Thinking about buying a Variac for my JTM45 (input needed)

[lespaul339]

I want to get a Variac to find that voltage sweet spot my amp likes to run at. I've noticed certain days my amp sings like no other. The tone is amazing and so inspiring and it's harmonically rich sounding and other days the tone just isn't quite there like it was the day before. I know the wall voltage where I live can fluctuate. It's the only explanation for that. I mean even on an "off" day, my amp still sounds good, but I want that inspiring tone all of the time.

I was looking at the Brown Box, but at $350 that's too expensive. Found some Variacs on Amazon. They're not as pretty looking as a Brown Box, but they do the same job at a fraction of the cost.

Looking at this one. I like the idea of a digital display. My thought process is a smaller 5A one like this would be better than a 20A one for my JTM45 since my JTM has a 3 Amp fuse I don't see the need to get one rated at 20A. I like the idea if something goes wrong that it blows the 5A fuse first. Here's what I'm looking at. What do you guys think?

https://www.amazon.com/Circuit-specialists-Variable-Autotransformer-Digital/dp/B084T5N2QS/ref=sr_1_4?keywords=120v+variac+5+amp&qid=1674833140&sr=8-4&ufe=app_do%3Aamzn1.fos.006c50ae-5d4c-4777-9bc0-4513d670b6bc

 

[cooljuk]

Your red Chinese variac is a death trap

I knew these were junk and poorly constructed. ...but I didn't realize how much so until I took mine apart beyond just a peak inside. I started off with a plan to remove the core from mine and use it in another power supply project. Those meters are HUGE and it's going to be an awesome power...

www.mylespaul.com

You can buy a NOS or used US-made decent one on eBay for about the same price.

I would aim higher than 5A. Some amps draw that much and you’ll want some headroom. Your logic that the 5A fuse will blow before a 3A fuse, just because it’s first in line, isn’t how that works.

 

[lespaul339]

Thank you for sharing that. I was wondering how the quality would be. I will start looking elsewhere.

 

[Dogs of Doom]

I've heard over & over about those chinese ones, that they are very inaccurate. You'd still do well to buy an external voltage meter. Even w. the US made ones, they typically don't have a voltage readout, & so, when you turn the dial, to say 110v, it's assuming that you have the desired input to put out 110v. So, as your wall fluctuates, you need something to read what's coming out of the variac...

 

[Tatzmann]

Lets just say, the what, 1 to maybe 4 volts max. difference at your wall outlet from time to time have very little to do with your "amp" sounding off on some days and "good" on others.

It goes way deeper than that.

I tried the variac thing once or twice and was not impressed with any of the "benefits".

I sometimes do use one on older equipment that was built for 110/220v and put it at the appropriate voltage.

If any help, i'd get an older western made one,
should be more sturdy overall.

 

[Maxbrothman]

The same thing happens with modelers. Our hearing changes depending on loudness. The louder something is the more the mids are reduced and the bass and highs are brought out in your hearing, not the amp. Fletcher Munson Curve.

Tube amps are partially statistical in nature which means the amp's tone, like JCM, is a ballpark tone with the tubes operating somewhere in that region. It why most tube amps need dialing in individually.

If you are hunting the Brown sound for Van Halen then his pickups are quite important along with the rest of his gear. You should get that brown sound without needing variac.

 

[lespaul339]

I'm not hunting for the Brown Sound at all. Just looking to keep my amp running at the best sounding voltage. Basically trying to keep the voltage consistent for consistent tone.

 

[junk notes]

Yes, sounds like your ears are not lying. Perhaps saving up and getting the AmpRx is a good idea.

Nice amp! What year - MKII?

 

[Fernieite]

Another option is the Amp Maniac, made in the USA by Vintage Sound. The variable knob makes it easy to dial in your prefered voltage.
I've got one for my vintage amps, and it works really well.

Amp Maniac

The Amp Maniac was developed in response to requests for a completely variable version of the Tone Preserver. You can dial in any output voltage you desire with the knob on the top of the unit. The Amp Maniac is the same size and weight as the Amp Preserver, so its easy to handle and take to...

vintagesoundworkbench.com

 

[lespaul339]

Another option is the Amp Maniac, made in the USA by Vintage Sound. The variable knob makes it easy to dial in your prefered voltage.
I've got one for my vintage amps, and it works really well.

Amp Maniac

The Amp Maniac was developed in response to requests for a completely variable version of the Tone Preserver. You can dial in any output voltage you desire with the knob on the top of the unit. The Amp Maniac is the same size and weight as the Amp Preserver, so its easy to handle and take to...

vintagesoundworkbench.com

Thanks for sharing that. I wasn't aware of this. That seems like a very good option!