JGale Posted November 30, 2019 Share Posted November 30, 2019 Fellow said it needed work, the amp cackled at volume. New tubes. Booyah! Am I going to fry my vintage tubes in this thing? The splitter makes a hella difference. I found an old RCA *greyplate* 12AX7. Mucho roundo. Much softer top end than the mee'suh stuff. I have the option to purchase.... Link to comment Share on other sites More sharing options...
RobB Posted November 30, 2019 Share Posted November 30, 2019 You'll prolly be safe. Mesa biases their amps very cold. That way they can shill their tube sets to go with their amps. Link to comment Share on other sites More sharing options...
tbonesullivan Posted December 1, 2019 Share Posted December 1, 2019 Those are pretty nice little power amps! Nice sound and reliable. I would check to see what plate voltage they run EL84s at, because the "modern" EL84s they use tend to be able to withstand much higher plate voltages. Link to comment Share on other sites More sharing options...
Lockbody Posted December 1, 2019 Share Posted December 1, 2019 18 hours ago, RobB said: You'll prolly be safe. Mesa biases their amps very cold. That way they can shill their tube sets to go with their amps. The exception to this are most of the el84 amps. My Lonestar Special runs pretty hot, and the DC-3 goes through el84s like nobody’s business. Not sure about the 20/20 though. Link to comment Share on other sites More sharing options...
Jeff R Posted December 1, 2019 Share Posted December 1, 2019 Every time I have tried to use non-Boogie power tubes in a Boogie, I have blown a screen grid resistor. Maybe it's my dumb luck, but I ignore the message board hoohoo now and just use Boogie tubes. In three decades of using Boogies, I have never had one person actually listen to my rig and claim the glass in its ass was holding it back in some way. That's enough proof for me. Link to comment Share on other sites More sharing options...
kizanski Posted December 1, 2019 Share Posted December 1, 2019 29 minutes ago, Jeff R said: ...I have never had one person actually listen to my rig and claim the glass in its ass was holding it back in some way. WITNESS! Link to comment Share on other sites More sharing options...
JGale Posted December 1, 2019 Author Share Posted December 1, 2019 I'm still searching for the big fat clean. The combination of the old RCA and a couple Sovtek EL84s has a nice woody feel to it. Softer top end. Mullard splitter combo'd with Tesla and some obscure tubes with "6011" on the side come across as too bright and edgy. What immediately springs to mind is a stereo 2x12 with that WGS combination; ET-65 + Retro 30. A volume control for each speaker, plus the chance to play with tube combos for each. Geek heaven. Still...I think I will pass. Thanks all! Link to comment Share on other sites More sharing options...
BillW Posted December 1, 2019 Share Posted December 1, 2019 My live rig consisted of a MB 20/20 for over a decade. Changed tubes right when I bought it (JJs, if I recall correctly) and once about 6 yrs later (don't remember the brand). The change was just precautionary - I never had any issues with the amp or tubes. MB makes great stuff. Link to comment Share on other sites More sharing options...
The Shark Posted December 1, 2019 Share Posted December 1, 2019 6 hours ago, Lockbody said: The exception to this are most of the el84 amps. My Lonestar Special runs pretty hot, and the DC-3 goes through el84s like nobody’s business. Not sure about the 20/20 though. The original .50 Caliber amps were notorious for eating tubes. Mesa changed to 6L6's very quickly. And it killed the desired tone of the design. A Boogie tech told me that years ago. Link to comment Share on other sites More sharing options...
tbonesullivan Posted December 2, 2019 Share Posted December 2, 2019 10 hours ago, The Shark said: The original .50 Caliber amps were notorious for eating tubes. Mesa changed to 6L6's very quickly. And it killed the desired tone of the design. A Boogie tech told me that years ago. From what I've heard, those were one of Mesa's semi-infamous "class A" designs, which unfortunately were designed around the EL84s around at that specific time. Once those old production tubes ran out, the newer production tubes would be run super hot, and would burn up, often taking the PCB with it. I have heard of people using them without issue after modifying the bias circuit, and at least one person sent it back to Mesa for that modification. Link to comment Share on other sites More sharing options...
The Shark Posted December 2, 2019 Share Posted December 2, 2019 7 hours ago, tbonesullivan said: From what I've heard, those were one of Mesa's semi-infamous "class A" designs, which unfortunately were designed around the EL84s around at that specific time. Once those old production tubes ran out, the newer production tubes would be run super hot, and would burn up, often taking the PCB with it. I have heard of people using them without issue after modifying the bias circuit, and at least one person sent it back to Mesa for that modification. I've had about five of them. Only one had "damage" requiring repair. My local guy called Boogie and they instructed him as to how to "fix" it. The tubes ran cooler and the sound was brittle and the headroom (albeit very little to begin with) was diminished. The one I have now is dead mint and the guy I bought it from said he'd played it for years, but was sick of buying tubes. I've used it about 12 hours so far and it's good to go! Link to comment Share on other sites More sharing options...
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