TU8200 with Klipsch speakers

[jdsackett]

Hi all. Thinking about building a 8200DX kit. My main speakers are Klipsch rf7s. Anyone who knows Klipsch is aware of the impedance curve being all over the charts. What can I say, I like em. Anyway, will this amp have a problem driving these speakers?? Thanks, J.D.

[planet10]

The high output impedance of the SE amp will mean that a portion of the impedance curve will be convolved with the FR (as measured with a low output impedance amp).

Usually a wild impedance is a prescription for a low output impedance amp.

So unless the speakers FR just happens to complement the change caused by the impedance it is not likely to be a good match.

These are RF7-II (don’t know how different it is):



And the FR:



In this case, driven by a typical SE amp, looks like the impedance dips are close to the FR dips and the peaks are cloase too, so interaction will likely produce more uneven FR than w a low output impedance amplifier.

dave

[Badchile]

I run a TU-8200 with Heresy III...no problem at all.

[jdsackett]

Yeah, I was a bit afraid of that. Thanks Planet10.

Heresy speakers are different than the rf series, but thanks for the reply.

I.ll search around and see if i can find suitable speakers before I buy the kit. Thanks again, J.D.

[planet10]

Can’t find an impedance curve of the Heresy III, the one i found for H1 has as dramatic rise maxing out at about 3kHz.



The FR of the HIII from elsewhere:



In your room, if the rise caused by the interaction of the impedance of the speaker and the SE amp, is countered by a dip in the speakers FR (as measured with a low output impedance amp) then the anaomaly fixes itself, if not you’ll have at least a slight rise.

dave

[gpdavis2]

The 8600 might be a better choice.

[jdsackett]

I thought of that. Have a couple reasons not to. First is the difference in cost. Much more inclined to spend less on a product i haven't personally heard. Second, I have 2 or 3 ribbed plate 12au7 tele's laying around and a matched quad of old winged c 6550s someplace. While you could do better than the winged c, you could also do a whole lot worse. So, I already have good tubes to fit the 8200. Not so with the 8600. Thanks for the reply. J.D.

[gpdavis2]

Understand........ the problem being, it is becoming more & more difficult to actually listen to any gear with the increasing lack of bricks & motar shops. Am driving 100mi Saturday to one and would not be going if there wasn't an excellent used LP store adjacent to their shop.

[planet10]

I don’t know the numbers but i suspect the SE 300B amp will have even higher output impedance, making the issues with the ugly impedance worse.

dave

[paczeltf]

The TU-8600 uses some local negative feedback to the cathode of the output tube, but I agree that it will hardly give you much better results from a damping factor perspective.

btw, the measured output impedance of the TU-8200 is 2.93 Ω at the 8 Ω setting and 1.88 Ω at the 4 Ω setting.