mfunk49 Posted March 9, 2010 Share Posted March 9, 2010 I picked up a Gibson "The Gold"(GTS 70) amp for pretty cheap and was wondering if the 2 tubes in it (12AX7A China and 12AX7EH Russia) are compatible with a couple tubes i pulled out of an old Gulbransen organ (12AU7A Holland) X2. Is this even a good idea. Also, the original ones dont match...should they? I also pulled out a Sylvania 5U4 GB and a Sylvania 6L6 GC. I have the Bugera V22 on the way this week. Would any of these tubes be good to put in the Bugera? Or not good idea because they dont match? Last thing (sorry). I pulled out the 12" Wilder speaker (model 12526?) made in usa and theres a 223 by the usa marking. Dont see an ohm rating anywhere? Could this be usefull in the Bugera? Thanks in advance! Link to comment Share on other sites More sharing options...
Blackie Posted March 9, 2010 Share Posted March 9, 2010 Does the amp work as is ?.............cause we got to start some where.............on the spkr get a multi-meter to check ohms...... Link to comment Share on other sites More sharing options...
mfunk49 Posted March 9, 2010 Author Share Posted March 9, 2010 yes the amp works. the dirt side has pop sounds when volume is turned up but goes away after your done turning knob. Probably just dirty?? Thanks for the simple insite on the speaker. Sounds simple enough! just checked with multimeter....5.3. Would this be 4 ohms? Link to comment Share on other sites More sharing options...
Blackie Posted March 9, 2010 Share Posted March 9, 2010 yeah..........close enough Link to comment Share on other sites More sharing options...
mfunk49 Posted March 9, 2010 Author Share Posted March 9, 2010 Any advice about the tubes? Link to comment Share on other sites More sharing options...
Blackie Posted March 10, 2010 Share Posted March 10, 2010 not much.....mix and match and see what works........... Link to comment Share on other sites More sharing options...
Reiska666 Posted March 12, 2010 Share Posted March 12, 2010 commonly, replacing with 12ax7 with 12AT or 12AY means lower preamp gain: Tube Gain: 12AX7 = 100 5751 = 70 12AT7 = 60 12AZ7 = 60 6072/12AY7 = 44 5965/12AV7 = 27 12AU7/6189/5814 = 20 -less gain often means less noise and less distortion.... see some related story here: http://www.torresengineering.com/realinonprea.html http://www.jt30.com/jt30page/micKtubes/Tube-types.html -as Blackie said, mix and match... Link to comment Share on other sites More sharing options...
saturn Posted March 12, 2010 Share Posted March 12, 2010 I'm no expert, so don't take what I say too seriously. I don't think changing the pre-amp tubes from 12AX7 to the 12AU7 will "hurt" anything. I don't know how it will sound. Plus I don't think pre-amp tubes are necessarily matched. Most are 12AX7 of some sort. My amp has 5 12AX7s and I have everything from GT, EH, JJs and Sovteks in there. I wouldn't change the power tubes, unless they're matched and you know they're compatible with your amp. Some amps only use 6L6s for example while other can use either 6L6 or EL34s. Also, will the amp bias itself or does it need to be manually set? A 5U4 might be a rectifier tube? Link to comment Share on other sites More sharing options...
KL Posted March 12, 2010 Share Posted March 12, 2010 Buy a can of Servisol super 10 and spray those pots with a little bit, and they will almost certainly improve. Link to comment Share on other sites More sharing options...
djroge1 Posted March 12, 2010 Share Posted March 12, 2010 For your pre-amp section (12AX7/12AU7) read this article: The Tube Store I know on the chart it does not recomend you use a 12AU7 in place of the ax7 but I have done it before. In short yes you can swap a 12AX7 for a 12AU7. What you will get is more clean head room. This means you will need to turn the amp's vol up more to get it to distort. The 5U4 is your rectifier tube. The rectifier is what changes the electricity from AC into DC. Different amps have different tube types and some use solid state diods to rectify the current. I don't believe you want to swap this tube around. The 6L6 is a common tube for amps but you really don't want to just add them into another amp that doesn't run with 6L6 tubes. I have no idea about the Bugera. You will need to look that up and see what tubes it contains. However, if you are buying the amp new why bother swapping out the tubes. New amps take around 40 hours of playing to break in ~ both the speaker needs to break in and the internal electrical components. I wouldn't do anything with it until after the break in period. Link to comment Share on other sites More sharing options...
mfunk49 Posted March 12, 2010 Author Share Posted March 12, 2010 thanks very much guys. this has been helpful for me. i havent messed with tubes before. ill leave the bugera alone and let time do the adjusting. thanks!:- Link to comment Share on other sites More sharing options...
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