Wizard owners….loop question please

[mctallica1]

I have used an MXR 10 band EQ in the loop of most of my amps over the last 20 years or so for a lot of reasons, but one thing iI’ve done more and more over the years is use the volume slider as a bit of an attenuator, so I can push the power tubes just a bit to get a little squish.

Enter the Wizard MCII MKII 40 I recently bought. Even with the volume slider at the bottom, I am not getting much volume reduction, so I started fiddling with the send and return knobs and found that if I keep the send knob at noon and the return knob at about 9 o’clock, I get the attenuation I am looking for to provide that last bit of squish/sag. I have the lead master at 4.

My question is….can what I’m doing cause any harm to the amp?

Even with over 35 years experience with tube amps, I don’t have a lot of electrical knowledge.

Thanks!
T

 

[glpg80]

That’s a valid question. You’re fine - the send and return levels are there just to help with the specific outboard gear you’re using. There’s either instrument or line level and most just design for level controls that can compensate for either. All you’re doing is playing with where the attenuation occurs in the amp to get the feel you want alongside the master volume.

 

[mctallica1]

Thanks dude. I knew someone with more knowledge than me would answer.

I know A LOT about what tubes get me the tone I’m looking for, but the actual electrical stuff is a bit of a mystery to me.

 

[* velcro-fly *]

I have used an MXR 10 band EQ in the loop of most of my amps over the last 20 years or so for a lot of reasons, but one thing iI’ve done more and more over the years is use the volume slider as a bit of an attenuator, so I can push the power tubes just a bit to get a little squish.

Enter the Wizard MCII MKII 40 I recently bought. Even with the volume slider at the bottom, I am not getting much volume reduction, so I started fiddling with the send and return knobs and found that if I keep the send knob at noon and the return knob at about 9 o’clock, I get the attenuation I am looking for to provide that last bit of squish/sag. I have the lead master at 4.

My question is….can what I’m doing cause any harm to the amp?

Even with over 35 years experience with tube amps, I don’t have a lot of electrical knowledge.

Thanks!
T

That's basically exactly how I've run my MCII 25 for years and a few hundred gigs (yours is basically the same amp with another set of 6V6's) I use a clean boost in the loop for solo volume bump only (TC Spark mini right now, but have used Koko Boost, Suhr ISO Boost, CAE Line Driver)

 

[Jimty]

I jump the effects loops on a lot of my amps and use the loop controls as additional volume controls - including on the Headfirst version of the MCII I have

 

[TheGreatGreen]

Wizard loops have dedicated level controls for both the loop Send and Return jacks on the back, and they are NOT subtractive only. You get a pretty huge boost in level running both knobs at max.

Instead, a good starting point is to use a simple patch cable in the loop and toggle the loop on and off while you adjust both knobs equally until you hit unity, or no difference in volume with the loop on or off. That will give you the most volume range to begin working with in both the Send and Return jacks, and also probably the the best (meaning lowest) noise floor starting point. On my Wizards, I get unity gain with these knobs set equally somewhere around 2:30-3:00. I find that to be a pretty good starting point. From there, if the Send volume clips your loop effects, turn the Send volume down and increase the Return volume to compensate. If you want more attenuation, keep turning the Return volume down until you get where you want.


Regarding attenuating a tube amp power section: Messing with effects loop volumes isn't attenuating the poweramp. You can't use changes in effects loop volume to manipulate the power tubes into compressing or clipping earlier than they otherwise would. The amount of distortion a power section generates per physical volume it attempts to output will be the same no matter what happens before it. The only way to lower your physical volume while retaining your power section's compression and harmonic characteristics is to use a reactive load + 2nd poweramp reamping solution, which will be in the signal path after the power section. If you're hearing additional distortion or harmonics that aren't there when you turn off the loop, what you're probably actually doing is overdriving the effects loop's dedicated preamp tube, OR you're overdriving your effects loop EQ pedal's input or output stage.

Either way though, like @glpg80 said, you're not going to physically hurt anything no matter how you set your loop levels, so it's fine to experiment however you like!

 

[mctallica1]

Wizard loops have dedicated level controls for both the loop Send and Return jacks on the back, and they are NOT subtractive only. You get a pretty huge boost in level running both knobs at max.

Instead, a good starting point is to use a simple patch cable in the loop and toggle the loop on and off while you adjust both knobs equally until you hit unity, or no difference in volume with the loop on or off. That will give you the most volume range to begin working with in both the Send and Return jacks, and also probably the the best (meaning lowest) noise floor starting point. On my Wizards, I get unity gain with these knobs set equally somewhere around 2:30-3:00. I find that to be a pretty good starting point. From there, if the Send volume clips your loop effects, turn the Send volume down and increase the Return volume to compensate. If you want more attenuation, keep turning the Return volume down until you get where you want.


Regarding attenuating a tube amp power section: Messing with effects loop volumes isn't attenuating the poweramp. You can't use changes in effects loop volume to manipulate the power tubes into compressing or clipping earlier than they otherwise would. The amount of distortion a power section generates per physical volume it attempts to output will be the same no matter what happens before it. The only way to lower your physical volume while retaining your power section's compression and harmonic characteristics is to use a reactive load + 2nd poweramp reamping solution, which will be in the signal path after the power section. If you're hearing additional distortion or harmonics that aren't there when you turn off the loop, what you're probably actually doing is overdriving the effects loop's dedicated preamp tube, OR you're overdriving your effects loop EQ pedal's input or output stage.

Either way though, like @glpg80 said, you're not going to physically hurt anything no matter how you set your loop levels, so it's fine to experiment however you like!

Interesting.

Based on what you are saying, I must be overdriving the preamp tube or one of the pedals. Regardless what it is, I find it to be that last bit of grease I’m looking for.

 

[TheGreatGreen]

Interesting.

Based on what you are saying, I must be overdriving the preamp tube or one of the pedals. Regardless what it is, I find it to be that last bit of grease I’m looking for.

Well with chasing sound, the rule that supersedes everything is: if it sounds good, it is good.

 

[DanTravis62]

That's basically exactly how I've run my MCII 25 for years and a few hundred gigs (yours is basically the same amp with another set of 6V6's) I use a clean boost in the loop for solo volume bump only (TC Spark mini right now, but have used Koko Boost, Suhr ISO Boost, CAE Line Driver)

i was literally going to comment "isn't this how velcro runs his 6v6 wizard at gigs every night?"

I don't think its a stupid question at all, especially not for an amp that expensive, but I'm pretty sure you both are kosher

 

[fusedbrain]

.........Regarding attenuating a tube amp power section: Messing with effects loop volumes isn't attenuating the poweramp. You can't use changes in effects loop volume to manipulate the power tubes into compressing or clipping earlier than they otherwise would. The amount of distortion a power section generates per physical volume it attempts to output will be the same no matter what happens before it. The only way to lower your physical volume while retaining your power section's compression and harmonic characteristics is to use a reactive load + 2nd poweramp reamping solution, which will be in the signal path after the power section. If you're hearing additional distortion or harmonics that aren't there when you turn off the loop, what you're probably actually doing is overdriving the effects loop's dedicated preamp tube, OR you're overdriving your effects loop EQ pedal's input or output stage.
..........

This is correct, but with the Wizard MCII circuit, there is an anomaly:
There is a gain stage after the master volume, so attenuating at the loop, and turning the master volume up a bit more, does add a wee bit more "grease" to the signal, notwithstanding what else is happening with the fx loop level, and how hard you are hitting whatever is in the loop.