Temporary Phono Preamp

davidlzimmer · 11th July 2006, 12:34 AM

Can I take an EQ with lots of gain and input the turntable in either the tape or line input and set the controls to simulate an RIAA curve until I build a phono pre?

The reason I ask, instead of just doing, is the EQ is 2 hours away.

Thanks,

anatech · 11th July 2006, 01:26 AM

Hi David,
It's better than nothing. Whether it's useable or not is another question. I would expect a great deal of noise and hum.

Radio Shack used to sell a really inexpensive preamp powered by a 9 V battery. That would work much better than the EQ idea. If you can build a circuit, you could make a temporary unit too. The RS unit is cheaper when you are done.

-Chris

davidlzimmer · 11th July 2006, 01:02 PM

I suspect you have a better idea. I have two urges. One to go back to analog (an antique dealer freind of mine told me I could sample his 500+ LP collection) and another to build a tube project.

I think what I will do is get my present projects completed, then build a little 12AX7 phono pre. If I buy a cheap one first, it might just stay that way.

Thanks for bringing me back down to earth Anatech!

sreten · 11th July 2006, 01:29 PM

Quote:

Originally posted by davidlzimmer
Can I take an EQ with lots of gain and input the turntable in either the tape or line input and set the controls to simulate an RIAA curve until I build a phono pre?

The reason I ask, instead of just doing, is the EQ is 2 hours away.

Thanks,

Hi,

It would work in a fashion, but one of your problems would be incorrect
cartridge loading. Another would be most EQ's don't have enough range.

/sreten.

anatech · 11th July 2006, 01:43 PM

Hi David,
Good luck and keep building!

Since you like tubes, get a copy of the Radiotron Designers Handbook, Rev4 (electronic or real). Another great book is Morgan Jones "Valve Amplifiers", available at Amazon.com.

After reading some of RDH4 and Valve Amplifiers, you'll have a much better idea on how to go about designing a good preamp.

-Chris

davidlzimmer · 11th July 2006, 02:02 PM

Thanks folks.

I need some brushing up for sure but, tubes are my old freinds. Built my first project in 59. A 3 tube reciever. Beat the c.r.a.p out of my crystal set!

anatech · 11th July 2006, 02:23 PM

Hi David,
I was born in 1959. I missed all the instruction on tubes that was available to you. You may have old magasines and text books that have most of this info in it.

The Morgan Jones book is a modern look at how to use these devices, with modern semiconductors thrown in to allow some extra tricks. Worth a read or three!

-Chris

davidlzimmer · 11th July 2006, 03:16 PM

Kids!

phn · 11th July 2006, 07:11 PM

I'm not going to debate which is better, tubes or chips, any more than I'm going to debate who's stronger, Hulk or Superman. But it's a good idea to make a simple chip phono preamp to use as a reality check. The chip pre is cheap, easy to make and sounds surprisingly good. The tube pre is supposed to outperform it.

davidlzimmer · 11th July 2006, 07:24 PM

Tempting. Very tempting.

11th July 2006, 12:34 AM	#1
davidlzimmer diyAudio Member Join Date: Jan 2006 Location: Fairmount, GA	Temporary Phono Preamp Can I take an EQ with lots of gain and input the turntable in either the tape or line input and set the controls to simulate an RIAA curve until I build a phono pre? The reason I ask, instead of just doing, is the EQ is 2 hours away. Thanks, __________________ Poor stereo mix? Switch to mono! Perfect.

11th July 2006, 01:02 PM	#3
davidlzimmer diyAudio Member Join Date: Jan 2006 Location: Fairmount, GA	I suspect you have a better idea. I have two urges. One to go back to analog (an antique dealer freind of mine told me I could sample his 500+ LP collection) and another to build a tube project. I think what I will do is get my present projects completed, then build a little 12AX7 phono pre. If I buy a cheap one first, it might just stay that way. Thanks for bringing me back down to earth Anatech! __________________ Poor stereo mix? Switch to mono! Perfect.

11th July 2006, 02:02 PM	#6
davidlzimmer diyAudio Member Join Date: Jan 2006 Location: Fairmount, GA	Thanks folks. I need some brushing up for sure but, tubes are my old freinds. Built my first project in 59. A 3 tube reciever. Beat the c.r.a.p out of my crystal set! __________________ Poor stereo mix? Switch to mono! Perfect.

11th July 2006, 03:16 PM	#8
davidlzimmer diyAudio Member Join Date: Jan 2006 Location: Fairmount, GA	Kids! __________________ Poor stereo mix? Switch to mono! Perfect.

11th July 2006, 07:24 PM	#10
davidlzimmer diyAudio Member Join Date: Jan 2006 Location: Fairmount, GA	Tempting. Very tempting. __________________ Poor stereo mix? Switch to mono! Perfect.


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11th July 2006, 01:26 AM	#2
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi David, It's better than nothing. Whether it's useable or not is another question. I would expect a great deal of noise and hum. Radio Shack used to sell a really inexpensive preamp powered by a 9 V battery. That would work much better than the EQ idea. If you can build a circuit, you could make a temporary unit too. The RS unit is cheaper when you are done. -Chris

11th July 2006, 01:43 PM	#5
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi David, Good luck and keep building! Since you like tubes, get a copy of the Radiotron Designers Handbook, Rev4 (electronic or real). Another great book is Morgan Jones "Valve Amplifiers", available at Amazon.com. After reading some of RDH4 and Valve Amplifiers, you'll have a much better idea on how to go about designing a good preamp. -Chris

11th July 2006, 02:23 PM	#7
anatech diyAudio Moderator Join Date: Jun 2004 Location: Georgetown, On	Hi David, I was born in 1959. I missed all the instruction on tubes that was available to you. You may have old magasines and text books that have most of this info in it. The Morgan Jones book is a modern look at how to use these devices, with modern semiconductors thrown in to allow some extra tricks. Worth a read or three! -Chris

11th July 2006, 07:11 PM	#9
phn diyAudio Member Join Date: Oct 2004	I'm not going to debate which is better, tubes or chips, any more than I'm going to debate who's stronger, Hulk or Superman. But it's a good idea to make a simple chip phono preamp to use as a reality check. The chip pre is cheap, easy to make and sounds surprisingly good. The tube pre is supposed to outperform it.

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