edrowland

Hmm. Ok. Pulled the schematics for the Spider IV. Those two controls are on an analog multiplexer chip. I probed the the outputs of the mutiplexer. Works fine. Signals look good. The multiplexer is multiplexing. Interestingly, this looks like a SOFTWARE PROBLEM. Not enough settle time between changing the multiplexer select and sampling the control values off the shared input ADC line. The symptom again: changing the Channel Volume control knob causes immediate changes in both the channel volume value and the Fx1 control value. Changing the Fx1 control causes an immediate change in the Fx1 control, followed by a subsequent reset of the Fx1 control value to the value read from the Channel Volume control about 1/2 second later. I'd have to guess that there's some funky de-bouncing code handling the ADC values for the Channel Volume/Fx1 ADC line. And that the output of the MUX is not settling fast enough following toggling of the MUX select. I can't see any other way to explain the observed behavior. Is there any way to get this comment to be relayed to Line 6 developers for consideration as a software bug? Thanks.

There's two things you need to adjust in may windows sound cards. There's a level setting, and many sound cards have a gain setting as well. I think level is a post-ADC adjustment, and gain/boost is pre-ADC analog boost to allow the Analog to Digital Converter to deal with everything from mic to line to headphone level. (Typically not instrument level though on consumer cards). YOu can find both settings as follows. (For Windows 10, but I think Windows 7 and 8 are pretty close to the same). Find the speaker icon in the Windows notification tray. The notification tray is the set of icons at the right end of the start bar at the bottom of the screen. You may need to click on the up arrow in the notification tray to see all notification icons. Right-click on the speaker icon, and select "Recording Devices". You should see your input in the list of available recording devices. There will be a little LED VU meter control to the right of the entry for your device. Play something. The VU meter should respond to whatever you play. You want it to be neither maxed-out (clipping on input) nor too quiet (produces a high noise floor). To adjust recording levels, select your input device in the list, and click on the "Properties" button. That will bring up a dialog. One of the tabs in the dialog should be "Levels". Click on that tab. What you see will depend on your audio device/ You will see either one or two slider controls. I have two. The first controls recording volume. The second is called "Microphone Boost" on my sound card, and works in 10db steps. I've also seen "+10db gain" checkbox on other devices". If you move the Properties dialog over a bit, you should be able to see the VU meter on the recording device in the first dialog while making adjustments in the second dialog. I'm not totally sure about this, but I believe the "gain" stages are pre-analog-to-digital-converter amplifiers, while the "volume" sliders are post-ADC amplifiers (in the digital domain). Basic guideline: you want the "volume slider" as high as you can get it without clipping. Adjust the gain stage downward to allow higher settings on the volume setting. The headphone output on the line 6 is very hot. You probably want to set the gain as low as possible. And you will probably still need to turn down the master volume a fair bit. If you are on Windows 7 and have a Realtek DAC (#1 most popular on Windows devices of that era) the Realtek software replaces the standard Windows notification icon. If that's the case, right click on the Realtek speaker icon, select "Audio Devices", click on the "Recording Devices" tab, and proceed as before from there. (You didn't do us any favors, Realtek developers. You replaced perfectly functional stock Windows UI with a buggy ugly disaster of an interface that provides no additional functionality that could not have been provided in the standard UI, while making it difficult to access truly useful features like the application mixer. May you rot in the 4th circle of programmer hell for all eternity). Also make sure you are using stereo plugs, adapters and cables all the way from the Line 6 amp to the microphone jack. If you don't, you run the risk of shorting the left and right channel signal of the line 6 output together which will drastically impair signal quality, apparently. If your microphone jack is actually mono, it will ignore the right channel, but won't short it to the left channel, so no harm no foul. My microphone jack is stereo. Your mileage may vary. Microsoft-certified computers are REQUIRED to deliver 80db s/n ratio while recording, so there's nothing wrong with using the standard audio card. Pro-quality devices may give 102db s/n ratio (20 bits), and higher sample rates, and lower latency, and better controls, and better input trim options &c &c &c. But there's nothing wrong with an 80db s/n ratio, and no fundamental reason why you should not be able to produce decent recordings on a stock windows audio card on the vast majority of windows computers. ps. Plug your amp into the same power bar as your computer.

The Spider IV most certainly does have a MIDI implementation. When you plug the FBV MkII pedal into a computer USB port with a Spider IV connected, you can see three standard USB midi devices through any midi-capable software on the system. The third MIDI device sends and receives midi data for the amp. If you change presets using the amp's controls, ,midi software listening on the third port will receive MIDI program change messages. Sending a program change message on the third USB device from software will change the preset on the amp. All the controls also send midi commands, most of which seem to be sysex messages. And the amp responds when these sysex messages are sent back. There are also a few standard MIDI CCs sent and received (volume, channel volume? can't remember). The FBV pedal, for what it's worth sends MIDI messages on the first of the three USB midi channels. No idea what the second MIDI channel does. So. Midi implementation chart, anyone?

I have a MKII pedal. The amp sends midi commands over one of the midi USB channels on the USB interface; and also responds to those commands as well. I can -- I suppose -- reverse engineer all the messages. But it would be much easier if there were a midi implementation chart for the Spider IV 75. Is there a midi implementation chart?

What the title says. A Spider IV 75. When I turn the channel volume control, the effect one control setting changes to what it would be had the effect 1 control dial been set to the same position as the channel volume control. The channel volume also changes, but the last thing on the display is the value (and selected effect) for effect #1. When I turn the Effect 1 control, the effect 1 setting and value take effect for about 1 second, and then revert to what the setting would be had the effect 1 dial been set to the same position as the channel volume dial (i.e. the channel volume dial seems to be transmitting constantly, and then sending the same value to the effect 1 control as well). Fortunately presets still work, and I can edit both values through the FBV USB. Very annoying though. And a serious problem for using the amp on stage. Has anyone seen this? Is there a user-servicable fix for this? Can't afford to send this amp in for service. I'm perfectly willing to crack the case to look at this problem. Is it worth cleaning the pots, or something? Help!

So why the heavy handed warning to ONLY use a TRS cable on the line out?

lol. Wicked! The single thing I dislike most about this amp is the inability to disable the amp model. Would have been nice to have effects too; but I can work with this. Thanks! ps. if anyone's looking for features for revision 2.1 of the ROMs, a "No Amp" amp would be really really nice. Thanks.

Ideally you need some type of audio interface, which will convert the audio signal to digital. This audio interface will take the place of the built-in soundcard in your computer which is really not made for music recording. No, that's not true. This is a wrong answer. The DACs on Windows computers are exceptionally good. And have been for almost a decade now. (Latency may suck, but Microsoft certification requires that the DACs themselves be excellent). My built-in soundcard (for example) has 192k 24-bit recording, with about 100db s/n ratio. It's a a stock Realtek dac that's probably found on the majority of PCs these days. Most probably you need to trim the input levels to sure the input is neither to loud (causes clipping of the signal) nor too quiet (causes excessive white noise). The headphone outputs on the Line 6 Spider IV are very hot, so you probably want to set the master volume to something very low. Or you may be able to set trim levels on the sound-card itself. This web page gives a lesson on how to trim audio recording levels with the very popular and very free Audacity audio mixing program. http://manual.audacityteam.org/o/man/record.html

Is the TRS line out on a Spider IV TRS balanced, or TRS stereo? Doesn't seem to say anywhere. And WHY can't you use a non-TRS cable?? Seems kinds strange. Supplementary question: if it's TRS stero, I have a 200W PA speaker with TRS balanced input. What would happen if I just run a TRS cable from the Spider IV to the PA speaker?

The speaker in the Spider IV 75 is a relabeled Celestion g12p-80 "Seventy 80" speaker. Celestion was kind enough to put the part number on the speaker for us, despite the "custom" relabelling done for line 6. Specs are here: http://celestion.com/product/22/seventy_80/

You do want to pay particular attention to dispersal of sound. Your tone will sound muddy standing anywhere but well in front and center. The major problem you face is that high frequencies have fairly narrow dispersal, while low frequencies are almost omnidirectional. So if you're standing anywhere but in the high-frequency "cone of death", high frequencies will be significantly attenuated. When you're indoors, high frequencies bounce around. When you're outdoors high frequencies go out and never come back. I have a friend who busks outdoors. His solution is to boost high frequencies as much as he can. I call it the "cone of death", because in his particular case, if you step into the cone in which high frequencies are being dispersed efficiently your ears bleed. The cone of death is somewhere in the neighborhood of 20 to 40 degrees wide on a 12" spider iv 75 for standard guitar frequencies (~80 to 5k hz is what the specs on a 12" guitar speaker work out to). Stand as far in front as you can, and crouch down to hear what your tone actually sounds like to everyone else. If you're standing close the high frequencies will go out under your knees; if you're off to the side, all you'll hear is low frequencies. You can also tip the amp up a bit to give yourself more working room to hear what you actually sound like. A workable strategy is to get the amp as high as you can and stand in front of it.. Preferably about 5 feet high, and at least 10 feet in behind you if you value your hearing. You can get ok tone; but chances are pretty good that what you will hear is not what everyone else will hear. Pretty difficult to work with. But any solution short of a full PA and stage monitors outdoors is going to have the same sort of problems. You'll also be playing a lot louder than you ever would indoors. There's a distinct risk that you can fart out the amp as you hit max volume. You should be prepared to add a significant amount of reverb if you're playing somewhere that has no natural reverb. And you'll probably still have to tweak eq. No reason why you can't be loud with 50w. No reason why you can't be really loud with 100W. You didn't say how big your amp was. I've played a 75w spider IV outdoors. It's ok. Loud enough for my purposes (jazz, so I'm not pushing the amp hard). I'm much happier playing though a 200W PA speak though, because it has a high-frequency horn that spreads the "cone of death" over a very wide angle horizontally (about 120 degrees). But it still needs to be raised because vertical dispersal of high frequencies is still pretty tight.

On my amp, there's no glue. There is a foam tape strip along the front edge that seems to stick to the top of the cabinet in places. Running a thin blade along the top front edge of the brain released it easily. There were two spots where the foam tape had stuck to the top of cabinet. No need to run along the entire edge. I put a pillow on the floor,and flipped the amp onto it's back so as to cushion the fall if the brain were to come away quickly. It was pretty obvious when I'd run the knife through the spots where the foam tape had bound to the top of the cabinet. Once the stuck spots are cleared, the entire brain slides out pretty smoothly. My guess is that once I remount the brain with screws on the top, the mostly-undamaged foam strip will continue to serve the purpose for which it was intended.