• TalkBass has been independent since 1998. Add your voice.
    Create a free account to reply to discussions, view embedded media, and browse with fewer display ads.
    Join freeLog in
    Want zero display ads or expanded classifieds tools? Compare plans.

TC Electronics Impedance chart

Hi guys!

I just wanted to share this pdf file from TC Electronics, it explains the impedance of their cabs.

I had a problem finding out the ohm of the RS212 and RS210, I thought that they we're 8 Ohm cabs but I got confused with the impedance matching of their heads (they seem to go down to 2.6 Ohm but only with their cabs???)

Anyway, I hope this helps someone... :hiding:

Byron
 
they seem to go down to 2.6 Ohm but only with their cabs???
There's some evidence out there that the TC cabs actually should be rated at 10 ohms, but to do so would have a negative impact marketing wise, as would rating their amps for their actual RMS output rather than whatever standard it is that they've unilaterally adopted. Caveat Emptor.
 
From the charts in the BGM article, the impedance curves on the TC cabs looked to bottom out around 7ohms. Rounding off there blowing up hard to see charts but that's close. A little on the high side for 8ohm cabs. For a while I thought that's how they were pulling off the "you can use 3 of our cabs but only 2 of anyone elses" advertisement but then they went ahead and changed the amp rating to 2.67...but not 2.0. Who knows what the hell's really going on there.
 
From the charts in the BGM article, the impedance curves on the TC cabs looked to bottom out around 7ohms. Rounding off there blowing up hard to see charts but that's close. A little on the high side for 8ohm cabs. For a while I thought that's how they were pulling off the "you can use 3 of our cabs but only 2 of anyone elses" advertisement but then they went ahead and changed the amp rating to 2.67...but not 2.0. Who knows what the hell's really going on there.

I still want to know if they just changed the rating on paper or if newer amps have been modified electronically to accommodate 2.67 ohms.
 
I still want to know if they just changed the rating on paper or if newer amps have been modified electronically to accommodate 2.67 ohms.

I've never figured that one out, although it is a whole lot easier to changed a line of ad copy than it is to redesign an amplifier without so much as a hiccup in availability and no need for retrofitting earlier models.:smug:
 
Bowlus' magazine rated them at 10.54ohms and 11.54ohms in their review.

I read that but I never understood how they came up with it. It's not an average, I don't think it's nominal either, at least not in both cases (210&212). The graphs tell the story. Both cabs have the 2 spikes typical of ported boxes and both seem to bottom out around 7 or so.
 
My suspicion is they just decided to reduce their factor of safety a notch.

I think you're right but I still don't understand it. To my understanding, the vast majority of these microheads rated 300 @ 8ohms, 500 @ 4ohms all use the same power modules. Supposedly these things are good for 250 each and these heads use a pair bridged internally. None of them are stable at 2ohms.

This stuff a bit above my skill level. Maybe TC uses a different power module or maybe because of the high DCR of their cabs, they figure it'll take the cooking of running 3.

Maybe someone with more expertise can explain that. You can look up ICE power module and read a ton of stuff but I don't see many simplified explanations.
 
From the charts in the BGM article, the impedance curves on the TC cabs looked to bottom out around 7ohms.
That equates to a nominal 10 ohm impedance. While there's no such thing as a set impedance figure, due to its being different at every frequency, the AES/IEC standard sets the minimum impedance as 0.7 times the nominal impedance. Therefore an 8 ohm cab will generally have a minimum impedance of 5.6 ohms. In most cases the minimum impedance closely corresponds to the voice coil DCR, which is what you read if you use a VOM to measure the cab.
 
I'M SOOOO SOOOORRRRYYYY!!! I forgot to paste the link!!! :hiding:

Here it is:

Link Removed

I apologize!!!

Unfortunately, that's no help at all -- no fault of yours, Byo, it's TCE again.

The APM document refers to minimum impedance allowances of 2.67 ohms for the RH amps and 2 ohms for the BH500 IIRC, which should clearly make them useable with 3 of anyone's 8-ohm nominal cabs. If I had 3 cabs, I'd be happy to experiment -- the worst that will happen (assuming TCE's electronics is up to snuff), that it will go into protect mode.

Don't know if anyone else is prepared to trust them at this point ...
 
Unfortunately, that's no help at all -- no fault of yours, Byo, it's TCE again.

The APM document refers to minimum impedance allowances of 2.67 ohms for the RH amps and 2 ohms for the BH500 IIRC, which should clearly make them useable with 3 of anyone's 8-ohm nominal cabs. If I had 3 cabs, I'd be happy to experiment -- the worst that will happen (assuming TCE's electronics is up to snuff), that it will go into protect mode.

Don't know if anyone else is prepared to trust them at this point ...

At this point?