6V6 line preamp

[Salas]

Originally Posted by merlin el mago

Salas the link for "A recommended series regulator" doesn't work.

It was about a Mosfet Maida. It went down for good apparently. I will look to find something to replace it.

[nhuwar]

K thanks Salas. Once built I might give it a go. If the results are good I'll report back.

Nick

[ncc]

Salas,

I've built a resistor loaded version of your 6V6 preamp with my B+ of only 300V, so I used 7.5K anode resistor as recommended by you with very good result.

I have a pair of Magnequest plate chokes, BCP-15 which is 50H/40ma/575ohm. I'd like to know if theirs inductance is enough for adequate bass response and in the case they can be used then how is the new B+ should be.

[Salas]

Congratulations for your build. Let us know more about the system you added it in. Build photos are welcome. About the plate chokes, yes they are a bit on the low Henry side...

It will roughly show -3dB at 10 Hz and 40deg phase shift there theoretically as a combination. Not great for zero LF phase shift, but it will play bass. Up to you deciding a test if its handy so to see how you like them. It will play couple of dB louder also, so normalize that when comparing. You will be needing 180V B+ for them.

[ncc]

Salas,

Thanks for your response, The system I'm using now consist of:
Source-Mac mini =>DAC-TEAC UD501 => 6V6 preamp => Fetzilla Power amp =>ProAC 2.5 clone

With 6V6 preamp, the system has become very dynamic and the frequency response is good from bass to treble, very good for classical music which I listen most of the time. I'm sorry no picture at the moment.
I'll try choke load and compare with resistor load later.

[Salas]

OK good luck with the experiment, and keep us posted.

[tubo]

Hi Salas,

I just wanted to verify if you are now using a 2.2uf output capacitors. If. Im not mistaken you have mentioned in one of your posts but cannot remember where. Im ordering parts for the build, and want to get the right one.

Thanks

[tubo]

Hi Salas,

One more question, sorry for the inconvenience. I also have an ldr based volume control which i will be usinginstead of the 100k pot. Do i still need to wire a 100k resistor from the grid to the ground of the 6v6? Also is it very important to retain the 1k resistor at the grid of the 6v6? In my last build i took it out as it sounded a little better without it.

Thanks

[AJT]

not Salas, but it is a good practice to install a 1meg grid bias resistor(not absolutely required) and a 1 ik carbon com resistor closest to the grid, pin 5...

the choice of output capacitor size is dictated by the input impedance of the amp that your preamp will drive...

[stajo]

Originally Posted by Salas

You will be needing 180V B+ for them.

Now isnt that on the low side?