6V6 line preamp

[Salas]

Hi Salas,

Thanks again... ill see if heyboer can make those opts. My friend heard my 6v6 pre and loves it. His amps is a 3 stage pp 6l6 design which already has enough gain that a normal 2v source can drive it to full power.

He wants to build a 6v6 too and I told him to build the cathode follower version but since an output transformer can be used to step down the output of the common cathode design, what step down ratio is ideal so the common cathode 6v6 will have a 2v output?

I think just the capacitive coupled buffer is enough in his case. Still less THD and mechanical feedback without the Tx cost. If he wants Tx coupling and CC topology instead it should be 1:10.

 

[tubo]

Thank.you salas...

 

[yellowbanana]

http://www.diyaudio.com/forums/tubes-valves/149211-6v6-music-machine-build-help.htmlello Guys,

Hope every body is well. Im new to the forum and new to diy. Im thinking of building the 6v6 cathode follower as buffer for my passive preamp. Looking in my parts box ive found a power transformer and a choke that I got to build a 6v6 pp amplifier of poindexter... here is the attached scheme of the powersupply. Will it work as the power supply for the cathode follower version?

Thank you..

 

[Salas]

Welcome to the forums. That link does not work but all you need to know is that a well filtered 300-330V B+ 120mA capable rail will suffice for this preamp.

 

[yellowbanana]

http://www.diyaudio.com/forums/tubes-valves/149211-6v6-music-machine-build-help.html

Salas,

Thank you for having the design available to the public and for your efforts. It is greatly valuable to guys like me. I think the power transformer is only capable of 80ma. Im really new to the hobby so I won't know if this supply will work. Here it is again..

 

[Salas]

The preamp will take 40-45mA for two channels to bias. I just recommend more for ample headroom. 80mA will still work.

 

[yellowbanana]

Thanks Salas...

I'll build the pre using the power supply of the attached 6v6 amp..... sorry to.keep asking... the power supply will work right?

 

[Salas]

Yes, looks alright for the task. Always fuse the transformer's primary side to spec.

 

[tubo]

hello salas,

i will build the common cathode with OPts and report back. thank you

 

[yellowbanana]

Hi Fellas,

Ive read that some of our members have built the 6v6 cathode follower version.

To those who have built it and heard it, what is your impression to how it sounds compared to other pre? Is it just as good as the common cathode version?im just excited and wanted to know your impressions.

Hi Salas, thank you for your help. I'll build the cathode follwer version and report back.

 

[yellowbanana]

Hey fellas,

Just an update on my build... top plate chassis is almost done... the middle tube between the 2 6v6 is just for probs as underneath it will be an ldr volume control...

Do I need to.elevate the heaters? My b+ estimate is 330v to 340v? How do I calculate the.voltage divider to getthe right.voltage? I.aapologize for.all.the.questions...

Ty

 

[stajo]

you dont need to elevate the heaters if you dont have a problem. Otherwise 100 k on top and 10 k at the bottom would give you 33-34 v in the middle for sure.

 

[yellowbanana]

you dont need to elevate the heaters if you dont have a problem. Otherwise 100 k on top and 10 k at the bottom would give you 33-34 v in the middle for sure.

Thank you very much. It is greatly appreciated.

 

[yellowbanana]

Hello fellas,

An update to the painted caps and trannsformer.cover...top.plate needs to be sanded and clearcoated...

 

[yellowbanana]

Hello Fellas,

I'm almost done wiring the cathode follower circuit and for.the life of me forgot to get the 1k grid resistor...

that is the only think missing. Can I still use it without that 1k resistor in the grid?

 

[Salas]

Maybe, depends on the wiring and what comes in from source. If you will hear no whistling its probably not excited by inductance yet. If you got a smaller value than 1K in hand use it. Solder it directly on the grid's socket pin with a short trimmed lead.

 

[yellowbanana]

Hello guys,

Salas, thank you... and thank.you all for the guidance and help... I finished the preamp and it sounds amazing.. wow... it is very natural and dynamic... I have a lil hum and hiss but very much tolerable... im using ac heaters and elevated it to 33vdc... also my power suppl is clc.... 0.22uf to 20h to 1000uf to15h to 470uf....

The sound is phenomenal.... made my.class d icepower amps come.alive...very rich tones, right timbre, and soinds big and effortless....

Thank.you.guys again...

 

[Salas]

Congrats Yellow. Happy listening. If ever to regulate DC lines we will be here for any questions.

 

[Bas Horneman]

I have a lil hum and hiss but very much tolerable

Going to dc should fix the hum. I did it...and was even happier than with ac. Good to see another happy Salas 6v6 amp builder.

 

[TonyTecson]

did you put an ecap on those voltage dividers lifting the filaments?