Hi everyone,
I was wondering if someone of you could help me out with this one.
I am trying to design a phono stage based on some EC8010 triodes that I have lying around. I was told, that this would make a "wonderul phono stage" - the only problem I am having is that I cannot find anything on that on the web.
All I found was the article by Morgan Jones from his famous book, using EC8010 at the first stage together with some 6J5GT and 12B4A at the second and third stages.
Has anyone tried this setup? What is the sound like?
So far I am listening to a DIY Borbely phono stage using 6922 cascoded with 2SK369 and the sound is really good with my DL103.
I thought about doing a cascode of EC8010 plus a JFET (2SK170 or 2SK369 maybe) for MC (DL103) cartridge, but again, not really any designs about this out there.
Thomas Mayer from vinylsavor is saying that the EC8010 can be seen as "half" the EC8020, which is unobtainable, and that the EC8020 makes up great phono stages.
Could someone of you maybe enlighten me on how a EC8010 circuit might look like?
Thanks a lot!
poli
I was wondering if someone of you could help me out with this one.
I am trying to design a phono stage based on some EC8010 triodes that I have lying around. I was told, that this would make a "wonderul phono stage" - the only problem I am having is that I cannot find anything on that on the web.
All I found was the article by Morgan Jones from his famous book, using EC8010 at the first stage together with some 6J5GT and 12B4A at the second and third stages.
Has anyone tried this setup? What is the sound like?
So far I am listening to a DIY Borbely phono stage using 6922 cascoded with 2SK369 and the sound is really good with my DL103.
I thought about doing a cascode of EC8010 plus a JFET (2SK170 or 2SK369 maybe) for MC (DL103) cartridge, but again, not really any designs about this out there.
Thomas Mayer from vinylsavor is saying that the EC8010 can be seen as "half" the EC8020, which is unobtainable, and that the EC8020 makes up great phono stages.
Could someone of you maybe enlighten me on how a EC8010 circuit might look like?
Thanks a lot!
poli
I have built a few phono stages using EC8010, one design was EC8010 - composite riaa - 5842, and another was triode wired D3a - composite riaa - EC8010. in each case the first stage was biased with SiC Schottky on the cathode, and the 2nd stage with a AA battery on the grid.
If you like the Morgan Jones first stage, then just decide if you want to go split riaa with 2 low mu gain stages to follow, or composite riaa with one high gain stage to follow. If you go with the latter, try D3a or 5842 or EC8010 as the 2nd stage and you will be fine.
You WILL need grid stoppers, and possibly cathode stoppers and anode stoppers to avoid VHF oscillation. The EC8010 often sounds a bit thin, this tends to be when it is oscillating at radio frequencies.... it is v good at it
With oscillation addressed, it can make a really wonderful phono stage
If you like the Morgan Jones first stage, then just decide if you want to go split riaa with 2 low mu gain stages to follow, or composite riaa with one high gain stage to follow. If you go with the latter, try D3a or 5842 or EC8010 as the 2nd stage and you will be fine.
You WILL need grid stoppers, and possibly cathode stoppers and anode stoppers to avoid VHF oscillation. The EC8010 often sounds a bit thin, this tends to be when it is oscillating at radio frequencies.... it is v good at it
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An externally hosted image should be here but it was not working when we last tested it.
With oscillation addressed, it can make a really wonderful phono stage
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Thank you, guys! Really great answers!
Good idea about replacing the ECC83 with two EC8010 as well as the other designs you guys mention. I do have some D3a flying around as well because I wanted to try another phono stage setup by Stewart Yaniger, that he described in detail in this forum. I also sounds very promising, but I haven't tried it yet.
But I wanted to avoid the MC input transformers and rather go for some JFET/triode cascoding instead.
Thanks again guys!
poli
Good idea about replacing the ECC83 with two EC8010 as well as the other designs you guys mention. I do have some D3a flying around as well because I wanted to try another phono stage setup by Stewart Yaniger, that he described in detail in this forum. I also sounds very promising, but I haven't tried it yet.
But I wanted to avoid the MC input transformers and rather go for some JFET/triode cascoding instead.
Thanks again guys!
poli
Thanks, I built two like that.
the ptfe board has been repurposed from another design, hence selection of superfluous holes [emoji1]
6922 has very good heater noise rejection, much better then 12AU7.
I can use the 6.5v AC power from dial lights to power 6922 heater
the 12AU7 buzzed loudly.
DC heater power may be a necessity with the higher phono gain as frequencies below 120hz have the full 50db - 60db gain applied by the RIAA curve
I can use the 6.5v AC power from dial lights to power 6922 heater
the 12AU7 buzzed loudly.
DC heater power may be a necessity with the higher phono gain as frequencies below 120hz have the full 50db - 60db gain applied by the RIAA curve
I prefer the sound of ferrite beads but try cc resistors first from about 50R to 470R to see what sort of value works best, then try to replace with ferries offering similar RF impedance.
Also think about noise reduction and noise bypass on the heater supplies.
It is so layout depended it is v difficult to give specific recommendations.
Search through the forum and there a bunch of good posts, mainly discussing dealing with 5842, 417A and 6S45PI.
Best of luck
Also think about noise reduction and noise bypass on the heater supplies.
It is so layout depended it is v difficult to give specific recommendations.
Search through the forum and there a bunch of good posts, mainly discussing dealing with 5842, 417A and 6S45PI.
Best of luck
Hi,
I'm also interested in a phono stage with EC8010.
Please can you provide me your .asc file for sim ?
I would also like to try an input stage (first stage) with full triode (EC8010) cascode.
Does anyone have any suggestions?
Thank you.
Have a look at the ECC8100, one half is allmost the EC8010.
And not very expensive, round 13€ at AJZ (die-wuestens)
Mona
A quick reminder of the golden rule for gridstops on the control grids of triodes.
8/gm is the value I see quoted most often in the old text books.
Higher resistance than that gives no more protection. You may well get away with less or even no gridstop but good design says use gridstops on every triode stage and use that 8/gm value.
For 12AX7 that means 8/1.6mA/V =5K, at replace me now gm value (70%) of 1.12 mA/V then 7.14 K, I just use 10K.
For EC8010 (which BTW will NOT work in 12AX7 circuits without major changes) the gm is 24mA/V (15 times higher). Gridstops are more important for high gm tubes but paradoxically you need a smaller resistor. 8/24mA/V = 333 Ohms, you will usually see 300 Ohms in EC8010 circuits and that will do 99.9% of the time, for "Brute Force and Ignorance" design I usually indulge in, I would use 390 Ohms or even 470 Ohms - again, no point in going larger than that.
Cheers,
Ian
8/gm is the value I see quoted most often in the old text books.
Higher resistance than that gives no more protection. You may well get away with less or even no gridstop but good design says use gridstops on every triode stage and use that 8/gm value.
For 12AX7 that means 8/1.6mA/V =5K, at replace me now gm value (70%) of 1.12 mA/V then 7.14 K, I just use 10K.
For EC8010 (which BTW will NOT work in 12AX7 circuits without major changes) the gm is 24mA/V (15 times higher). Gridstops are more important for high gm tubes but paradoxically you need a smaller resistor. 8/24mA/V = 333 Ohms, you will usually see 300 Ohms in EC8010 circuits and that will do 99.9% of the time, for "Brute Force and Ignorance" design I usually indulge in, I would use 390 Ohms or even 470 Ohms - again, no point in going larger than that.
Cheers,
Ian
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Thank you very much ! Sorry but I dont know your exact name...
I see that in .asc file that you use 6C45P in first stage, indeeed EC8010 like seen in previous schematic.
What is your final triode choice for input stage ?
Do you have build this preamp ?
Thanks.
Regards.
No, long ago I decided for D3a-E180F (all in triode mode) RIAA preamp. Simply, I've easily come for these tubes.
Same preamp also DIYed Damir and wrote about it on another forum:
AudioRoundTable.com: Group Build >> RIAA preamp project
Best diying.
Same preamp also DIYed Damir and wrote about it on another forum:
AudioRoundTable.com: Group Build >> RIAA preamp project
Best diying.
Poli,
If you haven't started building yet you might also be interested in taking a look at using Rod Coleman's shunt cascode circuit with the EC8010. The circuit wants a higher GM tube and the 8010 fits. (I could say I recommend it but who in the world knows who is going to like what without comparing notes for a while first.)
I've built his shunt cascode circuit for phono before with the 7963 (submini close to 6DJ8) and recently the PC86 - both with and without the jFet front end pictured in the schematic. Both tube types needed stoppers and ferrites but under control it sounds really good! It's a great circuit.
Also, for the PC86, Rod's shunt reg driver experimenter's kit was used with step-up transformer at the input and the filter on perf-board on the out. The one I did on my own I also had to use my own shunt regulators for the transistor base control. Rod's board has one as part of the circuit which saved some effort.
The shunt cascode can simplify your tube lineup but on the other hand it can take more care in setting up with such high GM tubes.
The last couple of days I've been setting up a friend's old reel to reel to make digital copies of his tape which brings the thought that this circuit might be good for the playback on tape decks as well.
If you haven't started building yet you might also be interested in taking a look at using Rod Coleman's shunt cascode circuit with the EC8010. The circuit wants a higher GM tube and the 8010 fits. (I could say I recommend it but who in the world knows who is going to like what without comparing notes for a while first.)
I've built his shunt cascode circuit for phono before with the 7963 (submini close to 6DJ8) and recently the PC86 - both with and without the jFet front end pictured in the schematic. Both tube types needed stoppers and ferrites but under control it sounds really good! It's a great circuit.
Also, for the PC86, Rod's shunt reg driver experimenter's kit was used with step-up transformer at the input and the filter on perf-board on the out. The one I did on my own I also had to use my own shunt regulators for the transistor base control. Rod's board has one as part of the circuit which saved some effort.
The shunt cascode can simplify your tube lineup but on the other hand it can take more care in setting up with such high GM tubes.
The last couple of days I've been setting up a friend's old reel to reel to make digital copies of his tape which brings the thought that this circuit might be good for the playback on tape decks as well.
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Can you name a few of these books which say this?
(I have no argument; just never saw it put that way.)
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