Forums :: Resources :: Features :: Photo Gallery :: Vintage Radio Shows :: Archives :: Books
Support This Site: Contributors :: Advertise


It is currently Oct Sat 21, 2017 3:52 am


All times are UTC [ DST ]





Post New Topic Post Reply  [ 1205 posts ]  Go to page Previous  1 ... 57, 58, 59, 60, 61  Next
Author Message
 Post subject: Re: A new 300B amp project
PostPosted: Oct Tue 10, 2017 5:25 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20701
Location: Haledon, NJ, usa
Flipperhome wrote:
Yes, it is very simple. I keep asking you what there is to "learn" from this and all you can do is stomp and whine there's something to learn. Well, don't just sit there, man, tell us what it is.

YES... it is VERY simple. All I am saying is that the more john reads and learns the better position he'll be to understand the things he asks about before he just blindly follows step by step instructions.
The real question to ask here is why do you not get this Flip?

I am not trying to "tell you you" or John ANYthing... I have no bias here and no motive.

I am simply only helping to direct him to other sources on the subject and I do not have a bias... I am not suggesting AC or DC or XYZ... I don't care.

I am helping only to point john in the direction of articles about what others have done all different ways.

Now it's about time for you to please...STOP accusing me of things. Especially of "stomping and whining" ... Where do you get that dumb idea from?

Do you think that my helping John by pointing out links to him is "stomping and whining" ... ????

How?
All you do is fight against anything and everything that hasn't come from you.

But how can John learn if all you do is close all doors for him to learn
Time for you to reassess your role.
Try simply adding the educational information needed and not forced dictates to constantly defend.
These other links are NOT meant to challange your ideas... NO ... they are meant only for John to help him get a broader grip on the subject.
STOP attacking people. Esp me.

_________________
To be a man, Be a non-conformist, Nothing's sacred as the integrity of your own mind.
-Emerson


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Tue 10, 2017 7:46 pm 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
Well, I like the circuit we are gona build. I have read all I can find about the 300b, motor run caps, filament powering.
Along with you guys, we have about the best ideas available IMO.
Every article I read about the amp, the builder claims superiority over any other.
Still waiting for the Edcors. Then can get the chassis under construction.

_________________
John Smith, over and out.
If I did something right, I made a mistake.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Fri 13, 2017 4:20 am 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
Four weeks ago I ordered the transformers. So should be soon.
The order was for 8 transformers, including one choke.

_________________
John Smith, over and out.
If I did something right, I made a mistake.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Fri 13, 2017 5:04 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20701
Location: Haledon, NJ, usa
john8750 wrote:
Four weeks ago I ordered the transformers. So should be soon.
The order was for 8 transformers, including one choke.

I found it very helpful to call them and make an inquiry as to the date you might expect them. This 'nudge' seems to "wake them up' a bit... and next thing you know your order starts bubbling up to the top of the list of jobs... and you get your parts soon after.

_________________
To be a man, Be a non-conformist, Nothing's sacred as the integrity of your own mind.
-Emerson


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Fri 13, 2017 5:37 am 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
An excellent idea. Seems like about 4 weeks has been the norm of all my Edcor orders.
I hope they noticed my new shipping address, and didn't ship to the old PO Box :roll:

_________________
John Smith, over and out.
If I did something right, I made a mistake.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Tue 17, 2017 1:54 am 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
A different 300b idea. Uses James output transformers. And four motor run caps in the power supply.
I noticed the weird 5vct powering, through the chokes, B+. And the 300ma fuse in-line on the
high voltage center tap to ground. And an unusual power switch set-up.
Look at the 50watt filament balance resistor.


Attachments:
91Aschematic[1].gif
91Aschematic[1].gif [ 23.27 KiB | Viewed 97 times ]

_________________
John Smith, over and out.
If I did something right, I made a mistake.
Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Tue 17, 2017 2:06 am 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
Or is that 50watt for the cathode?

_________________
John Smith, over and out.
If I did something right, I made a mistake.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Tue 17, 2017 2:43 am 
Member
User avatar

Joined: Nov Sat 26, 2011 4:09 am
Posts: 7738
Location: Texas. USA
john8750 wrote:
A different 300b idea. Uses James output transformers. And four motor run caps in the power supply.
I noticed the weird 5vct powering, through the chokes, B+. And the 300ma fuse in-line on the
high voltage center tap to ground. And an unusual power switch set-up.
Look at the 50watt filament balance resistor.
That's just the way you use a 5Z3. It actually has two 2.5V filaments (internally) in series. The 300 mA fuse in the ground leg means it doesn't have to break high voltage. The power switch is just switching both ends of the AC. The 50 Watt resistor is the cathode resistor.

The only thing unusual, besides the schematic layout, is the hum cancellation on the 300B filaments simulating a CT where there isn't one and elevating the 5693 heaters (apparently intended as hum reduction). That 5693 saves a gain stage but pentodes are a no-no for true 'SET' aficionados.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Tue 17, 2017 2:57 am 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
Flipperhome wrote:
john8750 wrote:
A different 300b idea. Uses James output transformers. And four motor run caps in the power supply.
I noticed the weird 5vct powering, through the chokes, B+. And the 300ma fuse in-line on the
high voltage center tap to ground. And an unusual power switch set-up.
Look at the 50watt filament balance resistor.
That's just the way you use a 5Z3. It actually has two 2.5V filaments (internally) in series. The 300 mA fuse in the ground leg means it doesn't have to break high voltage. The power switch is just switching both ends of the AC. The 50 Watt resistor is the cathode resistor.

The only thing unusual, besides the schematic layout, is the hum cancellation on the 300B filaments simulating a CT where there isn't one and elevating the 5693 heaters (apparently intended as hum reduction). That 5693 saves a gain stage but pentodes are a no-no for true 'SET' aficionados.



Thanks Flip. Another cool circuit. But not as cool as ours :lol:

_________________
John Smith, over and out.
If I did something right, I made a mistake.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 3:37 am 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
Flip
I saw a tube power supply with a .01 disc cap paralleling the filters. What do you think about that?
Is it just something else to do, or could there be a good reason. I guess it wouldn't hurt. I don't know.

_________________
John Smith, over and out.
If I did something right, I made a mistake.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 3:45 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20701
Location: Haledon, NJ, usa
john8750 wrote:
Flip
I saw a tube power supply with a .01 disc cap paralleling the filters. What do you think about that?
Is it just something else to do, or could there be a good reason. I guess it wouldn't hurt. I don't know.

The large caps are filtering lower freq like 60hz ripple... the .01 filter higher freq noise or pulses and spikes.

_________________
To be a man, Be a non-conformist, Nothing's sacred as the integrity of your own mind.
-Emerson


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 4:49 am 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
Pbpix wrote:
john8750 wrote:
Flip
I saw a tube power supply with a .01 disc cap paralleling the filters. What do you think about that?
Is it just something else to do, or could there be a good reason. I guess it wouldn't hurt. I don't know.

The large caps are filtering lower freq like 60hz ripple... the .01 filter higher freq noise or pulses and spikes.



Well, I have some 1k-volt .01's, if it will help. I like to install a .1, 1k-volt across the power switch. Without it the audio makes a loud pop when powering off. Seems to work good. Also, a .01 snubber on the power pins of IC's. And, a .1
on the output of any 78xx regulator.
I even saw some power supply with a .1- .01- .001 all across a filter. That should be very clean. And a full wave bridge with
caps across each rectifier.
But is this necessary, or just in case?

_________________
John Smith, over and out.
If I did something right, I made a mistake.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 5:11 am 
Member
User avatar

Joined: Nov Sat 26, 2011 4:09 am
Posts: 7738
Location: Texas. USA
john8750 wrote:
Flip
I saw a tube power supply with a .01 disc cap paralleling the filters. What do you think about that?
Is it just something else to do, or could there be a good reason. I guess it wouldn't hurt. I don't know.
That's fairly common practice and it won't hurt anything but, in reality, it won't likely help anything either.

The theory goes that 'large' capacitors have (a small) inductance (which is true) so the small bypass cap will become active at 'higher frequencies' but, truth be told, even 4,700 uF caps work as well, or better, than, say, a 1 uF bypass cap up to over 2 MHz. It's even higher for a .1 uF.

But, as I said, it won't hurt anything either.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 5:15 am 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20701
Location: Haledon, NJ, usa
john8750 wrote:
Pbpix wrote:
john8750 wrote:
Flip
I saw a tube power supply with a .01 disc cap paralleling the filters. What do you think about that?
Is it just something else to do, or could there be a good reason. I guess it wouldn't hurt. I don't know.

The large caps are filtering lower freq like 60hz ripple... the .01 filter higher freq noise or pulses and spikes.



Well, I have some 1k-volt .01's, if it will help. I like to install a .1, 1k-volt across the power switch. Without it the audio makes a loud pop when powering off. Seems to work good. Also, a .01 snubber on the power pins of IC's. And, a .1
on the output of any 78xx regulator.
I even saw some power supply with a .1- .01- .001 all across a filter. That should be very clean. And a full wave bridge with
caps across each rectifier.
But is this necessary, or just in case?

Caps across each diode in a bridge rectifier are called "snubber caps"
Some diodes can have high switching noise.

http://audiokarma.org/forums/index.php? ... on.742694/

_________________
To be a man, Be a non-conformist, Nothing's sacred as the integrity of your own mind.
-Emerson


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 5:27 am 
Member
User avatar

Joined: Nov Sat 26, 2011 4:09 am
Posts: 7738
Location: Texas. USA
john8750 wrote:
Pbpix wrote:
john8750 wrote:
Flip
I saw a tube power supply with a .01 disc cap paralleling the filters. What do you think about that?
Is it just something else to do, or could there be a good reason. I guess it wouldn't hurt. I don't know.

The large caps are filtering lower freq like 60hz ripple... the .01 filter higher freq noise or pulses and spikes.

Well, I have some 1k-volt .01's, if it will help. I like to install a .1, 1k-volt across the power switch. Without it the audio makes a loud pop when powering off. Seems to work good. Also, a .01 snubber on the power pins of IC's. And, a .1
on the output of any 78xx regulator.
I even saw some power supply with a .1- .01- .001 all across a filter. That should be very clean. And a full wave bridge with
caps across each rectifier.
But is this necessary, or just in case?
Those all have different reasons. The "switch" cap isn't for ripple filtering, it's to bypass the switching arc.

A .01 uF across IC power pins is because of inductance in the PCB traces (especially with fast digital switching times).

The capacitor on the output of 78xx regulators is for stability (feedback loop).

Caps across bridge diodes are to snub the switching transients. Ironically, 'fast' diodes are worse that 'slow' diodes on this regard. It's usually not a problem with tube power supplies, because of the filtering and high voltage, but adding snubbers won't hurt.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 6:03 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 7385
Location: Beautiful Downtown Burbank CA
Is there a chart somewhere that you guys use to choose these caps? I see someone recommends a .001 cap for this and a .01 cap for that and a .1 cap for something else.
I have searched and only found vague answers.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 6:53 pm 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
Mike Toon wrote:
Is there a chart somewhere that you guys use to choose these caps? I see someone recommends a .001 cap for this and a .01 cap for that and a .1 cap for something else.
I have searched and only found vague answers.



I suppose Flip would know about that science. Must have a calculation to determine just what size will handle the noise rejection required.
How about you Peter.

_________________
John Smith, over and out.
If I did something right, I made a mistake.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 7:03 pm 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
very interesting Peter. I have been reading similar posts about the caps for diodes.
Would it be best to scope the final B+ to find any high freq. interference?
If the interference is above 20khz, would that bother the output frequency?

_________________
John Smith, over and out.
If I did something right, I made a mistake.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 7:12 pm 
Member
User avatar

Joined: Dec Mon 29, 2014 9:39 pm
Posts: 2992
Location: Los Angeles
Flip- thanks for that brief but to the point class. Very understandable. Fits right in explaining the caps I remember seeing
on the schematics for some 400hz aircraft power supplies. There, nothing was overlooked. Plus, I'm sure the Gov. contractor
gets paid for every part used.

_________________
John Smith, over and out.
If I did something right, I made a mistake.


Top
 Profile  
 
 Post subject: Re: A new 300B amp project
PostPosted: Oct Wed 18, 2017 9:17 pm 
Member
User avatar

Joined: Jan Thu 01, 1970 1:00 am
Posts: 20701
Location: Haledon, NJ, usa
john8750 wrote:
Mike Toon wrote:
Is there a chart somewhere that you guys use to choose these caps? I see someone recommends a .001 cap for this and a .01 cap for that and a .1 cap for something else.
I have searched and only found vague answers.



I suppose Flip would know about that science. Must have a calculation to determine just what size will handle the noise rejection required.
How about you Peter.

Hi Mike and John:

There isn't a chart per se' .... but if there were it would need to show EVERY possibility for every frequency at every capacitance... so that's not exactly practical.

But here's what's going on:
A capacitor of a particular value will react differently at different frequencies.
This is called Capacitive Reactance aka (Xc) The formula is Xc=1 / 2*pi * fc
The reactance is expressed in ohms of resistance.
Read the whole theory here with examples:
( this site explains all the details: --> http://www.electronics-tutorials.ws/fil ... ter_1.html )

Image

So this simply means that if you were to apply a frequency to a capacitor it will "resist" or react to allow that frequency to pass through the capacitor more easily or less easily.
More reactance will tend to resist more ..and less reactance will resist less.

If you take a .22uf cap (220nf) and try to pass 1-khz through it, the .22uf cap will tend to "look like" about 723 ohms of resistance.
Image

But if you take that same .22uf cap (220nf) and now try to pass a higher frequency of 20-khz through it. Now the .22uf cap will "look like" about only 36 ohms of resistance.
Image

So you can see that a .22uf cap will allow higher frequencies through easier than lower frequencies.

So depending on the frequency of the noise you are trying to eliminate ( or pass through to ground) you will need to select the correct size cap.

But generally .. low frequency noise like 60hz you need big caps like 400uf
and for much higher frequencies like RF noise or static hiss you use smaller caps like .1uf or .22uf .01uf. or even smaller like 250pf and 20pf etc.

Easy peasy.

_________________
To be a man, Be a non-conformist, Nothing's sacred as the integrity of your own mind.
-Emerson


Last edited by Pbpix on Oct Thu 19, 2017 3:44 am, edited 1 time in total.

Top
 Profile  
 
Post New Topic Post Reply  [ 1205 posts ]  Go to page Previous  1 ... 57, 58, 59, 60, 61  Next

All times are UTC [ DST ]


Who is online

Users browsing this forum: Pbpix and 7 guests



Search for:
Jump to:  




















Privacy Policy :: Powered by phpBB