^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.
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
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 |
I have several sets of cables at home, my favorite are high count twisted litz. These cables definitely qualify as high capacitance. This capacitance problem is also effected by the speaker crossover itself that is attached to the cable. So depending on crossover design and layout combined with cable, a problem with speaker cables capacitance can occur with amplifiers that have a lot of feedback and some high-feedback push-pull tube amps. A capacitive load can drive the feedback phase far enough to lead to oscillation, sometimes at ultrasonic frequencies. You might not hear it, but soon there's smoke coming out of your tweeter. |
- 62 posts total