Help with tubes Roadster

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chomii

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Hello. I plan to retube my Roadster. I saw some retube sets on http://www.rototubes.com/Roadster-Trem-O-Verb/
I know that Roadster have fixed bias and they recomend Mesa tubes for Mesa amps. Do i need any additional moding or i can just install some of this sets and go play.
 
From what I learned thus far with the Roadster.

V3 (tone stack triode) V5 (FX loop send) are cathode follower circuits. Either use Mesa (selected JJ tubes) or Chinese (have nickel plated clips on the plates). Russian made tubes will fail prematurely in the Cathode Follower circuits due to the voltage differential between the heater and cathode. An alternate is the JAN/GE 5751 which is supposed to be compliant with cathode follower circuits.

Somehow I believe that Mesa also selects their preamp tubes for matched triodes, otherwise there would be an out of balance signal to the power section (matched triodes are better served with Class A/B power amps, it probably does not matter much with the Simul Class circuits of the Mark Series amps but it does not hurt to used matched triode tubes there either).

I honestly prefer the Mesa tubes in the Roadster. I love the way the Mesa power tubes sound in this amp when saturated. They come close to the SED=C=6L6GC that I have used in the Mark V. I have experimented with EH EL34, TAD6L6GC STR, SED =C=, and KT77 (all of which I specifically ordered for my Mark V ) The TAD6L6GC-STR sounded great as well as the EH34's. I have not tried the newer set of SED =C= 6L6GC or the EL34 (in use with my RA100). I prefer the tone of the Ruby (Mesa Branded STR440 in the Roadster). Since I am not using the SED =C= 6L6GC at the moment (loaded the KT77 in the Mark V) I should give them a shot in the Roadster. I have also tried some of the different preamp tubes (EH, Tung Sol, Mullard reissue, Mullard CV4004, Preferred series 7025, and vintage Mesa Chinese tubes (which I think sound the best overall in my other amps). The Roadster seems to benefit tone wise with the Mesa branded JJ 12ax7a tubes. I did not notice much difference in gain structure, but I did notice more brightness with the Mullard reissue and a Sovtek LPS in V6. However, it became apparent that the tone I liked with the stock tubes was not the same with the different preamp tubes. My experience with the Mark V is quite the opposite, I did not like the Mesa JJ tubes, actually it is a fault with the power section as I believe it is running a much hotter bias than it should ( I have red plated many of the commonly bought tubes except for SED or Gold Lion KT77 ( I ordered them specifically for a fixed hot bias amp and so far no issues). Roadster and rest of the DR family, they run on the cold side as I recall.

The weak link is the rectifier tubes, not many available. I did try a NOS JAN 5U4G but it was a dud. I normally use either Mesa or EH 5U4G (same tube). I believe the Roadster would sound great with many of the 6L6GC tubes available since it has a moderate bias and does not run as hot as the Mark V.

If you were considering a different tube than a standard EL34, 6CA7 had some interesting character too them. (I would avoid the JJ 6CA7, many have had great success with the EH 6CA7). Also you can run the EL34B (lower bass response). As far as EL34 are concerned, the SED =C= EL34 are tops but much higher cost. Gold Lion KT77 are also a big expense. I like the EL34 (SED) the best.

The Svetlana (not true SED or Sevetlana from St Petersburg) are not too bad either (made by Reflektor, also makes Tung Sol, Sovtek, Mullard, etc...) I have been running them in my Mark IV for the past 2 years. Close but not close enough to the SED =C= tube. Tung Sol 7581 are also killer tubes (has more complex harmonics than the Svetlana). I have a quad of those, wonder what they would sound like in the Roadster ?
 
Thank you for your reply. It was very helpfull for choosing type of tubes for me. My concern is can i put any tubes not only Mesa branded in my Roadster and just use it or non mesa tubes need some kind of biasing or moding the amp.
 
If your amp is under warranty, best to use Mesa tubes. I have experimented with some of the preamp tubes and power tubes just briefly so I could compare the effect on tone. Tung Sol in V1 will tend to brighten up the amp as well as a Mullard Reissue. I did not care for the change in tone. Unfortunately, most of the power tubes I have available were ordered specifically for the Mark V so they were not as defined in the Roadster or RA100.

If you are not concerned about warranty and are really eager to experiment with different tubes, the Roadster is more forgiving than the Mark V due to a cooler bias. Typical power tubes will work well. When you order tubes, some places allow you to specify what tubes the amp will be installed in, and if it is a combo or not. Groove tubes with gain factor ranging from 4 to 7 are acceptable. The lower the number the earlier the distortion would be. Some tubes vendors rate them in terms of low, medium or high distortion levels, stay in the middle range and indicate your amp make and model. Not sure if specifying a Combo will make much of a difference but I assume they will be more stable in the mechanical aspects (less vibration of the internals). I think the next time I order tubes I will indicate a combo amp. I have gotten some noisy tubes in the past, vibrations were not noticeable at higher volume but at low volume the tubes sing (vibrate and rattle, this is more prone for EL34 and associated narrow bottle tubes that are similar )

There are tubes that hold up better than others. TAD are not bad at all, SED expensive but hold up well, Gold Lion are good but cost more than the SED tubes. Some of the Reflektor branded tubes (Tung Sol, EH, Sovtek, Mullards, and Svetlana) are also good. It can be hit or miss when it comes to tubes and quality. Generally using a source that selects tubes and sorts them for quality of sound and mechanical stability (Mesa and Groove Tubes). Also finding a good source for a good matched duet or quad. I generally use "the Tube Store" or "tube Depot" for the other brands of tubes. Just my opinion and I will restate it, I found the Mesa tubes to have the best overall sound quality in the Roadster. The Complex harmonics are present when saturated in CH3 and CH4. So my Roadster will only get Mesa tubes. As for preamp tubes, I believe the Mesa 12ax7 are match triodes. If you decide to use other brands, it should be required to get a matched triode for the PI tube (V6). Having all of the preamp tubes with matched triodes would not hurt (except your pocket book). You could probably use most common tubes available for V1, V2, V4, V6. However Russian tubes will fail in V3 and V5 due to cathode follower circuits (JJ or Chinese Shuguang {with additional chrome like clips on the plates}). If you get a bad tube and something happens to the amp, your warranty will not cover you unless it is a Mesa tube (not sure about GT).

You do not need to modify anything in the amp at all. No bias change needed as long as you stay in the mid range. Always good if the resource you are using will match the tube for the amp requirements based on its bias data they keep on hand.

A reminder on the Rectifier tubes, stick with the exact same type tube. 5U4GB. Mesa or EH have these available.
 
I really love the Winged C 6L6s in my Roadster head and Mark V head. I feel they are a slight upgrade over the stock 6L6s. However, as we all know, they have stopped making the Winged Cs. So the quest to to find a similar replacement for me
 
I have been searching quite a while for a suitable replacement for the =c= 6L6GC. What does come close is the Tung Sol 7581A (at least for the Mark V).
TAD 6L6GC-STR are a bit different but sound great. I actually liked those more in the Mark V than the SED =C= 6L6GC. What I did not like about them was the plastic base, the center guide pin can break off easily. If you get them, use a silver Sharpie to mark where the key on the center pin is on the side of the plastic base. Forget about the Svetlana tubes as those will not last long in the Mark V. For the Roadster no issue as the bias is not the same.
 
bandit2013 said:
I have been searching quite a while for a suitable replacement for the =c= 6L6GC. What does come close is the Tung Sol 7581A (at least for the Mark V).
TAD 6L6GC-STR are a bit different but sound great. I actually liked those more in the Mark V than the SED =C= 6L6GC. What I did not like about them was the plastic base, the center guide pin can break off easily. If you get them, use a silver Sharpie to mark where the key on the center pin is on the side of the plastic base. Forget about the Svetlana tubes as those will not last long in the Mark V. For the Roadster no issue as the bias is not the same.

I would have thought the longevity issue was due to the fact that it's enclosed in a smaller head cabinet, as opposed to be a bigger one which may help ventilation
 
bandit2013 said:
Just my opinion and I will restate it, I found the Mesa tubes to have the best overall sound quality in the Roadster. The Complex harmonics are present when saturated in CH3 and CH4. So my Roadster will only get Mesa tubes.

Hey Bandit2013,

You seem to know a lot when it comes to tubes and the Roadster. I recently blew a one of my power tubes in my Roadster. You say you only use the Mesa branded power tubes because you think they sound the best. I really love the sound of the amp and don't want to change anything but at the same time if there is a tube that would be better suit what music I play I'm open to using a different tube. I mostly play Metal and Progressive Metal. I love Metallica, Dream Theater, 80's metal as well as guitarist like Steve Vai and Joe Satriani. I was going to take your advice and just get a matched pair of the 6L6 STR 440's but if you have any thoughts otherwise I would greatly appreciate it.
 
I would think that replacing your power tubes with the same type would be best, unless you can find a compelling reason to change it up. They also really are the tubes the amp was designed around.

EL34s will give you more of a crunchy mid, high mid sound, and a tighter, less rounded bass response.
 
Sorry for not noticing this....
Thing to take into account is the plate voltage of the amp. Not all Mesa's are operating at the same plate voltage and thus each model will have a specific bias for the plate voltage. Not exactly sure where the roadster stacks up with the Mark series amps or others in that regard. Depends on the power tube arrangement if it is a full Class A/B (all Rectifier amps I believe are this, not sure on the one's that use the EL84) Some Mark amps use the Simul-Class circuit and a select few run the full Class A/B. Each will have its on character.

I would suggest if you were to venture outside of the norm and select tubes that are different, indicate to the vendor what amp they will be used in so they can at least select a tube that will perform best when they are performance matched. The Ruby MSTR which are the same as the Mesa STR440 do have a slight different tone to them. May be due to the selectin process. I actually like them just as much if not a bit more but it depends on what amp I have them in. However, once you change V1 in your amp (Roadster is almost a necessity to do so) the bottom end and lower mid gain character of the Mesa tubes is a bit reduced. There may not be much to change in terms of tubes that the Roadster will respond well due to the cathode follower driven tone stack.

Only time I really noticed much of a change was using a JAN/GE 5751 in V2 (this tube does not share both triodes with all channels one half is used for the CH1 and CH2 and the other CH3 and CH4. V1 needs to have a good gain characteristic as well as V2 but the frequency response of the tubes will matter. Tube rolling has not been as much fun in the Roadster as it is in the Mark V. Other than the usual Tung Sol in V1, there is not much out there to experiment with due to the cathode follower V3 that drives the tone stack late. Not much else I can think of on the Roadster... How to get there from where you are at is or may be difficult. In short you have options for V1 and V2 for tone and character shaping and that is basically it except for the PI tube V6 and of course the power tubes. Power tubes with an early distortion characteristic may not be as desirable as you may think. I typically find that less is better than more, you can only distort the signal so much before it becomes mud. I would prefer a bit of mud verses brittle ice pick.

There may be some power tubes that would be killer. Tung Sol 7581 sounded great but I had already spent most of the tube life in the Mark V before trying them. I have read somewhere in the forums on the Mesa 5881 tubes. I have not tried them so hard to relate how they would sound in the Roadster. The SED =c= were kick *** tubes but harder to get those now. Also a quad of 6CA7 would be interesting to hear, I need to get a set to find out. My try the EHX version as I had the JJ versions and they were incredible in the Mark V but crapped out in too short of time (2 seeks, lost one tube due to open circuit issue internal that was intermittent ). Some do like the JJ EL34L as well.
 
Bandit2013,

Thanks for the info about my tube options. Looks like I have a little research to do before I get some new tubes. In the meantime I decided to use some tubes from my Road king and may have messed something up. While I was waiting to get some new tubes I pulled the 4 6L6's from my much newer Road king II. The Roadster sounded so good with the newer tubes I decided to swap the 6 12AX7's as well. I follow the tube charts in the manuals but when I powered up my Roadster things sounded really bad. Channel 1 sounded fine but when I switched to channel 4 it had no gain. It sounded like an overdrive pedal. Then when I switched it back to channel 1 there was barely any volume at all. So I decided to swap back the original 6 12AX7's but there was no change. I double checked to make sure the tubes were seated properly. I really don't understand what I could have done. Any thoughts how to correct this would be greatly appreciated.
 
The Road King II has the same tube assignment as the Roadster. Not sure what would be causing the lack of gain or other issue. Typically if it only effects CH4 and CH3, it may be V3 but it can be V2 as that tube circuit is where the signal splits for the high gain channels and the low gain channels. Also check your FX send level in case you moved it to a negative setting if you are using the FX loop and master volume control. That gets me every time.
 
bandit2013 said:
The Road King II has the same tube assignment as the Roadster. Not sure what would be causing the lack of gain or other issue. Typically if it only effects CH4 and CH3, it may be V3 but it can be V2 as that tube circuit is where the signal splits for the high gain channels and the low gain channels. Also check your FX send level in case you moved it to a negative setting if you are using the FX loop and master volume control. That gets me every time.


I checked my FX send level but that wasn't it. It is definitely something I did when replacing the preamp tubes. I have to admit I've never replaced or swapped preamp tubes before so I must have done something wrong. I watched a mesa video on youtube about replacing tubes and it looks like they kept the amp on in stand by when replacing the preamp tubes. Is that the correct procedure? Seem odd to leave the amp on unless you were trying to find a bad tube.

Last night I did some more testing of the Roadster and found that CH 1 works fine but Ch's 2,3 and 4 seem to be missing gain. The weird thing is as soon as I come back to channel 1 after switching to one of the other Ch's then 1 also suffers from the same issues. A lack of gain and volume. This is exactly how it sounded with the Road King tubes in it.

Feeling discouraged I decided to forget about the Roadster and reinstall the original road king tubes back into my road king which have been sitting properly labeled in a box. The road king worked fine with these tubes before I removed them and installed them into the Roadster. Once they were swapped I was really sad to discover that my Road King is also suffering from issues now. Almost the same issues. The Road king sound weak and quite on all channels.

I can't understand what I'm doing wrong. None of the tube have been changed in either of the amps. The roadster is 9 years old and the Road king is 7. Could it be that the tube are just to old or that I damaged them by moving them? I was very careful to do them one at a time and line up the pins correctly. Is it possible to put them in wrong? Where as the power tubes have a little notch to slide in the preamp tubes didn't. I didn't remove the chassis from the amp so I had a difficult time with V1 being behind the transformer. I also had a difficult time putting those caps with the springs back on due to the lack of space and leverage. A couple of time when the cap when on I heard a little pop noise. I wonder if I could have damaged the tube from the force of pushing that cap down and turning it.

My plan is to buy a new set of tubes for my roadster but I would hate to get them and make the same mistake I already made when swapping the road king tubes. I would also hate to have to drag both of these amps to a tech just to install some new tubes if nothing else is wrong. I would think I should be able to do this myself. any thoughts on what I've said here would be greatly appreciated.
 
One rule of thumb I would follow..... Never install any preamp or power tubes with the power switch applied and the amp power chord plugged in.

It is difficult enough to get the pins in the recessed holes let alone having some current available though the heater circuit. Sure it is only 6.3V but why risk it.
I always power down when I change tubes. It does not take long to power it back up again.

Your problem sounds like a cracked tube. The glass can get fractured even at the pins and once the vacuum is no longer present in the tube, the heater will not function properly and the tube will be dead. It may be possible you have a broken tube.

Did you remove the power tubes as well? Check that the rectifier tubes are in the correct position. Does it make a difference if the diode switch is set to diode or tube on the back?

Also, since the tubes face upward, the aluminum tube shields may leave metal debris around the tube socket. If so you can clean that away with compressed air as the fragments may be conductive if there is enough of them and may depend on humidity levels. I had this issue with an RA100 where the Hi/Lo channel was completely dead and the clean channel was not. Amp was not sounding all that great, Easy fix was the blow out all of the metal fragments around the preamp tubes and all was good after that. If the rubber o rings look silver, clean them off, If you had a silicon oil to wipe on them that will keep them from drying out and the metal flakes stuck to the o ring will be cleaned off, tube shields go on much easier with the o-ring clean and sort of lubed up.
 
Another observation, chance of tip damage is possible.
When changing tubes in the Roadster I generally keep the rest of the tube shields off when installing the V1 shield. It can be tricky at best but if there seems to be too much resistance on the spring it may be pinching the wick of the tube or tip. (not sure what to call the tube seal but that is where the tube gets vacuumed pumped (probably under inert gas such as nitrogen or argon). I used to work for a company that made glass type mercury filled thermometers and miniature thermostats and it was interesting how it was done. I would assume the valve manufacturing is similar in some respects.

When installing the long tube shield, look into the amp at an angle where you can almost see the tube. I go by feel on the spring tension. If it is difficult to compress I attempt to re-center the spring. Note: it is not mandatory to use the long tube shield on V1 as it is the same as the short one's but with an aluminum tube extension placed onto it. If you find it easier to use one of the short shields do so and put the long one on another tube. I had to do this with the Mark V before converting it to a combo unit. No room at all. Roadster has more available room to change tubes than other amps. To reach the other preamp tubes, you may need to pull a power tube or two. Just remember which is which when you put them back in.

Note when you take out the suspect preamp tubes, count the pins, there should be 9 pins on them. If you see a pin in the glass that is missing the part that is supposed to stick out it may be in the socket. It will take some time to get used to installing the shields and preamp tubes. Just take your time. You can just install the tubes without the shields in place and run the amp that way. The shields do not do much for noise interference. Older Mark amps did not have any shields on the tubes except for V1 and they hung down not upward (unless your Roadster is a combo). It is okay to reposition the amp for a better view or ease of access. Try laying the amp face down if that helps (do that on carpet or some padded surface to prevent nicking the tolex covering).


Note that the amp may have stored energy in the power supply capacitors. The potential for high voltage is possible. Always assume the internal components have a high voltage charge and try not to touch anything inside the chassis. (before removal of the chassis, unplug the power chord and place the stand by switch into the position it will be in when you are playing though the amp and let it sit for an hour or so as this will connect the power supply capacitors to the rest of the amplifier circuits to aid in discharging any stored energy. The power supply caps do have bleed off resistors intended to discharge the caps during shut down. Do not rely on them.

If this is too difficult, the best way to remove the chassis would be to unplug the amp and disconnect all external connections. Before disconnecting the reverb wires, take a picture of it with a digital camera or cell phone so you know what wire goes where as reference.
place the amp face down and loosen but do not remove the 4 bottom screws. Once the turn freely loosen the two bottom screws but leave them in the holes, on one side only (does not matter what side), loosen one of the rear screws. when it can be removed freely take hold of the metal strap and both screws should come out. The next step will require you to hold the chassis against the bottom of the amp, use one hand and place your thumb on the bottom of the shell and clamp down with your fingers on the chassis. With the other hand remove the other rear chassis screw. If both screws have been freed from the chassis nuts, they can be pulled out at the same time while pulling on the metal strap or you can remove each screw one at a time. Note: if you loosen one screw and remove it while the other is still tight, when you loosen the other screw the strap may swing out on you and rip the tolex covering. I generally keep the screws in place when loosening them. Once the screws have been removed, grab hold of both transformers (PS and OT) and carefully slide the chassis out. You may need to allow it to drop towards the top to do it as you do not want to slid the chassis along the bottom of the shell as there is a foil shield mounted on the shell. Place the amp chassis down on a flat surface with the tubes facing upward. This will give you full access to the preamp tubes, allow for inspection into the tube sockets to check for debris or broken pins missing from a tube.

You can remove the power tubes but it is not necessary. I keep mine in place (also my Roadster has the tube cage on it). If yours does not have the tube cage or you feel you need to remove them, mark the tube with a sharpie on the base where it came from for outer pair I place an "O" on the mesa label, on the inner pair I place an "I" or simple line. That way the pairs are marked. Also remember where the rectifier tubes are inserted and where they need to go when placing them back in. The Rectifier tubes should be installed in the sockets closest to the power cord. Refer to the tube chart in the manual or on the inside of the chassis. Rectifier tubes are marked as 5U4G. they look very similar to the power tubes but only have 4 pins and there are two elements you can see though the tube where as a power tube has a huge plate structure and is only one element or structure inside).

If you can manage replacing tubes without chassis removal that is the preferred method.
 
bandit2013,

Once again thank you for your in-depth response to my questions. I followed all you advice and the new tubes are working great in my Roadster. I did however leave out the springs in the preamp tube casings. I think the tension created by the springs some how caused me to damage some of the tubes last time I reinstalled them into both of my amps.

Now I'm left with the two sets of old tube from both the Roadster and Road King. I now want to reinstall a working set left over from the two sets into the Road king. I thought I could spot the damaged preamp tube be sight but I can't see any obvious damage to any of them. I was hoping I could test the preamp tubes heater pins with my multimeter to find the bad tubes but that didn't work. They all tested fine. Even an old cracked power tube I had tested fine. Is there another way to fine the bad preamp tubes besides just popping them into the amp one buy one? Thanks again for all the wisdom!
 
No problem at all...

Unfortunately if you do not have a tube tester, the only way to find out what is bad is to plug it into the amp. A cracked tube is an easy one to spot even if you do not see the crack in the glass as the heater will glow extremely dim if at all. It may start out bright but then dim. It is easier to see that on the Power tube but the preamp tubes will also look dark if they have damaged glass. Heater may test out fine impedance wise but may not get hot if the vacuum has been relieved (cracked). I have dropped a few expensive tubes and learned a few things from that.....

As for the springs I never tried to remove them. They are a pain to get on over the wick of the preamp tubes, especially V1 on most amps if hidden behind the OT transformer. The long extended tube shield I generally do not use as I can use the small one easier. I bought a few from Mesa along with some bear claw clamps as I broke a few on the Mark V. Hint, do not bend them too far or they crack where they get screwed to the chassis. To spring or not to spring, in some respects the springs act as a heat sink since they make contact with the glass but on the cooler areas at the top. It is the sides that get hot, similar to a power tube but they do not heat up as high in temperature. Tube shields are not really necessary but seems to be the trend. The Mark III I had for 24 years only had one on the V1 tube which was more painful to install than the current ones at it was a bayonet style of clip. The other tubes did not have any shields.

I would say my preference would be to go without, if you do not hear radio signals or other interesting stuff (shields will not prevent that anyway) you can live without them. amps that have tubes facing upward like the Roadster and Roadking as well as the RA100 are prone to aluminum metal dust contamination on the surrounding surface of the preamp tube socket on the PCB. Enough tube changes or too much fighting on getting the shield back in place causes enough friction to shave off small metal flakes. Compressed air usually helps to clean that out. I am generally conservative with the tube shields if I am tube rolling, they remain off until I am satisfied. That small rubber gasket is normally black in color, I use a liquid was (liquid ice automotive wax) to clean and lubricate the o ring. That makes installing the shields so much easier. Even an oil may help like 3-in-one as long as you wipe any excess off. The liquid ice is an oil as well but also protects the rubber o ring from drying out. For amps that have the tubes facing downward, I believe the Roadster combo and perhaps the Roadking have the chassis inverted, may be good idea to keep the shields in place. I have taken the shields on and off so many times I can tell by feel if the spring is over the tip and not on the side of it. However going from one amp to another, not all tubes face in the same direction. The Mark III was the most difficult as the preamp tube was at a 45 degree angle or something similar vs the others were the missing pin may be at 90 degrees or facing the front of the amp.
 
bandit2013,

Again, thank you for all the great advice. I will do what you sugested and just pop them in and look for the lightly dimmed preamp tubes. Should take that long.

I do own the combo version of the roadster with the tubes hanging down. Right now I don't have any of the Tube shields on and it sounds fine. At some point i will try to get them back on but I really don't want to crack or damage any of the new tubes right now.

I will say I can't believe how much better my amp sound with the new set of tubes. I know it's crazy but I've had this amp for 9 years and never changed a tube. I always loved the sound of the amp so I just didn't bother. But wow, what a difference the re-tubing did for the amp.

At first I was struggling a bit with the change in sound but now I'm getting used to it. I'm really noticing the increase in treble. It's almost like there is another presence pot in the amp now. Because of this it sounds like there is less bass but I'm sure I can just readjust the controls a bit. The other thing is that there is so much separation between the notes when you play a big chord at high gain. I remember John Petrucci using that to describe the characteristics of the boogie sound and thinking to myself, my amp doesn't sound like that. Lastly, everything screams more. Notes, pinch harmonics, everything just sings so much more. It's really crazy. Maybe the tubes are still getting broken in because it sound better now than when I first put them in. Crazy.

I ended up just getting the tubes from Boogie but at some point I definitely experiment with some other preamp tubes to see what other tones I can get. I can't believe I waited so long. Stupid.
 
To be honest, I actually prefer the stock tubes in the Roadster. There can be a bit of change with selection of V1 or V2 (one being stock and the other something else). I did like the tone I was getting with all stock tubes and used a Jan/GE 5751 in V2. It may drop the gain just a small amount but enhanced the tone far more than I expected. Typical users stick a Tung Sol in V1 and the rest stock tubes. That does change many things especially with the brightness. Generally I found the Mesa SPAX7 tube curbs most of the low end drone and still retains the character of the amp.

I am surprised you had not issues with the 9 year old tubes. The cathode follower tube in V3 (only used on CH3 and CH4) will degrade overtime a bit faster than the others. The one on V5 position is not as degrading as it is used to attenuate the signal for the loop. If you notice your tone is suffering on CH3 or CH4, the suspect tube will be V3.

I have also heard the Beijing tubes work well with the Rectifier amps. I had a few old stock Mesa Chinese tubes of that variety and loaded up the amp with them (including the cathode follower circuits) and did not notice much of a change. They were well used tubes so perhaps that may be the problem. I do have new one's I got for use in the Mark V (NOS Beijing 12AX7 with square foil getter, same tube as the 1990 Mesa 12AX7) and those are awesome in that amp. Considering I have not fired up the Roadster in some time now (been busy with TC-50 and JP-2C for the past few months). The Roadster is a beast for sure but also has two great clean channels. So far, the Roadster is the only amp that I never had issues with the footswitch control or cable. The Mark V uses the same cable but slightly different footswitch control and I am having issues with that, reason why I do not use it).

What I love about the Roadster is the different gain characteristics you get with the rectifier tubes. Spongy or variac operation is also fun for some effect. I generally go for the extreme on Modern settings but had found that Vintage on CH3 set to 50W is an awesome setting especially for lead. There is so much about the amp that I have not learned yet. Another trick is to use an inverted V shape on an EQ pedal in the loop as that seems to act as a gain boost. Taming the bottom end is the key on this amp as it has plenty of it.
 
bandit2013,

Well, I did start to have power tubes fail. That's how I ended up swapping tubes from my other boogies until I got some new tubes. I actually took your advice and stuck with the boogie branded tubes. I always loved the sound of this amp so why mess with perfection. However, in the future I will definitely explore some of the other preamp options you mention in V1 and V2.

I too haven't explored this amp as much as I could. I do spend most of my time in the modern mode in Ch 3 and 4 since I'm heavy into playing Metal, Progressive Metal and Shredding. I will say I've been using a OD pedal in Ch 2 in Brit mode and I'm really liking the classic rock and non metal tones I can get. And I've always loved the clean tones that Ch 1 provides. I've owned boogies off and on for over 30 years and I always seem to keep coming back to them. This truly is one of the best and versatile amp I've owned from them.

So I didn't have any luck this weekend figuring out my issues with the Roadking. I reinstalled the original tubes and looked for the signs you mentioned but everything looked good to me. All the tubes glowed evenly with the power tubes glowing the brightest. Nothing looked super bright or dark.

The issues I'm having are a bit weird. Ch 3 and 4 sound fine but Ch 1 and 2 have barely any volume. They work but they are super quiet. I decided to take 2 preamp tubes that I know work and put them in V1 and V2, then 3 and 4, and lastly 5 and 6 but that made no change. I then did the same with a set of matched power tubes, switching one pair and then the other but still no difference. Next I tried switching the Rectifier tubes with no change. I also tried all the amps channels in both the diode and rectifier mode and in all the power tube options with no change. Lastly I removed my G-system effects unit out of the loop and just plugged my guitar into the amp but again no change was heard. I wonder what I could have do to my amp to create this issue? All I did was swap out the tubes between the Roadster and Road King. Crazy.
 

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