I really wanted to build a push pull amp for myself. I tried it once and I posted it here, the design, if you can ever call it, was just pasted TubeCAD results. It did put out a sound and Wayne spent some time with me privately optimizing it. Thanks again Wayne.
I know that there is another EL34 PP amp project where Wayne is again involed, but that talk of CCS, long tail with negative supply, and all that parts, just doesn't inspire me. I'm lazy
I was browsing the Lundahl site when I saw this LL1660S SE to PP interstage transformer. I haven't made an interstage project yet! Yes!
The LL1660S Alt-B connection has max of 18mA and I suppose my favorite driver tube at 10mA load *and* LED bias will just be perfect.
I drew up this schematic on our whiteboard and took a pic.
I think I might have screwed up on the output tubes' cathode.
Do you guys think this will work?
I know that there is another EL34 PP amp project where Wayne is again involed, but that talk of CCS, long tail with negative supply, and all that parts, just doesn't inspire me. I'm lazy
I was browsing the Lundahl site when I saw this LL1660S SE to PP interstage transformer. I haven't made an interstage project yet! Yes!
The LL1660S Alt-B connection has max of 18mA and I suppose my favorite driver tube at 10mA load *and* LED bias will just be perfect.
I drew up this schematic on our whiteboard and took a pic.
I think I might have screwed up on the output tubes' cathode.
Do you guys think this will work?
Attachments
I finally prototyped this project 
Since I don't want to blow up my 417A/5842 tubes, I decided to use my Hitachi 6SN7 as the driver for the prototype, just to know whether this thing will sing or not. And it did
I wanted it to be a monoblock so I made separate power supplies in the same chassis. Here's what it looks like.
Since I don't want to blow up my 417A/5842 tubes, I decided to use my Hitachi 6SN7 as the driver for the prototype, just to know whether this thing will sing or not. And it did
I wanted it to be a monoblock so I made separate power supplies in the same chassis. Here's what it looks like.
Attachments
And this is the current schematic.
I'm using two orange LEDs to bias the paralleled 6SN7 driver. Currently my power transformer HV is low, as I haven't asked my winder to make a suitable one. The rectification is solid state and using a bridge W02M (warning! the W02M is rated *only* for 200V, do not do this even if I did ) to put out a B+ of around 280V. As I said, just want to know if this will put out a sound.
At this weird operating point, I'm surprised at the sound it does- smooth and heavy. The all important "tone" is good to pursue this project further. It does not sound like the ST-70 (note! personal bias here- I never liked the ST-70) or the push pull EL34 monoblock I was loaned before (sounds balsy and impressive at the start then becomes boring and fatiguing in the long run). I don't know if I should attribute the sonic to the LL1660S, as this is the first time I've heard this specific one.
Where would be the best place to put in a CCS?
I'm using two orange LEDs to bias the paralleled 6SN7 driver. Currently my power transformer HV is low, as I haven't asked my winder to make a suitable one. The rectification is solid state and using a bridge W02M (warning! the W02M is rated *only* for 200V, do not do this even if I did
) to put out a B+ of around 280V. As I said, just want to know if this will put out a sound.At this weird operating point, I'm surprised at the sound it does- smooth and heavy. The all important "tone" is good to pursue this project further. It does not sound like the ST-70 (note! personal bias here- I never liked the ST-70) or the push pull EL34 monoblock I was loaned before (sounds balsy and impressive at the start then becomes boring and fatiguing in the long run). I don't know if I should attribute the sonic to the LL1660S, as this is the first time I've heard this specific one.
Where would be the best place to put in a CCS?
Attachments
alex, the Lundahl 1660S will cost you some $200 so you compare that with tube phase splitter, it will be much higher. But it's your call. For me, I haven't done one like this, so there
jane, maybe so. My mind is still thinking 417A perhaps so the paralleled 6SN7 maybe getting more than what they need.
jane, maybe so. My mind is still thinking 417A perhaps so the paralleled 6SN7 maybe getting more than what they need.
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