Pumpkin preamp - ordered by Steen , official making thread

[Zen Mod]

read last page in Cook Book

if you're using 0,25W ones , along with some superduper low ESR caps - decrease those resistors to 1 ohm

 

[3GGG]

Thanks, read the cookbook. I use low ESR so will sub them out for now.

Cheers

 

[ANADIGIT]

How do I use 6DJ8 instead of 2SK170 in diff stage ?

Thanks
Anadigit

 

[Zen Mod]

easy

but I have no time right now , to construct entirely new preamp

 

[ANADIGIT]

easy

but I have no time right now , to construct entirely new preamp

Can 6DJ8 use +/- 35V and operating well ?
I loved 6DJ8 sound.

 

[Zen Mod]

Can 6DJ8 use +/- 35V and operating well ?
I loved 6DJ8 sound.

no ;

6DJ8 needs at least 75V between anode and cathode , to operate properly ;

that means ( really depending of overall construction ) , that positive PSU must be greater than that , also considering nature of load ( is it CCS , gyrator , resistance , choke ) .........

so - no low voltages with tubes ....... and rare low voltage ones doesn't have most important virtues of tubes .......

that's my , modest as always , opinion

 

[ANADIGIT]

no ;

6DJ8 needs at least 75V between anode and cathode , to operate properly ;

that means ( really depending of overall construction ) , that positive PSU must be greater than that , also considering nature of load ( is it CCS , gyrator , resistance , choke ) .........

so - no low voltages with tubes ....... and rare low voltage ones doesn't have most important virtues of tubes .......

that's my , modest as always , opinion

Mybe we can use 6GM8 instead of 6DJ8 as I saw from Borbely Hybrid Line Stage !
Does his schematic look like Pumpkin ?

 

[ANADIGIT]

Do someone need 66 Steps attuator 70dB, each 1 dB ?
I saw something special in Pass X0.2 and take it to my control by ATMEGA MCU and 7-SEGMENT display, jogging volume control also remote control for selector and volume control.

Regard
Anadigit

 

[Zen Mod]

Mybe we can use 6GM8 instead of 6DJ8 as I saw from Borbely Hybrid Line Stage !
Does his schematic look like Pumpkin ?

no , and no

as I said - I don't like neither low voltage for tubes nor low voltage tubes

but - maybe you'll like them

 

[3GGG]

Finding a suitable trasformer is proving harder than it should be for this. There is nothing suitable locally, Tortech and Harbuch havent even replied to my emails (which included 4 toroids for Aleph project)! Any linkies?

 

[Zen Mod]

tell me your needs for output swing , and I'll tell you what's possible for PSU

+/-36V PSU is chosen for F4 balanced , and that value isn't carved in stone

Pumpie is operative pretty well from +/-24V

I made , by request , calcs for Shunty used for Xono .... etc ....

 

[3GGG]

I will be running Pumpkin into Standard Aleph J. Well actually 3 AlephJ's in an active horn setup.

Thanks Zen

 

[Zen Mod]

what xformer is easy to find , in your neck of wood ?

starting from 2x24Vac

( preferably with higher voltage )

 

[3GGG]

2x25v 160va and 2x30v and just found they have a 2x 45v 160va are readily available.
Should I use 1 per channel?

http://www.altronics.com.au/index.asp?area=item&id=M5345

 

[Zen Mod]

go for 2x30Vac

one is good for both channels - regs are of that breed that channel intermodulation is simply impossible

later - this evening , I'll post variant for that voltage

 

[3GGG]

Thanks Zen

reading tru the whole thread showed a link to the below R-Core. I emailed an there are still a few available. I am not sure of their quality though.
About $60 delivered so similar price to local offerings.
Hot news from THLaudio

 

[Zen Mod]

I think that one was good

 

[jacco vermeulen]

Good ones, and look brand new btw.

The odd part is that i bought up the entire stock they said they had left, the minute i saw their ad, that was before 2010.
Need a datasheet, an image of the integrated amp they came out of, or a close-up(s) of the tranny ?

(cough, me pay less than $21, mucho less )

 

[Zen Mod]

shoot

 

[Zen Mod]

so ?