Which Sowter or OEP for G7 ??

[rafafredd]

[quote author="sismofyt"]
Yes, an OEP'ed G7 will have a tiny bit more gain, not really anything you'll notice in practice.[/quote]

On the G7 microphone, the transformer is reversed, working as a step down, so the OEP will give less gain the the lundahl.

On the G9 micpreamp, the OEP gives more gain than the lundahl...

Let me know if I´m wrong.

 

[Jazzy_Pidjay]

yes rafafred it's what i'm trying to say
with my poor english

so if OEP is reversed it's provided less gain

thanks

 

[sismofyt]

It's not your poor english, it's my confusion of the G numbers

 

[Jazzy_Pidjay]

hmm...

Jakob say in the Gyraf web site :

" a Lundahl LL1538 microphone input transformer, here used the "wrong" way around, converting the 15K output impedance of the tube into more useable 600R, and so driving the cable and your microphone preamp with low impedance. "

so, if the lundahl transform 15k output impedance to 600R

how to know the value of the OEP output ???

if it's not 600R, what the consequence to the sound ? :roll:

 

[zebra50]

impedence ratio will be square of turns ratio... so a 1:5 transformer will give your 1:25.

15K divide 25 = 600

1:6.5 gives 1: 42 (near-as!)

15K divide 42 = 360 ohms.

 

[Jazzy_Pidjay]

and 360 Ohm

it's good for a mic output ?

 

[mcs]

[quote author="Jazzy_Pidjay"]and 360 Ohm

it's good for a mic output ?[/quote]
Why wouldn't it be? Most dynanic mics are in the 100-600 Ohm range.

Best regards,

Mikkel C. Simonsen

 

[Jazzy_Pidjay]

thanks :grin:

 

[dukasound]

Hi
Anyone has excatly explanation of transformers polarity on tube microphone (also in athode follover cicruit)?
Duka

 

[Jazzy_Pidjay]

so...

for the a262a3e in the G7

i put the A262A3e reverse and connect
the two "primary" together, like for the LL1538...

but do i connect the two "secondary" together ?

the LL1538 have only one secondary, so i don't know
what to do ??

thank u