[f] AMB on Facebook

Ye Beta24 build

beta24

Ye Beta24 build

Postby zhanqian » January 29th, 2018, 11:35 pm

Hi Ti, Everyone

I am Ye from China,I have built a active ground Beta22 before, It gives me so many great times.
Thank you, Ti, for your great work and your help, not boring about my questions.

I start building Beta24 on December, I am close to the final setup, here some picture of my build.My Beta24 use a custom 800VA and a custom 60VA toroidal transformer, EPCOS 10000uF capacitor. The main difference from Ti's build is I use micro-controller board, the chip is STM32F103.

The controller board is hand made.It's simple, four relay control, controls the bleeder resistor, the Crydom 4850 SSR, the soft start circuit(a 22R 10W resister and a short cut relay), and the speaker turn on delay.The controller board handles the power button press, turns on or turns off the amplifier by switching the four relays, the controller board also controls the light of the power button. I also plan to add temperature detection to the board.
You do not have the required permissions to view the files attached to this post.

2 people like this post.
zhanqian
 
Posts: 27
Likes: 14 posts
Liked in: 10 posts
Joined: October 24th, 2017, 8:02 pm
Location: Shenzhen
Country: China (cn)

Re: Ye Beta24 build

Postby amb » January 30th, 2018, 3:42 am

Looks excellent!
User avatar
amb
Site Admin
 
Posts: 10379
Likes: 175 posts
Liked in: 482 posts
Joined: March 29th, 2010, 9:49 pm
Location: Sunnyvale, CA
Country: United States (us)

Re: Ye Beta24 build

Postby zhanqian » January 30th, 2018, 4:16 am

Thank you, Ti

I miss the controller part pictures. I am learn KiCad recently, plan to change controller part to printed circuit board.

Ti, I have some question,

1. The AC wire connect order is AC --> fuse --> Crydom SSR --> soft start circuit, or is
AC --> fuse --> soft start circuit --> Crydom SSR?

2.
The power on sequence in the program is:
A. Switch off bleeder resistor relay, delay 500 ms
B. Switch on Crydom SSR, delay 2 seconds
C. Switch on soft start relay,delay 2 seconds
D. Switch on speaker relay

The power off sequence in the program is:
A. Switch off the speaker relay,delay 1 seconds
B. Switch off the Crydom SSR, delay 1 seconds
C. Switch off soft start relay,delay 1 seconds
D. Switch on bleeder resistor relay

In the power off sequence, is the order of B and C correct? or they need to be swapped?
You do not have the required permissions to view the files attached to this post.

cobretti likes this post.
zhanqian
 
Posts: 27
Likes: 14 posts
Liked in: 10 posts
Joined: October 24th, 2017, 8:02 pm
Location: Shenzhen
Country: China (cn)

Re: Ye Beta24 build

Postby obee » January 30th, 2018, 8:22 am

Looks great!
obee
 
Posts: 153
Likes: 0 post
Liked in: 2 posts
Joined: September 5th, 2012, 4:03 pm
Country: Hong Kong (hk)

Re: Ye Beta24 build

Postby Pieterh » January 30th, 2018, 8:39 am

Nice build! What chassis do you use?
Pieterh
 
Posts: 132
Likes: 93 posts
Liked in: 54 posts
Joined: December 29th, 2015, 12:50 am
Location: Netherlands
Country: Netherlands (nl)

Re: Ye Beta24 build

Postby amb » January 30th, 2018, 11:12 am

zhanqian wrote:Ti, I have some question,

1. The AC wire connect order is AC --> fuse --> Crydom SSR --> soft start circuit, or is
AC --> fuse --> soft start circuit --> Crydom SSR?

Since it's all in series, it doesn't matter.

2.
The power on sequence in the program is:
A. Switch off bleeder resistor relay, delay 500 ms
B. Switch on Crydom SSR, delay 2 seconds
C. Switch on soft start relay,delay 2 seconds
D. Switch on speaker relay

I think you want to switch on the soft start first (i.e., open the relay that would otherwise short circuit the soft start resistor), and while soft start is still on, switch on the Crydom SSR. Then, after a few seconds delay, switch off the soft start relay (close the relay and short out the soft start resistor).

I am also not sure why you would delay 2 seconds after switching on the SSR. What do you to with the SSR after 2 seconds? After all, that's really the power switch, so once you turned it on, it should stay on until the pushbutton is pressed to turn it off.

The power off sequence in the program is:
A. Switch off the speaker relay,delay 1 seconds
B. Switch off the Crydom SSR, delay 1 seconds
C. Switch off soft start relay,delay 1 seconds
D. Switch on bleeder resistor relay

With my suggestion above, the soft start would have already been turned off at start-up time, so there is no need for step C. You might want to shorten the delay between turning off the SSR and turning on the bleeders.
User avatar
amb
Site Admin
 
Posts: 10379
Likes: 175 posts
Liked in: 482 posts
Joined: March 29th, 2010, 9:49 pm
Location: Sunnyvale, CA
Country: United States (us)

Re: Ye Beta24 build

Postby zhanqian » January 31st, 2018, 5:43 am

Thanks, obee

Hi, Pieterh
The case is brought from taobao.com; It's big enough(412*413*200mm), I think it's good, for I don't have to worry about the space as I am a beginner.
I post the picture below, and the link is https://item.taobao.com/item.htm?spm=a1z09.2.0.0.2517f497rl5rXw&id=555220821297&_u=v1ot9a0d575

Ti, OK, I will shorten the delay between turning off the SSR and turning on the bleeders.
I thinks I missed the the important part, the relay I use are all "off" if not powered.The soft start resistor are connected to the the AC by nature,If the soft start relay switch on, It will short the soft start resistor. The reason for delay 2 seconds after switching the SSR, it's for avoid the big current.
You do not have the required permissions to view the files attached to this post.
zhanqian
 
Posts: 27
Likes: 14 posts
Liked in: 10 posts
Joined: October 24th, 2017, 8:02 pm
Location: Shenzhen
Country: China (cn)

Re: Ye Beta24 build

Postby obee » January 31st, 2018, 8:30 am

I think the big current can't be avoided as it's due to empty capacitors.
Some people would add a soft start circuit that connects some resistors with a relay in series to the AC to transformers, the relay will turn off after few seconds and connect the AC main directly to transformers. I am also thinking to buy this kind of time delay soft start circuit board.
obee
 
Posts: 153
Likes: 0 post
Liked in: 2 posts
Joined: September 5th, 2012, 4:03 pm
Country: Hong Kong (hk)

Ye Beta24 build

Postby amb » January 31st, 2018, 12:49 pm

zhanqian, so your relays are normally-closed? NO problem, just reverse the turn off/on logic. I still don't understand why you need to delay for 2 seconds after turning on the SSR. It is exactly at that time that there will be high inrush current. As long as your soft start circuit is in effect, all is well. What do you do after those 2 seconds anyway? You would still leave it alone, because the SSR must stay on...
User avatar
amb
Site Admin
 
Posts: 10379
Likes: 175 posts
Liked in: 482 posts
Joined: March 29th, 2010, 9:49 pm
Location: Sunnyvale, CA
Country: United States (us)

Re: Ye Beta24 build

Postby cobretti » January 31st, 2018, 2:34 pm

I have also custom made slow start circuit in my b24. I don't use any triac based(such as Crydom) switching devices on AC mains. I put relay instead. I programmed 1 second delay between power ON relay and by-pass resistor relay to limit the inrush current.
The switching OFF sequence is not needed. You can drop everything at the same time. I do it like this and there is no issue.
User avatar
cobretti
 
Posts: 602
Likes: 18 posts
Liked in: 23 posts
Joined: July 9th, 2011, 5:41 am
Location: Weymouth, Taxachusetts
Country: United States (us)

Next

Return to β24 fully-differential power amplifier

Who is online

Users browsing this forum: No registered users and 1 guest

Quick Links

AMB audio DIY resources
AMB audio shop

cron