valviac.com -> audio/diy ->
30somethang
(click photo to see pp-schematic - ~50kB)
( click to see the Power Zupply schematic ~ 50KB)
April, 2nd.
2007
Ever wondered why there are the UX4 sockets on the BaRBaR Chassis ???
I'm pretty sure that you now know why.
As I told already, my first "ZERIOUS" Line Amp was a copy
of Doede
Doumas DDPRE
(a 30 Tube in a mu-follower configuation).
Ever since I own 2 pairs of
30's - one pair of 230 Silvertone's and one pair of RCA 30's
and wanted
to know how they are going to sing in a LC-coupled configuration.
Bad newZ iZ: I burned the RCA's due to an error in the connection
of the current source for the heaters (:-(
(You know - one kind of the mistakes: May happen to anyone - dumbest first)
Really GOOD newZ iZ: after getting the circuit right,
the Silvertones really ZZZZZZZZANG.
The circuit is basically the "BaRBaR"
circuit, with the Ba's substituted by the 30's.
Don't know if they're
really same level - or if one can beat the other. I need to
"investigate" that..
Addendum April, 21st.
2007
The
1H4G won.
No really, the 1H4G is the octal-socket successor of the 30
established in the late 1930's.
The advantage of this tube is that it
is relatively cheap to get as NOS in the US.
So I ordered some for $5
each :-) and tried 'em.
I think that tube has the best price-performance
ratio of all tubes
I ever bought (griiiiiiiiiiiiiiiiin) especially with
the nowadays really
FAT EURO (griiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiin) it costs me less than €5 per tube incl. shipping.
And the sound is in my setup better than with the Ba.
New schematic version is 1.1. because the 1H4G needs other B+ than the 30.
Don't ask
me, I don't understand it.
The datasheets tell you that these tubes
are more or less identical beside of the capacitances.
Maybe that the root cause is that I always dealed with used 30's and the now installed 1H4G is NOS.
Have a nice weekend
v.
Feel free to contact
me, if you have any questions, suggestions, comments etc.