Weber impedance matcher

[Boudoir Guitar]

I think I remember @la szum lamenting the difficulty of matching impedance of speakers or loads with some fender low impedance amps? (Side note, in a professional setting I once spent a half hour interviewing a patent attny about a case she was handling, the crux of which was the internal impedance of a battery system. She clearly knew nothing about the technology and spent the entire interview pronouncing impedance “impotence”, despite my heavy emphasis of the word every time I correctly pronounced it. It was hard to keep a straight face, much less take anything she had to say seriously).

Z-Matcher 100w Impedance Matcher – Weber Speakers

www.tedweber.com

 

[itchyfingers]

I just picked up a 64 Bandmaster, which has a 4ohm out, but I have zero 4ohm cabs so I can't run the amp. I'd like to run it to a 16ohm 212 cabinet, and seeing the Z-matcher, I'm thinking it might solve all my problems. However, there's this little nugget on their site:

"The Z-Matcher is not a dummy load by itself – it only matches impedance, so you will need to have a load connected to your amp (usually the speaker cab is the load, but for dummy load purposes you will want to look at our attenuators, which can all be used as dummy loads.)"

If I just wanna play guitar > amp (+ Z-matcher) > cab, I have no need for IRs or anything like that, do I ALSO need to run an attenuator in addition to the Z-matcher or will just the Z-matcher do the trick?

 

[Boudoir Guitar]

I just picked up a 64 Bandmaster, which has a 4ohm out, but I have zero 4ohm cabs so I can't run the amp. I'd like to run it to a 16ohm 212 cabinet, and seeing the Z-matcher, I'm thinking it might solve all my problems. However, there's this little nugget on their site:

"The Z-Matcher is not a dummy load by itself – it only matches impedance, so you will need to have a load connected to your amp (usually the speaker cab is the load, but for dummy load purposes you will want to look at our attenuators, which can all be used as dummy loads.)"

If I just wanna play guitar > amp (+ Z-matcher) > cab, I have no need for IRs or anything like that, do I ALSO need to run an attenuator in addition to the Z-matcher or will just the Z-matcher do the trick?

No -- you just need some sort of load after the impedance matcher. That load can be a cab OR a dummy load (i.e., an attenuator/electrical reactive load).

 

[itchyfingers]

Thanks BG, I'm all over it, and I appreciate the 700ish bucks you just saved me!

 

[itchyfingers]

Just wanted to say thanks again, @Boudoir Guitar.

Ordered this last Friday, showed up yesterday afternoon. Pretty outstanding engineering, service, and packing by Weber. Anyway, it does the thing! Got to jam the Band Master through a few different cabs last night.

 

[jay mitchell]

Ordered this last Friday, showed up yesterday afternoon. Pretty outstanding engineering, service, and packing by Weber. Anyway, it does the thing! Got to jam the Band Master through a few different cabs last night.

The need for "matched" impedances for tube amps is largely overblown. There are two possible negative effects:

1. Excess thermal loading of the power tubes and output transformer. This can potentially happen if the load impedance is too low, but a 2:1 mismatch - e.g., 8-ohm OT secondary w/4 a ohm cab - is extremely unlikely to cause problems.
2. Inductive flyback at the OT primary, which can damage power tubes. This could be a problem if you run an amp unloaded with a high signal level going through it, but the complete lack of sound from the amp would usually be a clue that something ain't right.

FWIW, I owned and gigged for several years with a brownface Bassman head. Like the Bandmaster, its factory cab was 4 ohms. The cab I used for most of that time was a 4 x 12 I built that I series/parallel wired for 8 ohms. I never had the slightest problem with that head. While it was indeed louder when used with a 4-ohm cab, it had no problems whatever driving 8.

 

[itchyfingers]

I'd agree with pretty much all of that, but for 200 bucks it's a no brainer. My vintage amps always end up in the shop eventually, so any way to minimize those trips is welcome. I'd just rather not risk any of the 59 year old components in the BM, and the amp's response to 8 and 16 ohm cabs is pretty noticeable.

 

[GreatGreen]

How does an impedance matcher work on a technical level?

 

[gearJunkie]

Just ordered one of these so I can safely run a 4 ohm cab in parallel with any of my other 8 & 16 ohm cabs. Seems like a cool passive gadget.

Was going to use my Iron Man II, but it ignores the impedance switch settings when attenuator is set to 0db.

The Z-Matcher is passive, smaller, and purpose built, so I expect it is a better solution.