Speakerplans.com Homepage
Forum Home Forum Home > General > General Forum
  New Posts New Posts RSS Feed - amplifier DC on 2" hf drivers, coupling caps?
  FAQ FAQ  Forum Search   Events   Register Register  Login Login

amplifier DC on 2" hf drivers, coupling caps?

 Post Reply Post Reply
Author
Message
bob4 View Drop Down
Old Croc
Old Croc
Avatar

Joined: 29 February 2004
Location: Finland/Germany
Status: Offline
Points: 1842
Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Topic: amplifier DC on 2" hf drivers, coupling caps?
    Posted: 07 April 2017 at 12:39pm
Greetings gentlemen,
apologies for the rather beginnerish question, despite my wannabe-expert ramblings on this forum....

Doing some system tuning, and have a question about amplifier dc

I have some naked comps for a threeway system. I want to connect them straight to the hf amp, but trying to cultivate diligent practice, i decided to check first that the amps dont output any dc. Turns out there are 2-5 mV DC coming from The various amps.

Is it safe to connect a hf driver to an amp with this amount of dc offset?

If not, which spec of coupling caps should i use?


EDIT: Comps are b&c de75
Bless,
Bob

Edited by bob4 - 07 April 2017 at 12:40pm
Back to Top
Earplug View Drop Down
Old Croc
Old Croc


Joined: 03 January 2012
Location: Europe
Status: Offline
Points: 7199
Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 07 April 2017 at 1:13pm
A few mV is normal - even up to 100mV or so is not unusual on older amps. Any more and I´d get them serviced, but 2-5mV is nothing.

In any case, a blocking capacitor is a good idea. Use a capacitor which gives you a -3dB point at least one octave below your crossover frequency.




Edited by Earplug - 07 April 2017 at 1:14pm
Earplugs Are For Wimps!
Back to Top
bob4 View Drop Down
Old Croc
Old Croc
Avatar

Joined: 29 February 2004
Location: Finland/Germany
Status: Offline
Points: 1842
Post Options Post Options   Thanks (0) Thanks(0)   Quote bob4 Quote  Post ReplyReply Direct Link To This Post Posted: 07 April 2017 at 2:34pm
Cheers! What kind of voltage rating do you reckon could be good? 50ish volts? Or more like 100?
Back to Top
studio45 View Drop Down
Old Croc
Old Croc
Avatar

Joined: 16 October 2007
Location: United Kingdom
Status: Offline
Points: 3863
Post Options Post Options   Thanks (0) Thanks(0)   Quote studio45 Quote  Post ReplyReply Direct Link To This Post Posted: 07 April 2017 at 2:39pm
For high power PA work use minimum 250 volt, non-electrolytic/film type capacitors. It's actually the AC current rating that's important - but that's not quoted by the majority of manufacturers. 
However, it scales with the voltage rating, and I've found from experience that 50v caps will blow up quickly, 100v ones will blow up eventually (that goes for electrolytics as well as film types), whereas 250v and 400v types seem to last a long time. The thin foils and dielectrics in low-voltage types just can't take the continuous power.
Studio45 - Repairs & Building Commotion Soundsystem -Mobile PA
Back to Top
Earplug View Drop Down
Old Croc
Old Croc


Joined: 03 January 2012
Location: Europe
Status: Offline
Points: 7199
Post Options Post Options   Thanks (0) Thanks(0)   Quote Earplug Quote  Post ReplyReply Direct Link To This Post Posted: 09 April 2017 at 12:39pm
Earplugs Are For Wimps!
Back to Top
madboffin View Drop Down
Old Croc
Old Croc


Joined: 03 July 2009
Location: Milton Keynes
Status: Offline
Points: 1537
Post Options Post Options   Thanks (0) Thanks(0)   Quote madboffin Quote  Post ReplyReply Direct Link To This Post Posted: 09 April 2017 at 9:17pm
Back to Top
 Post Reply Post Reply

Forum Jump Forum Permissions View Drop Down

Forum Software by Web Wiz Forums® version 12.06
Copyright ©2001-2023 Web Wiz Ltd.

This page was generated in 0.047 seconds.