@unsound - It's good to know Goertz includes the Zobel network free - perhaps a few other companies should do that as well.
Thanks for the info.
Thanks for the info.
Would you change your amp selection knowing...?
OK - so this thread was promted by some comments on another thread - not wanting to hijack that thread I created this one...
ISSUE: some high current designed amps have an issue with speaker cables that have a high capacitance.
- the amp can be driven to self destruction because of internal oscilation caused by the high capacitance of the speaker cable
- this does NOT apply to Tube amps - i.e. to my knowledge
The amps I know of that are affected in this way are Ayre, Gryphon and NAIM
- only NAIM warns of this up front AND instruct their dealers to let customers know about it
So why don’t other brands warn about the possibility?
QUESTION:
- would it put you off?
- would you select a different amp if the manufacturer warned of this "issue" up front?
Cheers
ISSUE: some high current designed amps have an issue with speaker cables that have a high capacitance.
- the amp can be driven to self destruction because of internal oscilation caused by the high capacitance of the speaker cable
- this does NOT apply to Tube amps - i.e. to my knowledge
The amps I know of that are affected in this way are Ayre, Gryphon and NAIM
- only NAIM warns of this up front AND instruct their dealers to let customers know about it
So why don’t other brands warn about the possibility?
QUESTION:
- would it put you off?
- would you select a different amp if the manufacturer warned of this "issue" up front?
Cheers
- ...
- 62 posts total
^I’m not sure if they still do. When I got mine the RC networks were separate. I’ve since read that some have them directly integrated into the cables. I’m not sure, but I seem to recall that separate RC network replacements were available for $20, but I also seem to recall that some might have received them gratis. Some have even made their own. |
Adding a network to an amplifier to correct for a cable is a tailspin, just adding eq to eq. I’d like to see how Goertz calculates a Z of 4 or 8Ω at audio frequencies from their geometry. SS amplifier outputs are a tiny fraction of 8Ω which is what gives rise to large damping factors. Characteristic impedances are beneficial when the source and load impedances are matched. Almost no speaker is a flat 4 or 8Ω impedance, largely negating any supposed benefit. Typical impedance variations of 4:1 are common and 10:1 is not uncommon. See Cable Snake Oil Antidote Amplifier Output to see how amplifier output impedance can interact with cables. |
I’d like to see how Goertz calculates a Z of 4 or 8Ω at audio frequencies from their geometry.Hi Ian, The table near the bottom of the following page of their website indicates R, L, C, and Z for their various speaker cables: http://www.bridgeportmagnetics.com/contents/en-us/d62_MI_AG_Speaker_Cables.html As I’m sure you are aware, characteristic impedance can be calculated to a close approximation as the square root of (L/C), using those parameters on a per unit length basis and provided that conductor resistance per unit length and dielectric conductance per unit length are insignificant. The L and C values shown in the table appear to be consistent with the indicated characteristic impedances, which range from "~1.7" to "~4" ohms. Best regards, --Al |
- 62 posts total