[f] AMB on Facebook

THE BALANCED BETA 22 BUILD LOG

beta22

Re: THE BALANCED BETA 22 BUILD LOG

Postby amb » June 3rd, 2018, 4:31 am

I recommend that you stay with multilayer ceramic C0G/NP0 type, as these are particularly good for ultrasonic frequencies, which is what you want in those locations.
User avatar
amb
Site Admin
 
Posts: 10381
Likes: 175 posts
Liked in: 482 posts
Joined: March 29th, 2010, 9:49 pm
Location: Sunnyvale, CA
Country: United States (us)

Re: THE BALANCED BETA 22 BUILD LOG

Postby Energy » November 4th, 2018, 2:15 am

I am working on getting a new case for my Beta 22 but am confused regarding one thing.

For awhile I have had the DAC connected to the B22 using XLR cables. Each time I switch over to my studio monitors I have to swap out the XLR cables. I did this for a more direct signal path. The speakers have a volume control of it's own and so the B22 did not sound good as a pre-amp. I only have the headphone amplifier or the speaker on at a given time, never together. Given this, is it fine to add an XLR output to the B22 as a loop-out and connect it to the input XLR's? Would this affect the sound quality of either devices if their wires were connected even if they are not in use? Furthermore, if this does not work, do I need to use a 4PDT? The grounds can be connected at all times right?

Thanh
Computer (Ethernet) Intel NUC7i7DNHE (USB) SOtM tX-USBultra (USB) Denafrips Terminator (XLR) AMB Laboratories β22 (Balanced) Focal Utopia

= ︿ =
User avatar
Energy
 
Posts: 86
Likes: 3 posts
Liked in: 4 posts
Joined: September 30th, 2012, 4:07 pm
Location: San Francisco, CA
Country: United States (us)

THE BALANCED BETA 22 BUILD LOG

Postby amb » November 4th, 2018, 3:40 am

You can add a pair of XLR jacks as input loopouts, there is no problem with sound quality. No switch is necessary, as you can control whether the headphones or the powered speakers are playing by varying the volume controls or turning one of them off.

Yes the grounds (input and loopout XLR pin 1) should all be connected together, to the chassis (depending on configuration, you may need a ground loop breaker), and to the input grounds of the amp boards.
User avatar
amb
Site Admin
 
Posts: 10381
Likes: 175 posts
Liked in: 482 posts
Joined: March 29th, 2010, 9:49 pm
Location: Sunnyvale, CA
Country: United States (us)

Re: THE BALANCED BETA 22 BUILD LOG

Postby blackshuck13 » November 13th, 2018, 11:12 am

Hmm, maybe I need to upgrade my 3 board beta 22 to a 4 board. Something to do this winter I think :)

Energy likes this post.
blackshuck13
 
Posts: 4
Likes: 0 post
Liked in: 1 post
Joined: October 3rd, 2011, 10:30 am
Country: United Kingdom (uk)

Re: THE BALANCED BETA 22 BUILD LOG

Postby Energy » December 6th, 2018, 4:22 pm

blackshuck13 wrote:Hmm, maybe I need to upgrade my 3 board beta 22 to a 4 board. Something to do this winter I think :)

I would highly recommend it! It sounds much better to my ears, especially with a balanced pair of headphones.
Computer (Ethernet) Intel NUC7i7DNHE (USB) SOtM tX-USBultra (USB) Denafrips Terminator (XLR) AMB Laboratories β22 (Balanced) Focal Utopia

= ︿ =
User avatar
Energy
 
Posts: 86
Likes: 3 posts
Liked in: 4 posts
Joined: September 30th, 2012, 4:07 pm
Location: San Francisco, CA
Country: United States (us)

Re: THE BALANCED BETA 22 BUILD LOG

Postby Energy » December 6th, 2018, 4:48 pm

Lately I have heard some weird static noise that comes and goes on my right channel of the amplifier. It comes random times when I listen to it, but not very often. It's like a light static whisper or like a microphone that just has been plugged that creates a light pop zzzz noise. It comes and goes for a couple of seconds and then disappears. Sometimes it will come back but there's no definitive time that I can say. Certain times it lasts for a minute and that makes me restart the amp. Other times it comes for a few seconds and doesn't come back again during that on session. Any ideas what it could be? I did the initial setup properly and made sure there were no DC bias offsets. All part numbers and resistor values are correct. There was a time once before if I can remember correctly where the amplifier didn't work on one side and that was because installed either C9, 10, C11, or C12 backwards (the polarity, and it was just 1 capacitor). I reversed it and it has worked since, but now I wonder if that had anything to do in perhaps lightly damaging one of the nearby transistors or perhaps messing up how that capacitor charge and discharges now to where there's an audible noise when the right capacitance isn't achieved.

& update!
I've decided to replace the 1uF MKS2 film capacitors with recently acquired 1uF MKP2 (polypropylene) that i have been waiting to become available for the last 3 years. They finally came out with PCM of 5mm. It's a little big but it can be mounted beneath the B22 and O22 boards perfectly fine!
I know these films aren't in line with the signal but usually based on experience, everything about the design up to it's parts have made a sound (to my ears). I will also be upgrading the dual Avel Lindberg Y23 80VA transformers to Toroidy TTSAS0060 Supreme Audio Transformers. A friend of mine told me about the benefits of a better shielded transformer and how that could attribute to lower noise and so I took it into consideration. Speaking of noise, the previous GoldPoint Series Stepped Attenuator will be also be replaced for a Khozmo Ladder Stepped Attenuator. That should remove a decent amount of resistors from the signal path and hopefully lead to better sound quality. I know I could use relays but I wanted this build to be as purist as possible.

Pictures for reference:
Image
Image
Computer (Ethernet) Intel NUC7i7DNHE (USB) SOtM tX-USBultra (USB) Denafrips Terminator (XLR) AMB Laboratories β22 (Balanced) Focal Utopia

= ︿ =
User avatar
Energy
 
Posts: 86
Likes: 3 posts
Liked in: 4 posts
Joined: September 30th, 2012, 4:07 pm
Location: San Francisco, CA
Country: United States (us)

Re: THE BALANCED BETA 22 BUILD LOG

Postby amb » December 6th, 2018, 7:24 pm

Maybe external interference? Such as from a cell phone.
User avatar
amb
Site Admin
 
Posts: 10381
Likes: 175 posts
Liked in: 482 posts
Joined: March 29th, 2010, 9:49 pm
Location: Sunnyvale, CA
Country: United States (us)

Re: THE BALANCED BETA 22 BUILD LOG

Postby Energy » December 6th, 2018, 10:40 pm

Thanks for the input. I'll try leaving the phone outside to see if the noise is still there.
Computer (Ethernet) Intel NUC7i7DNHE (USB) SOtM tX-USBultra (USB) Denafrips Terminator (XLR) AMB Laboratories β22 (Balanced) Focal Utopia

= ︿ =
User avatar
Energy
 
Posts: 86
Likes: 3 posts
Liked in: 4 posts
Joined: September 30th, 2012, 4:07 pm
Location: San Francisco, CA
Country: United States (us)

THE BALANCED BETA 22 BUILD LOG

Postby Energy » September 24th, 2019, 3:40 am

d
Last edited by Energy on September 24th, 2019, 8:18 pm, edited 1 time in total.
Computer (Ethernet) Intel NUC7i7DNHE (USB) SOtM tX-USBultra (USB) Denafrips Terminator (XLR) AMB Laboratories β22 (Balanced) Focal Utopia

= ︿ =
User avatar
Energy
 
Posts: 86
Likes: 3 posts
Liked in: 4 posts
Joined: September 30th, 2012, 4:07 pm
Location: San Francisco, CA
Country: United States (us)

Re: THE BALANCED BETA 22 BUILD LOG

Postby Energy » September 24th, 2019, 3:00 pm

I am still having problems with a very light static noise coming from my right channel audio. Even when I pull out the modem, router, turn off all phones in the house, it's still making noise.

I took a look at both the RIGHT+ and RIGHT- boards and there doesn't seem to be anything wrong externally with any of the parts. Every part is seated correctly and in the right orientation. I even went and redid the initial setup but that didn't fix it. Could this be the MOSFET or one of the other transistors going bad internally? If so where should I start troubleshooting?

For starters I am going to connect the power cable umbilical cord from the left side Sigma 22 to the right side Beta 22's just to make sure it's not the power supply that's the issue.
Computer (Ethernet) Intel NUC7i7DNHE (USB) SOtM tX-USBultra (USB) Denafrips Terminator (XLR) AMB Laboratories β22 (Balanced) Focal Utopia

= ︿ =
User avatar
Energy
 
Posts: 86
Likes: 3 posts
Liked in: 4 posts
Joined: September 30th, 2012, 4:07 pm
Location: San Francisco, CA
Country: United States (us)

PreviousNext

Return to β22 amplifier

Who is online

Users browsing this forum: No registered users and 0 guests

Quick Links

AMB audio DIY resources
AMB audio shop