Another TC-100 vs Badlander topic + a novel trick

[bandit2013]

Yes, the STR448 are the TAD red base 6L6GC tubes. They sound good in the JP2C and that was about it. Tried them in my other amps and just did not like the end result. STR415 are probably the best, a bit tighter than the STR448. For a slight softer low end and a bit more air the STR448 sound great. Mark VII, made the amp sound boxy. Same with the STR415. I did try the STR445 in the JP2C, actually sounded great, much closer to the STR415 then I expected than the STR448.

 

[starbelly]

@bandit2013

I’ve been having pretty severe issues with my TC-100 effects loop; the tone of the amp is MUCH worse when the loop is engaged vs off. This seems like a fairly well documented issue with this amp, but it’s a slight volume drop, and the amp becomes much “duller” (more tubby and less highs).

Will replacing the V5 tube with the JAN Philips 12AX7 help with this at all? Honestly this issue just makes me want to sell an otherwise awesome amp (right now I’m preferring my Badlander 100).

 

[domct203]

@bandit2013

I’ve been having pretty severe issues with my TC-100 effects loop; the tone of the amp is MUCH worse when the loop is engaged vs off. This seems like a fairly well documented issue with this amp, but it’s a slight volume drop, and the amp becomes much “duller” (more tubby and less highs).

Will replacing the V5 tube with the JAN Philips 12AX7 help with this at all? Honestly this issue just makes me want to sell an otherwise awesome amp (right now I’m preferring my Badlander 100).

What do you have for effects in the FX Loop? Does this happen with nothing in the FX Loop?

V5 is always in the signal path, regardless of whether the FX Loop is on or off.

Anything placed in any FX Loop (beyond just a patch cable) of any amp is going to impact the tone, all effects color the sound to an extent. Signal drop could be either the effect clipping in its input stage or an impedance mismatch.

For troubleshooting purposes, if you remove all effects from the FX Loop and just use a short good quality patch cable from send to return do you have the exact same issues with the FX Loop engaged vs off?

Dom

 

[bandit2013]

Dom is exactly correct on this.
V5 circuit never gets bypassed. It is always active, meaning the signal from the preamp will pass through the cathode follower FX driver triode and then through the FX recovery triode circuit.

The only thing the footswitch button (or back panel toggle switch) does is break the internal jumper that links the send/return connection so that all signal will run through the jacks.

Note that the FX loop is at line level, meaning +4dBu strength. Not all FX units are suitable for this signal level and are mostly designed for instrument level which would be -20dBu.

I basically got rid of most of the FX I used with the Mark III and Mark IV after getting the Mark V90. Nothing worked in the FX loop of that amp, except for one brand, Strymon. There may be others out there, just read the manual, if it does not have any mention on signal level at +4dBu or higher, it will not work and tone suck is what you get. This also holds true to the TC, BAD, RA, MWDR, Roadster. Instrument level devices will suffer either with excessive compression due to a swamped buffer or drop in volume as the output of those devices is also rated for instrument level. Not sure on the Mark VII or JP2C, I can run a Line-6 DL4 in the FX loop and no tone suck. I cannot do the same with the Mark V90. Odd, I was able to run the same in the TC, BAD, RA, MWDR and Roadster without issue. The Mark V90 has other issues so we can rule that one out.

All the JAN/Phillips 12AT7 will do is improve on sound quality as it is a much better tube than the Chinese 12AT7 or the Tung Sol 12AT7. Most of them are also balanced and matched as it is a military grade tube. I was loosing volume with the amp, no FX units in the loop either. The TC50 was way louder than the TC-100. The TC-100 was loosing the ability to recover its own signal. Once I changed V5, the TC100 never sounded better.

I got curious since many were complaining on tone suck or other issues with the TC, but the issue does not stop there, this covers most of the Mesa products except for the early models of the Mark amps as they were more compatible with instrument level fx units.

I have the Ebtech Line Level Shifter but that device will not work with the high impedance instrument level as it is only intended to convert +4dBu down to -10dBu and back again. Both the +4dBU and -10dBu are classified as line level signals. -10dBu is more like a CD player or your basic stereo equipment gear for home audio. Since I also have a 32-channel mixer I use with the drum kit, standard +4dBu (balanced TRS or unbalanced TS). It also has two channels that can be used with external FX units, same with the TASCAM digital recorder. I have used the Strymon BigSky with those devices without any issue. There are not many FX units that can operate with the line level signals and yet be used with instrument level except for one brand which is basically all I am using now. Strymon.

There are some devices available that will work with instrument level fx units that can be used with the FX loop at line level. They are called re-amp devices. Most are just one way but I did find one that has two channels as its purpose was to make use of instrument level FX units with a line level mixer or recording device. It also serves as a re-amp unit. I do not have one though as I no longer have any instrument level fx pedals or units. I copied the link on this subject. In case you were wondering, Theresa is a Mesa person who may comment on subject. I did this out of curiosity and this is what I found.

https://boogieforum.com/threads/there-may-be-a-fix-for-instrument-level-fx-pedals.87299/

 

[starbelly]

What do you have for effects in the FX Loop? Does this happen with nothing in the FX Loop?

V5 is always in the signal path, regardless of whether the FX Loop is on or off.

Anything placed in any FX Loop (beyond just a patch cable) of any amp is going to impact the tone, all effects color the sound to an extent. Signal drop could be either the effect clipping in its input stage or an impedance mismatch.

For troubleshooting purposes, if you remove all effects from the FX Loop and just use a short good quality patch cable from send to return do you have the exact same issues with the FX Loop engaged vs off?

Dom

The effects loop current contains a DOD Rubberneck, Boss DM-2W, Walrus Audio Monument V2, and Hardwire Supernatural. I’ve tested it with nothing in the loop, as well as Mesa’s own ClearLink Send buffer, and the issue is exactly the same.

One weird thing I noticed yesterday is that when I was trying to test it with just an EBS flat patch cable, the loop would not engage; it would only engage when I had standard instrument cables from my pedals.

Any feedback would be appreciated!

 

[domct203]

Was the ‘EBS’ cable a TRS (stereo) cable?

I don’t have the schematic for the TC-100 but it should be either a relay or basic solid state circuit switching the effects signal in and out, there should be hardly any difference when there is nothing but a short guitar patch cable in the loop.

At this point I’m not sure if changing V5 with an NOS tube would make a difference. Do you have any other 12AT7 tube to try first? Maybe something from another amp?

 

[starbelly]

The EBS Flat Patch Cables are just regular patch cables. And yeah, I just think it wasn't plugged in all the way; there is little difference when the loop is engaged vs not engaged.

It's unfortunate how hyper selective the TC 100 is with the effects loop; I think most people are going to be using pedals that the TC-100 won't like. They work flawlessly in my other amps (Including a Badlands 100), as far as I can tell, but the TC-100 has the curse of being able to quickly A/B the tone by engaging and disengaging the loop.

None of this would be a problem if you could compensate for the significant change in tone with the TC 100 with the effects loop engaged using the tone controls, but you can't; in my experience you can't get the same high end presence back or dial out the added flub. Some have suggested using something like a Hotline Fat Buffer at the end of the loop, and I can say that it DOES work, but not for the reason that the user who initially suggested it provided. They said it was because of the buffer, but I think it's more to do with the onboard EQ that do a close enough job of being able to compensate for the tone suck in the way a graphic EQ in the loop would.

 

[bandit2013]

The Badlander runs a basic Rectifier 12AX7 cathode follower for the send and typical triode circuit for the recovery. I would almost feel that if it works with the Badlander it should work with the TC-100 but I never measured the signal strength on the BAD. Only the Mark V, JP2C and TC-50 (which is the same preamp as the TC-100). The Triple Crown had a much higher signal level. +8 on clean if you max out the channel volume. CH2 and CH3 were not as high due to compression. They were +3dBu or a bit lower. I do not remember that test I did, it was a few years ago.

How long are your cable runs? You mentioned you are using a Clear Link Buffer. In order for that to work you need two of the send and two of the receive units for using the fx in the loop of an amp. Most of the instructions are for front end devices (guitar, fx, and then to amp). Between the clear link send and clear link receive use a microphone balanced cable. XLR which will have a much lower impedance. then again, you could probably just use one link-send and link-receive at the amp and the EXTC-SA for the fx units where ever you put it. XLR cables again. For long runs, always use the XLR microphone cable since the send/receive have the jacks for such as well as the EXTC-SA. This is out of my experience so I will leave it up to the experts on that subject.

However, many just keep their gear in a drawer and use some other form of interface to control the fx units. That way only the controller signal is running the long distance and the guitar signal remains short and close to the amp(s). I never went down that path and my runs are 6-8 feet long. I sort of ended up running a 4 amp rig so that has its own tricks but much easier than long FX loop runs.

Not sure if there is any merit in the FX tube swap, it will not hurt to change it. It may actually sound better. Tone suck is more related to the cables, and the FX units not capable of line level (low impedance).

 

[starbelly]

How long are your cable runs? You mentioned you are using a Clear Link Buffer.

My cable runs with the effects loop include a 10’ cables for each send and return. I am not presently using the ClearLink; I purchased it on suggestion of a Mesa tech who said the effects loop tone issue “shouldn’t be happening”. Ultimately they blamed my gear, which was a huge help, haha.

 

[bandit2013]

OK, I see. The effects are a major contributor to any issues with the FX loop. That is unfortunate.
Yeah, the Badlander has a dedicated loop, whatever you place in the fx circuit becomes the signal path. The only means to turn off the fx loop is to disable the effect with its onboard bypass switch. The RA100 is much the same way and has no means of bypassing the send/return jacks with a relay like the TC100. The JP2C is also this way but does have a controllable relay but only with midi or the mini toggle switch on the front panel. Not easy to A/B test unless there is only one effect in the loop or you have a pedal that can serve as a bypass control.

Change of the V5 tube should help if the tube you have in there is causing issue. My TC was loaded with the Chinse 12AT7 tube (actually both TC100 and TC50 were this way). I noticed Mesa changed to the Tung Sol 12AT7. I tried one from the TT800 bass amp and thought it was too bright for my taste. Since I had a few of the JAN/Phillips 12AT7 tubes I gave that a shot and was happy that made an impact. Not only did the amp get louder it sounded much better. Lets just say the output was not what a 100W amp should sound like. Now it is almost on par with the BAD100 but that beast is quite different.

Look at the effects manuals, If it does not have the maximum input signal level stated like this, the device is more or less instrument level (-20dBu).

I looked up the DOD Rubberneck, no mention of signal levels. If not stated, it is instrument level.

I did not look up the other devices.

As it seems, most FX manufacturers are still living in the past where amps did not have any FX loops. Sure, they show how to hook it up to an FX loop, but they are still working with yesterday's requirements from 1957-1997. High impedance inputs/outputs specifically for instrument level so it can be used on the front end of your Fender Champ without saturating the first and probably only gain stage. There are not many FX manufacturers that have a universal FX unit design. I am not trying to plug Strymon stuff here, I can use the majority of the devices intended for FX loop in front of the amp as well without issue. Not all of their stuff is for FX loop like the OD/sustain stuff. That is the first thing I look at is the specifications, is it compatible with line level signals or not?

However, that Radial device may work for your application with the TC100.

I would suggest in trying each of your pedals in the FX loop by itself. No other pedals in the chain. Some may work or will compress, distort, or lose volume. I would use the clean channel without any distortion first.

What does work: Boss DD-200 and Boss EQ-200. I have them and used them for quite a long time with the RA100 and TC amps. What states line level but drops the volume is the Source Audio Ventris. I may have done something wrong with it, I hated the pedal after using the USB features. But I did not like it before that either. Too much volume reduction but the effect still sounded good.

Boss TerraEcho is not line level but works with all of my amps, go figure. I had thought it was a +20dBu but perhaps I miss-read the information.

I have gone through many effects to find what works with the Mark V90. Not many would work with that amp. Mark III and Mark IVB were more compatible with instrument level effects. At that time I assumed there was some sort of standard for FX loops. Not true. That is how I stumbled upon Strymon. First the DIG, and then the BigSky. Now I have several of those products. I do not use anything else except for the Boss DD-200 or Boss EQ-200 if I need that in a stereo format.

 

[domct203]

There is also impedance matching. It’s best to have a high input and low output impedance to keep the signal between devices consistent. The DM-2W has a somewhat high output impedance of 1K ohm, compared to most line-level devices where that would usually be 100 ohm, like the Strymon Brig referenced above.

Instrument level signals (high Z) will generally have high output impedance compared to line level (low Z) devices that will have a much lower output impedance.

Have you tried using each pedal individually to see if one (or more) are loading up the FX Loop dropping your signal level? If each pedal works ok, start adding pedals one at a time to see what happens.

Impedance mismatch can cause strange signal issues. I have a TC Quintessence that works fine in my FX Loop alone, and in the loop signal chain after my G-Major. If I put it in front of the G-Major it overdrives the input and clips the G-Major.

Dom

 

[starbelly]

I'll have to try each pedal one at a time. Again, this wouldn't be an issue if you could compensate for the tone changes with the loop engaged with the amp's tone controls, but you can't :/

 

[domct203]

I'll have to try each pedal one at a time. Again, this wouldn't be an issue if you could compensate for the tone changes with the loop engaged with the amp's tone controls, but you can't :/

Or it could be an impedance mismatch and/or improper signal level.

But yea, I use a Graphic EQ in the Loops of my TC-100’s.

Dom

 

[starbelly]

Or it could be an impedance mismatch and/or improper signal level.

I know the TC manual also states the best balances for the channel masters and output for best levels at the loop. I've tried following these, and the issue persists. As such, I'll need to look into what you suggested; I appreciate the help!

 

[starbelly]

Got the new tube and yeah, no real improvement with the issue (maybe a small one, if any). I still get a slight volume drop and noticeable tone change. I'll keep tinkering though.

 

[domct203]

Throw a graphic EQ in the loop, it really wakes up the TC series and a quality one will take care of any signal gain/tone issues. I purposely use mine to enhance the tone of the amp with overdrive tones, EQ is not needed for cleans as ch 1 is not as filtered as the high gain channels. I also always leave the loop switched in as I never play dry in a live setting so my tone is dialed in to be its best with the loop in use. I don’t get hung up on the fact that the amp sounds different with the loop in or out, because of how I use my FX Loop my amps actually sound better with the loop engaged. If I switch off the loop I lose my EQ and the amp sounds thin and dull in comparison.

 

[starbelly]

Throw a graphic EQ in the loop, it really wakes up the TC series and a quality one will take care of any signal gain/tone issues. I purposely use mine to enhance the tone of the amp with overdrive tones, EQ is not needed for cleans as ch 1 is not as filtered as the high gain channels. I also always leave the loop switched in as I never play dry in a live setting so my tone is dialed in to be its best with the loop in use. I don’t get hung up on the fact that the amp sounds different with the loop in or out, because of how I use my FX Loop my amps actually sound better with the loop engaged. If I switch off the loop I lose my EQ and the amp sounds thin and dull in comparison.

Yeah I have a graphic EQ pedal, but I'd have to kick another pedal off my board. Decisions decisions, haha. Where do you put your EQ in the loop? Before delay and reverb?

 

[domct203]

I have my EQ last in the FX Loop chain. I use a TC Electronics G-Major for all my loop effects, chorus, pitch, delay and reverb mostly.

https://boogieforum.com/threads/stereo-tc-100-rig.87239/

 

[bandit2013]

I also did that, GEQ as the last unit in the chain. This way I can cut back on any bright effects (shimmer or reverb with some bright overtones). The Boss DD-200 was first in the chain, send(s) from each amp (left and right), followed by the Strymon BigSky reverb, then to the Boss EQ-200 and the left and right returns are taken back to the two amps. This is what I use with the two RA100's and have done the same with the TC100 and TC50. If this was just a mono setup, omit the right channels.