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View Full Version : Bypassing Bi-Amp switch on 4345s



Ricpan
10-08-2017, 03:01 PM
I have a Electrovoice DX38 so I can just bypass the switch and go straight to the woofer with the low freq. Do I have to do anything with the mids and highs?

Goldjazz
10-10-2017, 01:52 AM
Hi, I'm not familiar with that EV unit. Can you adjust the crossover point and slope?

So This is how I do it on my 4343's:
-I use a First Watt B4 active crossover which allows me to set crossover points and slopes and slip the signal into a high pass and low pass
- The crossover point for the 4343 LF is 300hz and 12db per octave slope.
- This is optional: That biamp switch is nasty and degrades the signal. Now I have no intent of going back to a single amp so I totally disconnected the biamp switch. i did this by flicking it to biamp mode and tracing where all the connections went, then desoldered the wires from the switch and connected the wires up again directly to each other as the switch would have. You can also do it by leaving everything attached to the switch but adding little jumper conductors so the signal doesnt have to rely on passing through the contacts.
- I was able to have the low freq signal go directly to the woofer because in the 4343 in biamp mode it just flicks the LF signal directly to the woofers. Not sure if thats also the case on the 4345.

Hope that helps

Ricpan
10-18-2017, 12:47 AM
Yes you adjust the high low crossover points and the slope on the Electovoice DX38. It is a 24 bit machine and I like it a lot. Greg at Home Audio Sound turned me on to it and he recommended it to me and I'm glad he did. I bough it the same time I got the 4345s and McIntosh Mc2500 from him and everything turned out wonderfully. You can adjust the time also which is handy if you want to run subs. I think to weak point of the biamp switch is the contact of the pins so I would jumper over them.

sfan
10-18-2017, 04:27 PM
Hi, I'm not familiar with that EV unit. Can you adjust the crossover point and slope?

So This is how I do it on my 4343's:
-I use a First Watt B4 active crossover which allows me to set crossover points and slopes and slip the signal into a high pass and low pass
- The crossover point for the 4343 LF is 300hz and 12db per octave slope.
- This is optional: That biamp switch is nasty and degrades the signal. Now I have no intent of going back to a single amp so I totally disconnected the biamp switch. i did this by flicking it to biamp mode and tracing where all the connections went, then desoldered the wires from the switch and connected the wires up again directly to each other as the switch would have. You can also do it by leaving everything attached to the switch but adding little jumper conductors so the signal doesnt have to rely on passing through the contacts.
- I was able to have the low freq signal go directly to the woofer because in the 4343 in biamp mode it just flicks the LF signal directly to the woofers. Not sure if thats also the case on the 4345.

Hope that helps

First post here. Is there any prove or comparison to conclude biamp switch on the back is nasty? I recently bought a pair of 4333A and plan to turn them into biamp mode soon.

Thanks

Sfan

BMWCCA
10-18-2017, 07:01 PM
First post here. Is there any prove or comparison to conclude biamp switch on the back is nasty? I recently bought a pair of 4333A and plan to turn them into biamp mode soon.

Welcome.

You could start here (http://www.audioheritage.org/vbulletin/showthread.php?10613-4345-Includes-Designer-s-Post&p=110349&viewfull=1#post110349) where the system's designer suggested:
"Get rid of the bi-amp switch. Hardwire it in which ever mode you want it. The switch is not that great.

Ricpan
10-18-2017, 07:59 PM
I just finished one of my 4345s and the other is still stock. It is so much better without the switch. Thanks Ian for your help. I also bypassed the L-pad with resisters on the mid filter which showed me how much I was missing using the L-pad. I left the high and ultra high through the L-pads for now because is gives me more flexability and it seems to be less of an issue on my speakers.

Ian Mackenzie
10-19-2017, 12:41 PM
Cool

Ian Mackenzie
10-19-2017, 12:45 PM
Welcome.

You could start here (http://www.audioheritage.org/vbulletin/showthread.php?10613-4345-Includes-Designer-s-Post&p=110349&viewfull=1#post110349) where the system's designer suggested:
"Get rid of the bi-amp switch. Hardwire it in which ever mode you want it. The switch is not that great.


Yes it switches both polarities of the signal so there is significant contact resistance for an audio application requiring ac current.

Goldjazz
10-20-2017, 05:54 PM
I just finished one of my 4345s and the other is still stock. It is so much better without the switch. Thanks Ian for your help. I also bypassed the L-pad with resisters on the mid filter which showed me how much I was missing using the L-pad. I left the high and ultra high through the L-pads for now because is gives me more flexability and it seems to be less of an issue on my speakers.

Nice one! I'd also recommend taking the Lpad out for the highs and mids once you experiment and find levels your happy with. I noticed good improvements on those drivers too.