Phonostage with tube moving coil

[legarem]

Hi

I want to resurrect my old Curcio Daniel preamplifier to use it as a phonostage. As I use a low MC cartridge, I thought using all the preamp including full gain incorporated linestage to feed another preamp to get the required gain. I loaded the MM input at 100 ohms and tried it. It didn't work because I have motorboating problems. I tried smaller signal caps and had the same results.

Can I take the linestage and convert it as a MC pre preamplifier before the RIAA stage ? Will I end with the same problems ?

As the Curcio preamp has buffers to decouple each stage, I'm surprised to have motorboating problems.

Can I do something with this preamp ?

Thanks

 

[Eli Duttman]

Even if you solve the stability issues, the result will be unsatisfactory. At the μV. level associated with LOMC carts., S/N ratio is item 1 through item 99. It's nearly impossible to get an acceptable S/N ratio out of tubes at the LOMC signal level.

Can I do something with this preamp ?

Yes, you can. Buy or build a step up transformer setup and use it with all your signal sources.

 

[fdegrove]

Hi,

Or build a MC Hammer pre-pre stage as the one I posted on here. It's quiet and has sufficient gain to go with most phono pres.

Be ware: you do want a BF244A FET as a CCS and nothing else.

Ciao,

 

[Defiant]

Even if you solve the stability issues, the result will be unsatisfactory. At the μV. level associated with LOMC carts., S/N ratio is item 1 through item 99. It's nearly impossible to get an acceptable S/N ratio out of tubes at the LOMC signal level.

You can do it if you use a high gm planar triode.

 

[kevinkr]

You may need to replace power supply caps in the Daniel at this point in time as it's quite long in the tooth. With all of those individual regulators you should not have any stability issues like motor boating if everything is working as it should.

Use a SUT, and as Eli suggested use it for all of your sources. It's quite a good pre-amplifier.