Tube Phono Pre-Amplifiers

[mr2racer]

Does anyone have design for a tube phono pre-preamp?

[SY]

First questions to consider before choosing (or designing):
1. Cartridge output?
2. Best loading for cartridge?
3. Desired gain?
4. Load to be driven? (usually 47k in parallel with some capacitance)
5. Acceptable degree of complication/expense?

[6L6]

Yes. However, it would be helpful to see your answers to SY's questions.

[artosalo]

Here is one quite basic circuit which gives good results with MM cartridges. Gain is some 46 dB.



Kuva 19470 - Kuva.termiitti.com

[SY]

The OP was looking for a pre-preamp, i.e., a flat gain amp to step up an MC to MM levels.

[Eli Duttman]

Originally Posted by mr2racer

Does anyone have design for a tube phono pre-preamp?

If (as SY thinks) you are looking for something to use instead of a SUT between a LOMC and a "routine" phono section, you are asking for trouble. Tubes are simply too noisy for use at these μV. level signals.

OTOH, if you want something to put between a MM level cart. and the line section, there are any number of satisfactory tube based designs available.

Please clarify your intentions and needs.

[artosalo]

The OP was looking for a pre-preamp, i.e., a flat gain amp to step up an MC to MM levels.

How can you make such assumption ? I could not.
To me phono pre amplifier is such that contains RIAA correction and adequate gain.

mr2racer, could you clarify.

[SY]

He said pre-preamp, not preamp. Yes, clarification is in order.

[artosalo]

Yes indeed, pre-preamp.

[Original Burnedfingers]

If he is going to use a MC then how about a simple step up transformer using 2) 4722 Altec transformers to provide the necessay gain to marry the signal to a standard phono preamp? I believe Altec 15095 or 15095A's will also work also.

Http://members.myactv.net/~je2a3/mic-mcstep-up.htm