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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 7:26 am 
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Flipperhome wrote:
How could I know that?

Because I covered that several pages back:
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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 7:45 am 
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Pbpix wrote:
Flipperhome wrote:
How could I know that?

Because I covered that several pages back:
Good grief, that's channel 2 and not running them at 108 mA mA instead of 150 mA.

108/150 = .72, less than 3/4.


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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 7:53 am 
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Flipperhome wrote:
Pbpix wrote:
Flipperhome wrote:
How could I know that?

Because I covered that several pages back:
Good grief, that's channel 2 and not running them at 108 mA mA instead of 150 mA.

108/150 = .72, less than 3/4.

Chuck's Plate Curve program shows that with:
B+ 268
250 from plate to cathode.
-17.5v G1
25ma /tube at Zero signal.

So that's 50ma per channel for a total of 100ma + SGs ( 1ma each now) .... and another 13-15ma for the preamp and Zeners.

So 3/4 of what?

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 8:03 am 
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Because THIS thinks it's Fixed Bias I have to enter the Plate voltage and cathode differential at correct potential as reflected in cathode-bias.

Image

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Last edited by Pbpix on Apr Wed 15, 2015 8:07 am, edited 1 time in total.

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 8:07 am 
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Pbpix wrote:
Flipperhome wrote:
Good grief, that's channel 2 and not running them at 108 mA mA instead of 150 mA.

108/150 = .72, less than 3/4.
Chuck's Plate Curve program shows that with:
B+ 268
250 from plate to cathode.
-17.5v G1
25ma /tube at Zero signal.

So that's 50ma per channel for a total of 100ma + SGs ( 1ma each now) .... and another 13-15ma for the preamp and Zeners.

So 3/4 of what?
I gave you the equation. Figure it out.


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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 8:13 am 
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Flipperhome wrote:
Pbpix wrote:
Flipperhome wrote:
Good grief, that's channel 2 and not running them at 108 mA mA instead of 150 mA.

108/150 = .72, less than 3/4.
Chuck's Plate Curve program shows that with:
B+ 268
250 from plate to cathode.
-17.5v G1
25ma /tube at Zero signal.

So that's 50ma per channel for a total of 100ma + SGs ( 1ma each now) .... and another 13-15ma for the preamp and Zeners.

So 3/4 of what?
I gave you the equation. Figure it out.

What are you taliking about?
Which equation?
You lost me again.
Why not EXPLAIN it.. instead of telling me to go figure out what you mean?
Can't you try to be a little more helpful?
Why just toss out smarty-pants comments like that?

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 8:34 am 
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Pbpix wrote:
What are you taliking about?
Which equation?
You lost me again.
Why not EXPLAIN it.. instead of telling me to go figure out what you mean?
Can't you try to be a little more helpful?
Why just toss out smarty-pants comments like that?

----->>>> 108/150 = .72, less than 3/4 <<<<-------

Every post you've made with my 'modified' schematic says B+ current to the tubes is 108 mA.

"Yes.. total B+ sb about 108ma."

And with 268 V into a load of 2481, as shown on your schematic, it's 108 mA. The same.

Mine is 150 mA. 108 mA is less than 3/4 of 150 mA.


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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 8:44 am 
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When I use Chucks program and enter -15v for bias with pushes idle current up to 33ma.
The power output actually seems lower compared with -17v and 25ma idle current.
Image

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 8:51 am 
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Flipperhome wrote:
Pbpix wrote:
What are you taliking about?
Which equation?
You lost me again.
Why not EXPLAIN it.. instead of telling me to go figure out what you mean?
Can't you try to be a little more helpful?
Why just toss out smarty-pants comments like that?

----->>>> 108/150 = .72, less than 3/4 <<<<-------

Every post you've made with my 'modified' schematic says B+ current to the tubes is 108 mA.

"Yes.. total B+ sb about 108ma."

And with 268 V into a load of 2481, as shown on your schematic, it's 108 mA. The same.

Mine is 150 mA. 108 mA is less than 3/4 of 150 mA.


Yes... ok.. I think.

Your 150ma number came from the data sheets running -15v bias AB 37ma idle current .... right?

But I'm running -17v bias @ only 25ma

So when I build that doubler I show only 123ma total going through the 300 ohm resistor.
Two channels at 50ma apiece = 100ma + SG... right?
And another 13-15ma for the preamps.

So yes I see my current number is less than "your current number"
but What is the conclusion?
What are you indicating?

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 9:05 am 
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Pbpix wrote:
When I use Chucks program and enter -15v for bias with pushes idle current up to 33ma.
The power output actually seems lower compared with -17v and 25ma idle current.
The datasheet load for 10 Watt is 10K PP, not 8K.


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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 9:07 am 
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Pbpix wrote:
...but What is the conclusion?
What are you indicating?
The ripple current is lower that what I said it was for 150 mA.


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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 9:10 am 
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Flipperhome wrote:
Pbpix wrote:
When I use Chucks program and enter -15v for bias with pushes idle current up to 33ma.
The power output actually seems lower compared with -17v and 25ma idle current.
The datasheet load for 10 Watt is 10K PP, not 8K.

I tried 10k to see if power improved but it did not show it on that program. Optimum kept showing 8k.

If I kick up B+ or plate up to 300 v then I think (not sure) the 10k load shows more power.

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 9:20 am 
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I don't know exactly what changed but NOW entering -15v bias and 33ma current ... I get 11 watts @ 8k load.
10k load shows abot 8.8watts.
Image

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Wed 15, 2015 9:25 am 
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Flipperhome wrote:
Pbpix wrote:
...but What is the conclusion?
What are you indicating?
The ripple current is lower that what I said it was for 150 mA.

oh... lol ... is that all you were saying?
Yes since the actual load is lower than you anticipated the burden on the caps is less.

I'm easily confused?
it helps (me) a lot if you slowly & clearly state your conclusions and why. :lol:

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Thu 16, 2015 7:26 am 
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Hey John:
I was in Michale's Stores yesterday looking for plastic parts bins boxes ( found nice ones on sale for $4.49.)
... and then I saw these basswood frames 9 x 6 x 1-5/8"

I thought I might make a box top and bottom out of two of these if I hinge them in the back. That would be a bit over 3" deep.

So I got two.... mostly to give me a little more space on the top for those large octal 6V6G tubes and the two OTs.
( I'm also going to mount four 7-pin sockets in parallel with the four octal sockets to allow a choice of using 6AQ5 tubes instead.)

I stained them tonight and have the hinges all ready.

Of course I'll need a thin brass strip in the front (with the wood cut out behind) so I can mount the output jacks and input etc along with the on/off lamp and a slide sw to opt for 6v @450ma or 12v @225ma filaments if I want to use some 12V6 tubes.

Image

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Thu 16, 2015 7:53 am 
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Pbpix wrote:
Flipperhome wrote:
Pbpix wrote:
When I use Chucks program and enter -15v for bias with pushes idle current up to 33ma.
The power output actually seems lower compared with -17v and 25ma idle current.
The datasheet load for 10 Watt is 10K PP, not 8K.
I tried 10k to see if power improved but it did not show it on that program. Optimum kept showing 8k.

If I kick up B+ or plate up to 300 v then I think (not sure) the 10k load shows more power.
All I can say is the datasheet says 10K for 10 Watt and every commercial amp maker used 10K (when B+ was 250 V).


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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Thu 16, 2015 8:21 am 
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Flipperhome wrote:
All I can say is the datasheet says 10K for 10 Watt and every commercial amp maker used 10K (when B+ was 250 V).

Did you look at the 2nd screen-shot I posted for 15v bias?
I said " Something MUST have changed because it NOW shows 11 watts"

entering 10k made the power drop.... so it peaked at 8k.
Maybe chuck knows why.

Scroll back up 4 posts.

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Thu 16, 2015 8:43 am 
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Pbpix wrote:
Hey John:
I was in Michale's Stores yesterday looking for plastic parts bins boxes ( found nice ones on sale for $4.49.)
... and then I saw these basswood frames 9 x 6 x 1-5/8"

I thought I might make a box top and bottom out of two of these if I hinge them in the back. That would be a bit over 3" deep.

So I got two.... mostly to give me a little more space on the top for those large octal 6V6G tubes and the two OTs.
( I'm also going to mount four 7-pin sockets in parallel with the four octal sockets to allow a choice of using 6AQ5 tubes instead.)

I stained them tonight and have the hinges all ready.

Of course I'll need a thin brass strip in the front (with the wood cut out behind) so I can mount the output jacks and input etc along with the on/off lamp and a slide sw to opt for 6v @450ma or 12v @225ma filaments if I want to use some 12V6 tubes.

Image


Great idea Peter. I like the two halves hinged. We need the bottom room for those two coke can size caps.
I meant to call you tonight but really busy at work.

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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Thu 16, 2015 8:56 am 
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Pbpix wrote:
Flipperhome wrote:
All I can say is the datasheet says 10K for 10 Watt and every commercial amp maker used 10K (when B+ was 250 V).

Did you look at the 2nd screen-shot I posted for 15v bias?
I said " Something MUST have changed because it NOW shows 11 watts"

entering 10k made the power drop.... so it peaked at 8k.
Maybe chuck knows why.

Scroll back up 4 posts.
Yes, I saw it and my post stands. The datasheet says 10K for 10 Watt and every commercial amp maker used 10K (when B+ was 250 V).


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 Post subject: Re: 6V6 / 6AQ5 PP Stereo Amp
PostPosted: Apr Thu 16, 2015 4:44 pm 
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Flipperhome wrote:
Pbpix wrote:
Flipperhome wrote:
All I can say is the datasheet says 10K for 10 Watt and every commercial amp maker used 10K (when B+ was 250 V).

Did you look at the 2nd screen-shot I posted for 15v bias?
I said " Something MUST have changed because it NOW shows 11 watts"

entering 10k made the power drop.... so it peaked at 8k.
Maybe chuck knows why.

Scroll back up 4 posts.
Yes, I saw it and my post stands. The datasheet says 10K for 10 Watt and every commercial amp maker used 10K (when B+ was 250 V).



Well, I am stuck with 8K.

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If I did something right, I made a mistake.


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