RPascarella

Good point about the 212 noise level - you're probably right, I had the mic closer to 1 speaker than the other. When I use my 112 at church, I typically stay away from the topo 3 setting since it is so loud when idle - the sound guys pick it up for sure since I'm mic'ed. So I usually try to find a topo 1 amp, one of the Fenders, to get a more chimey tone to substitute. I suppose they could put a gate on it. I'm going to try the new Fawn Normal during Wednesday's rehearsal - we'll see if the sound guys notice the idle noise level. This will also be my first out-of-the-house test of my 112 since fixing it (fingers crossed!).

Oh, and forgot to mention, I have a little Honeywell fan from Home Depot that measures around 76dB. So yes, my topo 3 on both amps is actually louder than my fan!

Hey Ronnie, great to hear, but sad that you'll be without the amp for a while again. Very frustrating, but it sounds like Line 6 wants to do you right. Hey Mike, I don't have a schematic, but I'd love to get one. That'll never happen though. So I have some notes and diagrams I drew up by hand while debugging my amp. Mostly the op-amp circuit connections, some of the pre-amp tube connections, and some of the phase inverter tube connections. Not a whole lot. I found that what I was probing matched quite closely to most of the Fender/Marshall schematics you can find on the internet, especially with the phase inverter and power tubes. As for noise, I get an annoying hiss while in topology 3 like most people. I find that the noise grows in this topology order (no guitar connected): topo 1=quietest, topo 4=same amount of hiss, slightly more hum, topo 2=more hiss and more hum than both 1 and 4, and topo 3=most hiss and hum. I just downloaded the free Sound Meter app for my Galaxy S5 and did some measurements on my 112 (the one I repaired). I don't know how to calibrate it yet, so consider the relative differences of my measurements: topo 1=46dB; topo 2=66dB; topo 3=80dB; topo 4=67dB; standby mode=26dB. All measurements done 12" from my 112 combo speaker, Pentode, default class. On the 212: topo 1=34dB; topo 2=56dB; topo 3=77dB; topo 4=64dB. So this one is a bit quieter than my 112. Perhaps the tubes make the difference. Hope this helps! Randy

Great plan. Either way, we WILL get this working for you. You can't sell it broken. Parts are available. Future's so bright, we gotta wear shades! So tell me again (haven't read all the details on the other posting), Line 6 did repair work for you. So the tubes are new? And did they replace the power transformer? Did they replace the analog board or anything else? Trying to figure out what else we can eliminate as culprits in case you have a blown fuse.

Brazzy, that is awful, so sorry to hear that. Hey, if you're up to it and feel capable of digging in, we can try to debug here on this forum! Judging by the symptoms, it should actually be fairly straightforward to troubleshoot. You'll need a Digital Multimeter (DMM) in order to do some basic debugging. So first off, assuming the tubes themselves are good - when you say the tubes aren't lit up, do you mean all 4 of them? Like even the power tubes? Do the front panel lights come on? Do you hear relays clicking after a few seconds of powering on? What should happen is when you turn on the power switch, the heater circuits should fire up to warm up the tubes. Also, the digital board gets full power and starts booting up. The tube B+ voltage remains off until the Standby switch is turned on. If none of the tubes light up, it sounds like a fuse problem, a power transformer problem, or some analog board circuit problem (like I had). As far as fuses, there are 3 I know of. One on the input AC connector on the back panel, another just to the right also on the back panel, and one on the analog board right next to the heater voltage connector H2. So you'll want to see if any of these are blown, and if so, we'll have to figure out why. If the fuses all look good, you'll want to try to measure them with the DMM to make sure they measure 0 ohms. Sometimes a fuse may look good, but actually be an open circuit. If the fuses all check out, then the next culprit would be the power transformer. H2 is the connector that accepts the 6.5VAC used for the heater circuits. If there is no voltage available, the transformer could be bad. You can get new transformers on fullcompass.com for like $70USD. They are very easy to replace. If the transformer checks out, there could be a circuit problem on the board. So, what do you think?

Thanks guys. I've been spending quite a bit of time jamming in stereo with my 2 DT-50s, and I've had absolutely no problem with the one since the repair. I've got probably 15 hours of use on it now - used to drop out after 5-10 minutes (if it was working at all). And no more crackling/popping when flexing the analog board. @FlyingsCool - I really don't know whether any of the components I replaced were faulty. My first hunch is that there was a bad connection with the electrolytic cap, either at the solder joints or in the body of the cap itself. My second hunch is that the cap was bad, but it didn't measure as shorted out when tested with my meter. Who knows. Something strange was definitely going on. I wasn't intent on finding the root cause as much as I just wanted to get it working properly again, so I just replaced all 4 diodes and the cap (all in the same circuit). Bottom line is I love these amps and I highly recommend getting one!

Based on your description and what I've learned from my own debug of my DT50, it sounds like one of the relays on the analog board may not be working. I don't believe there are different signal paths on the analog board for either the 2 channels or the topologies, so if one works and another doesn't, to me it sounds like a relay, which is used to "personalize" the signal path. There should be 2 separate boards in the amp - one digital, one analog. Which was replaced in your amp? Here's one thought - you should be able to find out if the analog board is the problem by running a signal into the effects return. The problem still exhibits, the analog board is the culprit. You can order a new board through fullcompass.com and have a local shop install it for you. Since it is out of warranty, no need to go with the authorized repair dude if he isn't pleasant to work with. The analog board is very easy to replace, just 6 screws and about 14 cable connections (at least on my DT50). If you have any electronics repair under your belt, you could do it yourself and save even more. Then again, if Line 6 offered to replace parts at their cost, you might be better just taking the hit on shipping it out there. I've had quite a history with my DT50 here, so I can relate to your pain. One thing also to try is to pound your fist on the top of the cabinet (no joke!). If there is a loose connection somewhere inside, you'll hear it. I had either a bad solder joint or a tube not making solid contact with the socket at one point during my journey, and I could pound on the chassis and hear very loud pops and crackles. This is helpful for eliminating root causes of the problem. After resoldering the analog board and retentioning my tube sockets, that problem is gone. Heck, I wish I could help more, if you were in the Austin, TX area I'd offer to take a peek at it.

OK guys, after what, almost 2 months, I finally solved my amp problem and learned a ton in the process. I want to share my experience and learning with everyone. So my symptoms started with a slow fade-out of sound after 5-10 minutes of playing. Most of the time the sound would fade back in and be fine, but eventually it just went out completely. Since I have 2 DT50's, I was able to swap out the analog board between them and verify that the analog board itself had the problem. Digital board fine, transformers fine, tubes fine. I called fullcompass.com and asked them about a replacement. After some digging, they quoted me about $275 and 4-6 weeks lead time. Since I wanted to spend my money on the new HD500 model packs, I decided to go ahead and debug my board as time permitted. Why not, if I can always buy a replacement? First, I got a feel for the signal flow. There's a lot on the board, and I'm not an analog guy, so I did what I could. I found first that the signal arrives from the effects return board on the back of the amp and runs first into TI TL074C quad op amp and a Microchip Technology MCP4241-503E digital potentiometer. I suspect this is the circuit that allows you to control the volume remotely over MIDI - who knows. It then goes to V3, the first 12AX7 tube, which seems to only use 1 of the two triodes to buffer or pre-amp the signal before running over to V4, the phase inverter, and then on to the power tubes. After poking around a bit, I concluded that from the output of V3, the pre-amp tube, everything was working fine. I could touch pin 1 of the 12AX7 and get a very loud pop out of the speaker. This told me that the problem was before or at the first tube. So I started on my first dead-end rabbit trail by comparing the resistance values of various pins and components surrounding the op-amp and digital pot circuit between my working amp and the failing amp. First I thought maybe the digital potentiometer was bad, crushing the output signal. Nope, this wasn’t the problem. Then I thought maybe the op-amp was bad. No, that wasn’t it either. I actually found a cool debug tool on this guy’s website: http://billmaudio.com/wp/?page_id=1254 This is a probe that allows you to trace the audio signal through the circuit. This helped me determine that the signal was getting to V3 properly. So after hours of poking and prodding, I realized I was on a rabbit trail. So now the focus was on V3. Maybe the tube was bad afterall? No, I realized it was fine after swapping V3 and V4, then swapping the pair with the tubes from my good amp. Well what the heck is the problem then? I was getting very frustrated. By now I had something like 12 hours into this project over about 2 weeks. And I was getting obsessed! Next rabbit trail – from my old board design & debug days, I used an old trick to find cracked solder joints. I took a pencil and started pressing down in different areas of the board while running a test signal into the amp. I noticed that pressing near the op-amp and digital pot area of the board would cause some big time static, cracks, and pops. This indicated to me either a bad solder joint or fractured PCB traces. So out the board came yet again from the chassis to reflow the solder joints. I reflowed everything on that half of the board, just to be sure. I popped it back in and wow, the static problem disappeared! I played at room volume for about 5 minutes and thought, viola, the problem is solved! But then – pop! It went out again! This time it went it quickly, no fade. Dang! I give up! So I set it aside for a few days and pondered. I’m thinking now that there really was something else going on that was in fact solved by reflowing the joints, since the static when pressing the board is gone, but it didn’t solve my first problem. Incidentally, if I count the bad diode above, this problem, and the fade-out problem, that totals 3 different issues with this one board! Sheesh, I think I got a lemon or something. Over the next several days, I kept thinking about it. Then it hit me – maybe the B+ voltage to the tubes was going out. That would definitely explain the problem I was experiencing. Maybe a bad cap? So I probed the B+ voltage around V3 and V4. After some time I was able to probe while working properly and while exhibiting the fade-out, and wouldn’t you know, the B+ voltage was constant the whole time. Time to bang my head against the wall, cuz I’m giving up again. For some reason, I decided to probe the heater voltage of V3, out of curiousity. I mentioned in my first post above that there is a full wave rectifier diode bridge that provides about 5VDC to V3. So when I probed in the failing state, I found that there was almost 0V. I almost jumped for joy. I almost couldn’t believe what I was seeing. So I probed again, and again 0V. I pressed a bit harder to make sure the probes were cutting through the solder flux, and pop! The amp started making noise and I registered about 5VDC. Bingo! I found my problem, but I could not figure out why the problem was occurring. After studying this circuit and comparing schematics on the internet, I determined that the 6.5VAC connector from the power transformer provides voltage to 4 1N4007 diodes forming the full wave rectifier. Each diode has a forward voltage drop of about 1V, so that should leave between 4.5V to 5VDC at the heater pins of V3. There is also a 1000uF, 35V cap soldered directly under V3. So I figured it must be one of the diodes flaking out, or the cap. After measuring the diodes over and over again, I became confident that they weren’t the problem. On to the cap. I probed the heater voltage of V3 and sorta wiggled the cap around and noticed that the voltage would cut out (I think, or maybe my probe was intermittently making contact while I was wiggling). That was enough for me. Time to replace the cap. I found a local Radio Shack that carried this cap in stock. Sweet! They also had the diodes, so I bought all of them for about $5.00. The V3 socket is soldered on the backside of the board, covering the solder pads of the cap, so I had to remove the socket first, then the cap. I went ahead and replaced the diodes too, just to be safe (I’m about sick of disassembling this amp!). After putting everything back together, I fired it up and pow, it works. I played at loud room volume for about 15 minutes so far, which is much longer than I was able before. Works like a champ. Let’s hope I’m not back on this post to say it still fails in a few days! Incidentally, after replacing the diodes and cap, my heater voltage now measures 5.6V, 1V more than before. Now, some background for you techies out there. I did a bunch of circuit tracing and learned a few things that might be interesting. As mentioned above, only ½ of the 12AX7 tube is used – the other half seems to be no-connected. The functional half is there to amplify the signal from the effects return. The 12 in 12AX7 means that the heater voltage is meant to be 12V. Since there are 2 heaters, one for each triode, that would be 6.3V for each, totaling 12V. Cool! This amp only supplies 5VDC to each heater, less than the 6.3V. Not sure why. I saw some posts on various forums indicating that lower heater voltages can emulate the variac effect used to get Eddy Van Halen’s brown sound. Others claim it is for better tube reliability. Not sure why Line 6/Bogner does this. The V3 tube uses a DC heater voltage, while the remaining tubes use AC voltages. The V4 phase inverter voltage is 6.3VAC * 2 = 12VAC. I read somewhere that the pre-amp tube must have a DC heater voltage to reduce hiss/hum. I read somewhere else that using DC voltages on all the tubes’ heaters further reduces noise. I’m not bold enough to try that experiment! Incidentally, I also read that the SLO100 uses AC voltages on all its tubes, so who knows. The V4 phase inverter circuit follows what is called a “Long Tail Pairâ€, which apparently was used by Marshall and Fender amps. Note that this circuit greatly amplifies the signal in addition to splitting the phase. While in topology #1, the B+ voltage on my amp reads 340V. In topology #2 and #4, it reads 440V. And in topology #3, it reads 270V. At least one of the relays on the board is used to switch in a pair of large wattage resistors to reduce the B+ voltage. These resistors are easy to spot because they are soldered on the back side of the board, likely because they ended up being larger than the footprint provided for them on top side of the PCB. Perhaps Line 6 realized they underspecified the wattage of the resistors they originally intended to use. Well I hope this is helpful to someone someday. Let me know if you have any questions or anything, I hope I can help. Thanks, Randy

Hi Igloo, This may be a dumb question, but is there any way to put the Global EQ on the DT side in a future DT firmware release? And allow control from the POD? Thanks!

Hey, just out of curiosity, when it goes out, is it a slow fade-out? My DT50 combo is doing that now with a fresh set of EH tubes from Guitar Center. It has done this off and on for years, but for some reason a lot lately. It will fade out gently while tone is unchanged, and most of the time it gently fades back in. Sometimes it won't come back at all until a shutdown/reboot. I'm beginning to think it may be a 12AX7 tube issue. Last weekend I was determined to find the cause, so I cracked it open. I noticed if I touched pin 2 of the 12AX7 buffer tube, there would be a noticeable pop sound. Once the sound faded out completely, touching pin 2 did nothing. But if I touched pin 2 of the phase inverter, sure enough there was a big pop. This tells me the 12AX7 preamp tube lost its mind. I don't have the equipment to fully debug, so for now I swapped the 2 12AX7 tubes and so far I haven't seen the problem, but then again I've only played for about 15 minutes on it.

Thanks everyone for the kind comments. Funny, I was hesitant to post this thinking it wouldn't be of interest to anyone, but I was certainly wrong! My amp is still acting flaky after this fun repair. For years now, randomly, the sound will gradually fade out to nothing, and most of the time, fade back in to full volume. Usually it happens once about 15 minutes after powering up. Last weekend, it happened 3 times within a 5 minute period, and one of the times it wouldn't come back up. So I rebooted it and it worked, only to fade again the 3rd time. I hoped that this problem would disappear when I fixed the diode. All of this to say that, once again, I think I'm going to be digging in for another attempted repair job. Only this time will be tough because the problem rarely occurs. Oh, and this is with a brand new set of EH tubes (had JJs, but after the recent threads on tubes, went back to EHs). I'm curious if anyone else has run into this with their amps?

What may suck is that the relays are on the analog board, so if the new DSP board doesn't fix the problem, you'll have to wait another week or so to get a new analog board. I had a problem with my DT50 due to a diode that protects the coil in one of the relays. The diode was shorted so the relay couldn't switch. Maybe your amp has a similar problem, where the DSP is sending the right control signals, but the relay (or relays) are not able to switch properly. Here's my story: http://line6.com/support/topic/10123-dead-dt50-repair-fun/ Good luck!

A few months ago I used some contact cleaner/lube from Radio Shack to clean my HD500 stomp switches and the lube leached into the layers of the display. Looked horrible, and I thought it was ruined for good. I had nothing to lose so I took the unit apart and found that the display is actually easy to remove once you get to it. I peeled apart the layers and found a sheet of opaque backing paper to diffuse the side-lighting and it was soaked with lube. I was able to clean it and the glass with isopropyl alchohol, button everything back up, and viola, it looked good as new. Then the next day I turned it on again and the same thing happened again!!! I think I didn't thoroughly clean the glass. So once again, tore it apart, repeated, and now it's good. What a pain. All of this to say that if you have basic electronic repair skills, you should be able to replace it pretty easily. No soldering, just screws and cables.

OK, update on this. After some dialog with Line 6, here's essentially what they said: if you use an external MIDI controller to control the DT via MIDI In, you can control a downstream device (like the Big Sky) via MIDI Out. The MIDI Out is not intended to be used this way if instead connecting a Pod HD via L6 link. It appears that if you use the HDxxx and L6 link to connect to the DT amps, you'll get a flood of MIDI messages that will confuse any devices attached to the DT's MIDI Out. I haven't had time to dump the contents, but I believe it will contain the MIDI messages the HD is using to control the DT. On the other hand, if you control the DT via the MIDI In and external controller, the MIDI Out will act as a Thru to allow controlling a downstream device. Therefore, if I want to attach my Big Sky to the DT's MIDI and effects loop, I can't use the HD/L6 link. If I want to use the HD/L6 link, I must use the HD's MIDI Out to control the Big Sky. I do, however, have the option of using the HD's effects loop for a stereo return, or the DT's effects loop for a mono return. I've been able to achieve both setups effectively. So if I use a single DT amp, I'll probably put the Big Sky on the amp's MIDI and effect loop. If I go HD direct or HD to 2 DTs in stereo (which I totally LOVE!), I'll use the HD's MIDI and effects loop to maintain the Big Sky's stereo out. Hope this helps someone someday!

Thanks guys! I am able to run the Big Sky in the DT's effects loop while controlling it from the HD500's MIDI out. That does work. @ricstudioc - I saw that too, but too expensive for me! Probably would solve my problem though. I have MIDI-OX, but when I try to dump the messages, it locks up. I got it off of ebay, some cheepo chinese unit. I may end up getting an UNO and trying to dump with that someday. @jakeman19 - my HD500 is on stage at my feet, while my amp is backstage being mic'ed. I have only the L6 cable to connect the two. What I was hoping for was to leave the Big Sky sitting on my amp, and use short MIDI and effects loop cables between them instead of running a bunch of long cables back to the HD500. At this point, all I need to do is run an additional MIDI out cable along with the L6 cable from the HD500 back to the amp/Big Sky. Not bad. @Tboneous - For my situation with 1 amp being mic'ed, I don't think there is an advantage either way. As mentioned above, the advantage for me is shorter cables, not having to run them from my HD500 backstage to the amp. But, in general, the HD500 effects loop is advantageous since the return is stereo. The Big Sky has a stereo loop, and it sounds gorgeous in stereo. So if I ran direct from HD500 to FOH in stereo, that would be awesome, but with a single amp, the DT effects loop works fine. One other comment - using the DT effects loop frees up a slot (and therefore DSP) on my HD500's effects chain for other use. No word from Line 6 yet. I'll post an update when I hear from them.

Hi everyone, I connect my HD500 to the DT50 using the L6 link. I have a new Strymon Big Sky (oh, so beautiful!) to use instead of the HD500 reverbs. I want to run it in the DT50's effects loop so I don't have to use up a slot in my HD500's effects chain. I also want the Big Sky to see the program change MIDI messages so I can create a reverb patch for each HD500 patch. When I wire everything up on the DT50, I am able to 1) get the Big Sky into the effects loop path successfully and 2) get the Big Sky to respond properly to program changes. However, the problem I run into is the DT50 seems to send a bunch of other unwanted additional MIDI CC messages to the Big Sky, overriding the saved patch settings. One hint of this is when I select a patch on the HD500, the Big Sky switches to its associated patch, but the reverb machine selected is Room instead of the programmed machine, plus the LED indicator is Orange instead of Green, which means the programmed patch has been modified since loading. When I rotate the patch selector knob to the intended patch, it loads properly with the correct reverb machine and the LED stays Green as it should. So I believe the additional MIDI CC messages are confusing the Big Sky. When I run the Big Sky off of my HD500 directly, it works as it should. So the DT50 MIDI out is sending more info that desired for this. I have a support ticket filed, but I figured I'd throw this question out there to see if anyone else has solved this. Thanks! Randy

Here's some info on the fuse: http://www.marshallforum.com/marshall-amps/9265-full-description-fuses.html I had a similar issue a while back and got some replacements from a local Radio Shack: http://www.radioshack.com/2-0a-250v-5x20mm-slow-blow-glass-fuse-4-pack/2701064.html And yes, you should use the H15 connection. That's what my DT50 is connected to (I'm in the states).

So last week at rehearsal my DT50 112 insisted on pleading the 5th - I couldn't get a sound out of it. Fortunately I have my HD500, so I was able to run direct as a workaround (that sure is nice!). Neither the L6 link nor the front input jacks worked. So I brought it back home for some debug. Symptoms: no output, faint hum, no hiss. All front panel switches/controls were functional. No fuses blown. I am lucky enough to have a DT50 212 at home, so I figured I could do some A/B comparisons to see where the problem lie (btw, I'm a hardware design engineer and have been working on electronics and amps most of my life). I wanted to avoid a) the long drive to the nearest authorized service center, b) the cost of a repair, and c) the dreaded 3 month wait time, so I decided to roll up the sleeves and dig in. Both amps are out of warranty, so what do I have to lose? First thing I did was eliminate the problem down to a board assembly. The DT50 has 2 main boards, one is digital and one analog. Since I could hear a faint hum and some pops when changing topologies, I figured the power amp stage was working. So the first thing I did was swap digital boards. Sure enough, the problem did not follow the digital board. OK, either the analog board or a transformer is the problem. Next step, swap analog boards. Sure enough, problem followed the analog board, so that eliminated the transformers. On the analog board, I noticed that V3, the 12AX7 buffer, was not glowing. V4, the 12AX7 phase inverted was glowing nicely. I swapped the two tubes and the problem remained on V3, so the tube wasn't the problem. After some probing around (all I had was a DMM), I found that V4 has an 13V AC heater voltage, while V3 has a diode rectifier that converts the 13V down to 5-6V DC. So I think the tube wasn't glowing as brightly as V4 due to the lower voltage rather than there being a problem with it. So this turned into a rabbit trail. So while looking at this, I noticed a relay near V3 whose switching coil pins measured differently from the working amp. There is a 14 pin connector from the digital board that controls this relay and several others. It appears that these relays are used to switch in and out the different analog components for the different topologies. I was able to find that something like 9 pins of the connector control 11 or so relays throughout the board. Comparing each of the relay controls, I found that there were 3 differences from the working amp. So after hours of poking and pondering and at the point of giving up, I stumbled across one of the relays having a short across the control coil. Turns out there is a diode that sits across the 2 input pins and the diode was shorted out, preventing the relay from switching. Fortunately for me, the diode was a 1N4148, a pretty common diode, and I actually had a few sitting in my Nerd Box from college EE labs. So I swapped out the bad for the good, put everything back together, and sure enough it worked like a champ! I could not believe it. I wanted to share the experience in case it is helpful to others. Thanks, Randy

To sum up the DT50/HD500 combination: "If you like your tone, you can keep your tone."

Word of caution for anyone D'ingIY (doing it yourself :-): First, I got my contact cleaner at a local Radio Shack, and boy does that stuff come out in a full blast. So it sprays way more than you need, even with the straw attached. And it is a combination cleaner and lubricant, not just a cleaner, so it gets very oily. Second, it sprayed so much volume, it actually got into the layers of my display. I turned it on after my cleaning job and the display had blobs seeping in from the edges that looked horrible. So I ended up taking the display apart to dry it out the oil. It actually took 2 times, which was very frustrating. But hey, the switches have worked great ever since. They don't go bad necessarily, they just get flaky from dust, grime, whatever. And lastly, the button mechanisms themselves (not part of the switches) have solid mechanical stops, so I don't think you have to worry too much about stomping on them too hard to cause damage. They're protected pretty well.

So I've been following this off and on for some time since I have a JTV-89 with the hard tail bridge. My low E string sounds "plinky" as one poster eloquently described. I filed a ticket with Line 6 and received this response: Hi, We have been involved in this thread online for a while. There is no issue with your guitar. The short answer is piezos sound different than mag pickups because the string rests across the pickup element. The larger the string the more pressure. More pressure = frequency build up. If you are using a guitar model or amp that already has a lot of build up in the high-mids you are going to hear a "plink" especially at high gain levels. This can be EQ'ed out and is not anything outside of the normal operation of the guitar. You can hear this same sound on a lot of acoustic/electric guitars that use piezo systems. It's just not as apparent because you are not using high gain effects. Thanks, David At first I thought, no way, it sounds to me like a cocked wah on the low E string, maybe bad filtering either in hardware or software. So the first thing I did to prove this wrong was take an A string I had laying around (0.36" diameter) and put it in place of my low E. I tuned it first to A, then to E, and sure enough in both tunings the plink disappeared. So it must be harmonics or vibrations on the fat E string. Next, I took a piece of felt I had and cut a very small strip and placed it over the piezo below the string. Viola, problem is about 90% gone, definitely subtle enough that no one would notice unless I told them. In the following recordings, the first section is the magnetic pickups, then the piezos in standard tuning, then the piezos in 1 Down tuning. So here is a recording before the felt strip: https://www.dropbox.com/s/et1s3055ossmggx/Before.m4a And the recording after putting in the felt strip: https://www.dropbox.com/s/valysmw87f3hijg/After.m4a And here are some photos showing the felt and what it looks like installed: https://www.dropbox.com/s/ac342i95ofdoyei/20140616_212407.jpg https://www.dropbox.com/s/01yfmyrj2zkjefd/20140616_212510.jpg The felt must be acting as a damper to dampen out the ringing and excessive vibration of the fatter E string. My next task is to dampen the strings at the nut with some Velcro or something. You can definitely hear the ringing when using the piezos. I hope this helps some of you guys. It sounds way better to me and just saved me from selling this guitar. I wanted the Dream Rig, and the crappy sound of the low E string when chugging was definitely not part of that Dream! Randy

Might be a cheesy idea, but could this be a Stagescape-based amp with two channels, where each channel could be a separate modeled amp with its own speaker, but with the ability to blend the two together in stereo? After a quick search, I didn't see any new patent disclosures from Line 6, so I'm thinking whatever this is, it likely isn't something far beyond what they already have technology-wise. If you look at what we have today in the dream rig, we have a fully stereo signal in the HD500 with two separate amps, and we have the ability to connect multiple DTxx's or StageSource amps to achieve stereo. Maybe this is a way to reduce the load down to a single amp to carry around. Might also eliminate the latency in switching between different topologies, since each side would already be configured up front.

What I infer from the video is that there are two "entities" and the ability to blend between them. The first part of the video shows something like a Stagescape casing with a division between the left side (with red styling) and the right side (with grey styling). Maybe this is symbolism for a wet and dry version of a guitar signal or sound. The remainder of the video hovers around that big knob that has a volume indicator on one side and a blend indicator on the other. Looks like pushing in the knob enables blending the wet and dry signals? Now if I could just figure out what is being blended!

Cool post. I flipped my P75 patch to topology III and wow, it really jumped out at me. So here's the question - how can I assign the topology change to a foot pedal on the HD500? Is this possible? I want to use this for a solo boost.

Power transformers and output transformers are two different things. The problem many of us had were due to power transformers, which are the transformers in the main power supply that convert the 120V (or 220V) input voltage to the various supply voltages used in the amp's circuitry. These are the bigger, heavier transformers and endure the most stress. The output transformers sit near the end of the signal path between the power amp tubes and the speaker and are used mainly to convert the output impedance of the amp circuit to match the impedance of the speaker. I'm no amp expert, but you can think of an analogy of a sneeze. Unplugging your speaker and playing through your amp is like sneezing while plugging your nose and shutting your mouth. All that energy has to be dissipated. The sneeze must be released or your head would explode! In an amp, the amplified power must be dissipated to the speaker, where the energy is converted to physical motion, otherwise the amp's circuitry would blow at the weakest link, wherever it may be. I doubt that just turning your amp on would cause a problem, I believe it would be a problem only while playing and cranking up the volume to get the circuitry working. In other words, when there is sufficient energy to blow the weakest link. Again, just my thoughts as a hobbyist. Others can correct me if need be.