Setting up a ESP active crossover with gainclone - Page 3 - diyAudio
Go Back   Home > Forums > Amplifiers > Chip Amps

Chip Amps Amplifiers based on integrated circuits

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 23rd July 2007, 12:37 PM   #21
diyAudio Member
 
Join Date: Jul 2006
Yep, found the formula, did a few calcs, although could parallel the caps I was looking at worst case scenario (speaker is rated at 4ohms but not sure of individual drivers - unlikely but 2ohm each? I know absoltulty nothing about passive crossovers at present)

Therefore I would be looking at a 99.5uf cap, and when it comes to non electro's they get quite pricey! (actually its probably not, im just used to trying to find high voltage AC rated examples)

I will most certainly be giving it a go to see what it sounds like, im just stuck at work at the moment and was intersted to pre-empt what might happen.

Regards

Dan
  Reply With Quote
Old 23rd July 2007, 01:22 PM   #22
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Hi,
being British retail, the speaker is less likely to be 4ohms, more likely to be 4 to 8ohms, meaning a 4ohm bass/mid driver and an 8ohm treble driver.

If it has a 4ohm bass/mid driver then you become quite limited on what you can do with the chipamp supplying the bass/mid.
__________________
regards Andrew T.
  Reply With Quote
Old 13th August 2007, 08:14 AM   #23
diyAudio Member
 
Join Date: Jul 2006
Right well I've sorted the 4ohm speaker issue by building a pair of bookshelves with the hivi d6.8 (8 ohm) and sd 1.1a tweeter - should be finished shortly.

Finally finished the 2nd set of amps as well and have begun testing using the jamos.

At certain volume levels or at certain levels using the trim pots a contstant ermm hiss and cripsy crackle (low level ish) comes through the tweeter of the channel being ajusted. It seems to build up as I'm ajusting in one direction and then drop down again to almost nothing once it has been passed.

Can anyone hint me in the direction of what causes this effect/ proposed rectifiction or has anyone else experienced this? Im using a 50k alps log for volume and 20K trimpot as sugested.

Oh and hint for anyone using the ESP active crossover, there is a error on the silkscreening of the board (LP and HP the wrong way around) which is noted in the manual but doesnt jump out if in a rush!

Regards

Dan
  Reply With Quote
Old 13th August 2007, 08:38 AM   #24
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
You might have damaged one of the op amps whilst soldering. If you have a spare, I'd try swapping it out.
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 13th August 2007, 08:44 AM   #25
diyAudio Member
 
Join Date: Jul 2006
I have 3 spare so I guess I could. Will have another look into it tonight, I have a feeling it occurs on both channels though, and only one opamp is shared between the two channels (the 1st, the other, 12 are channel specific - hope that make sense)

I did pay attention to ensure minimal heat was applied for shortest duration possible whilst still achieving satisfactory join.

Complete stab in the dark (no idea what im talking about here) but its nothing to do with the output impednce becoming a value which somehow interacts with the amplifiers?
  Reply With Quote
Old 13th August 2007, 08:56 AM   #26
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
If you have the 100ohm resistors in the outputs that Rod recommends then that is unlikely. You could try swapping the amps over that drive the mids and tweets and see if the same thing happens.
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 14th August 2007, 07:52 PM   #27
diyAudio Member
 
Join Date: Jul 2006
Pinkmouse,

Circuit is 100% as per Rods 2way design.

Have tried swapping them over and it still occurs, I can confirm this happens on both channels ( now that I used a SPL meter to get the outputs of both channels matched)

It appears many other people have experienced such hiss but cannot find a definative answer to it.

At the current levels (trimpot positions) as the volume is increased it sounds like one is tuning a radio in (that varying tone). When 12 oclock is reached all his disspears and the whloe system sounds perfect, when around 3 oclock is reached the hiss comes back for the last 1/4 turn. (however all hum in the mid/low amp diminishes)

I also tried the amp with my new tweeters and the same thing happened.

Its driving me mad as I have quite limited time before I go to university!

I breifly tried a 1uf (didnt have any 2.7's to hand) / 1ohm zobel and the problem was still there (if it made a difference it was only very slight).

For the 1st 5 - 10 seconds the problem does not exist, but them builds up to a steady level.

shorting the inputs on the active crossover makes no difference

All help and input much appreciated!!
  Reply With Quote
Old 14th August 2007, 08:23 PM   #28
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
I really have no idea. Have you tried asking on the ESP forum?
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote
Old 15th August 2007, 07:12 AM   #29
diyAudio Member
 
Join Date: Jul 2006
Ahah didnt know they had one! Just waiting to be authorised by an admin.

I know you have said that you havent got a clue on this one..

But this morning I tried the x-over with my surround receveiver and guess what, no hiss!

Did measure an increase from around 0 (using 20 Meg range on meter) to 14Mohms within the first 5-10 seconds on the outputs, which co-incides with the introduction of the hiss on the gainclone.

Therefore both amp and xover are happy on their own as long as they are not brought together! Which kinda sucks!
  Reply With Quote
Old 15th August 2007, 07:21 AM   #30
diyAudio Moderator
 
pinkmouse's Avatar
 
Join Date: Apr 2002
Location: Chatham, England
Which GCs are they? Do they have DC blocking and LP filters on the front?
__________________
Rick: Oh Cliff / Sometimes it must be difficult not to feel as if / You really are a cliff / when fascists keep trying to push you over it! / Are they the lemmings / Or are you, Cliff? / Or are you Cliff?
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Help with GainClone gain setting johan851 Chip Amps 35 15th February 2008 05:33 PM
Passive crossover into active crossover hahfran Multi-Way 16 10th February 2008 06:16 PM
Gainclone for an active subwoofer m127 Chip Amps 13 19th November 2004 02:47 PM
Gainclone amp with DAC in active speakers borges Chip Amps 15 16th April 2004 07:13 AM
XVR1 active crossover, discrete active stage promitheus Pass Labs 18 22nd July 2002 01:29 AM


New To Site? Need Help?

All times are GMT. The time now is 02:17 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2