Bi- amp amplifier?

[admin_exported]

Hi ,

I urgently need your help to establish if my old Technics SU- CH7 amplifier (part of a mini system) is bi amp and if this makes any difference to the type of speakers I connect to it. I know that it is bi wireable and that I need bi wireable speakers...but does it mean that if I connect speakers that only have 2 brass posts at the back (1 positive 1 negative) the amp might blow?

The old speakers had 4 connection slots at the back, not two, and I thought that it wouldn't matter if I bought some new smaller bi wireable ones providing I respect the right polarity (2 positive wires can go into into the positive post and 2 negative wires into the negative post) so I've just bought 2 Cambridge Audio SL20... and 6m of bwireable cable (4 wires)....but I am having cold feet now...

Many many thanks to anyone who takes the trouble to reply. I am really stuck.

 

[Anonymous]

Sounds like a bi wirable amp not a bi-amp. In a bi-amp there's two separate amplifiers one to drive treble one for bass. The two can't be connected to a single set of posts because they'd drive into eachother via the speaker and damage themselves.
A bi-wire amp simply has four binding posts on the rear to allow either 4 speakers or 2 runs of cable to a single pair of speakers. (improves composure in some crossovers) this is how it was stock from the shop. if it's a bi-wire simply only wire up one output terminal set to the two posts on most small speakers. Done! No need for bowie cable.
If it really is a bi-amp unit (highly doubtful) it will require a bi ampable 4 post speaker.

 

[Andrew Everard]

The SU-CH7 was a biamplifying amplifier, with separate amp channels and speaker terminals for high and low frequencies.

However, if I recall correctly it also had filtering built into the amp, and not the speakers, so using it with conventional speakers with passive crossovers built-in may give unpredictable results.

This really is one of those amps designed only to be used with the matching speakers - in this case the SB-CH7 speakers.

 

[Anonymous]

Someones going to spending alot of time On eBay lol

Does sound like a very impressive mini system!

 

[The_Lhc]

fizzyhair:Someones going to spending alot of time On eBay lol

Does sound like a very impressive mini system!

Not that impressive, I bought my missus a JVC mini system a few years back that does the same thing. I'll say this for it, it does put out a surprising amount of bass for such small speakers, it's now serving kitchen duties and regularly spoils my lie-in on a Saturday (the kitchen is directly below our bedroom).

 

[Anonymous]

I recently picked up the Panasonic version of this same mini system. Same model number SU-CH7 that was sold here in the US. I found it at a recylce center and paid $7.50 for it. It was missing the CD player and speakers so it just had the tape deck, amp, and tuner. I only bought it because i've been wanting to experiment with the bi-amp idea and liked the small amp and tuner (will not use the tape deck). I had an old pair of Polk bookshelf speakers laying around so i disconected the internal crossovers and connected the amp directly to the tweeters and woofers. I used an old Sony Playstation 1 (original version and a terrific CD player - Google it) for the CD transport and it sounds good. If this amp has internal crossover processing then is this method of wiring it directly to the speakers okay? If so, I have some better paradigm speakers i'll try it with for kicks.

I'd love to get my hands on a copy of the owner's manual if anyone has one. I'm sure its the same as the technics version. I have an E flashing on the tuner that i'd like to reset. Not sure what error it is representing but the system seems to work fine. It even had the remote. Thanks for any insights.

 

[pwiles1968]

MJS68:
If this amp has internal crossover processing then is this method of wiring it directly to the speakers okay? If so, I have some better paradigm speakers i'll try it with for kicks.

Not familiar with the Amp but I would be tempted to put a capacitor across the tweeter as a simple high pass filter to protect it from any LF or DC signals reaching it, just in case.

 

[Anonymous]

Thanks Paul,

Any specific capacitor and would i just bridge the + and - of the tweeter? Thanks. I found a manual and it doesn't really tell me anything. Just that you need to use the specific SB-CH7 speakers, which i don't believe have any crossovers in them.

 

[pwiles1968]

You would need to do a bit of searching on the internet to get the correct size but for some reason 3.3uF comes to mind, not sure what the crossover frequency is for that. It goes across the + and -

 

[Anonymous]

Thanks - i'll see what i can find on the internet. For $7.50 i'm willing to risk tinkering with it. Paradigm speakers were also very inexpensive so they are good for experimenting on as well. As in $4 for the pair with ripped woofer surround foam. Otherwise in great shape - $20 re-foam kit was more expensive than the speakers and Panasonic system together. Thanks again for the suggestions.