TC-50 fixed and sounding just as good as new

[bandit2013]

Since I got the amp back from Mesa for a minor repair (not related to the issue I previously had but almost thought it was ) to correct a latched mute circuit. Yes the TC-50 has a mute just like most Mesa amps to basically null the signal during channel changes. I had to check the amp to ensure the same performance was intact as this amp does not shut down the reverb and ramp it up after channel change like most Mesa amps (JP-2C, Roadster, Mark V which some say sounds like a reverb wash or fade in effect). Response time is fast as it was so I do not notice any reverb wash. FX loop is the same as it was from the start. I do not understand where this FX loop tone issue is coming from as my amp does not exhibit this problem. I ran the amp though all of the Strymon pedals and all is pristine and clear, followed by the Line6 DL4 and the TC Electronics Flashback x3 (has the crown on it). Not the last two do not work with the Mark V. I am not getting any tone suck or change in tone, no volume creep like I heard in recording from those who are having that issue. If you listen close enough you hear the volume creep after the loop was turned off too.

Being reunited with my new friend has been a pleasure (one that is difficult to stop playing though).

Also discovered one thing on CH3 with tight mode enabled and high gain settings.....The preamp of the TC-50 is similar to that of the RA100 except for the additional presence control and separated channels for Hi/Lo. Channel volume and gain interact with each other. Example: set your channel volume at noon and then raise or lower the gain (within a reasonable setting between 10oclock and 3oclock) the gain control will behave as a volume control as well as increase or decrease the gain characteristic. Same would apply if you set the gain and just adjust the channel volume. With a fixed gain setting and increase in control volume the gain characteristic will also change with a higher volume setting. If you what more gain, back off the channel volume to compensate otherwise you may get too much feedback. Sure a different amp will behave differently so if you suspect your guitar is causing the feedback it may as well be doing such as the response of the TC-50 is different than say a Mark series or Rectifier amp. The same would apply to the RA100 and what makes that particular amp a bit difficult is that the Hi/lo channel shares common tone and gain settings. What may be dialed in with the lo gain may just be swamped with feedback on the hi gain channel. I am sure one can find a happy median between the gain and volume control.

I generally like to boost the bass (more than what is recommended) say about 3 o'clock (pointing directly at the midrange control for those who have the combo the orientation will be inverted). Perhaps using a % would be more appropriate. 75% on the Bass, 50% to 60% on the midrange and 15% to 35% on the treble, adjust the presence to shape the gain character. 75% on gain and adjust the volume to your liking. If you are having issues with feedback, you may need to swap or replace either the V3 or V4 tube as one may be on the microphonic side. Try this, with no guitar plugged in, change channels with your desired settings. If you hear a slight ping though the speaker when changing from CH2 to CH3 or vs versa or from CH1 to the other two, chances are you may have a hyper sensitive tube. You can also use your fist and lightly knock on the enclosure across the top. You would hear some rattle or pinging noises if you have a hyper tube (microphonic or one that is on the onset of going microphonic). I had a couple in the JP-2C doing this (also you can hear it sometimes if it seems odd or responds erratically to the G string if muted.

This is one amazing amp. Also it does not rip my ear drums to pieces to get that awesome saturated gain. One analogy that comes to mind (not keen on analogies here as I dislike them in many ways but only on the SAT or college entrance exhams): The TC-50 is to the RA100 as is the JP-2C is to the Mark V. One step up and two steps back. if that makes any sense. Consider it an upgrade to what was current before the release of the amp but yet reverts back to some roots with more polish and precision to make it better. :roll: never mind...

 

[Joshwah333]

Glad to hear you got it back!! My bass settings are also at 3 o'clock.

Hopefully I get some time to experiment with midi tonight!

 

[bandit2013]

Higher bass settings on CH2 and Ch3 compensate for the brightness (especially on CH2). RA100 is quite similar in the Hi/Lo gain channels too. Bass response is a bit more refined with the TC-50. I have not popped in the Mesa Siemens EL-34 STR450's since the amp was returned. I believe that may have been the culprit for the fuse going. That may have resulted in transients on the supply line that took out the Triac that is used on the strobe mute circuit. Note that the fault occurred as a coincidence when the fuse failed.

As for the Midi, sounds great, sooner or later I will have to make use of the midi functions.

 

[Joshwah333]

So I finally sat down and figured everything out with midi and the TC-50. Way easier than I anticipated. I’m using a Line Helix via 4CM. First of all, I highly recommend the Pedal Python if you’re using a 4CM connection. Makes set up, tear down and transporting super easy. This is my first time using an effects processor 4CM - I’ve always been a pedalboard guy. My pedalboard setup is a Pedal Pad board that has custom in/outs for 4CM and vox fx processor connections. So basically - the Helix is a digital version of my analog pedalboard. Wasn’t sure what I would end up preferring, but I like the idea of both right now, for different purposes as well. The Helix sounds fantastic with some IR’s I downloaded from Sigma Audio 3 - tube amps will always sound better live but I can definitely record with this and no one would tell the difference.

But back to midi - I’m sold. Love the ease of setup and use. I got everything I need at the tap of a foot switch. Can’t wait to test it with the band at next weekends rehearsal.

 

[bandit2013]

The huge benefit I see with the Midi is the ability to daisy chain two amps. Unfortunately the commands for channel, fx loop, solo, reverb, are in conflict to the JP-2C so daisy chaining those to amps together will not work. If I wanted to run a dual amp rig I would probably opt for two JP-2Cs vs two TC-50.
I like the TC-50 as it is fun to play though but the JP-2C gets more use. Also new speakers for the Mark V and 12AT7 in V4 has also stolen my time from the other amps including the JP-2C. There is one thing that is really cool, blending the RA100 with the TC-50 is definitely an incredible experience as they are both similar yet different. Too bad the RA100 does not have midi. The TC-50 does make a good compliment with my other amps too. Running CH3 with a moderate gain setting along with the Roadster on CH4 Modern voice is quite interesting.

Friday night I decided to power up the TC-50 that sits on top of a Vertical 212 cab. What is right next to it is the JP-2C on another Vertical 212 cab. I had to get a second Mesa Vertical 212 cab as I am lazy on moving heads and reconnecting cabs as both amps it is easy to plug the speaker into the wrong jack (return or send) as they are close to the speaker outputs. Besides that, considering how the JP-2C sounds with the Vertical 212 running parallel to the Horizontal 212 I wanted something a bit more compact so the other vertical 212 was in order. I do not use the horizontal 212 cab all that much but does help to have one if you have the large sized heads as the vertical cabs are too narrow for them. Well, the JP-2C running two vertical 212 cabs is ideal, actually unbelievable, so I wanted to hear the difference if any with the TC-50 running both vertical 212 cabs in parallel. It was not bad at all, and this also reminded me how loud the TC-50 can be. I will have to compare that to the OS Recto 412 I use with the RA100. May even run the RA100 and TC-50 in parallel again as that was awesome (each amp has its own cab, transformer isolated signal splitter works and I would definitely recommend getting one to run tube amps in parallel, more so important if you attempt to run a tube amp in parallel with a solid state amp. This also keeps the signal path noise free and having a phase switch also may add a dimension to the tone.)

 

[Joshwah333]

I would recommend programs over commands.

I have a Marshall JVM at the band's rehearsal space and the TC-50 at home. So I made a list of MIDI program settings - just a basic list of what I needed and assigned a program number to each setting (0 - Clean/Reverb, 1-Clean/Reverb/FX Loop, etc.) I then set up the TC-50 with these programs and lastly, the JVM. This way, no matter what amp I was using, the program channels remained the same with my Line 6 Helix.

I'm pretty sure I'll never buy an amp that doesn't have midi again!

If you set it up this way, instead of commands - you can blend the two different amps with the same program settings for each.

 

[smallcrap]

Old thread but I was hoping bandit2013 might chime in on a question or issue I’m having with my TC-50 specific to HI channel gain levels and feedback.

I can’t put the gain past 1:30/2:00 without unbearable feedback from a few different guitars. And this isn’t at very high volume levels; 10/11:00. The manual talks about ranges from 3-5 etc. so it seems this shouldn’t be feeding back so early.

Can you (or other TC-50 owners) tell me how high you are able to get the gain on the HI channel, and at what Master and Output level? Thanks.

 

[mace]

With the TC-50 I've found gain can be set at 3:00 without squealing, but not sure i've played this setting at high volumes. General things to do are to stand further away from the amp, point speaker away from guitar etc. but, you probably knew that.

It is so annoying when the strings are muted and the pick-ups squeal. I've had that squealing issue happen with the rectoverb at band practice. This was with guitars that do not have squealing with a high gain Mark V. I've not noticed it so much on the TC-50 but I haven't gigged with that so much. I think the issue is more a combination of amp and guitar and the frequencies which are sensitive to squealing in the pick-ups and the frequencies emphasized by the distortion in the amp.

Now that you mention it, this just happened last practice with a PRS Holcomb and old Krank amp. The Holcomb is not a squeal prone guitar. But, I was close to the amp, it was loud and the cab was tilted up. In fact, I've used this set-up a lot at practice and it hadn't squealed until last practice.

Long time ago I tried "potting" the pick-ups in wax on a old 1970s Epiphone guitar which was prone to squealing. It knocked the resonant frequency down in pitch so the squeal was not quite as irritating and also did help with reducing the occurrence of squealing.

 

[smallcrap]

Thanks for the input mace. Where would you say your channel Master and output are set? I can certainly get guitar feedback on my RA-100 if i push the HI channel gain past 2 oclock, but it is much louder overall before I get to that point. It just seems quite low/early on the TC-50.

 

[bandit2013]

Been a while since I logged in....
I think mace has the correct answer.
Some other ideas, stuff some compressible foam behind the pickup, it needs to be very compressible, if it is too stiff it will push the pickup out. I had several guitars that would just roll into feedback and was more so an issue if I place my hand over the bridge pickup. The guitar in question almost has a chambered body based on how the wire route was made. Maple neck though design with koa body wings. Pickup wire channels were milled into the side of the lower body section which did create a hollow chamber. My fix was to use some the soft foam that used for packing guitar pickups. Cut to size and inserted into the pickup cavity under the pickup to dampen some resonance. Not a sure fix but helps. With that guitar, my usual settings may excite the issue you described. Have a few more Stratocasters and some Charvels that are sensitive too but can push the gain high on the TC series if you compensate with the channel volume level and cut back on the presence. I also use the guitar volume control much more than I used to. I was one who would dime the guitar volume and tone control and expect to dial in the amp. That method does not always work out with some high gain amps like the TC, Multi-watt Dual Rec, JP-2C, Mark V. Roadster and Royal Atlantic.

If tube related:
Triple Crown does have a compensated gain structure for the hi/lo gain channels. For one, the presence control is a high pass filter and I believe it is using an op-amp for this function. Same would apply for the tight mode circuit. I am assuming it is op-amp compensated since I do not have the schematic of the TC but have seen a few op-amps on the preamp board. Royal Atlantic has this too but only for the clean channel. Change in preamp tubes to other types in the same 12AX7 family will not make any difference. You could have a hyper tube though so if it excites easily into feedback, compensated or not, you will have some problems. You could try swapping out v1 or v2 with v3 or v4. V1 and V2 are for the clean channel only and V3 and V4 are used for the hi/lo gain channel only. If that does nothing, you may want to get another 12AT7 tube and replace V5. Since V5 is a cathode follower circuit for the send signal and return is just standard gain stage to return signal level, if the triodes are not match you can get some weird things going on. Note that the FX tube V5 is always in the signal path, the FX on/off is just a relay to split the path to the jacks.