Issue matching pre amp and Dax

Discuss anything about Apogees

Moderator: Graz

Issue matching pre amp and Dax

Postby DarthDiva on Wed May 17, 2017 10:11 am

After many years of being shut down I am reviving my system . I'd like to keep my 4 mono Lumley amps because they did a wonderful job driving my Divas through the original DAX . I had been using a custom built pre amp by the guys who started Sonic Frontiers .
I'm thinking of getting a Coincident Statement Phone with line stage instead . But I fear an impedance mismatch . The Coincident outputs 250k ohms and the DAX input is 80k . I've heard that the mismatch could roll off the high and low frequencies as volume is turned up . Perhaps not a happy match ? I'd very much appreciate comments and direction
DarthDiva
 
Posts: 2
Joined: Tue May 16, 2017 8:59 pm

Re: Issue matching pre amp and Dax

Postby apogee_admin on Tue May 23, 2017 11:06 am

Think you misread the spec says output impedance is 250ohms, so you are ok.

I probably shouldn't say this, but I have tested the DAX against upgraded crossovers and found it very bland and lifeless sounding in comparison.
User avatar
apogee_admin
Site Admin
 
Posts: 169
Joined: Thu Jul 01, 2010 3:27 pm
Location: Birmingham, UK

Re: Issue matching pre amp and Dax

Postby DIVA_Paris on Fri Jun 09, 2017 10:20 am

And what about upgrading the Dax in order to keep a biamp configuration?
Or maybe a better active crossover exists?

Thank you for any advice

BTW I recently mesured the frequency respons of my divas with a microphone.
There is a continuous drop above 12 kHz. Is it due to the Med/treb filter?
Also a drop around 50hz on the bass
The Dax is working ok up to 20 kHz, so it is not a problem coming from DAX or the preamp
DIVA_Paris
 
Posts: 2
Joined: Mon Aug 22, 2011 10:22 pm

Re: Issue matching pre amp and Dax

Postby Zardoz on Fri Jun 09, 2017 1:30 pm

Certainly upgrading the DAX would help it, but I don't have any idea if it would be economical or not. If you are using 4 identical amps, you can still biamp with the passive cross over. John can tell you better about that, but that is my understanding of biamping.
Best,
Z
"When I die, I want to go peacefully in my sleep like my grandfather,
not screaming in terror like his passengers..."
User avatar
Zardoz
 
Posts: 154
Joined: Wed Sep 14, 2011 10:17 pm
Location: Virginia USA

Re: Issue matching pre amp and Dax

Postby DarthDiva on Tue Jun 20, 2017 2:01 pm

Thanks so much for the reply.

So, I should be thinking of addressing the DAX / cross over upgrade issue. Which path is the best, upgrade the DAX or avoid that entirely and replace the cross overs all together?

In either case, who might be the right person to do the DAX upgrade or the crossover upgrade?
DarthDiva
 
Posts: 2
Joined: Tue May 16, 2017 8:59 pm

Re: Issue matching pre amp and Dax

Postby DIVA_Paris on Wed Jun 21, 2017 12:29 pm

One issue with Dax is the remaining medium /treble passive filter . The medium filter is only a an inductance and everybody agree on the value 0.055mH. But what about the tweeter filter values ?
DIVA_Paris
 
Posts: 2
Joined: Mon Aug 22, 2011 10:22 pm


Return to Apogee speaker chat

Who is online

Users browsing this forum: No registered users and 1 guest

cron