Heretical Unity Gain line stage PLUS a little gain ?

yagas · 19th January 2006, 05:50 PM

SY, I would like to see another thread on how to couple a gain stage to your "Heretical line stage" using the same techniques...
although time is limited and valuable ...

Michael

SY · 19th January 2006, 06:35 PM

It's very, very easy. Use a step-up transformer. A JT-11P-4 will give you about 3dB. The nice thing about the circuit setup is that you can optimize the load for nearly any transformer, so if you want more gain, just use a higher step-up. I did a quick trial with a Magnequest/Peerless 15095 and it worked very well, albeit with too much gain for me to reasonably use.

yagas · 23rd January 2006, 11:31 AM

Sorry for my delayed response...

Agree ... but can my phono stage drive a 10K input transformer ?

Mic

pinkmouse · 23rd January 2006, 11:36 AM

Depends on the output voltage/impedance of your phono stage. Do you have any details?

SY · 23rd January 2006, 01:20 PM

If it can't, it's not difficult to up the input impedance. What sort of phono stage are you using?

yagas · 24th January 2006, 10:55 AM

I use the cornet phono from Hagerman.

http://www.hagtech.com/images/cornet2schem.gif

http://www.hagtech.com/cornet2.html

The output stage consists of 12AU7@175V@6mA
Output impedance is 1K
What about raising the output coupling cap to 8-9uf or to change the ccs to sink about 10 mA ?

Michael

SY · 24th January 2006, 12:35 PM

You don't have to change anything, it will work fine as-is. 10K is not an unreasonable load for a 12AU7 cathode follower, and if you want a higher load impedance anyway, the input shunt resistor of the Heretical can be increased.

yagas · 24th January 2006, 02:30 PM

Thank you

19th January 2006, 05:50 PM	#1
yagas diyAudio Member Join Date: Sep 2004 Location: Athens	Heretical Unity Gain line stage PLUS a little gain ? SY, I would like to see another thread on how to couple a gain stage to your "Heretical line stage" using the same techniques... although time is limited and valuable ... Michael __________________ Mic

19th January 2006, 06:35 PM	#2
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX	It's very, very easy. Use a step-up transformer. A JT-11P-4 will give you about 3dB. The nice thing about the circuit setup is that you can optimize the load for nearly any transformer, so if you want more gain, just use a higher step-up. I did a quick trial with a Magnequest/Peerless 15095 and it worked very well, albeit with too much gain for me to reasonably use. __________________ "It is not seemly, after wiping your nose, to spread out your handkerchief and peer into it as if pearls and rubies might have fallen out of your head." - Erasmus

23rd January 2006, 11:31 AM	#3
yagas diyAudio Member Join Date: Sep 2004 Location: Athens	Sorry for my delayed response... Agree ... but can my phono stage drive a 10K input transformer ? Mic __________________ Mic

23rd January 2006, 11:36 AM	#4
pinkmouse diyAudio Moderator Join Date: Apr 2002 Location: Chatham, England	Depends on the output voltage/impedance of your phono stage. Do you have any details? __________________ Al The miracle is not to fly in the air, or to walk on the water; but to walk on the earth. Chinese Proverb

23rd January 2006, 01:20 PM	#5
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX	If it can't, it's not difficult to up the input impedance. What sort of phono stage are you using? __________________ "It is not seemly, after wiping your nose, to spread out your handkerchief and peer into it as if pearls and rubies might have fallen out of your head." - Erasmus


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24th January 2006, 10:55 AM	#6
yagas diyAudio Member Join Date: Sep 2004 Location: Athens	I use the cornet phono from Hagerman. http://www.hagtech.com/images/cornet2schem.gif http://www.hagtech.com/cornet2.html The output stage consists of 12AU7@175V@6mA Output impedance is 1K What about raising the output coupling cap to 8-9uf or to change the ccs to sink about 10 mA ? Michael __________________ Mic

24th January 2006, 12:35 PM	#7
SY diyAudio Moderator Join Date: Oct 2002 Location: Austin, TX	You don't have to change anything, it will work fine as-is. 10K is not an unreasonable load for a 12AU7 cathode follower, and if you want a higher load impedance anyway, the input shunt resistor of the Heretical can be increased. __________________ "It is not seemly, after wiping your nose, to spread out your handkerchief and peer into it as if pearls and rubies might have fallen out of your head." - Erasmus

24th January 2006, 02:30 PM	#8
yagas diyAudio Member Join Date: Sep 2004 Location: Athens	Thank you __________________ Mic

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