DA41 Push Pull Interesting design
- Paul Barker
- Social Sevices have been notified
- Posts: 8874
- Joined: Mon May 21, 2007 9:42 pm
#1 DA41 Push Pull Interesting design
A number of differences to what we do today.
they have bridged the transformer with a cap which raises the HF performance. Scott someone back in the day did a It 6em7 design with a cheap Allied interstage transformer bridged with a cap, but it was SE. first time I have seen it anywhere else.
Notice the 1,000v power supply. Very small cap, Choke input.
Note the AC heating of the DA41.
Added 300ohm in line with the primary IT windings to bias the CF drivers.
AC heating and minimal PS filtering? What were they thinking of?
From the data it is a valve that either has to be used in Class B push pull or permanently in A2 SE. the curves look more like Pentode.
I think this circuit would be great fun to build.
Shame the lack of transformers would prevent it. Can only dream.
A mere 175 watts.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
#2
this one?
there are quite a few interesting circuits in those old valve data books. I bought one of those CDs of old data books a few years back and I havn't seen a circuit on the net that can't be found in them....Thoroughly recommend buying one(the CD) if you see one advertised....about £5 for just about every data sheet ever published....
there are quite a few interesting circuits in those old valve data books. I bought one of those CDs of old data books a few years back and I havn't seen a circuit on the net that can't be found in them....Thoroughly recommend buying one(the CD) if you see one advertised....about £5 for just about every data sheet ever published....
There's nowhere you can be that isn't where you're meant to be
-
- Amstrad Tower of Power
- Posts: 10552
- Joined: Wed May 30, 2007 12:25 am
- Location: South Yorks.
#4
I have a pair of NOS Tungsram OT100/8005 transmitter triodes.
Their curves look like pentodes. It takes 1500V to get them out of class A2,
so obviously they are meant to be run A2 all the time.
I'll never use them (Gawd knows why I bought them)
Their curves look like pentodes. It takes 1500V to get them out of class A2,
so obviously they are meant to be run A2 all the time.
I'll never use them (Gawd knows why I bought them)
Sgt. Baker started talkin’ with a Bullhorn in his hand.
- Paul Barker
- Social Sevices have been notified
- Posts: 8874
- Joined: Mon May 21, 2007 9:42 pm
#5
Yes near enough.
Edit: meant for Phil.
Edit: meant for Phil.
Last edited by Paul Barker on Mon Apr 01, 2013 9:33 pm, edited 1 time in total.
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
- Paul Barker
- Social Sevices have been notified
- Posts: 8874
- Joined: Mon May 21, 2007 9:42 pm
#6
Yes near enough.pre65 wrote:Very similar to TZ40 ?
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
- Paul Barker
- Social Sevices have been notified
- Posts: 8874
- Joined: Mon May 21, 2007 9:42 pm
#7
Look quite interesting.SteveTheShadow wrote:I have a pair of NOS Tungsram OT100/8005 transmitter triodes.
Their curves look like pentodes. It takes 1500V to get them out of class A2,
so obviously they are meant to be run A2 all the time.
I'll never use them (Gawd knows why I bought them)
"Two things are infinite, the universe and human stupidity, and I am not yet completely sure about the universe." – Albert Einstein
-
- Amstrad Tower of Power
- Posts: 10552
- Joined: Wed May 30, 2007 12:25 am
- Location: South Yorks.
#8
Yes, they were used in the Mcintosh MI 200 amp.
I suspect the 200 nomenclature stands for 200W
I suspect the 200 nomenclature stands for 200W
Sgt. Baker started talkin’ with a Bullhorn in his hand.
- Mike H
- Amstrad Tower of Power
- Posts: 20157
- Joined: Sat Oct 04, 2008 5:38 pm
- Location: The Fens
- Contact:
#9 Re: DA41 Push Pull Interesting design
That looks like a very old (e.g. pre WW2) design like the Bavaria-Hunt DHT amp I've got circuits of, that used DA30's.
Given the period, what alternatives were there? Apart from batteriesPaul Barker wrote:AC heating and minimal PS filtering? What were they thinking of?
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."
- IslandPink
- Amstrad Tower of Power
- Posts: 10041
- Joined: Tue May 29, 2007 7:01 pm
- Location: Denbigh, N.Wales
#10
Many similarities to the 'Amity' really. DA41 must have plenty of gain . Choke-loaded cathode-followers - nice !
"Once you find out ... the Circumstances ; then you can go out"
- Mike H
- Amstrad Tower of Power
- Posts: 20157
- Joined: Sat Oct 04, 2008 5:38 pm
- Location: The Fens
- Contact:
#11
DA41 at National Valve Museum:
http://www.r-type.org/exhib/aaa1213.htm
"Sensibly equivalent to:- CV1076 - TZ40 - VT76"
http://www.r-type.org/exhib/aaa1213.htm
"Sensibly equivalent to:- CV1076 - TZ40 - VT76"
"No matter how fast light travels it finds that the darkness has always got there first, and is waiting for it."