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Old 15th January 2013, 12:48 PM   #12821
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Thanks root2.

May consider your products in the future.

I've been researching this ssr relay and its specifications concerning high inductive transformer startup and zero crossing and all. It talks about resolving the issue with a suppressor diode. (don't know what product to buy nor where to place in circuit) There are also better SSR products more suited for tfo startup. The one I am using is probably not suited for such purpose but it does work well for 1 F5 Power supply. I am not familiar enough with the subject matter so I am tending to go the coil relay route.

what I've tested with SSR relays (120v 40 amp version):
1 relay for 1 f5 ps --->> OK results
1 relay for 2 f5 ps ----> noise problem probably caused by what root2 is stating
2 relays in series for 2 f5 ps ---> noise problem present

I haven't tested 1 relay for each f5 PS but I suspect that this would be OK but I'm doubling the already expensive crydom components.

Also, I have seen higher rated crydom products (H1 series fo which I believe that probably would work).

I will use the ssr for my dac project so its not a lost cause.

thanks all for feedback.
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Old 19th January 2013, 02:19 PM   #12822
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crydom ssr hum on tfo resolved

I noticed that the coil relay functionned with no hum and the ssr experienced a hum on the transformers in a dual mono config.

The Live wire was going through the relay and to the 2 tfos in parallel. I changed that to serial and hum was no more when going through the ssrClick the image to open in full size.
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Old 19th January 2013, 07:00 PM   #12823
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sorry fro the bad info

that did not work.

no hum but only half the voltage.

So I'm going back to coils. will try to find an appropraite zero cross ssr relay.

Last edited by necplusultra; 19th January 2013 at 07:03 PM.
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Old 20th January 2013, 06:21 PM   #12824
Root2 is offline Root2  United Kingdom
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Quote:
Originally Posted by necplusultra View Post
sorry fro the bad info

that did not work.

no hum but only half the voltage.

So I'm going back to coils. will try to find an appropraite zero cross ssr relay.
You could still use a SSR so you get Zero crossing and the in parallel with it
run relay, the relay will take longer than 10-20ms to operate but will not be killed by the inrush, now using a Snubber and still having the SSR on switch the relay OFF then the SSR lets say 60mS later should solve cross over hum and inrush.

A good SSR will not be open circuit until one complete cycles and at about 1.4V below zero volts.

Have fun

Last edited by Root2; 20th January 2013 at 06:24 PM.
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Old 21st January 2013, 12:36 AM   #12825
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Smile psu concerns

Hello,
I need your opinion about a psu.

I'm trying to make a psu for F5 using many components from my box.
the transformer is a 45vac output that give around 64v avec diode bridge.
Using virtual ground each side is near 32v. the bleeders resistor is ok.
the main problematic is on the PI resistor.
As the target is 24v,I have to drop near 8volts if I'm right.
As described in nelson pass f5 manual, 24volt for 6amp continuous and more than 10amp for peak.
In this case, for drop 8volt in 6A, near 1.33 ohms is needed. and using 1.33 ohms in 10amp peak, the voltage drop will be near 13.3 volts... seems too much!!!

So regarding this problem, do you think that I have to use regulator, or using the right resistor value will be ok ?

About regulator, i'm thinking of using lt1083, or see in zen variations #5 as nelson pass recommends.
About resistor, what do you think about the use of bigger capacitors to reduce the problem?

thank you for your help
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Old 21st January 2013, 01:07 AM   #12826
6L6 is online now 6L6  United States
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To be honest, the best action is to purchase the proper transformer for the F5.

Use the transformer you have for another project.
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Old 21st January 2013, 01:54 PM   #12827
kcray is offline kcray  Indonesia
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Hello fellow DIYers,

I am about to build a stock F5, just reach page 1052 of this thread.
Wish me luck.

Hope Papa someday would bring us an alternate solution for input stage circuit, since genuine 2SJ74 is getting more more difficult to source.

Regards,

-- Peter
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Old 21st January 2013, 05:23 PM   #12828
Renron is offline Renron  United States
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Lineal Technologies says their about to introduce a substitute.
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Old 21st January 2013, 05:55 PM   #12829
kcray is offline kcray  Indonesia
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Quote:
Originally Posted by Renron View Post
Lineal Technologies says their about to introduce a substitute.
"LSJ74" presumably, is long overdue. Not sure anymore whether the Linear Systems would really release it.
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Old 21st January 2013, 06:18 PM   #12830
flg is offline flg  United States
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Quote:
Originally Posted by kcray View Post
"LSJ74" presumably, is long overdue. Not sure anymore whether the Linear Systems would really release it.
I heard some of us have had some in hand! Maybe at BAF last fall???
At any rate, they are still available ju$$t a few dollars more
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