4 replies to this topic

[Pete B]

>>>I have all the drives and the grils in nice cabinets
>but
>>no
>>>crossovers I do have the big caps any ideas I would
>like
>>these
>>>to match the other pair so I can stack them.
>>>thank you
>>>Jim
>>
>>You're interested in a solution that does not require an
>>autotransformer I take it?
>Well only if I can't find the crossover and it will match the
>other speakers we are talking about staked LST I took one of
>the auto xformers in and the local places could not make
>another without takeing this one apart and it would cost 500
>for two new ones . not going to happen.
>so its a waiting game to fine a pair of crossovers.

I've probably said this before, that the AR-3a and LST crossover are very similar. With the autotransformer in the LST obviously, rather than pots.

I suggest that you build the AR-3a topology crossover, with the LST component values which are similar to the 3a values. You could use pots, or make a stepped switch arrangement with resistors for level adjustment. Then remove the pots/switches when/if you find an autotransformer at some time.

The midrange crossover in the LST has a gentler LF rolloff IIRC probably allowed by having 4 mids to handle the power. Just use the LST values and you should be fine.

This will allow you to set up the crossover for bi-amp/wiring and it eliminates the auto-transformer and the associated distortion. You might like it better. I'd like to hear you're listening impressions if you try it.

[roundhome]

>>I have all the drives and the grils in nice cabinets but
>no
>>crossovers I do have the big caps any ideas I would like
>these
>>to match the other pair so I can stack them.
>>thank you
>>Jim
>
>You're interested in a solution that does not require an
>autotransformer I take it?
Well only if I can't find the crossover and it will match the other speakers we are talking about staked LST I took one of the auto xformers in and the local places could not make another without takeing this one apart and it would cost 500 for two new ones . not going to happen.
so its a waiting game to fine a pair of crossovers.

[Pete B]

>I have all the drives and the grils in nice cabinets but no
>crossovers I do have the big caps any ideas I would like these
>to match the other pair so I can stack them.
>thank you
>Jim

You're interested in a solution that does not require an autotransformer I take it?

[onplane]

Jim, no one is going to agree with my suggestion here, but since you lack those autotransformers (and I don't think this is all bad) I'd simply bi-amp your LST's. When you bi-amp, you move the control over balance back to the amps rather than in the autotransformer.

Now, there are two ways to bi-amp:

1. ACTIVE - where you'd get an active xover like:

http://www.partsexpr...tnumber=245-862

You'd then drive the woofers direct (no coil or cap necessary) and add a low pass filter for the mids and the standard 6mfd cap for the tweeter.

2. PASSIVE - here again you use two amps one for the woofer and another for the mids/tweeters, but you'd duplicate the xover for the AR-3a. This is necessary to insure the correct frequencies are being sent to the drivers.

Jim, in both of these schemes balance is controled by the respective power sent to each half of the speaker. I do this every day with my 3a's and just love the resulting sound.

Regards,
Jerry

[roundhome]

I have all the drives and the grils in nice cabinets but no crossovers I do have the big caps any ideas I would like these to match the other pair so I can stack them.
thank you
Jim