Cleaning up the Roadster today.

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bandit2013

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Was having some issues with it running on the bright side. Very weird.
Decided to pull the chassis out and check around the tube sockets. Yep, lots of aluminum dust. Not enough to cause issue though. I had it worse with the RA100. I will be changing tubes and see if that makes much of a difference. Power tubes and Rectifiers are in good shape, Have not run the Roadster much since I changed them to new. Still running the STR440 yellow bias colors. Have plenty of extras since I stocked up a few years ago.

Want to see if the STR448 (Red bias color) have the same ill effect as they did in the MWDR. My reference for the work ill was sic, nasty and huge dark grind I never heard before especially with a 7 String guitar. Before that tube swap, it was not possible to run the MWDR with 7 string unless you like mud-fest tone.

I did not take any pictures of the aluminum dust though, Already cleaned it up and ready to install tubes.
 
Aluminum dust is from the tube shields. No component damage. If a component blew up, say an electrolytic cap, not only would that make a huge bang and lots of smoke, you get wads of insulation all over the place and a huge mess to clean up. I had to do this a few times with the RA100 head as I had been tube rolling, run amp, then change things again. Once you notice the rubber o-ring turn silver in color, chances are you have dust around the tube sockets. Also a good time to clean the 0-rings. They are supposed to be black in color, not silver or gray.
 
Well this turned out to be interesting. I much prefer the STR440 yellows in the Roadster over the STR448 reds. Color indicating bias color code.

Phase inverter is back to the Mullard reissue long plate 12AX7.
Mesa branded Beijing 12AX7 from 1990 in V1
Ruby Beijing 12AX7 in V2, V3, V5 and a stock Mesa branded JJ EEC83s in the reverb V4.

6 or 7 string guitar sounded great and that was with the STR440 tubes! No more flubbing out or low end drone. It was more due to the Beijing tubes in V2 and V3 that may be contributing to the low end drone when palm muting and flubby tone with the 7 string. Now it is tight and bold. Cleaning around the tube sockets on the PCB was also a big help. A while ago it became excessively bright and did not matter if I changed preamp tubes, the tone was still off. Checking for that aluminum dust from the tube shields sometimes is a good thing to do. If the PCB is clean around the tube sockets, you are good to go. If not, that dust can cause issues. It was not that bad just a light dust in some areas. Not sure if this can happen if you leave the tube shields alone and not remove them a few times. Much easier to get the shields back on when the chassis is out of the head shell. Trying to reach in to get the **** things back into their respective holes by feel is more or less what results in metal to metal rubbing. Those tube shields are made of softer alloy than the chassis.
 
I also love STR440 YEL in my Roadster. Unfortunately, It became very difficult to find them...I am trying to buy some as soon as they pop up but that's difficult...I have 2 new duets as a spare, but also some 440 BLU (that I never tried). Did you ?
 
I also love STR440 YEL in my Roadster. Unfortunately, It became very difficult to find them...I am trying to buy some as soon as they pop up but that's difficult...I have 2 new duets as a spare, but also some 440 BLU (that I never tried). Did you ?
You can try the Blues, They may sound over the top. I was sort of getting tired of the drone from the amp in general. A while back I ran some NOS tubes in the preamp that did make a good change. A few JAN tubes: 5751 in V1, 12AX7WA in V3, V5. Then with current production Mullard reissue in V2 and V6, V4 remained stock. That seemed to improve the CH1 and CH2 characteristics more than I expected, The drive channels CH3 and CH4 were a bit tighter. However, that still had the low frequency drone when palm muting, not suitable for 7 string guitar. So for S&Gs, I tried the old Mesa Chinese Beijing tubes, actually only V1 was the Mesa labeled one. The rest from V2, V3 and V5 were Ruby 6N4-J square foil getter tubes. I kept the Mullard in V6. Holy crap, that made a major difference in how I view the Roadster. It went from mean grind with that soft low end to one that has a much tighter low end with more useable gain. I could have tried the STR440 grays to see if that changed anything. The yellow bias colored STR440 seemed to fit well with the Roadster. I was surprised to find how good the 7 string guitar sounded in the amp. No more drowning in the sub harmonics. Not sure if it was the combination of the Chinese Beijing tubes or just the change in V2 which has the cold clipper triode circuit that is root cause for the sub harmonic sound. Amp is still deep but response is more bold and tight.

There may be other substitutes for the STR440. It will have a different sound though. I did run a quad of Tung Sol 7581 that I wore out in the Mark V90. Those sounded good in the Roadster. I never really explored the possible array of different 6L6 tubes I have. Most of what I have is out of production now. SED =C= 6L6GC, STR440. I sort of stocked up on tubes long before Covid hit.

The STR448 just did not make the desired list. Those seem to work well in the JP2C or Badlander (depends on the bias color code, the reds are lame, green or gray is more ideal). I will have to try the gray bias colored tubes. Perhaps there is hope for those. The red bias colored tubes did fair well with the MWDR. Still sounded thin on the top end and nasty growl on the bottom end.

STR443, I have a quad I tried in the JP2C and did not like them. Does not mean it will not sound good in the Roadster. I will have to see how those work out, perhaps this weekend.

STR441, have not tried those either. I have a set in the Mark V90. Will have to try them in the Road and see if they are ok.

I can also try out the STR445 (still waiting for them to arrive) but I can borrow those out of the Mark VII.

Perhaps some others could suggest a good alternative to the STR440. Bummer they shut down the Shuguang Sino factory.
 
Thanks for your answer ! What do you mean by "They may sound over the top" ?

From what I read about the STR448, I understand what you mean. It seems that the STR445 would be a far better replacement for STR440 in order to retain the sonic character of the 440, these 2 tubes seeming to share better similarities compared to 440 vs 448. Unfortunately, STR445 are also unavalable in Europe....

You're right, it's really bummer the Shuguang Sino factory does not produce anymore (it burnt if I am not wrong ?)...
 
I went back to STR440’s in my Roadster after they stopped making the SED ‘winged C” (=C=). IMO those =C= 6L6GC’s were made for Rectifiers.

I’m now running JJ’s and really like them.

Dom
It seems that STR445 are JJ's 6L6GC if I am not wrong ? If right, and if the sonic character of the 445 is indeed similar to the 440 one, it could explain why you like them ;-)
 
Not sure if the STR445 has the same sonic character as the STR440. I have not tried those in any of the Dual Recs I have to date. I may see if I can get them out of the Mark VII, pins are larger and are difficult to remove from the sockets. Not much wiggle room to get the tubes out. I can manage this weekend.

Yes, STR445 are JJ 6L6GC tubes. If they are made with any modifications per Mesa spec is unclear.
Perhaps this weekend I may try to experiment with them. They are supposed to sound more like a 6CA7 according to the description but are a 6L6GC tube. Tighter bass response. They are stock tubes they are using in the MWDR and Mark VII. JJ tubes are made in Europe, not Russia.

I have run the STR448 (red bias color and gray bias color). The grays had too much early distortion. The reds were on the headroom side of the tone spectrum. The reds sounded interesting in the MWDR but not as much in the Roadster. A bit thin sounding actually. The grays in the JP2C were ideal and a close match to the STR415, a bit more airy and not as tight as the 415 but sounded really good.
Not a good choice for the Mark VII or Mark V90. I did experiment with them. When I did pull the STR445 out of the Mark VII, I did try them in the JP2C and thought they sounded good in that amp too. I do want to hear how they sound in a Dual rectifier. Odd that I ordered those a month before I decided to buy the Mark VII. The amp arrived in a few days after ordering. Still waiting on the STR445 tube order. Almost been 2 months now. I do not see those listed at Sweetwater though. Odd. I bought them through AMS.
 
Not sure if the STR445 has the same sonic character as the STR440. I have not tried those in any of the Dual Recs I have to date. I may see if I can get them out of the Mark VII, pins are larger and are difficult to remove from the sockets. Not much wiggle room to get the tubes out. I can manage this weekend.

Yes, STR445 are JJ 6L6GC tubes. If they are made with any modifications per Mesa spec is unclear.
Perhaps this weekend I may try to experiment with them. They are supposed to sound more like a 6CA7 according to the description but are a 6L6GC tube. Tighter bass response. They are stock tubes they are using in the MWDR and Mark VII. JJ tubes are made in Europe, not Russia.

I have run the STR448 (red bias color and gray bias color). The grays had too much early distortion. The reds were on the headroom side of the tone spectrum. The reds sounded interesting in the MWDR but not as much in the Roadster. A bit thin sounding actually. The grays in the JP2C were ideal and a close match to the STR415, a bit more airy and not as tight as the 415 but sounded really good.
Not a good choice for the Mark VII or Mark V90. I did experiment with them. When I did pull the STR445 out of the Mark VII, I did try them in the JP2C and thought they sounded good in that amp too. I do want to hear how they sound in a Dual rectifier. Odd that I ordered those a month before I decided to buy the Mark VII. The amp arrived in a few days after ordering. Still waiting on the STR445 tube order. Almost been 2 months now. I do not see those listed at Sweetwater though. Odd. I bought them through AMS.
Thanks for your answer, please tell us your thoughts in case you experiment STR445 ;-)
 
It’s been a long time since I had STR-440’s in my Roadster for comparison, but I think they felt a bit brittle compared to the JJ’s. IMO the 440’s have that trademark ‘raspy’ character, where the JJ’s are just a bit more refined.

Dom
Thanks for these informations !
 
I got around to pulling out the STR445 tubes from the Mark VII to try out in the Roadster. Note these have a green bias color.

Guitar cab used: Mesa Standard slant front 412 cab with original V30 speakers. Made in 2019.

With the STR440 yellows and running a staggard diode /tube tracking on each channel: Ch4 diode, CH3 tube, CH2 diode, CH1 tube. All set to 100W and operating at bold power mode. The highs were crisp and apparent, midrange as you would expect is rather scooped and the low end was much tighter than it was with the stock Mesa 12AX7 tubes. I basically loaded the preamp with the unobtanium Beijing Military grade 6N4-J (12AX7) that mesa used back in the 1990's. The phase inverter tube was a Mullard reissue long plate. I was very pleased with this setup. May change the V1 to something a bit brighter. Not sure yet. I just wanted to disclose this first.

Now with the STR445 greens, running the same diode/tube tracking and power modes. I ran through all of the voices starting with CH1 and ending on CH4. Something was way off. Even tried going past the typical gig level and it remained the same with a hint of what went missing. No top end at all. the Sound was all bass. Dialed up the presence and boosted the treble, dialed out the bass, and the end result was the same. The Roadster went from a Roadster to a Buster Bass. I did think briefly about grabbing the 4 string and see how that would work out. If I did not care about the power tubes I may have done so but those are all I have for the Mark VII. I did not venture further in exploring the new bass amp I discovered here.

Just for clarity, I started with the STR445 this evening. They were the first to power up for the day. Ended up with the STR440 to confirm nothing changed. I think the Roadster is a bit picky on power tubes, they are essentially coasting in 6L6GC power. Wonder if the STR443 tubes will work in this amp? Come to think of it, I do not member trying out the STR441 tubes either. At the time I bought those 441 and 443 it was either the JP2C or the MWDR I was focused on. The Roadster was left under its covers for quite some time. Reason why I cleaned it up recently.
 
I got around to pulling out the STR445 tubes from the Mark VII to try out in the Roadster. Note these have a green bias color.

Guitar cab used: Mesa Standard slant front 412 cab with original V30 speakers. Made in 2019.

With the STR440 yellows and running a staggard diode /tube tracking on each channel: Ch4 diode, CH3 tube, CH2 diode, CH1 tube. All set to 100W and operating at bold power mode. The highs were crisp and apparent, midrange as you would expect is rather scooped and the low end was much tighter than it was with the stock Mesa 12AX7 tubes. I basically loaded the preamp with the unobtanium Beijing Military grade 6N4-J (12AX7) that mesa used back in the 1990's. The phase inverter tube was a Mullard reissue long plate. I was very pleased with this setup. May change the V1 to something a bit brighter. Not sure yet. I just wanted to disclose this first.

Now with the STR445 greens, running the same diode/tube tracking and power modes. I ran through all of the voices starting with CH1 and ending on CH4. Something was way off. Even tried going past the typical gig level and it remained the same with a hint of what went missing. No top end at all. the Sound was all bass. Dialed up the presence and boosted the treble, dialed out the bass, and the end result was the same. The Roadster went from a Roadster to a Buster Bass. I did think briefly about grabbing the 4 string and see how that would work out. If I did not care about the power tubes I may have done so but those are all I have for the Mark VII. I did not venture further in exploring the new bass amp I discovered here.

Just for clarity, I started with the STR445 this evening. They were the first to power up for the day. Ended up with the STR440 to confirm nothing changed. I think the Roadster is a bit picky on power tubes, they are essentially coasting in 6L6GC power. Wonder if the STR443 tubes will work in this amp? Come to think of it, I do not member trying out the STR441 tubes either. At the time I bought those 441 and 443 it was either the JP2C or the MWDR I was focused on. The Roadster was left under its covers for quite some time. Reason why I cleaned it up recently.
Thank you for this very detailed answer 👍! I admit that I didn't expect that because Mesa stands on its website that STR445 present "articulate low-end for excellent bass definition along with beautifully balanced mids and a chiming top-end that cuts without harshness. It’s a great choice for our Rectifier Series" 😅
It seems that beside the now rare STR440, no tubes would match their sonic character as 448 and 445 seem to not make it...

I have the possibility to buy 440 RED that have been played for about 50h, but I love the YEL...do you think there will be a huge difference ?
 
Not sure if there is much of a difference. I have some reds to try out to see if there is. I think they are still good to use.

As for the STR445, I will have to try them in the MWDR to see if they work in that amp. It came equipped with the STR440 gray bias color. I tried the yellows and felt the grays were much better. The grays seemed to be too much for the Roadster though. Mesa claims you cannot hear the difference, I beg to differ. That one has a different sonic character to it compared to the Roadster which is a much darker amp. The Tung Sol 7581 sounded good as I recall when I tried those. Mind you they were used in the Mark V90 up util they shifted in tone and are probably spent. Makes me to believe what others have said about the Roadster in general, the power section is just coasting and not biased for any power tube saturation. The SED =C= 6L6GC are much brighter toned, besides being difficult to come by so that is not an option either.

The preamp tubes I have in the Roadster are also non-stock. Mesa Chinese Beijing 6N4-J tubes which cut some of the low end drone. If I run the STR445 in the Roadster again, will have to run the stock Mesa 12AX7 (JJ ECC83s) to see if there is much of a difference. The stock tubes just made the amp sound darker. Perhaps a change in the phase inverter tube may make a difference. I have a Mullard 12AX7 reissue long plate in there now.

I fear the roadster may be like the JP2C or the IIC+, you need to have the STR415. Some of the IIC+ that have the higher voltage transformer cannot run anything but the STR415.

Don't just rely on my opinion. Perhaps others have tried the STR445 in a different bias color and had good results. What came in the Mark VII were greens.
 
Interesting. First time I ever ran the STR440 red bias colors in the Roadster. I must have had those tubes in the cabinet for years. Come to think of it, the yellows have been in the amp for a few years too. I do not run the amp much so I am sure they still have plenty of life left.

So for the STR440 reds, not bad at all. If I had not just replaced the tubes in the Roadster, I probably would not be able to tell the difference. These tubes were removals from a Royal Atlantic combo I bought, when I do not remember but some time in 2015 as that was a date I found in one of my posts in the Atlantic series about cream back speakers. They tested fine but never used them. No need to go back to the yellows for now. The reds sound great.
 
Great ! From Mesa "color bias" it seems RED are in the same category than the YEL certainly explaining why you could not tell the difference between both. I think I 'll pull the trigger on these "almost new RED tubes" (about 50h of use).

Thank you again for your help 👍 !
 
A day late and a dollar short. I finally received the STR445 from AMS.
At least I can keep the STR445 in the Mark VII as it is a tight fit to get them in and out.

The new tubes have a yellow bias color. The one's I pulled out of the Mark VII have a green bias color. Not sure if that really makes a difference. I assume they will sound the same. I will have to try them in the Roadster sometime today. Eager to find out how they will sound in the MWDR as that is what was supposed to be in the amp moving forward from 2020 or around that point in time.

Roadster compared to the MWDR, not much to compare, they sound different from each other having the same tubes. However, the MWDR came with the STR440 grays and they are very aggressive tubes for the Roadster.
 

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