6V6 line preamp

[Zen Mod]

just toss them in Papa's Pub , if gentleman aren't willing to open dedicated thread(s)

 

[tinitus]

Papa's Pub ?

got me thinking of 'Bottles pop'

well, post are gone, to picture thread
hope thats acceptable

http://www.diyaudio.com/forums/tubes-valves/71300-photo-gallery-383.html

 

[Bonsai]

Any recommendations for a good line out transformer? I will need to drive quite a low load impedance (few k) so capacitive coupling is not the preferable output coupling option.

http://www.veiset.net/BO/BO26MAI07A.gif

Actually, what I meant to say is a 10k or 15k to 600 Ohm transformer for plate load. Anyone familiar with James Transformers (local brand here in Taiwan). Sowter's look ok, but quite expensive.

 

[DavesNotHere]

Any thoughts on having the tubes mounted horizontally for this very design? I've read that DHT's might show some issues when mounted horizontally, but does this apply for 6V6 and 5AR4, for example?

as long as pins 1&8 are in the same horizontal plane they should be ok.

 

[stajo]

Papa's Pub ?

got me thinking of 'Bottles pop'

well, post are gone, to picture thread
hope thats acceptable

http://www.diyaudio.com/forums/tubes-valves/71300-photo-gallery-383.html

Sorry went to bed

Ill start a "tune QII-thread" when I'm there, thanks. Intention was chassie and mates to my 6V6-pre build but discussion went OT somehow sorry

/Staffan

 

[toprepairman]

For horizomtal mounting just make sure the grids are aligned vertically.

 

[buzzforb]

Salas,
tube or solid state rectification? Recommendations or does it matter.

 

[nicoch58]

incredible Zen Mod are in all place

he must have a new server in class A

 

[bequerel]

Actually, what I meant to say is a 10k or 15k to 600 Ohm transformer for plate load. Anyone familiar with James Transformers (local brand here in Taiwan). Sowter's look ok, but quite expensive.

James transformers are beautifully made, and very nice quality at an acceptable price, but probably not in the Hashimoto or Magnequest league.

(If you are on a very low budget, Daburu is usually even cheapter than James.)

 

[merlin el mago]

I had thought Elna Silmic II is preferred over Panasonic FM. I can readily acquire Elna Silmic II.

All depends your personal taste, both are very good capacitors, FM strong with more mids & bass, Silmic II more refinated.

 

[Salas]

Salas,
tube or solid state rectification? Recommendations or does it matter.

I had used 5R4GY & 5AR4 mostly for it, never had it with SS. So no experience of pros and cons with this pre.

 

[buzzforb]

I had used 5R4GY & 5AR4 mostly for it, never had it with SS. So no experience of pros and cons with this pre.

Choke loaded?

 

[stajo]

Choke loaded?

Is never wrong, if you got the voltage and amps for 340 B+. Salas used caps tho.

/Staffan

 

[Salas]

Choke loaded?

CLC it is.

 

[buzzforb]

Salas,
I have orderd the last of the parts with a few exceptions. I have cohsen to go solid state on the B+ simplty because i don't have enough secondaires on my trafo, 2-300 and 2-6.3. The question i have concerns the LM317 regulator. I have never seen it wired this way an don't know the actual operating conditions. Since there are no voltage setting resitors, is the voltage equalt to that after rectification? Is the current set by the 5W resistors? I only have 6.3 V taps on my secondary. These seemed ok seince the thube datasheet showed 6.3V and 45mA for filament. You seem to have it running at higher specs if i am figuring correctly. Sorry for the basic question.

 

[Zen Mod]

download datasheet of 317 and you'll see that's basic CCS arrangement

you need few volts more for headroom ( CCS needs few volts for proper operation)

can you add several turns of enameled wire , connected in series with existing filament winding ( toroid ? ) ?

I hope 45mA is typo ......... with one zero missing

 

[buzzforb]

THanks ZenMaster. I took a quick glance at the formula at the top of the datasheet showing voltage regulation and went no further. RTFM applies here, I believe.

 

[stajo]

You could also serial the 2 secondarys. Connection between the two 300 would be your zero for tube rectifying.Serial the two 6,3 gives 12,6 wich is good headroom for the LMs

Staffan

 

[buzzforb]

Thanks to all. It is funny how much pleasure i get out of figuring out something as simple as a 317 CCS regulator!

 

[massimo]

you need few volts more for headroom ( CCS needs few volts for proper operation)

Ok, but how many (roughly)? 2? 4? 6? or....

P.S. If I'm not wrong Coleman's Regs work more or les on the same principle (CCS)