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Old 4th October 2012, 08:47 PM   #8111
Salas is offline Salas  Greece
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With a switch you can even have phono, line 1..5. Why keep the phono buffer when having another buffer?
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Old 4th October 2012, 08:50 PM   #8112
Salas is offline Salas  Greece
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Quote:
Originally Posted by RCruz View Post
Hi Salas

Back to the V12R

I decided to use a 30kr for vref so I will need 1.15mV to get the desired 35Vout.

So if I am correct Rs = Vp/Id * (sqr(Id/Idss) - 1) than admiting I use a 8mA Idss k170 and admiting it's Vp = -0.45V, I will need a Rs = 243ohm.

If my calc is correct, I can use a 500ohm fixed resistor // 20kohm trimmer to set the voltage to 35V.

Please let me know if I am in the right direction....

PS: In reality I would not need a 20k trimmer but that is the only one I have got now.
Find it with a trimmer first because it will deviate from theory with available Vds, warm up, your measuring accuracy, things like that.
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Old 4th October 2012, 08:59 PM   #8113
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I would use the Hypnotize in place of the buffer in Rush's image, as I have the PCB. Or I could use the Hypno as a shunt only and power the buffer on my phono board. Looks like I might need a bigger case.

And yes, I could do a switched line-in as well, good idea.
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Old 4th October 2012, 09:03 PM   #8114
Salas is offline Salas  Greece
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In both cases its one and same thing only the locality changes. One way or another signal wiring is gonna end up same too. Maybe a small edge on keeping the regulator's feed local and short to the buffer if using the Hypno as it is.
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Old 4th October 2012, 09:11 PM   #8115
Salas is offline Salas  Greece
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Forgot to mention that when combining a hypno you double up the number of PSUs and you isolate better than the RC was isolating the integral buffer of course.
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Old 5th October 2012, 04:58 AM   #8116
Salas is offline Salas  Greece
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Quote:
Originally Posted by kstlfido View Post
And yes, I could do a switched line-in as well, good idea.
You can combine what you got in one unity gain control box. Phono-selector switch-hypno-LSPD-output. I don't know how well that combo will drive low gain amps though. It would take a standard 28dB amp for fair dynamics. In general I think 33dB total is needed from line level to speakers output for 90dB class speakers and 20-40W amps. Tube amps are usually sensitive enough for such chains. Or a 12 to 16dB line level preamp for circa 20dB gain amps and usual direct radiating speakers.
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Old 5th October 2012, 05:11 AM   #8117
Salas is offline Salas  Greece
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Originally Posted by Rush View Post
See attached capacitor shoot out, if you haven't already.
Rush
I read it now and I liked what he says about Russian Teflon's resolution that we used many times here as frugal inter-stage solution. He also says silver in oil is all rounder as we also said yesterday. Weird what he says about the Jupiter though. Wasn't compressed when I had the chance to install it. I talk the newer harder shell guise. Subjectives....naaah, so uncontrolled, but we all got a little chef inside us it seems.
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Old 5th October 2012, 05:50 AM   #8118
Rush is offline Rush  United States
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Quote:
Originally Posted by Salas View Post
I read it now and I liked what he says about Russian Teflon's resolution that we used many times here as frugal inter-stage solution. He also says silver in oil is all rounder as we also said yesterday. Weird what he says about the Jupiter though. Wasn't compressed when I had the chance to install it. I talk the newer harder shell guise. Subjectives....naaah, so uncontrolled, but we all got a little chef inside us it seems.
I bought a couple of Mundorf .1 uF silver and oil. When they come in I will install and do the DCB1 at the output of the second stage. I will try to ground at the phono board first and go from there.
There is a thread for the metal can Russian Teflon caps where he cuts the can off and wraps them in tape and epoxies the ends. Says it makes them sound better and they get smaller.

Also on the gain front. I have 90 db speakers and an F5 with standard gain and with the DCB1 I can't max out the volume without bringing the family down on me. Even when I am by myself I can't listen that loud.
Maybe my room is small, 17 ft x 13 ft with 8 ft ceiling.

As always, thank you for your help,

Rush

Last edited by Rush; 5th October 2012 at 05:57 AM.
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Old 5th October 2012, 05:59 AM   #8119
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You saved many $ that way and still with a full chance to evaluate for yourself. Let us know how it worked out in the end.
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Old 5th October 2012, 06:10 AM   #8120
Salas is offline Salas  Greece
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Originally Posted by Rush View Post
Also on the gain front. I have 90 db speakers and an F5 with standard gain and with the DCB1 I can't max out the volume without bringing the family down on me. Even when I am by myself I can't listen that loud.
Maybe my room is small, 17 ft x 13 ft with 8 ft ceiling.
Even from phono as source? Max SPL maybe not needed but dynamics can still express fuller if system gain is spot on IMHO. Not always a priority if listening near to the transducers for some. F5T is 7dB more sensitive than normal F5 BTW.
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