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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 3:59 am 
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john8750 wrote:
I hear that Peter, must be a Woman situation.

What does that mean? What are you talking about????
Why are you talking in riddles?

if your shipping was adjusted lower I guess it's because the ship distance is closer?

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 4:07 am 
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Pbpix wrote:
Do not you see that price listed there ?
You ain't in the same location so the shipping cost is different that his.


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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 4:20 am 
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john8750 wrote:
I scored another babe. $32.80 and has a big transformer, and looks like Gort. :wink:
http://www.ebay.com/itm/201768115697
Congratulations. That one looks like a winner.


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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 5:46 am 
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Pbpix wrote:
john8750 wrote:
I hear that Peter, must be a Woman situation.

What does that mean? What are you talking about????
Why are you talking in riddles?

if your shipping was adjusted lower I guess it's because the ship distance is closer?




Don't know what you are looking at Peter.

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 5:47 am 
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Flipperhome wrote:
john8750 wrote:
I scored another babe. $32.80 and has a big transformer, and looks like Gort. :wink:
http://www.ebay.com/itm/201768115697
Congratulations. That one looks like a winner.



I agree Flip. I am slowly working on the amp. So far, so good.

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 6:04 am 
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john8750 wrote:
Flipperhome wrote:
john8750 wrote:
I scored another babe. $32.80 and has a big transformer, and looks like Gort. :wink:
http://www.ebay.com/itm/201768115697
Congratulations. That one looks like a winner.

I agree Flip. I am slowly working on the amp. So far, so good.
Good. Sorry, I forget to answer your question about assembly order. For this one, it doesn't really matter. What made a difference on Prince John was the output tubes draw the majority of current so testing that section first makes sure their current draw is right, plate dissipation is okay, and that B+ is correct for everything else. There's nothing so critical or sensitive with the preamp.

Btw, I've been contemplating building an amp with 'real' OPTs, the Edcors, which I've never done :mrgreen: mainly because of the cost. It's actually a 6 year old hankering I've resurrected and I actually bought 807s for one. I like the idea of making a WWII style amp, 'modernized' of course. What they might have made had they not been rather preoccupied with Pearl Harbor and Hitler.

I got more amps than I know what to do with and the iron alone cost $230 by the time it's shipped so what I need is someone to talk me out of it :wink:

See what you think.

Attachment:
6L6 - 12SL7 - 6SN7 - bootstrap v5.jpg
6L6 - 12SL7 - 6SN7 - bootstrap v5.jpg [ 156.41 KiB | Viewed 174 times ]


Attachment:
450V only w-MOSFET filter v3.jpg
450V only w-MOSFET filter v3.jpg [ 62.34 KiB | Viewed 151 times ]


Attachment:
Chassis EDCORs - Octals 3.jpg
Chassis EDCORs - Octals 3.jpg [ 102.33 KiB | Viewed 151 times ]


Last edited by Flipperhome on Jan Fri 13, 2017 7:09 am, edited 10 times in total.

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 6:59 am 
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Flipperhome wrote:
Pbpix wrote:
Do not you see that price listed there ?
You ain't in the same location so the shipping cost is different that his.

Yeah... lol
I just figured that out too.
It must show up differently based on my zip.

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 7:20 am 
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Flipperhome wrote:

Btw, I've been contemplating building an amp with 'real' OPTs, the Edcors, which I've never done :mrgreen: mainly because of the cost. It's actually a 6 year old hankering I've resurrected and I actually bought 807s for one. I like the idea of making a WWII style amp, 'modernized' of course. What they might have made had they not been rather preoccupied with Pearl Harbor and Hitler.

I got more amps than I know what to do with and what I need is someone to talk me out of it :wink:

See you think.

Attachment:
6L6 - 12SL7 - 6SN7 - bootstrap v5.jpg


Attachment:
450V only w-MOSFET filter.jpg


Attachment:
Chassis EDCORs - Octals 2.jpg

Wow!
Interesting idea.
Guess you must have gotten some Christmas money from granny in her card... lol

So how does the "simulate-UL" thing work?
What opamp?
How can that actually "simulate" UL if the OT isn't doing any of the load sharing?

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 7:30 am 
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Pbpix wrote:
Wow!
Interesting idea.
Guess you must have gotten some Christmas money from granny in her card... lol

So how does the "simulate-UL" thing work?
What opamp?
How can that actually "simulate" UL if the OT isn't doing any of the load sharing?
No, but some people I did computer repairs/upgrades for finally paid their bill. That doesn't even cover the iron, though.

The UL simulation just feeds 40% of the plate signal back to the screens (like the UL in the OPT does). It's not a perfect simulation (screen current doesn't go through the OPT) but a heck of a lot better than nothing. It isn't a real opamp, it's 'ideal'.


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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 7:48 am 
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Flipperhome wrote:
Pbpix wrote:
Wow!
Interesting idea.
Guess you must have gotten some Christmas money from granny in her card... lol

So how does the "simulate-UL" thing work?
What opamp?
How can that actually "simulate" UL if the OT isn't doing any of the load sharing?
No, but some people I did computer repairs/upgrades for finally paid their bill. That doesn't even cover the iron, though.

The UL simulation just feeds 40% of the plate signal back to the screens (like the UL in the OPT does). It's not a perfect simulation (screen current doesn't go through the OPT) but a heck of a lot better than nothing. It isn't a real opamp, it's 'ideal'.

I see.
Well.. I'd say.. go for it.
If you wait too long your ears will be too old to know the difference.

Why cant you get Edcor OTs w/ UL?
Can they make ones for you?

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 7:57 am 
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Pbpix wrote:
I see.
Well.. I'd say.. go for it.
If you wait too long your ears will be too old to know the difference.

Why cant you get Edcor OTs w/ UL?
Can they make ones for you?
The Edcors do have UL taps. It's the simulation that doesn't.

http://edcorusa.com/cxpp25-66k


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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 8:49 am 
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Flipperhome wrote:
Pbpix wrote:
I see.
Well.. I'd say.. go for it.
If you wait too long your ears will be too old to know the difference.

Why cant you get Edcor OTs w/ UL?
Can they make ones for you?
The Edcors do have UL taps. It's the simulation that doesn't.

http://edcorusa.com/cxpp25-66k

sO WHAT'S THAT ABOUT? ... SPICE?

And if it is only for spice... why not post the normal non-spice print?

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 8:59 am 
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Pbpix wrote:
Flipperhome wrote:
The Edcors do have UL taps. It's the simulation that doesn't.

http://edcorusa.com/cxpp25-66k

sO WHAT'S THAT ABOUT? ... SPICE?

And if it is only for spice... why not post the normal non-spice print?
LOL Yes, it's SPICE but there isn't a 'normal' print of anything. I have to make it and if I'm going to make one SPICE is first so I can see how well it works.


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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Sun 08, 2017 9:16 am 
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A 'normal' print for Peter :mrgreen:

Attachment:
6L6 - 12SL7 - 6SN7 - bootstrap v5 normal.jpg
6L6 - 12SL7 - 6SN7 - bootstrap v5 normal.jpg [ 135.5 KiB | Viewed 169 times ]


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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Mon 09, 2017 12:14 am 
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Image
How do the two mosfet resistors work to control it?

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Mon 09, 2017 12:17 am 
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Flipperhome wrote:
A 'normal' print for Peter :mrgreen:

Image

What is the role of C5?

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Mon 09, 2017 1:45 am 
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Pbpix wrote:
Image
How do the two mosfet resistors work to control it?
It's a capacitance multiplier. The first resistor biases the MOSFET 'on' and the cap filters it to a steady DC (which is reflected in the output). The second resistor gives it some voltage drop, otherwise it would be at the gate 'on' voltage (for that current) and, since the input ripple is large but the gate is held steady, the negative ripple spikes would pass through. I set it to 15 V (ripple negative to B+) so under load changes it stays in the conducting region, otherwise it might again pass ripple. I've used this filter before and it 'subs' for a very large value capacitance.

Btw, the quickie estimate for the heatsink is low. It's nominal dissipation is 6 Watt, not 2.5 Watt.


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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Mon 09, 2017 2:06 am 
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Pbpix wrote:
Flipperhome wrote:
A 'normal' print for Peter :mrgreen:

Image

What is the role of C5?
C5 is a bootstrap and causes R11 to look like a current source since both sides of it see (nearly) the same signal voltage. (Nearly) the same signal voltage on both sides of a resistor means (virtually) 0 current flow and (virtually) '0' current over voltage is (nearly) infinite resistance.

I say "nearly" because the V1B cathode follower gain isn't quite 1, it's a little less, so there will be some small signal current but, still, the "effective resistance" of R11 is in the neighborhood of 2.5Meg Ohm. That makes gain come close to the tube's mu and lowers distortion at the same time because there's a miniscule signal current (it's about 136 nanoamp). The RC time constant also makes for a convenient low frequency shelf to avoid motorboating.

I used the same technique on TopCat and it's quite effective. And no "solid state" needed.


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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Mon 09, 2017 2:58 am 
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Flip
Why the driver stage, V3? More output power, a buffer for less THD. Really good looking design. Is there any form of CCS there? How to balance the output tubes?
I could always use one more amp project, after the transmitter and tuner.
Of course I will need a tone stack. :lol:

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 Post subject: Re: PRINCELY PAUPER
PostPosted: Jan Mon 09, 2017 3:24 am 
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Flipperhome wrote:
Pbpix wrote:
I see.
Well.. I'd say.. go for it.
If you wait too long your ears will be too old to know the difference.

Why cant you get Edcor OTs w/ UL?
Can they make ones for you?
The Edcors do have UL taps. It's the simulation that doesn't.

http://edcorusa.com/cxpp25-66k



I have those 25watt Edcors on my 6V6. They are the best, not that I know the difference.

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If I did something right, I made a mistake.


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