Hello,
i was hoping some of you out there could share your impressions and recommendations for some diy single ended triode projects (i am and have been using only solid state up to this point, but now have 96db efficient speakers, so i figure its time to try this route) . preferable not kits, but if you have run across a particularily outstanding (and hopefully not too expensive) kit, i'd be all ears to that as well. thanks.
i was hoping some of you out there could share your impressions and recommendations for some diy single ended triode projects (i am and have been using only solid state up to this point, but now have 96db efficient speakers, so i figure its time to try this route) . preferable not kits, but if you have run across a particularily outstanding (and hopefully not too expensive) kit, i'd be all ears to that as well. thanks.
If you have 96db speakers a 2A3 amp would suffice.
And as Joe Roberts said in his article in Sound Practices "I Never Met A 2A3 Amp I Didn't Like"
Many would agree. So do a search for 2a3 se amp and choose one.
Regards,
Bas
And as Joe Roberts said in his article in Sound Practices "I Never Met A 2A3 Amp I Didn't Like"
Many would agree. So do a search for 2a3 se amp and choose one.
Regards,
Bas
funny that you mention that as i was just about to add the postscript that solid state diy has left me somewhat miserly (i don't fancy for instance spending $4-500 on a pair of 300b's alone). so. . . actually any simple tube designs that anyone out there feels are a good introduction to the world of valves would be appreciated. (simple not only for ease of construction, but i still very much prefer the least amount of parts in the signal path) thanks.
A pair of matched Sovtek 2A3 from triodeelectronics will set you back $64.90
The Sovtek happen to be some of the best sounding as well...
🙂
The JE labs 2a3 is appertenly good sounding. Think it is a lot like the Sun Audio 2a3. Then there are ofcourse the kits from Welborne ...the DRD kits that are getting rave reviews..or at least a lot of happy owners...
The Sovtek happen to be some of the best sounding as well...
🙂
The JE labs 2a3 is appertenly good sounding. Think it is a lot like the Sun Audio 2a3. Then there are ofcourse the kits from Welborne ...the DRD kits that are getting rave reviews..or at least a lot of happy owners...
Hello,
There is an article on a DIY single ended pentode amp in the new issue of audioXpress. It is very simple and inexpensive; intended for a first time builder.
Mike L.
There is an article on a DIY single ended pentode amp in the new issue of audioXpress. It is very simple and inexpensive; intended for a first time builder.
Mike L.
Konnichiwa,
Well, looking at the other stuff further down, I'd recommend a 2A3/45 Amp. If yu carefully select the Mains transformer you could also later convert to 300B's.
I'd recommend (purely on other peoples comments at this time, but people who have compared) the James 6123-HS Output transformer as an affordable choice that can be used with 45, 2A3 & 300B Outputs.
If you use a Mainstransformer with 380V + 380V AC and at least 200mA DC plus several Heater windings (James should have one that matches the Outputs) plus a nice Filter Choke you would have the basics to make an RC/LC coupled 300B Stereo Amplifier or a DC coupled 2A3/45 Amplifier.
Start using the sovtek 2A3 (which is not much more expensive than most decent Pentodes/Tetrodes), Sovtek 5U4 or the like and russian 6S45PE or 6S4PE or WE417A/5842 or 6Z9P/6688/E180F triode connected as drivers in a DC coupled Circuit like that I recommended to Arnold Cruz on Audioasylum.com a while back and you will have an excellent little Amp.
(note - +B should read 468V!!!)
Audio Asylum Comments on Finished Amp
Audio Asylum Comments on the design reasoning
The Sovtek 2A3 will actually work as "pseudo 45" with a 5K load and will work VERY WELL under these conditions (and last to the next Iceage BTW) or you can change two resistors (the 5k1 to 3k1 and the 43R to around 27R) to acommodate the 2A3 with 60mA current and a 2k5 Load.
In fact, if you wanted to, you could make the Amp fully switchable, simply switch 8k2 in parallel with the 5k1 and switch the output transformer tap, then adjust the resistor marked 43 Ohm (which should be adjustable anyway) to establish the correct bias.
To use a 300B simply change the Amp to RC/LC coupled, self bias 1k cathode resistor and 3k5 or 5k load from the Output transformer with the 68uF & 22uF caps retained as is, suitable +B dropper for the Driver Valve and cathode RC combo.
Anyway, I hope this points you along a possible route to get something to have fun with for a long time.
Sayonara
jesserparker said:
Well, looking at the other stuff further down, I'd recommend a 2A3/45 Amp. If yu carefully select the Mains transformer you could also later convert to 300B's.
I'd recommend (purely on other peoples comments at this time, but people who have compared) the James 6123-HS Output transformer as an affordable choice that can be used with 45, 2A3 & 300B Outputs.
If you use a Mainstransformer with 380V + 380V AC and at least 200mA DC plus several Heater windings (James should have one that matches the Outputs) plus a nice Filter Choke you would have the basics to make an RC/LC coupled 300B Stereo Amplifier or a DC coupled 2A3/45 Amplifier.
Start using the sovtek 2A3 (which is not much more expensive than most decent Pentodes/Tetrodes), Sovtek 5U4 or the like and russian 6S45PE or 6S4PE or WE417A/5842 or 6Z9P/6688/E180F triode connected as drivers in a DC coupled Circuit like that I recommended to Arnold Cruz on Audioasylum.com a while back and you will have an excellent little Amp.
An externally hosted image should be here but it was not working when we last tested it.
(note - +B should read 468V!!!)
Audio Asylum Comments on Finished Amp
Audio Asylum Comments on the design reasoning
The Sovtek 2A3 will actually work as "pseudo 45" with a 5K load and will work VERY WELL under these conditions (and last to the next Iceage BTW) or you can change two resistors (the 5k1 to 3k1 and the 43R to around 27R) to acommodate the 2A3 with 60mA current and a 2k5 Load.
In fact, if you wanted to, you could make the Amp fully switchable, simply switch 8k2 in parallel with the 5k1 and switch the output transformer tap, then adjust the resistor marked 43 Ohm (which should be adjustable anyway) to establish the correct bias.
To use a 300B simply change the Amp to RC/LC coupled, self bias 1k cathode resistor and 3k5 or 5k load from the Output transformer with the 68uF & 22uF caps retained as is, suitable +B dropper for the Driver Valve and cathode RC combo.
Anyway, I hope this points you along a possible route to get something to have fun with for a long time.
Sayonara
2A3 schematic
This one works quite well and is fairly easy to build. Though not shown on the schematic, a 1K grid stopper right at the grid pins on the driver is highly recommended...
Roscoe's DC 2A3/45 amp
Peace
This one works quite well and is fairly easy to build. Though not shown on the schematic, a 1K grid stopper right at the grid pins on the driver is highly recommended...
Roscoe's DC 2A3/45 amp
Peace
I have been trying to build a good sounding single ended triode amp for a while, and have come to the conclusion that you need to drive it with something really grunty. Also a good power supply with a choke sounds better.
I have tried 1/2 6SL7, 1/2 6SN7, cascaded 6SN7 (300B driver!) 6SL7 SRPP (angela SRPP) and I am now using a 6SL7 cathode follower (angela easy 2A3)
I have found they are all too distorted except the cathode follower... It sounds a bit too "clean" and "dry" but it has details, slamming bass and a good amount of power. I found the other configurations were syrupy- great with vocals but a distinctive SET sound I wasn't too keen on.
There is a thread
on this.
However I am no expert, just an experimenter!
And the sovtek 2A3 (or the 6.3V version, 6B4G) is a good tube to use, but very dull to llook at. You can't see the glow! Maybe the Full music mesh plate 2A3 is more your style...
I have tried 1/2 6SL7, 1/2 6SN7, cascaded 6SN7 (300B driver!) 6SL7 SRPP (angela SRPP) and I am now using a 6SL7 cathode follower (angela easy 2A3)
I have found they are all too distorted except the cathode follower... It sounds a bit too "clean" and "dry" but it has details, slamming bass and a good amount of power. I found the other configurations were syrupy- great with vocals but a distinctive SET sound I wasn't too keen on.
There is a thread
on this.
However I am no expert, just an experimenter!
And the sovtek 2A3 (or the 6.3V version, 6B4G) is a good tube to use, but very dull to llook at. You can't see the glow! Maybe the Full music mesh plate 2A3 is more your style...
Based on advice from members on this forum, I changed the driver for my 2A3 from a 6SL7 SRPP (Angela) to a CCS loaded ECC99 running at 20mA. I think it made a pretty significant improvement to the sound.
Sorry, I don't have a schematic handy, or any way to easily draw one. Here's a description, starting from the top (B+) to the bottom (ground), if that helps.
B+: 300 - 320V
CCS load set for 20mA, I used a Bottlehead C4S
ECC99 (plate), capacitor coupled to the 2A3 grid
Under the ECC99 cathode I've had the required resistor (bypassed) to get 4V at the grid with 20mA current. I replaced that with a NiMH battery, and that's what I'm using now. The +ve of the battery goes to the cathode, -ve goes to ground. I got my batteries from Radio Shack (cordless phone rechargables, 3.6V nominal, 4.1V fully charged), make sure their AH rating is high enough to be able to handle the steady state DC current through them.
Hope that helps.
B+: 300 - 320V
CCS load set for 20mA, I used a Bottlehead C4S
ECC99 (plate), capacitor coupled to the 2A3 grid
Under the ECC99 cathode I've had the required resistor (bypassed) to get 4V at the grid with 20mA current. I replaced that with a NiMH battery, and that's what I'm using now. The +ve of the battery goes to the cathode, -ve goes to ground. I got my batteries from Radio Shack (cordless phone rechargables, 3.6V nominal, 4.1V fully charged), make sure their AH rating is high enough to be able to handle the steady state DC current through them.
Hope that helps.
AKSA said:
Are you referring to something like the Erno Borbley 15W SE amp? I have been curious about that.
Hi,
B+ 200VDC
Vg- 80VDC
Zprim ~ 600 Ohm
Should sound great, needs grunty driver to overcome Miller capacitance.
SOME SOURCES OF INSPIRATION.
Cheers,😉
B+ 200VDC
Vg- 80VDC
Zprim ~ 600 Ohm
Should sound great, needs grunty driver to overcome Miller capacitance.
SOME SOURCES OF INSPIRATION.
Cheers,😉
Hi Frank,
Thanks a lot...
They seem to rave about them in Stereophile. Is this good or bad?
I was thinking of a 6BX7 driver, with rp around 1K3. I've ordered some at $US8 each.
B+, recommended by Alex Adrianov in Kiev, is 320V, 200mA, 85V of cathode bias. This is 235V across the tube, and 47W of dissipation, with max at 60W, so running at 78%, should last well, particularly if socket is raised for ventilation. They say a bit of pencil graphite rubbed on the pins prevents the filament current starvation which is the bane of these tubes.
I was thinking of a 1K:8R transformer to reduce H2/3 to the minimum. With increased voltage at B+ I should still get a good 10W.
First stage is 6SN7.
Comments?
Cheers,
Hugh
Thanks a lot...
They seem to rave about them in Stereophile. Is this good or bad?
I was thinking of a 6BX7 driver, with rp around 1K3. I've ordered some at $US8 each.
B+, recommended by Alex Adrianov in Kiev, is 320V, 200mA, 85V of cathode bias. This is 235V across the tube, and 47W of dissipation, with max at 60W, so running at 78%, should last well, particularly if socket is raised for ventilation. They say a bit of pencil graphite rubbed on the pins prevents the filament current starvation which is the bane of these tubes.
I was thinking of a 1K:8R transformer to reduce H2/3 to the minimum. With increased voltage at B+ I should still get a good 10W.
First stage is 6SN7.
Comments?
Cheers,
Hugh
Hi,
Depends on what side of the fence you're sitting, I suppose.😉
A fellow member, 316A I think, once offered the following tip to prevent carbonised heater pins: when wiring up the heater connection at the socket, just wrap the wire around it a few times than solder it. This should provide for some extra metal surface to help pass current and keep things a tad cooler.
If it were for my own use, I'd find myself some NOS Johnson septar sockets. They're the most reliable I've ever used.
Hadn't heard the graphite trick before...I wonder how that actually works.
Sounds fine by me.
Cheers,😉
Depends on what side of the fence you're sitting, I suppose.😉
A fellow member, 316A I think, once offered the following tip to prevent carbonised heater pins: when wiring up the heater connection at the socket, just wrap the wire around it a few times than solder it. This should provide for some extra metal surface to help pass current and keep things a tad cooler.
If it were for my own use, I'd find myself some NOS Johnson septar sockets. They're the most reliable I've ever used.
Hadn't heard the graphite trick before...I wonder how that actually works.
Sounds fine by me.
Cheers,😉
fdegrove said:
Graphite is greasy and conducting plus it has an inverse temperature coefficient (becomes more conducting as it's heated).
Could that help reduce the hot spots, hi resistance spots on the socket/pin interface??
I'll try that on my 300W halogen lamp contacts.
As for the sonics of the 6C33 I would say a good mix between SS, SET. Still missing the energy of my PP 6550.
Runs on 235V, 200mA. Long time to burn in. The first 100 hours the bias comes after 30-40 minutes! After the burn in period 15 minutes are OK. Driver 6N1P.
A lot of HEAT that should be taken in to account seriously!
Runs on 235V, 200mA. Long time to burn in. The first 100 hours the bias comes after 30-40 minutes! After the burn in period 15 minutes are OK. Driver 6N1P.
A lot of HEAT that should be taken in to account seriously!
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