Good question. I just have full-range Mark Audio Alpair 10 speakers and the bass is rather weak anyway. The bass I get from the 26 is OK for me. I should maybe user a larger coupling cap than 0.2uF.
With my 10Y preamp I used two 126C in series, and this might be a better load for the 26. But a single one isn't bad. The sound is full and warm. It might sound more controlled with two in series. I could try that out later.
As for Sowter, I've never used them. There are no doubt many plate chokes that would sound good. The usual Sowter models don't have enough inductance for me. I once had a pair of Lundahl plate chokes, but I don't remember them as anything special. I would be interested in trying an amorphous core plate choke. I think that would make a difference.
I haven't done it yet, but I can try that. The 126C are bifilar wound and that may create problems, but I can see.
Can anyone talk about nickel versus amorphous core plate chokes? I'm curious. Dave Slagle has some discussion on his forums, preferring nickel.
I bought (from Norway) some 1:1 nickel interstages (42H, 125H, 130H, made by Dave).
Measured them with excellent results.
I will try larger ones in my 801 preamp.
Hehe...
I have a pair custom wound nano core 600H 10mA choke... with explicit HF slope. :-(
The Norwegian owner bought for him, and some years later sell its on ebay.
Made by a hungarian winder:
L: 620-640H (depends of squeezing);
DCR: 5800
Cp: 44pF
Tube: 841
Ip: 8mA
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The Hungarian winder wound a massive amount of turns with very thin wire with that very high DCR of 5800 ohm!
And quite some capacitance.
Apparently not interleaved as well.
The HF sloping has nothing to do with the core material; it would have happened with any core material used for audio purposes.
And quite some capacitance.
Apparently not interleaved as well.
The HF sloping has nothing to do with the core material; it would have happened with any core material used for audio purposes.
I am stuck with CCS loading.
Using difference core materials is I think similar to playing around with the second transistor of the CCS, except it is relatively cost-less in comparison.
My friend could not want to believe such a so cheap CCS can perform so well !!
He bought plate chokes for his 10 line amp from Monolith (amorphous, not nano); and they are staying there.
Using difference core materials is I think similar to playing around with the second transistor of the CCS, except it is relatively cost-less in comparison.
My friend could not want to believe such a so cheap CCS can perform so well !!
He bought plate chokes for his 10 line amp from Monolith (amorphous, not nano); and they are staying there.
CCS is cheap and effective, and I've had good results with Ale's gyrator. I'm just curious as to how good the sound can get with plate chokes. Just a question of exploring the frontiers, the way you do....
In about 2003, it was not exactly that I was unhappy with my fully modified Marantz 7 (and of course we did not have SSHV and SSLV boards at that time ), I came across the VT-52 web site.
After a couple months of studying and communicating, I had then decided against going along the path of using plate chokesssss in my DHT projectssssss.
Plate chokes are heavy, but they are not cheap to try.......and for me, they are just too expensive for me to make any mistake with, as a true DIY person I do not have the least personal knowledge to choose chokes except just from reading commercial writings.
I went along with resistor loading for years happily.......then I stumbled across CCS loading.....ME2....SSHV.....SSLV.....Rod Coleman's boards.....filament bias......
and the rest are histories !!!
(luck has a lot to do with where I have looked along the path....and I am very lucky to have stumbled across this DIYAUDIO site )
After a couple months of studying and communicating, I had then decided against going along the path of using plate chokesssss in my DHT projectssssss.
Plate chokes are heavy, but they are not cheap to try.......and for me, they are just too expensive for me to make any mistake with, as a true DIY person I do not have the least personal knowledge to choose chokes except just from reading commercial writings.
I went along with resistor loading for years happily.......then I stumbled across CCS loading.....ME2....SSHV.....SSLV.....Rod Coleman's boards.....filament bias......
and the rest are histories !!!
(luck has a lot to do with where I have looked along the path....and I am very lucky to have stumbled across this DIYAUDIO site )
I just tried out 3 line stages into my PSE 4P1L output stage with O'Netics OPTs.
1. 10Y into 2 x Hammond 126C used as plate choke, 0.2uF FT-2 coupling caps
2. 2P29L into a single 126C used as plate choke, 0.2uF FT-2 coupling caps
3. 26 ST shape into a single 126C used as plate choke, 0.2uF FT-2 coupling caps
The sound of the 126C remained a constant, though inductance was doubled for the 10Y. Given the basic resemblance in the sound, 2P29L was comfortably better than the 26 in terms of clarity, timbre and detail, so for me it would now replace the 26 as a line stage. The 10Y was better than the 2P29L by the same margin - again more clarity, timbre and detail. The 2P29L was closer to the 10Y in sound than to the 26. By "comfortably" better I'm probably talking something like 5%, i.e. quite audible in an immediate A-B swap on the same music, and significant enough to prefer one over the other. The music I used was vocal jazz, modern gospel and Solti's Wagner Gotterdammerung, start of Act 3 plus vocal trio. So a lot of voices and a variety of jazz, funk and full orchestral backing.
Conclusions:
- The 26 might have sounded a little better if I played around with a lot of tubes including globes, but previous experiments made me think the 2P29L was going beyond any 26.
- The 26 would probably sound better into 2 x 126L with more inductance, but again so might the 2P29L, though its lower plate resistance gives it an advantage into a single 126C.
- The 10Y had an unfair advantage in having twice the inductance. I didn't try it with a single 126C so can't comment on that.
- If you want a considerably cheaper version of a 10Y line stage, use a 2P29L which will give you quite a lot but not all of the 10Y sound. It's also cheaper to use a single 126C as plate choke, and in fact this makes for a very good and very cheap choice if you like plate chokes.
I think I'm pretty much done with the 26 on today's showing, and would go with 2P29L or 10y instead. I haven't tried the 01A with the 126C because 3mA isn't ideal for driving the output PSE 4P1L stage. The 26 was running at 6.5mA and the 2P29L at 15mA.
Next comes some experiments with other plate chokes, including using interstages with primary and secondary in series. I can try 126C and LL1660/18mA this way.
1. 10Y into 2 x Hammond 126C used as plate choke, 0.2uF FT-2 coupling caps
2. 2P29L into a single 126C used as plate choke, 0.2uF FT-2 coupling caps
3. 26 ST shape into a single 126C used as plate choke, 0.2uF FT-2 coupling caps
The sound of the 126C remained a constant, though inductance was doubled for the 10Y. Given the basic resemblance in the sound, 2P29L was comfortably better than the 26 in terms of clarity, timbre and detail, so for me it would now replace the 26 as a line stage. The 10Y was better than the 2P29L by the same margin - again more clarity, timbre and detail. The 2P29L was closer to the 10Y in sound than to the 26. By "comfortably" better I'm probably talking something like 5%, i.e. quite audible in an immediate A-B swap on the same music, and significant enough to prefer one over the other. The music I used was vocal jazz, modern gospel and Solti's Wagner Gotterdammerung, start of Act 3 plus vocal trio. So a lot of voices and a variety of jazz, funk and full orchestral backing.
Conclusions:
- The 26 might have sounded a little better if I played around with a lot of tubes including globes, but previous experiments made me think the 2P29L was going beyond any 26.
- The 26 would probably sound better into 2 x 126L with more inductance, but again so might the 2P29L, though its lower plate resistance gives it an advantage into a single 126C.
- The 10Y had an unfair advantage in having twice the inductance. I didn't try it with a single 126C so can't comment on that.
- If you want a considerably cheaper version of a 10Y line stage, use a 2P29L which will give you quite a lot but not all of the 10Y sound. It's also cheaper to use a single 126C as plate choke, and in fact this makes for a very good and very cheap choice if you like plate chokes.
I think I'm pretty much done with the 26 on today's showing, and would go with 2P29L or 10y instead. I haven't tried the 01A with the 126C because 3mA isn't ideal for driving the output PSE 4P1L stage. The 26 was running at 6.5mA and the 2P29L at 15mA.
Next comes some experiments with other plate chokes, including using interstages with primary and secondary in series. I can try 126C and LL1660/18mA this way.
Certainly - here's 2 versions. The lower voltage one is what I have now. The higher voltage one is an operating point I may try in future.
And now to clear up the mystery of "does the 126C work as a plate choke with primary and secondary in series". The short answer is no, as Dave Slagle predicted on Audio Asylum specifically for bifilar wound transformers like the 126C. He predicted a very audible treble cut, and that's exactly what we get, so can't be used. However, Pieter is of course right in pointing out this option with conventionally wound interstages, so I'll try it with the LL1660. For the record the 126C for the series experiment was connected blue to anode, brown to black, and green to HT - it only works that way round. I normally connect blue to anode, brown to HT and don't use green and black.
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