I switch hard bypass to footswitch, no sound whatsoever.

Test 2: Took working 12AX7 out of old rectifier and put it in the V6 slot. Volume when hard bypass, but when switch flipped there is guitar sound, but at 1/10 volume and horrible hissing fizzing popping sound on all channels.
Test 3: Took other 12AX7 per above and put in V5. Volume when hard bypass, but when switch flipped there is guitar sound, but at 1/10 volume and horrible hissing fizzing popping sound on all channels.

Test 4: Swap inner power tubes to outer power tubes on 50 W.
-w bypass on at 50W on all channels, all 4 channels work, but still no control on main output, and solo does not work.
-w bypass on at 100W on all channels, all 4 channels work, but still no control on main output, and solo does not work. I had both controls all the way to down, and was still reasonably loud
-w footswitch mode engaged, same as above, amp loses volume and gets crackly.

Anyways I'm sick of pulling tubes now and just want to play it. It looks like there is likely a need for new tubes.

 

[knotts]

Sounds like shipping did a number on the tubes. If it's in the budget, simple fix is to retube the whole thing.

 

[Coleo]

Yup agreed. With only $50 put on the entire amp for insurance, it's definitely not in that budget, so will see. Regardless, it needs tubes.

 

[Authorized Boogie]

From your testing, it seems you've forgotten a few things we talked about ; )

With the loop engaged, put a short patch cable from the fx send to the fx return - as I mentioned when we spoke on the phone. If you get full volume, the fx send/return jacks need cleaning. spray some contact cleaner on the tip of a 1/4" plug and run it in and out of each jack 4-5 times.

Also, you may want to read the manual a little more thoroughly. In your tests you mention that the output and solo controls don't work when the fx loop is on bypass - this is normal, as they are only on-line when the loop is engaged.

Otherwise, it seems like the V2 tube was the problem. (And, as I recommended - to be thorough, run a new/known good preamp tube through EACH position, one position at a time.)

Thanks!

 

[Coleo]

Oh I didn't forget, though I was very excited to get it working so got sick of taking the hot tubes out for each preamp tube. I will be doing the test for patch cable tonight.

And I did actually read that after my test and deleted it from the post when after I originally wrote it, but for some reason it ended up back in the post. I figure there was something to that and it makes sense now.

I'm going to take it in to our dealer here and they have offered to test the tubes again, but definitely it will need some fresh tubes.

 

[Authorized Boogie]

Good to hear! Keep us posted!!