Commercial Gainclone kit- building instructions - Page 103 - diyAudio
Go Back   Home > Forums > Commercial Sector > Vendor Forums > Audio Sector

Audio Sector Kits & PC boards from AudioSector

Reply
 
Thread Tools Search this Thread
Old 16th February 2010, 06:16 PM   #1021
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
Originally Posted by Wavne View Post
One has a dc offset of 118mv and the other 0.1mv. The second one has no output but the chip does get hot.
which is which?
__________________
regards Andrew T.
  Reply With Quote
Old 16th February 2010, 09:42 PM   #1022
Wavne is offline Wavne  Canada
diyAudio Member
 
Join Date: Oct 2007
Location: Chatham ON
the one with offset of 118mv works. the one with 0.1mv does not.
  Reply With Quote
Old 17th February 2010, 01:43 AM   #1023
Wavne is offline Wavne  Canada
diyAudio Member
 
Join Date: Oct 2007
Location: Chatham ON
I got it fixed! It was the Rm not soldered properly. Thing is so tiny it was hard to tell. I have a dc offset off 121mv on that channel.

I am using a Cambridge Audio V500 Surround decoder as a pre amp. When the volume is all the way down it sounds like there is a relay as there is a clicking sound you can hear. When I measure dc offsets I get about 3mv both channels with the volume all the way down. With volume on it measures 118mv on one channel and 121mv on the other but does not change regardless of volume setting. Does this seem normal? I thought the offset changes with volume level?

I also noticed when the channel settings on the processor are set to 0db I don't get much from the amp. I set it to +3db on the left and right outputs and it seems to have a lot more output capability. It can be adjusted up to 12db per channel. I don't have a proper heat sink set up right now. Using a steel plate with thermal grease and plastic clamps right now so I just have it running very low and it stays cool.

Any comments or suggestions guys?

Regards,

Wayne
  Reply With Quote
Old 17th February 2010, 02:34 AM   #1024
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
The offset changes with volume when potentiometer is connected directly to the amp. When there are coupling caps between potentiometer and the amp, the offset will be at max and not changing. It looks like with volume all way down, a mute circuit is engaged.
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC
  Reply With Quote
Old 18th February 2010, 08:20 PM   #1025
diyAudio Member
 
Join Date: May 2005
Location: bogu iza nogu...
If I use GC as integrated amp with pot(50K),which resistor(I presume R2 22K) can be omitted?And of course what can I expect from that?
  Reply With Quote
Old 22nd February 2010, 04:59 AM   #1026
dstebs is offline dstebs  United States
diyAudio Member
 
Join Date: Feb 2010
Default Help selecting pot or attenuator

I have a premium kit on the way and am gathering the other components. I'm having a hard time selecting a pot or attenuator. Early in this thread a Noble pot was recommended, but partsconnexion doesn't seem to list them any more. Is the Noble a plastic or carbon pot?. There are several step attenuators on ebay from Hong Kong. Would these be a good choice? I'd appreciate any advice. I'm guessing a 25K would be better than 50K. Transformer is 22v and speakers are 8 ohm.

Also, I wonder if it would be OK to mount the pot or attenuator in a separate enclosure. Would the additional connectors and cables be a problem?

Thanks,
Dave
  Reply With Quote
Old 22nd February 2010, 04:30 PM   #1027
diyAudio Member
 
Peter Daniel's Avatar
 
Join Date: Jul 2002
Location: Toronto, Canada
Send a message via AIM to Peter Daniel
Noble has a plastic taper and I still have them available (50k). You can also source them from percyaudio: 25K is recommended, but 50k will work fine too.

It's better to mount the pot directly at amp's input, if you have it in separate enclosure you may have problems with impedance matching and drive capability.

Quote:
Originally Posted by kele1975 View Post
If I use GC as integrated amp with pot(50K),which resistor(I presume R2 22K) can be omitted?And of course what can I expect from that?
Don't remove 22k, it's needed there for protection in case pot fails. It's also needed in case you are using pot value higher than 25K.

However, you can certainly bypass R1 (220R)
Attached Images
File Type: jpg Noble.JPG (37.8 KB, 711 views)
__________________
www.audiosector.com
“Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

Last edited by Peter Daniel; 22nd February 2010 at 04:32 PM.
  Reply With Quote
Old 26th February 2010, 10:09 PM   #1028
Harolda is offline Harolda  Netherlands
diyAudio Member
 
Join Date: Jul 2005
Location: Hoensbroek
Default Anyone experience with passive line level crossover with (bridged) LM4780

Hi there,

i am finishing my amps now and have a rane ac22 crossover to use them one my 2 way speakers with seas w15cy001 and hiquphon OWI. I am using bridged LM4780, only because my current system is fully balanced.
However i am thinking about putting passive line level amps into the amps directly, because i read great advantages to the opamp machines like the ranes and other electronic XO's. Has anyone experience with this with (bridged) LM4780's. I am thinking about a second order PLLXO, because a first order is probably not sufficient for these components. another option would be a tube crossover. My preamp is a passive volume control with a 4 deck 46 step attenuator (acoustic-dimension attenuators). What is your opinion on this and could i use two identical PLLXO's for the + and - signal of a balanced connection?
many thanks
  Reply With Quote
Old 28th February 2010, 02:17 AM   #1029
chuck55 is offline chuck55  United States
diyAudio Member
 
Join Date: Dec 2003
Location: New England
Default Magazine review mentioned "Loud" quality of Chipamps

I read the excellent review of Peter's chipamp on his website. The reviewer at HiFi+ made the interesting comment:

"That track and many others have
a slightly ‘loud’ quality with these
amps that when compared to more
powerful designs seems like a slightly
unnatural effusiveness."



I recently read the technology section at the C37 website. They offer a varnish to coat electronic components. I got to wondering if it would tame a gainclone's "loud" quality. Or is the "loud" quality simply because of an underdamped design of the gainclone.

Here is what they had to say at http://www.ennemoser.com/c37theory.html:


"Materials possess their own specific tonal signatures, independently of shape or size, but directly related
to temperature. The mechanism of our ears, made of bone and tissue, has its own unique signature:

Carbon at body temperature = C37structure, where

C = carbon and 37 = temperature in °Centigrade.


These material-specific resonances of our ears would drastically distort our perception of other sounds,
but they are filtered out by the brain, leaving an accurate and apparently objective image of our
acoustic environment. However, this objectivity is deceptive. Although the timbre of our own hearing
mechanism is no longer audible, our subconscious senses transmitted energy. The sound then has a
subjective strength and warmth.

A comparison can help make this clear: Glass bottles thrown into a metal container produce a lot of noise
but little energy, since the sound
signatures of glass and metal have no similarity to C37. On the other hand, sounds made by wooden
objects (close to C37) or similar materials have high energy but without great loudness.
Loudness is used here subjectively and represents the total stress on our ears.
Stress is highest with non-C37 sounds where, due to the lack of acoustic impedance (adjustment),
the inner mechanism of the ear remains virtually in neutral, resulting in large, painful displacements
of the moving parts and eventually, damage. "


Any thoughts?
  Reply With Quote
Old 28th February 2010, 10:15 AM   #1030
AndrewT is offline AndrewT  Scotland
diyAudio Member
 
Join Date: Jul 2004
Location: Scottish Borders
gobble de gook.

The "loud" effect may be due to clipping of some of the transients.
That could be due to asking the chipamp to drive low to medium sensitivity speakers.
__________________
regards Andrew T.
  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
Commercial complete Gainclone kit for a beginner? gychang Chip Amps 365 4th October 2011 09:19 AM


New To Site? Need Help?

All times are GMT. The time now is 12:34 PM.


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