http://www.voxamps.com/forum/ VOX | Discussion Forums Tag: Capacitor en Tue, 21 May 2013 03:19:48 +0000 http://www.voxamps.com/forum/topic.php?id=5710#post-32605 Wed, 02 May 2012 12:23:48 +0000 darkstar05 32605@http://www.voxamps.com/forum/ <p>I've just heard back from vox support that say that C20 is the bass cap and C24 is the fixed middle one.<br /> This was a surprise as i looked and it seemed to be C24 that went to ground via a fixed resistor</p> <p>I wish there was a schematic out there </p> http://www.voxamps.com/forum/topic.php?id=5710#post-31999 Wed, 25 Apr 2012 16:02:37 +0000 darkstar05 31999@http://www.voxamps.com/forum/ <p>yes, the speaker change is a good suggestion. I love voxes, I have a uk TBR as well that has more low end. I really don't want a vastly different sound, just a tad bit more.<br /> I'm going to give it a try, I think it must be the one on the right under the bass pot.<br /> thanks </p> http://www.voxamps.com/forum/topic.php?id=5710#post-31941 Tue, 24 Apr 2012 20:45:28 +0000 sizzlingbadger 31941@http://www.voxamps.com/forum/ <p>To be honest you aren't going to get more bass out of this amp playing with the tone stack. The tone stack is passive and only cuts frequencies. These amps are not designed to give a lot of bass and if you try and modify the circuit for more bass you end up with a very flabby sounding amp. Changing the speaker from a greenback to a G12H or Alnico Blue can give you a deeper sound. Another option is an extension cab or an AC30.</p> <p>If your trying to get tight bass / metal sounds then you need a different amp. </p> http://www.voxamps.com/forum/topic.php?id=5710#post-31895 Tue, 24 Apr 2012 12:47:46 +0000 darkstar05 31895@http://www.voxamps.com/forum/ <p>Thanks, yes i want a bit more bass. I'm a bit unsure still, i'd be very grateful if you could look up the schematic :-) I've heard this been done to blues juniors so thought itd be good to try. thanks again </p> http://www.voxamps.com/forum/topic.php?id=5710#post-31860 Tue, 24 Apr 2012 06:03:40 +0000 sizzlingbadger 31860@http://www.voxamps.com/forum/ <p>I don't have a schematic in front of me but the one that goes down to ground via a fixed resistor (usually 10K) will be the "Bass" cap. Making this cap larger in value will allow lower frequencies to pass to the Bass control but I doubt you will notice much difference as they will be very low and not really audible.</p> <p>What are you trying to achieve ? </p> http://www.voxamps.com/forum/topic.php?id=5710#post-31825 Mon, 23 Apr 2012 15:51:59 +0000 darkstar05 31825@http://www.voxamps.com/forum/ <p>Hi, just a quick question i want to up the Bass pot capacitor from 22n. Could someone confirm which of the 2 is which? thanks </p> http://www.voxamps.com/forum/topic.php?id=5177#post-28417 Mon, 16 Jan 2012 18:02:19 +0000 joshuaans 28417@http://www.voxamps.com/forum/ <p>Thanks everyone! I found some of my old 12AX7s and did some swapping. I found one of JJs ECC83s caused the fizzling noise. I am going to take the amp in to have the electrolytic caps checked by a licensed Vox tech soon. </p> http://www.voxamps.com/forum/topic.php?id=5177#post-27786 Sun, 01 Jan 2012 21:03:50 +0000 dennismac 27786@http://www.voxamps.com/forum/ <p>I had a noise problem very much the same and found that almost any vibration or tapping would cause that noise. After pulling the tubes out, I turned the amp over and did some poking around and found that a wire on one of the EL84 sockets (solid core) was severed exactly where the shield was stripped away by the tech or underpaid assembly person during manufacturing and must have cut a little to deep into the wire but not enough to cause a problem at the time of production, However, from much use and vibration, the wire finally broke and was arking at the break point. I simply re-stripped the wire, cleaned out the broken wire from the socket and re-soldered the wire to the socket. Problem solved, However, before i put it all back together, I checked the tubes and found them all good except the EL84 from the socket that was arking, So I replaced them all with JJ tubes... All good now.<br /> I don't know if this could be the case for you but I thought I would share my AC30 noise issue since I know how frustrating it is while trying to locate a problem.<br /> Hope this helps </p> http://www.voxamps.com/forum/topic.php?id=5177#post-27397 Tue, 20 Dec 2011 00:41:29 +0000 dennyrane 27397@http://www.voxamps.com/forum/ <p>I completely reversed the OP.....sorry.<br /> Retro is right, of course.<br /> If the noise stays with the tube socket, your problems lie there. With the age of your amp, it is also possible you have dirty tube sockets. Because it is easy and cheap, you may want to try cleaning the captures on the sockets that are noisy. May as well re-tension them as well.<br /> Best </p> http://www.voxamps.com/forum/topic.php?id=5177#post-27368 Sun, 18 Dec 2011 23:59:52 +0000 retrobob 27368@http://www.voxamps.com/forum/ <p>Unless the tubes are reasonably new, when one power tube is found to be bad (burned?) it is usually a good idea to change all of them. And normally, fizzing/crackling/popping noises are associated with connection problems (solder/component), especially when the noise occurs while tapping or jostling. </p> <p>Albeit the bad connections can be inside a tube, however since you moved the tubes and it did not change the location of the noise, I suspect a tube socket connection or possibly a plate resistor and/or even a coupling cap at that tube.</p> <p>The electrolytic caps are used in the power supply to smooth the ripple and decrease A/C associated noise (hum), usually there is an increase in the amp’s background noise (hum) ratio as these deteriorate. Though since it is a 90's era amp and the electrolytic caps could be 20 years or better in age, it would be a good idea to check their values to see if they have fallen off and may need replacing, as well a good idea to check the power supply's de-coupling resistors and connections. </p> http://www.voxamps.com/forum/topic.php?id=5177#post-27367 Sun, 18 Dec 2011 23:44:09 +0000 joshuaans 27367@http://www.voxamps.com/forum/ <p>I retubed the amp last year with JJs. It's a 97. I just realized that I've been using the wrong Ohm THD Hotplate. I've been useing a 8hom and I should have been useing a 16ohm. So the amp has had more resistance than it should have. No wonder I burnt out a power tube so fast. </p> http://www.voxamps.com/forum/topic.php?id=5177#post-27364 Sun, 18 Dec 2011 19:30:12 +0000 dennyrane 27364@http://www.voxamps.com/forum/ <p>I hate to criticize on a whim......but is seems you have done a better job of trouble-shooting than your tech did.<br /> You definitely have to have spare tubes for just a situation. Buy enough pres to re-tube your amp.....PLUS<br /> How old are the EL84's .? Not that I suspect them of your noise issues<br /> I suspect all Eleytics after the 15 year mark. But again, start with the pres. I am sure that is the source of most your troubles.<br /> If you plan on keeping the amp (what year is it.?) save money to replace ALL the Elytics.<br /> Best </p> http://www.voxamps.com/forum/topic.php?id=5177#post-27363 Sun, 18 Dec 2011 18:52:46 +0000 joshuaans 27363@http://www.voxamps.com/forum/ <p>My AC30/6 TB is emitting fizzling and pooping noises. The problem occurs intermittently when turned on and while in use. It will also make the noises when the side of the amp is tapped. I tested the preamp tubes by tapping them and found that the tubes in the first and fourth position fizzle when taped. I moved the tubes around since I don't have any replacements. Position one still fizzles a little. I'm wondering if it is the tubes or that the Caps might be getting old. Any suggestions? I had the amp in to a local tech and he changed a burnt EL84 but didn't take care of the noises issue. After my past few experiences with this particular tech I'm inclined not to wast money with him again. The amp is 90s English made and I've heard that the Caps usually start to go after around 20 years. </p>