I have a variety of choices, fitting a range of applications and budgets.
That's great news. Hope those JFET's are not obsolete
.
Should I wait?
Is 15db gain enough to drive the MoFo (Mosfet-Follower) power amp?
F4 manual says 12db is enough for the F4. Do the MoFo and F4 follow the same drive rules/needs?
I just finished a BA-3 Pre and already looking for another preamp.
This needs to be categorized as a sickness. But, the mosfets-followers sound so much like the source before it.
The B1 with iron has 6 and 12db gain. Could it drive a MoFo?
Getting ahead of myself again.
Thanks,
Vince
if you use Edcor 600:15K , same as used in M2 , you can ......
I believe Iron Pre (from Store) will have that possibility too
addendum to my previous post ..... Edcor 600:15K is having (1+5) = 6V/V gain , which is 15.56db , somewhat lower in vivo .... closer to 15db
it'll be OK for better (by my book ) speakers ......... and anyway - you need that sort of speakers dealing with 25W amp
several preamps , shown around in last few years , are either already capable or tweakable to be capable of said swing and gain
Impasse for Bal F4 , BA3 FE for F4 , BA3 Bal FE for F4 Bal , I believe some of Juma's preamps are also capable of higher swing too ......
of course that I'm biased and I think that
is best 
I believe X1 is having eeeny output swing ...... though , X0 , practically being Babelfish of , is having much greater grunt on output
it'll be OK for better (by my book
) speakers ......... and anyway - you need that sort of speakers dealing with 25W ampseveral preamps , shown around in last few years , are either already capable or tweakable to be capable of said swing and gain
Impasse for Bal F4 , BA3 FE for F4 , BA3 Bal FE for F4 Bal , I believe some of Juma's preamps are also capable of higher swing too ......
of course that I'm biased and I think that
is best I believe X1 is having eeeny output swing ...... though , X0 ,
practically being Babelfish of , is having much greater grunt on output
You put 25k volume pot at the output and you have:
1. Preamp driven all the time to maximum swing (even clipping - depending on signal source's Vout)
2. High output impedance (6.25k at half of the pot's travel)
R6 sets the gain and Zout of the preamp, not the volume (its value has to be reasonably high or the preamp will distort, even be destroyed).
1. Preamp driven all the time to maximum swing (even clipping - depending on signal source's Vout)
2. High output impedance (6.25k at half of the pot's travel)
R6 sets the gain and Zout of the preamp, not the volume (its value has to be reasonably high or the preamp will distort, even be destroyed).
OK, thanks. So replacing R6 with a pot not a good idea...
Regarding 25k pot at the output:
1. My source output is about 1Vrms. That should not drive the preamp to clipping, am I right?
2. Output impedance can be decreased by something like B1 or DCB1 after the pot.
There are very rare situations where pot at the preamp's output isn't a bad idea and this is not one of them.
Many had the same idea before (do something differently from the mainstream, at any cost) but in the end it boils down to this (post #500) :
LSK pre - BAF 2013
I see that you are primarily interested to get a confirmation for your idea so go ahead, it's easy to try both (pot at the input and pot at the output) and keep what you like better.
Many had the same idea before (do something differently from the mainstream, at any cost) but in the end it boils down to this (post #500) :
LSK pre - BAF 2013
I see that you are primarily interested to get a confirmation for your idea so go ahead, it's easy to try both (pot at the input and pot at the output) and keep what you like better.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.