[f] AMB on Facebook

Need help on sound level vary between L & R

beta22

Need help on sound level vary between L & R

Postby Helios » September 9th, 2018, 7:39 pm

I need some help and advise for my 3 channel β22 amplifier, I built it for few years and recently something gone wrong on the right channel when connected with low impedance headphones (32 ohms), the sound level on right channel is about 50% less than the left channel, but without any problem when connected with a 300 ohms headphone, besides, the same 32 ohms headphone which has problem with β22 is perform perfectly on other amplifier, anyone has idea about it? Kindly please help to give me some advice.
Helios
 
Posts: 26
Likes: 0 post
Liked in: 0 post
Joined: December 17th, 2013, 9:00 pm
Location: HK
Country: Hong Kong (hk)

Re: Need help on sound level vary between L & R

Postby amb » September 9th, 2018, 10:27 pm

Do you have any extra resistance between the outputs of the amp and your headphones? It might be a degraded headphone jack contact or a cold solder joint in the wiring from the amp’s output to the jack.
User avatar
amb
Site Admin
 
Posts: 10378
Likes: 175 posts
Liked in: 482 posts
Joined: March 29th, 2010, 9:49 pm
Location: Sunnyvale, CA
Country: United States (us)

Re: Need help on sound level vary between L & R

Postby Helios » September 25th, 2018, 6:22 am

It seems no extra resistance between the outputs of the amp or my headphones, the problem only happens on low impedance headphones and the headphone which has the sound level issue is working perfectly on other amps.
Helios
 
Posts: 26
Likes: 0 post
Liked in: 0 post
Joined: December 17th, 2013, 9:00 pm
Location: HK
Country: Hong Kong (hk)

Re: Need help on sound level vary between L & R

Postby amb » September 25th, 2018, 7:35 am

Did you do actual resistance measurements?
User avatar
amb
Site Admin
 
Posts: 10378
Likes: 175 posts
Liked in: 482 posts
Joined: March 29th, 2010, 9:49 pm
Location: Sunnyvale, CA
Country: United States (us)

Re: Need help on sound level vary between L & R

Postby Helios » September 25th, 2018, 5:46 pm

No, would you mind to tell me how to do a proper measurement, I really need to fix it, thanks in advance!
Helios
 
Posts: 26
Likes: 0 post
Liked in: 0 post
Joined: December 17th, 2013, 9:00 pm
Location: HK
Country: Hong Kong (hk)

Re: Need help on sound level vary between L & R

Postby amb » September 25th, 2018, 7:40 pm

It would be handy to have a blank headphone plug (1/4” or 6.35mm TRS male plug) for this. Insert it into your amp’s headphone jack. Then measure the resistance between the left channel β22 board’s output solder pad and the plug’s tip contact. Do the same between the right channel board and the plug’s ring contact. They should both be close to zero ohms.
User avatar
amb
Site Admin
 
Posts: 10378
Likes: 175 posts
Liked in: 482 posts
Joined: March 29th, 2010, 9:49 pm
Location: Sunnyvale, CA
Country: United States (us)

Re: Need help on sound level vary between L & R

Postby Helios » September 25th, 2018, 7:44 pm

thanks, I will try this.
Helios
 
Posts: 26
Likes: 0 post
Liked in: 0 post
Joined: December 17th, 2013, 9:00 pm
Location: HK
Country: Hong Kong (hk)

Re: Need help on sound level vary between L & R

Postby Helios » October 4th, 2018, 2:31 am

I have done the resistance measurement, all values very close to 0 and I also measured the resistance between the output terminal on the circuit and the headphone jack, it is normal too. Do you have any idea?
Helios
 
Posts: 26
Likes: 0 post
Liked in: 0 post
Joined: December 17th, 2013, 9:00 pm
Location: HK
Country: Hong Kong (hk)

Re: Need help on sound level vary between L & R

Postby amb » October 4th, 2018, 9:04 am

When you’re using low impedance headphones, where is your volume control setting? If it’s on the low-end of the dial, then it might be a volume pot tracking issue.
User avatar
amb
Site Admin
 
Posts: 10378
Likes: 175 posts
Liked in: 482 posts
Joined: March 29th, 2010, 9:49 pm
Location: Sunnyvale, CA
Country: United States (us)

Re: Need help on sound level vary between L & R

Postby Helios » October 5th, 2018, 12:03 am

it occurs on the full range of the volume control.
Helios
 
Posts: 26
Likes: 0 post
Liked in: 0 post
Joined: December 17th, 2013, 9:00 pm
Location: HK
Country: Hong Kong (hk)

Next

Return to β22 amplifier

Who is online

Users browsing this forum: No registered users and 1 guest

Quick Links

AMB audio DIY resources
AMB audio shop