Rickresource Rickenbacker Forum

I'm looking for a review of the THD Hot Plate paired with the AC-30. Anyone using this setup?

Help me understand what the Hot Plate gives you - is the noise suppression, etc worth the cost of admission?

Thanks in advance!

I use a similar setup. The main reason for the Hot Plate is to reduce volume, while still allowing the output tubes to operate at higher levels. The hot plate does have a noise suppression feature, which people don't discuss much on the boards.

Full disclosure: I generally use either a DC30 clone (similar to an AC30) or a THD Flexi 50 into a Weber Mass unit for attenuation.

I pretty much always have attenuation engaged at some level. Most output tubes start to sound good at more volume than most people can manage at home, and even higher than I want to deal with on stage, so some attenuation is good. They do chew up a tiny bit of the tone, but more as they are engaged. And, I would maintain that what little of the tone they rob from the output tubes after you subtract the Fletcher-Munson curve (how the ear reacts to volume), they are still better than turning down the master volume. I am a fan of THD, but I picked the Mass over the Hot Plate for these reasons:

1. it has a speaker motor (reactive load) instead of a resistor, which would behave more like a speaker.

2. it has the ability to deal with different loads

3. tone controls (these aren't that useful)

Again, the Mass doesn't have a noise suppression feature, unlike the THD. In the end, I'm not certain I picked the better product, but I am happy with it.

I hope this helps.

This is new to me! It makes perfect sense, I just never thought about it much.....

"They do chew up a tiny bit of the tone"
can you elaborate here? I'm not sure I'm understanding. My AC-30s don't have a master volume, so I don't have that to compare to.

I thought the THD had some tone compensation in it too, I assumed it was like an EQ or something? Maybe I'm misunderstanding it.

Is the Mass similar in price to the THD?

Re: Tone chewing:

Because of the Fletcher-Munson curve, which causes your ear to respond differently to the same sound at different volumes, it is kind of hard to delineate how much effect the attenuator has. All attenuators I have tried, change my perception of the tone. I once had a Scholz unit that seemed to add a harmonic (until it died), others proclaim that they lose some HF, others midrange, but they seem to have a greater effect to me on bass and cleaner tone.

Some guitarists will not use an attenuator because of their perception of tone degradation. Others because it is an impure thing in the signal path. All I can say is I will probably continue to use an attenuator at least almost every time I plug into an amp. It is also some amount of protection for my alnico blues.

The THD does have some RC thing going on to attempt to compensate- you're right- but as much as I like the people there and respect them, that is a much harder sell to me than the dials on a Mass (which don't do much.) I also think that the resistive load imparts some amount of tone into the equation. (Reading what I've just said, I need to admit that quite a number of guitarists get an outrageously fantastic tone using them.)

I think the Weber Mass is in the price ballpark of a THD. They make several varieties. The one I mostly use is the hundred watt one. My rule of thumb is that the attenuator should be at twice the rated power of the amp (I learned this by destroying my old Scholz one.) And though an output transformer and tube set in an amp will tolerate an impedance mismatch, I really do feel better about getting close with respect to the reflected load back into the amp.

Mark: great info - thanks.

I found some other interesting write ups on the thd & the weber:
http://www.legendarytones.com/thdhotplate.html
http://www.legendarytones.com/weberma.html

I do like that the weber supports multiple impedances. It looks bigger than the thd. The thd does look to be a little simpler to use - less knobs & switches.

I'd still be interested in hearing from others who are using an attenuator with the Vox...

With my Dr. Z Stingray amp (which is inspired by the old AC30... EF86 preamp into 4xEL84 and out 2xCelestion Blues), I've been quite satisfied with the AirBrake, also by Dr. Z.

http://www.drzamps.com/airbrake.html

Also, I guess I tube my amps brightly, so maybe the reduction in highs is a relief.

It's funny, but at the bottom of Ted Weber's attenuator page it says "Cool attenuators from other companies: Dr. Z's Airbrake [and] THD Hotplate"

Timely thread!

I played my AC-30 at a gig Saturday, couldn't get anywhere near the Volume (tone) I needed.
Just got back from looking at Dr. Z's, and am considering an Airbrake for the Vox before buying an 18 watt Dr. Z.