Is this a bad idea?

Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.
I saw these subwoofer amps on ebay.com http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=1940556342 I came to an agreement with the seller, cause he lives with me that I would come pick them up and pay him $130 USD.

These amps have a fixed 100 HZ LP X-over as it says in the auction page and it's designed to be used with a passive x-over network. It is from the old Acoustic Research P315HO speaker. The new, but very similar or maybe same but with a different name is the Acoustic Research AR1. They have 36 db/octive x-overs, this might be important in the next paragraph. http://www.acoustic-research.com/ar1_content.asp

I works like this the input signal by passes the amp, then it goes through a passive x-over network, that part I know. I'm not sure if in that passive x-over it goes through a passive low pass filter as well as a high pass filter for the regular 2 mids and tweeter. Or if it sends the whole freq. signal to the amp and the x-over in the amp does all of the LP filtering. I was thinking that if it bypasses the amp on the way in it must be designed to go through the x-over and if it goes through the x-over it must be low passed. But maybe i'm wrong? I don't know what makes sense :confused: If I had to guess I would say it has a 12 db/octive passive x-over and a 24 db/octive active x-over for a total of 36 db/octive or vice versa. I guess my main question is if this is a good idea to use this amp in a pair of speakers or subs? Or is it only useful for the Acoustic Research design?

Also I don't know if these sub amps have phase adjustments? Is this important if you have active and passive components?

Hi Availus,

Sorry that this has nothing to do with this thread. But I haven't heard from you about your G4 x-overs for 3 weeks. How's it going with the x-overs? Somebody e-mailed me a little while ago about building some G4's and he says that Graham says that the 10 db spike at 3,750 Hz goes down to 2 db after 200 hours break in although I have not noticed this, I think. Just wanted to tell you maybe this will and you and later also myself.
 
Ex-Moderator
Joined 2002
Hi Jimmy,

If you can separate out the 500W sub amp, it would probably be usable for powering a subwoofer. I would expect to use any of the x-over stuff sight unseen. Then if you win the auction, any of the x-over stuff that is usable is a bonus, as long as the amps work.

Good Luck,
Rodd Yamashita
 
roddyama said:


I would expect to use any of the x-over stuff sight unseen.


I think the amp has an active x-over at 100 Hz inside it. I don't know what slope it is. I would like to disable it, possibly, once I get it. Then build a pair of 3-way speakers eventually, using the sub amp to power a pair of subs.

I don't know what the quote above means. So you think it would work?

I'm not bidding on it. I can buy the pair of amps up for auction for $130 which seems extremely cheap to me. He sells them about every week they go for $130 or more in his auctions. He lives near me so I can go to his business and look at them. Now that I think about it some more, I guess this is one of those times where I will have to buy them and see.
 
Ex-Moderator
Joined 2002
Hi Jimmy,

Sorry, that should have been, "I wouldn't expect to use any of the x-over stuff sight unseen."

You should be able to do a little reverse engineering to get right to the inputs of the amp.
Jimmy154 said:

I think the amp has an active x-over at 100 Hz inside it. I don't know what slope it is. I would like to disable it, possibly, once I get it. Then build a pair of 3-way speakers eventually, using the sub amp to power a pair of subs.
Exactly.;)

Rodd Yamashita
 
Status
This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.