Feel free to ask Myles

[myles_rose]

GT emulators - have a lot of them even today. There really is no recommended setting, it is trial and error but start with all knobs at noon initially. Have the EQ switched off until you get comfortable with input and output levels.

[simpleman3441]

I have a Fender Bassman Reissue. I like the tone but I'm wondering if there's a simple mod to get it to break up sooner? I bought it years ago and my tastes have changed. Hopin to make it work for me rather than look at something new.

 

Also, it's got a normal and bright channel that you can link and blend. Would that add or take away from how quickly it breaks up?

[myles_rose]

Jumpering the two sides really has little to do with output stage breakup. The front end uses 1/2 if V1 for the normal and the other half for the bright so in the end you are blending them two sides.

 

If you want the output to break sooner find a shorter plate 12AX7 phase inverter (V3) that has less plate current - something about 0.8mA vs the spec 1.2mA. You can also find s set of good 6L6 output tubes that are a bit on the weak side, bias a bit colder at say 28mA and this will help as well. This will help some bu tthese are pretty loud amps and you may have to go with something like an attenuator. There are a lot of good tube vendors out there ... some I like are:

 

www.kcanostubes.com www.dougstubes.com www.tubedepot.com

 

 

[simpleman3441]

Awesome, thanks!

[Caevan O’Shite]

If you want the output to break sooner find a shorter plate 12AX7 phase inverter (V3) that has less plate current - something about 0.8mA vs the spec 1.2mA. You can also find s set of good 6L6 output tubes that are a bit on the weak side, bias a bit colder at say 28mA and this will help as well. This will help some bu tthese are pretty loud amps and you may have to go with something like an attenuator. There are a lot of good tube vendors out there ... some I like are:

 

www.kcanostubes.com www.dougstubes.com www.tubedepot.com

 

 

I will certainly vouch for Doug at Doug's Tubes, whom Myles had recommended to me...

 

Tell 'im exactly what you're after with what amp and all, and he'll steer you right; and you'll be able to repeat the same sound and response with future replacements by simply getting the same tubes and specs from him down the road (keep a record of exactly what you buy, including what's been hand-written on the boxes your tubes came in from him).

[simpleman3441]

Thanks, Caev. You're a good guy to have around!

[Bluesape]

Hey Myles,

 

My buddy Dave(CL10 here) is having surprise shutdowns to Zero volume with his Classic 30, which recovers after a cool down. It usually cuts out in 1.5 to 2 hours playing nearly dimed. There is no standby switch, and he's wondering if it's possibly as simple as a resistor replacement. I've always heard good reliability reports with these. I know I'm not furnishing much info here, but do these units have known issues like this?

[myles_rose]

This could be a few things but if the tubes are known good then I'd look at a bad solder joint that is heat sensitive or a trace on the PCB, both common issues. The Classic 30 is indeed a classic and generally quite servicable but over time they can develop issues just as is more common in amps in this price range.

[Bluesape]

Thanks for getting back so fast!

[myles_rose]

You are quite welcome

[rouleau]

Hello !

 

What do you think about THD Hot plate and what do you thing of using it with an amp with a preamp distortion la mesa boogie dual Rectifier ?

 

ThanK's

[myles_rose]

THD Hot Plates are nice. I see no purpose for any device such as these though in a Mesa dual recto as all it's sound character comes from the front end and front end distortion in this amp always overpowers output section distortion and there is little if any touch sensitive or dynamic touch control of the output section of these amps. Just the nature of their design. If you want to push things so hard to get some different aspect of the output section then go ahead and use an attenuator. Won't really change the nature of the tone and it will wear out tubes faster but it is one option.

[Winston Psmith]

Greetings Myles,

 

I recently found a Roland amp at a local pawn shop, stupid cheap price; my only concern is that some idiot removed the ground pin. (Why do people still do this!?!) I powered it up just long enough to be sure everything worked, which it did, and then called a buddy who does repairs. He assured me that this was a $4 fix, if I just grabbed a replacement plug at my local hardware store, and that I should go ahead and buy the amp. Given that I'm cheap, guitar poor, and reasonably handy with a screwdriver, I'm inclined to do the job myself, but I'd appreciate any warnings or advice. Sorry to take up your time with a really basic repair issue like this, but it's worth asking, to avoid a night in the ER.

[myles_rose]

Replacing the plug on the end of the existing wire is easy, just note which wires are connected to hot - neutral - ground and have them arranged properly. If you are not sure use a proper tech as you do not want to risk death for $4.

[Caevan O’Shite]

Say, Myles, would you please kindly weigh-in on the following thread?

 

Here's a link for your convenience:

 

How does an amp take to pedals well?-thread

 

Thanks!

[Caevan O’Shite]

Thanks, Myles!

[Caevan O’Shite]

So, Myles-

 

Am I correct in thinking that a tube-amp with a higher impedance input will more properly load pedals placed before it and contribute to a better, more robust sound when using said pedals?

 

-And-

 

 

What does the way a given tube-amp handles current impart to the way the amp performs with pedals?

[myles_rose]

There are many many many many factors and it would take a big book to begin to cover the subject.

[Caevan O’Shite]

OK, let me ask you this-

 

if you were either designing or looking for an amp that would do well with most pedals placed in front of its input, what features and details would you design in or look for to that end?

[myles_rose]

Not a lot of gain in the front end is a good rule of thumb.

[Winston Psmith]

Thanks, Myles, for the grounded plug advice. Better to be safe than electrocuted . . .

[myles_rose]

Safety first

[chimera963]

Myles, a friend linked me to this thread.

 

I am having an issue with my Carvin x100b head, going through a Mesa Boogie Recto 2x12" (loaded with V30s). I get quite a muddy and fizzy distortion, which I know the amp shouldn't sound like.

 

I tried the Carvin through a friend's Mesa F-50 combo speaker (Black Shadow speaker) and it sounded meatier, clear and more focused, what I expect the amp to sound like!

 

Now without going as drastic as replacing the speakers in my cabinet, would you be able to recommend anything that could solve my issue?

 

Many thanks.

[myles_rose]

Speakers are a personal preference issue. Is the 2x12 cab open or closed back? Most folks prefer closed back config with your amp head type as it is in the Marshall camp. If you like a black shadow (Celestion 85 watter) over a V30 and the speakers were in the same cabinet that tells you something. If the cabs were not the same cab all bets are off.

[chimera963]

The Mesa Boogie 2x12" Recto is closed back, and I tried the Black Shadow through my friend's 1x12" combo, so not the same cabinet.

 

I also tried an Orange HP cabinet, loaded with Celestion K100's, which I hoped would solve this issue, but this was a bit fizzy too (possibly in a higher frequency range?).

 

Is there anything I can do in relation to the tubes, that could solve this problem?

[myles_rose]

Tubes will not really solve the issue here. It seems as if you are in a cycle of taking the basic nature of an amp that is not on the mark for your needs and altering the tone a bit via speaker changes. It may be time to hit a few music stores and visit a few friends with different amps and re-examine your needs and taste. As we grow as players our need for a more articulate, responsive and refined amp grows. Like a new driver who can get around in almost anything versus a driver who can utilize a car that handles well as their taste and requirements change with experience and as time passes. The Carvin X100B is a very basic amp with limited vocabulary. Nice amp for what it does but what it does falls within a specific range. There are parts such as caps in the tone circuit and things like transformers which limit what this circuit design can and will be able to do as well as make the amp somewhat abrupt in tone.

[Zephyr]

Hey Myles,

 

I recently purchased a balanced JAN 5751 from Tube Depot to experiment with as a Phase Inverter. I was looking at the specs, and it's gain is 95 per triode.

 

Is it just me, or does that seem more in the range of a 12AX7?

[myles_rose]

I would ask how they are measuring gain as the gain should be 60-70 based on book spec. Perhaps they mean 95% of spec or something like that? Ask them at what voltage and bias the tube was tested at, what was the mutual conductance, plate resistance and plate current if that data is available. Let me know and I will reply again.

[Zephyr]

I would ask how they are measuring gain as the gain should be 60-70 based on book spec. Perhaps they mean 95% of spec or something like that? Ask them at what voltage and bias the tube was tested at, what was the mutual conductance, plate resistance and plate current if that data is available. Let me know and I will reply again.

 

This is the reply I received:

 

Thank you for your email. For preamp tube testing, we use the Vacuum Tube Valley dual triode characterizer. This tester provides voltage readings that are unique to this specific tester, and the test readings provided do not correlate to readings from other testers. We do not have specs available for the voltage and bias ratings used with this tester.

Let us know if you have any other questions. Thank you.

 

I don't know what to make of this

[myles_rose]

OK ... all bets are sort of off as the VTV tester has a scale marked gain but it is not an actual gain scale.