external cab volume control?

[Steve Rosko]

I'm using a Tone Block 200 as the power amp in my rack case. It will drive one 4ohm, one 8ohm or two 8ohm speakers. I'm currently playing through one TT-15 which is 4ohms. I also have a TT-12 which is 8ohms. I'd like to play through both. According to Quilter, if I play through both the 4 and 8ohm speakers, the 4ohm will play about 5dB louder. So here's the question: could I not just install a volume control in the 4 ohm speaker cab to balance it out some with the 8 ohm? There are volume controls on every other piece in my signal chain, so I'm wondering why not? Of course, I wouldn't want it to interfere with the sound quality. I understand the newer Tone Block 202 will drive a 4 and an 8, but its $650 which is a lot more than the cost of a volume control
Thoughts?
Thanks, in advance.

[Jon Light (deceased)]

You need to understand that a speaker volume control is a very different animal than, for instance, a guitar volume pot. The guitar pot may be rated 1/4 watt. The speaker pot needs to handle the wattage that the speaker is handling. If your speaker is carrying 100W, you need a dedicated pot/attenuator rated for....actually I'm not sure if you need to over-spec this or not. I don't know much on the subject beyond the fundamental fact that it's very different situation than just thinking of throwing a basic pot at it.
Here are some parts. I don't really know how well suited they are for this but it's just to give you an illustration.
https://www.parts-express.com/search?or ... r%20volume

[Steve Rosko]

I emailed Travis Toy, who had a great suggestion: Just plug them in and see if there's a discernable difference. I'm probably overthinking this I can't tell any difference in my music room. Next time we play out, I'll play through both and see what happens.

[Stephen Cowell]

a) 200w L-pads are not cheap, nor easy to find. Any energy from being turned down will be dissipated as heat... these things are 4" wide and have vents. Here's some 100w ones, with an explanation:

https://willys-hifi.com/collections/l-pad-attenuators

b) 8 || 4 ohms equals 2.66 ohms... that's below the rated 4ohms of your 200 (discontinued, btw). This means that your amp will heat up and may shut down to protect itself.

Do you want to run the speaker just for thrills/looks? Then don't bother connecting it... safer all the way 'round. We had fake cabinets all through jr high/high school.

Are you trying to spread your sound to the other side of the stage? Then you might consider using another amp with the other speaker, and run the preamp signal (instead of a speaker signal) over to it.

[Steve Rosko]

I’ve been playing through 1 speaker at smaller venues. I’d like to bring 2 speakers for larger rooms or out doors.

[Dave Mudgett]

I use a Tone Block 201 quite a bit. I think the 200 and 201 are pretty similar, but here's what the manual for the Tone Block 200 states (which is similar to what happens with the TB 201):

Speaker Outputs
Connect a single 8-ohm speaker to the lower jack, marked 8-OHMS.

Connect a single 4-ohm speaker to the upper jack, marked 4-OHMS.

For two 8-ohm speakers, plug one into each jack. Power will divide equally between the two speakers.

The amplifier will adjust the output impedance and tone balance automatically. Other impedances may be connected, but the tone may change somewhat and the front-panel wattage markings may no longer be accurate.

I also tend to run two speaker cabs for larger rooms, but I stick to two 8-Ohm speakers in parallel for the recommended 4 Ohms total.

After reading and commenting on this thread - viewtopic.php?t=375885 - I tried running one of my 4 Ohm speakers into the 8 Ohm output, and vice-versa - 8 Ohm load into the 4 Ohm output. They sounded different from each other, and I didn't like the result either way. I'm not sure how this translates to running 8 || 4 = 2-2/3 Ohms when it's expecting a 4 Ohm load. I think these amps are load-protected so you shouldn't blow up the amp. But my 201 seems to like having the correct load, so I stick to two 8-Ohm speaker cabs if I want two speakers. I have a single 4-Ohm cab also, and as the manual states, the 4 Ohm output jack has a switch that gives it some attitional power. So there can be a volume advantage to using 4 Ohms.

If I didn't have an extra 8-Ohm speaker around and I was really hell-bent to use two speakers, I think the best and perhaps cheapest way to get a good result would be to just get another 8-Ohm speaker. If you're distributing the load over two 8-Ohm speakers, a 70-100 Watt speaker should be fine unless you're just cranking the blazes out of it.

As far as power attenuators such as Steven mentions go - I think you should know what you're doing before experimenting with that kind of stuff. In addition, I generally dislike resistive attenuators for guitar amps - they change the reactance character of the load impedance. I've had quite a few of different makes over the years and dumped them all in favor of a Fryette Power Station, which is great for my tube amps but I think is totally overkill here. And not cheap - something like $650!

[Dennis Detweiler]

The Quilter outputs are tempermental with load requirements. I experienced loud feedback screeching sounds from my 201 with mismatched loads. It never shut down. Just had loud bursts of noise when pushing the pot volume pedal. I resolved the issue by making a series box and using two 4ohm speakers in series plugged into the 8ohm output.

[Allan Revich]

Unlike tube amps, the solid state Quilters can be safely run without any speaker load… at least according to the Quilter ad copy. So it is unlikely that you can hurt the amp with mismatched loads. As far as the sound, volume, and tone goes, you’ll just have to try it and see. If I were you, I would just buy a nice 8 ohm speaker to swap out with the 4 Ohm.