Hsu 12Va questions:

[daltonlanny]

I am considering purchasing a used Hsu Research 12Va subwoofer to use along with my dual TN1220HO's, but I have a few questions.
1. Would the Hsu Research Model 500A Class H amp power 3 subwoofers, or would this be a bad idea?

2. If it would power 3 subs, what would the power output to each sub be?

3. If they cannot be run this way, would there be any way at all to wire a couple of the subs in series [instead of parallel]?

If so, how would I go about wiring them in series [please tell me in detail]?

4. What would be the lowest impedance that the amp would "see", if I did wire a couple of the subs in series?

5. Finally, if I purchase the 12Va and decide to replace the original woofer with one of the newest VTF-3 Mark 2 woofers, what performance gains, if any, could I expect:
In the ultra low bass?
In the low bass?
In the mid bass?
What about in woofer sensitivity?
Thanks so much for your help and answers.

[zora]

1. I would not recommend it, as I don't believe that the amp is rated for a long-term 2.67 ohm load.
2. If possible, then the total output would be most likely 600-700 watts - thus each sub would get about 200 watts.
3. Don't combine series/parallel loads with three subs. Either wire in parallel (bad) , or series (not good either).
4. Parallel wiring equals 2.67 ohms, Series wiring equals 24 ohms (all nominal of course).
5. The VTF MkII driver is a different size (smaller in diameter) than the old 12Va driver (I know from experience). You have to modify the 12Va enclosure for the new driver, which can be done but isn't easy.
6. I would not recommend getting the 12Va to use with your amp unless you can get two of them (then you can series/parallel your four subs).
7. All this said, the 12Va was/is comparable to the best $500-750 subs on the market today.

JP

[Lwang]

1. Each Hsu sub is rated at 4 ohm, so 3 subs would be 1.33 ohm. That's approaching a range that's only overbuild high end amps could handle. Hsu's 500w amp is rated down to a 2 ohm load.

Also, whichever way you wire them, the 12Va and 1220 might not have the sensitivity, thereby making it impossible for you to balance their level out in any way besides experimenting with placement, which will still be a hit or miss.

[zora]

Lwang,
Good catch, I forgot that the drivers were 4 ohms each. I wouldn't pair the 12Va with two TN1220's, but that is just my opinion.
JP