Simplistic NJFET RIAA

[Salas]

Simplistic Flexibilistic

 

[bucurb]

voltage for MM and HMC

Hello,

Several questions, if you please.
What would be the best transformers secondary tension for MM and / or HMC, please? What about the power of such transformers, please? Toroid transformers are well suited for such applications, in your opinion?
Warm regards and happy auditions!

 

[Salas]

33 to 35 VAC 30-50VA each. Many have used toroids with peripheral magnetic shielding with success. Antek for instance.

 

[alexkosha]

I use this one with no issues: AS-1236 - 100VA 36V Transformer - AnTek Products Corp
Relatively cheap and they have an excellent customer service. I have one trany (for different project) that made hum/vibration and they sent me a new one very quickly (lake two days and I already had it in my house). They care about safety and they told me not to use the noisy one and to trash it immediately. Good luck.

 

[bucurb]

THE MAGNETIC SHIELD AROUND THE OUTSIDE TO REDUCE THE MAGNETIC LEAKAGE

Hello,

I did search on Antek site the string "THE MAGNETIC SHIELD AROUND THE OUTSIDE TO REDUCE THE MAGNETIC LEAKAGE" and I didn't find any more details about.

In my previous RIAA preapms I did use two transformers having cross connected their primary coils. It made power supply dead quite.
Now I would wish do command such magnetic shield at my favorite manufacturer ... but I need something technically more precised.

Maybe a short circuit on the leakage magnetic field (a short circuit made by a lateral cooper band... may be).

What would be "THE MAGNETIC SHIELD AROUND THE OUTSIDE TO REDUCE THE MAGNETIC LEAKAGE" in your opinion, experience please?

 

[AndrewT]

gauss band is a normal name for it.

 

[Hikari1]

Antek is good. The ones with the shield are the "AS" series. Iam using one in my ba3 preamp. Also, i have a 38v antek Iam about to use with the salas shunt for the salas phono stage. Just have to build the other channels shunt and I can get rid of the batteries.

 

[Salas]

Nice matrix work stuffing.

 

[Hikari1]

Thanks Salas. I am thinking about the transformer and caps now. I am going to use a dual secondary transformer, one secondary per shunt. Is it better to leave the grounds of the two supplies separate or is it better to connect them at the negative terminal of the caps (see attached)?

 

[Salas]

Better use two thermistors and two earthing runs.

 

[Marra]

Thanks Salas. I am thinking about the transformer and caps now. I am going to use a dual secondary transformer, one secondary per shunt. Is it better to leave the grounds of the two supplies separate or is it better to connect them at the negative terminal of the caps (see attached)?

I can recommend the grounding arrangement as shown in the build guide.Totally hum free listening in both my MM and high gain MC versions.

 

[AndrewT]

Thanks Salas. I am thinking about the transformer and caps now. I am going to use a dual secondary transformer, one secondary per shunt. Is it better to leave the grounds of the two supplies separate or is it better to connect them at the negative terminal of the caps (see attached)?

Don't add zero ohm loops.
Keep them separate and ONLY make connections WHERE they are needed.

 

[Hikari1]

Finally got the shunts put together...just using a case I had lying around and an enclosure from a computer psu for now. Fired up no problem. Sounds good so far, its pretty late so I have not had a chance to crank it up yet. Thanks Salas.

 

[Hikari1]

Whoa...how hot are the heatsinks supposed to get on the shunt? I can hold my finger on them for maybe 2 seconds max. They are pretty hot. Its a 1.5 inch tall heat sink on the shunts and the case is open right now it will get hotter closed. Should I be worried?

 

[Salas]

Small sinks for 10R R1. They used larger ones or the floor of bigger boxes for that version. Use 15R later.

 

[Hikari1]

Thanks Salas. I will try 15 ohm for R1.

I have to say, so far I've used the shunt for a few hours and it is better than batteries. Bigger, more dynamic. But Ism also going from a single battery supply to dual shunts. But I like what Iam hearing so far.

 

[Salas]

That's nice. Enjoy.

 

[Turbon]

Another succesful trial - the Stanton 981LZS with D-98S and D-98 mkIIS stylii works just wonderfully with the 63dB FSP and CL Satisfy arm! Just wonderful!

Regards

 

[Marra]

Good to hear Turbon it really is something special this phonostage.

 

[Turbon]

Good to hear Turbon it really is something special this phonostage.

Yes and the pacekeeper is an PTP-5 Lenco A bit tweaked though...

Regards