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 Post subject: Re: A new 300B amp project
PostPosted: Nov Wed 29, 2017 4:43 pm 
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Mike Toon wrote:
john8750 wrote:
I also thought about the heater connections. Don't know what else to do with em. I twisted the ct conductor right in with them. When finished, I will power up, If you can hear the hum from your house, we'll worry about it then.



The guys at DIYAUDIO sure have opinions on twists.
Image

Lots to read/learn... http://www.diyaudio.com/forums/tubes-va ... -ugly.html



Thanks. So interesting, I read the entire article. I may want to delay the B+ power-up, and soft start the 300b.
What would you think?

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 Post subject: Re: A new 300B amp project
PostPosted: Nov Wed 29, 2017 4:49 pm 
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Pbpix wrote:
You guys need to pay attention to the EXACT details I describe... re-read the post I refer to and stop attacking me for trying to be accurate... when you guys are both ignoring the actual post John made on page 82.

Do I hear.. " I'm sorry Peter" ? ... lol



Im Sorry Peter.
I did not order that switch because it did not say latching toggle. It said momentary push button.
Sorry about the mix-up.

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 Post subject: Re: A new 300B amp project
PostPosted: Nov Wed 29, 2017 4:56 pm 
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Should I connect a dummy load to ensure a proper B+ now, or complete the wiring and power up?

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 Post subject: Re: A new 300B amp project
PostPosted: Nov Wed 29, 2017 6:23 pm 
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Here she is all wired, except the inputs.
Attachment:
300b wiring.jpg
300b wiring.jpg [ 140.78 KiB | Viewed 226 times ]


Don't know if I like the homemade component board idea. Could be nedden to a change.

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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 3:21 am 
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Pbpix wrote:
Flipperhome wrote:
Pbpix wrote:
Yes it can mean on/off. A momentary contact can be used to "toggle" or change state. Latching is something else.
For heaven's sake. Stop muddying the waters. Yes, with additional circuitry you can make any switch do just about anything. That isn't the point. The point is the description of the swiych itself and there they've no only misrepresented it they put every switch buzz word, including "latch," in the description. E.g. "Switch Latching Push Button Toggle." It's gibberish.

Flip: I was telling John not to interpret the "toggle on/off" as to mean "latch"
so...
You are flat-out WRONG buddy!...

What he may or may not have "interpreted" something to mean is irrelevant to my comment about you muddying the waters. I was referring to your weasel wording about "toggle."

THIS is a toggle switch. It's actuated by, unsurprisingly, a TOGGLE.
Attachment:
nkk_s1aw.jpg
nkk_s1aw.jpg [ 6.4 KiB | Viewed 217 times ]


This is NOT a toggle switch, despite the Chinglish "let's include every buzz word whether it applies or not" Ebay listing calling it one. It's actuated by a PUSH BUTTON.
Attachment:
s-l1600.jpg
s-l1600.jpg [ 25.25 KiB | Viewed 217 times ]



Both actuator styles are available in a variety of momentary and non-momentary (aka latching) actions.


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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 3:39 am 
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john8750 wrote:
So, I wired the three transformers and fuse. Plugged it in. Have 5.8volts for each 300b heater, 7.1volts for filaments. No tube load yet. Plugged in the 5u4. checked for b+ and pop! Then realized my meter is rated for 600volt max. The unloaded B+ must be running wild.
Decided to leave the component board alone for now. Could decide to change it later.
Question. Is it possible to take power from the 6.3volt supply for the cooling fan? Rectified and filtered of course.
It depends on the voltage of your fan but, in general, yes.

As for B+, you didn't give enough details to know what's going on. If, for example, you got across the HV winding (instead of ground) then, yes, it will be over 600V. Or, of course, there may be a wiring error. But judging by the heater supplies I suspect it's okay.

Judging by the "regulation factor" the (worst case) heater supplies are showing, B+ should max out at about 525VDC unloaded.


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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 3:59 am 
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Use a 6-12v fan and it should be fine. Just won't run all out if it is a 12v fan.


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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 4:05 am 
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Flipperhome wrote:
john8750 wrote:
So, I wired the three transformers and fuse. Plugged it in. Have 5.8volts for each 300b heater, 7.1volts for filaments. No tube load yet. Plugged in the 5u4. checked for b+ and pop! Then realized my meter is rated for 600volt max. The unloaded B+ must be running wild.
Decided to leave the component board alone for now. Could decide to change it later.
Question. Is it possible to take power from the 6.3volt supply for the cooling fan? Rectified and filtered of course.
It depends on the voltage of your fan but, in general, yes.

As for B+, you didn't give enough details to know what's going on. If, for example, you got across the HV winding (instead of ground) then, yes, it will be over 600V. Or, of course, there may be a wiring error. But judging by the heater supplies I suspect it's okay.

Judging by the "regulation factor" the (worst case) heater supplies are showing, B+ should max out at about 525VDC unloaded.



Thanks Flip. Got the fan power supply covered, 12v. The B+ unloaded voltage must be at least that. But who knows the actual limits of a cheap vom. I am gonna connect a load of four 100k's in series, read one and multiply by four to get the actual unloaded B+.
Would you rather redo the components, or leave them for now?

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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 4:12 am 
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sfox7076 wrote:
Use a 6-12v fan and it should be fine. Just won't run all out if it is a 12v fan.



Thanks. I am installing a function board with separate 12volt supply. The functions will be, 1/2 voltage 300b filament delay for about 12 seconds. At about 30 seconds the B+ will startup. And at about 45 seconds the signal inputs will activate. So I will take 12vdc to the fan from that supply.

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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 4:17 am 
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john8750 wrote:
Flipperhome wrote:
It depends on the voltage of your fan but, in general, yes.

As for B+, you didn't give enough details to know what's going on. If, for example, you got across the HV winding (instead of ground) then, yes, it will be over 600V. Or, of course, there may be a wiring error. But judging by the heater supplies I suspect it's okay.

Judging by the "regulation factor" the (worst case) heater supplies are showing, B+ should max out at about 525VDC unloaded.



Thanks Flip. Got the fan power supply covered, 12v. The B+ unloaded voltage must be at least that. But who knows the actual limits of a cheap vom. I am gonna connect a load of four 100k's in series, read one and multiply by four to get the actual unloaded B+.
Would you rather redo the components, or leave them for now?
Good idea.

As for the components, you might as well leave them as is until, or if, something crops up.


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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 4:23 am 
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Flipperhome wrote:
What he may or may not have "interpreted" something to mean is irrelevant to my comment about you muddying the waters. I was referring to your weasel wording about "toggle."

THIS is a toggle switch. It's actuated by, unsurprisingly, a TOGGLE.
Attachment:
nkk_s1aw.jpg


This is NOT a toggle switch, despite the Chinglish "let's include every buzz word whether it applies or not" Ebay listing calling it one. It's actuated by a PUSH BUTTON.
Attachment:
s-l1600.jpg



Both actuator styles are available in a variety of momentary and non-momentary (aka latching) actions.

Again you are flat out wrong.
I DO know what a toggle switch is. I was indicating that John might have been misled by the term "toggle" that the seller used as some strange stretch of a way to use a momentary. But certainly VERY misleading.
YOU FLIP simply chose to.... misinterpret MY statement instead of reading it as it was clearly written.
It would serve you well to give ppl the benefit of at least trying to READ their comments without bias before spewing out any kind of negative comments that you seem to love to toss around...such as "muddying the waters" .... ESPECIALLY since nothing could be further from the truth or my intent.
Please learn to take it as a SERIOUS suggestion for courtesy in comment replys.

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Last edited by Pbpix on Nov Thu 30, 2017 4:26 am, edited 2 times in total.

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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 4:24 am 
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Flipperhome wrote:
john8750 wrote:
Flipperhome wrote:
It depends on the voltage of your fan but, in general, yes.

As for B+, you didn't give enough details to know what's going on. If, for example, you got across the HV winding (instead of ground) then, yes, it will be over 600V. Or, of course, there may be a wiring error. But judging by the heater supplies I suspect it's okay.

Judging by the "regulation factor" the (worst case) heater supplies are showing, B+ should max out at about 525VDC unloaded.



Thanks Flip. Got the fan power supply covered, 12v. The B+ unloaded voltage must be at least that. But who knows the actual limits of a cheap vom. I am gonna connect a load of four 100k's in series, read one and multiply by four to get the actual unloaded B+.
Would you rather redo the components, or leave them for now?
Good idea.

As for the components, you might as well leave them as is until, or if, something crops up.


:lol:
If something crops up? Like a cloud of smoke :lol:

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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 6:31 pm 
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I tested the B+ by connecting four 100K's in series and reading the voltage across one of them.
I got 141volts X 4=564volts. Seems a bit high. The 300b maxes at 450volts.
That was with no tube load.
Flip, is that ok to test with tubes and speakers connected?
And, please let me know what you think about my startup sequence. Do you see a problem.
1- 300b heaters on at half power. 2- 12seconds, heaters to full power. 3- 30seconds, B+ starts.
4- 45seconds, inputs connect.

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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 7:24 pm 
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Unloaded B+ will usually be a good bit higher than it is when loaded.


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 Post subject: Re: A new 300B amp project
PostPosted: Nov Thu 30, 2017 11:04 pm 
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john8750 wrote:
I tested the B+ by connecting four 100K's in series and reading the voltage across one of them.
I got 141volts X 4=564volts. Seems a bit high. The 300b maxes at 450volts.
That was with no tube load.
Flip, is that ok to test with tubes and speakers connected?
And, please let me know what you think about my startup sequence. Do you see a problem.
1- 300b heaters on at half power. 2- 12seconds, heaters to full power. 3- 30seconds, B+ starts.
4- 45seconds, inputs connect.

Simple math John.
If you are expecting your B+ to be around 400v, and if the idle current through each tube is 75ma.... then 2 tubes draw 150ma?

So divide 400v by 150ma = 2,666 ohms @ 60W
P=IxE
400v x .15A = 60 watts ...then double it.

So you need a 2666 ohm dummy load for at least 60-120 watts..
Maybe five 510 ohm 10 or 20 watt resistors in series?

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 Post subject: Re: A new 300B amp project
PostPosted: Dec Fri 01, 2017 1:19 am 
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john8750 wrote:
I tested the B+ by connecting four 100K's in series and reading the voltage across one of them.
I got 141volts X 4=564volts. Seems a bit high. The 300b maxes at 450volts.
That was with no tube load.
Flip, is that ok to test with tubes and speakers connected?
And, please let me know what you think about my startup sequence. Do you see a problem.
1- 300b heaters on at half power. 2- 12seconds, heaters to full power. 3- 30seconds, B+ starts.
4- 45seconds, inputs connect.
That's a little higher than I predicted but, looking back, I used the wrong transformer voltage to calculate from. Just a brain fart, I used 350V instead of the 380V that it is and, taking that, it's actually a little bit lower.

Unloaded you don't have the voltage drop from PT winding resistance, choke DCR, and the rectifier. Also, remember, the 300b plate voltage is B+ minus cathode voltage, which is in the neighborhood of 70 V. Everything should settle out to (or near) the target B+ once it's all running and pulling current.

Whether your caps can handle the initial voltage surge is another question (they can usually withstand more than rated for some short period of time) but I don't recall what ratings the ones you got are. Refresh my memory.

I think the 'startup' sequencing is a waste of time and effort that mainly serves to exacerbate the time the filter caps have to withstand the initial voltage surge, among other things like suddenly zapping the tubes with full, unloaded, B+ with 0V on the cathode causing a temporary massive startup current surge.


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 Post subject: Re: A new 300B amp project
PostPosted: Dec Fri 01, 2017 2:00 am 
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Pbpix wrote:
Again you are flat out wrong.
I DO know what a toggle switch is. I was indicating that John might have been misled by the term "toggle" that the seller used as some strange stretch of a way to use a momentary. But certainly VERY misleading.
YOU FLIP simply chose to.... misinterpret MY statement instead of reading it as it was clearly written.
It would serve you well to give ppl the benefit of at least trying to READ their comments without bias before spewing out any kind of negative comments that you seem to love to toss around...such as "muddying the waters" .... ESPECIALLY since nothing could be further from the truth or my intent.
Please learn to take it as a SERIOUS suggestion for courtesy in comment replys.
I understood exactly what you were doing. You were trying to justify the clueless Chinglish false description of the switch, using the word "toggle," by making an equally specious claim for the use of "toggle." And then blaming John for 'misunderstanding' the 'clear' (hardy har har) meaning.

Let's look back at the sequence.

John: "It says in the description 'on-off toggle' which is not a momentary switch. They must be confused."

You: "Yes it can mean on/off. A momentary contact can be used to "toggle" or change state. Latching is something else"

Me: "For heaven's sake. Stop muddying the waters. Yes, with additional circuitry you can make any switch do just about anything. That isn't the point. The point is the description of the switch itself and there they've no only misrepresented it they put every switch buzz word, including "latch," in the description. E.g. "Switch Latching Push Button Toggle." It's gibberish."

It's not a toggle switch and "toggle" should not be used in the description PERIOD. Nor, for that matter, should "latching" be there. As I said, what one does with the switch is irrelevant and to argue what it "can be used" for, as you did, is muddying the waters.

The worst that John is guilty of is naively trusting in Chinese descriptions of anything. You have to read them with the understanding that they throw in any and everything whether it's useful, true, relevant or not.


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 Post subject: Re: A new 300B amp project
PostPosted: Dec Fri 01, 2017 4:16 am 
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Thanks again Men. I will make that dummy load, Peter.
My PS caps are 500volt 105c. B+ should be around 435.
I really don't care for any startup sequence either. I would like to
take care of the 300b life span.

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 Post subject: Re: A new 300B amp project
PostPosted: Dec Fri 01, 2017 4:19 am 
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Just thinking. I do have the lower voltage to work with, if the 760 wont work.

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 Post subject: Re: A new 300B amp project
PostPosted: Dec Fri 01, 2017 5:23 am 
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Flipperhome wrote:
.

You: "Yes it can mean on/off. A momentary contact can be used to "toggle" or change state. Latching is something else"

Me: "For heaven's sake. Stop muddying the waters. ..


OMG... stop splitting ... already split hairs.

Yes.. what I said is exactly correct... both in tone and meaning. And I was not "blaming" john.

The problem Flip is not the words or what John did ...
The problem is in the way YOU seem to always want to find fault or blame and worse is that you seem to enjoy making sharp-tone accusations which are abrasive and frankly offensive.

All THAT kind of baloney is totally unnecessary and out of line.
There is absolutely NO room in these technical help sessions for anyone to go around criticizing the manner or intent of another member.

So please stop it.

You have been a wonderful helpful technical source and you've helped teach me a lot and helped me solve problems... and for all that I thank you profusely.

Now I'll thank you to also please put away your sharp-tonged accusations and attacks. None of that is ever necessary or appreciated.

Please just try to remember Flip... this is supposed to be a friendly forum and we are all only trying to be helpful... nothing else.

And again.. thank you for all your generous help in the past and hope to be able to continue it in the future. Your depth of knowledge and willingness to share it is a great asset..

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Last edited by Pbpix on Dec Fri 01, 2017 5:36 am, edited 1 time in total.

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