What's wrong with the kiss, boy?

[Dennis Hui]

What's a decent volume potentiometer that can be purchased from digikey/mouser.

Maybe something like this?:

http://ca.mouser.com/Search/Product...Cvirtualkey68800000virtualkey688-RK27112A00CC

Cheers,
Dennis

 

[Zen Mod]

adequate (is it linear ? )

also these : http://tinyurl.com/yalo37cz

 

[JPS64]

@Zen Mod

Could I use 100R JFET gate resistors (instead of 330R)?

JP

 

[Zen Mod]

yup

 

[JPS64]

thanks Zen Mod for this simplest preamplifier.

ELMA switch, AVC (Tribute?), buffer and autoformer (using EDCOR one).

Is Jensen better choice? Needs shielding?

I´ll power with two gel batteries (simplest gauge something LM and power switch for Meanwell chip external charger).

JP

 

[Zen Mod]

why AVC then buffer then autoformer ?

as I wrote numerous times , goal with Iron Pumpkin(s) is to simplify things maximally

selector, buffer , AVC (connected to have gain, if needed)

difference between Tribute and Jensen - can't tell from experience

I'm having my own , anyway

 

[JPS64]

Selector --> Potentiometer --> Buffer --> Autoformer? (as showned on your blog).

or

simply: Selector --> Buffer --> AVC.

Right?

JP

 

[Zen Mod]

first one = Iron Pre

second one = Iron Pumpkin

re-read the thread , everything written more than once

 

[JPS64]

Done!

But a lot of questions remaining...

What is the value for the potentiometer/attenuator for the Iron Pre?

JP

 

[JPS64]

Both version enable.

Jensen/Edcor paralleling possibility to evaluate: question about shielding needs pending.

Searching for other connectors for simplest and optimal wiring (to potentiometer/AVC and batteries): help wanted.

JP

 

[Zen Mod]

pot - matter of sources (cojones) , but 25K is practical maximum

shielding - no need if mains xformer is far enough or outboard

 

[JPS64]

Iron-Pre with batteries.

Missing potentiometer/attenuator.

JP

 

[Zen Mod]

it seems I'm going to open new thread pretty soon .......

 

[Dennis Hui]

Woohoo!

 

[Soundhappy]

it seems I'm going to open new thread pretty soon .......

Bravo ZM !

 

[2 picoDumbs]

You've been hard at work

 

[MASantos]

Cool!!!

ZM, I am thinking of an IronPre/M2 integrated amp, any disadvantages here of having many transformers in the same case? Might they have interference between them? I don't know much about signal transformers.

 

[Zen Mod]

if you want that , you can skip input JFet buffer in M2 , driving M2's autoxformer directly from AVC

hypothetically ......... 2 possibilities

1. Iron Pumpkin ( buffer +AVC ) - M2 buffer omitted - M2 autoxformer
2. M2 buffer - AVC - M2 autoxformer

no harm done cascading two xformers , simply because AVC with preceding buffer is pretty low output impedance device

of course that , in case of No.1 you could have full preamp convenience , Iron Pumpkin is having shunt reg , buffer and selector on board

new , dedicated thread with full technical info - pending .... in few day's time

no interference between signal xformers ........ only thing you need to take care of is putting signal ones on one side of case and mains xformer in other side - just like in original M2

 

[MASantos]

But does it make any sense to mate those two together? too much "transformer" sound?

Could it be better mated with a BA3 for instance? I'll wait for the new thread and for the first build to get a better understanding of the various options.

 

[Zen Mod]

generally speaking - if you observe preamp and amp as black boxes , and you find them adequate for task - who cares what's inside them ?

Iron Pumpkin is (hardly novel idea) my last iteration of obtaining line stage with (settable) moderate gain and volume control in one element , with more than decent output impedance

that - speaking of both SE and balanced variant

speaking of balanced only - you get any possible combination of SE-bal and bal-SE conversion , in truly differential manner

all that - not because I'm any clever ...... simply because xformers are really great devices , when used properly

.......and M2 is ......... M2

best Papamp ever