after some discussions on another thread i think that making an integrated amp might be what might suit me after all. however since i need 4 channels of power (2 channels of EL 34 per stereo channel) i am looking for a cicuit with a low part count to keep the amp simple and as compact as such an amp can be.
post 12 on the link below crystallises what has been done so far.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=68850&perpage=10&highlight=&pagenumber=2
in short this amp will be a stereo amp but with a Low Pass Speaker Output and a High Pass Speaker Output.
any ideas? my goal is to manage with just 1 power transformer, 4 OPTs, 2 power tubes per channel and 2 more tubes (for the Low Pass/High Pass - Driver stage) per channel and use a SS current sink.
post 12 on the link below crystallises what has been done so far.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=68850&perpage=10&highlight=&pagenumber=2
in short this amp will be a stereo amp but with a Low Pass Speaker Output and a High Pass Speaker Output.
any ideas? my goal is to manage with just 1 power transformer, 4 OPTs, 2 power tubes per channel and 2 more tubes (for the Low Pass/High Pass - Driver stage) per channel and use a SS current sink.
Does this help?:
http://www.diyaudio.com/forums/showthread.php?postid=779911#post779911
Upgraded with EL34s UL, Dynaco OT, I'd probably use a 12AT7 driver.
You could of course improve it in other ways.
Pete B.
http://www.diyaudio.com/forums/showthread.php?postid=779911#post779911
Upgraded with EL34s UL, Dynaco OT, I'd probably use a 12AT7 driver.
You could of course improve it in other ways.
Pete B.
navin said:
PB2 said:
that is wicked! cool-wicked! thanks!
replace the driver with a 12AT7? it could end up like this
http://www.bonavolta.ch/hobby/fr/audio/el34_10.htm
but this other ckt looks simpler to me
http://www.bonavolta.ch/hobby/fr/audio/el34_9.htm
only question is how do we add a filter in this ckt.
with the ckt diagram you have shown it is more apparent.
thanks a lot.
what about this schematic?http://www.bonavolta.ch/hobby/fr/audio/el34_2.htm
it uses a 12AT7 driver and a 12AX7 input.
Can the 12AX7 be used a fitlered input instead?
it uses a 12AT7 driver and a 12AX7 input.
Can the 12AX7 be used a fitlered input instead?
I did find a tube crossver ckt but figured if I can do the same with the driver stage on my power amp i would save on the tube count and simplify thngs.
http://hififorever.diy.myrice.com/doc/diy_el34ae.htm
can the ckt above drive an EL34 PP power amp directly. maybe with a right tube used?
http://hififorever.diy.myrice.com/doc/diy_el34ae.htm
can the ckt above drive an EL34 PP power amp directly. maybe with a right tube used?
Your wecome,
This circuit below looks like something derived from the Kennedy site, the schematic style is even the same. It uses a 6 triode driver and is complex, and looks experimental, I would not use it:
This is essentially the common Dynaco topology, but with separate tubes for the pentode and triode stages. The Dynaco does it with a 7199 dual tube. Otherwise this looks like a good design, but I'd add a delay circuit to the HV. The first description of this circuit that I've seen was in Audio, "High Quality Dual Channel Amplifier" Jan 1956 - interesting that this article also covered passive filters for biamping. I don't know if Hafler had a prior implementation:
You could add passive XO filters. Depends on what type of filter your looking for.
This circuit below looks like something derived from the Kennedy site, the schematic style is even the same. It uses a 6 triode driver and is complex, and looks experimental, I would not use it:
navin said:
This is essentially the common Dynaco topology, but with separate tubes for the pentode and triode stages. The Dynaco does it with a 7199 dual tube. Otherwise this looks like a good design, but I'd add a delay circuit to the HV. The first description of this circuit that I've seen was in Audio, "High Quality Dual Channel Amplifier" Jan 1956 - interesting that this article also covered passive filters for biamping. I don't know if Hafler had a prior implementation:
You could add passive XO filters. Depends on what type of filter your looking for.
PB2 said:
I liked the simplicity of the EF86/ECC81 driver. If there is a ckt that is simpler I would like to see it too. Simple ckts usually sound better too. right?
Do you have the ckt with the 7199? I will look for the dynaco too ut figured you mgith have it handy.
I need about 12db/oct LP and HP filters. I could add line level pasive filters but i wonder why few others do. Anything wrong with it?
First let me say that at this point I might not use the 7199 because the price is going up, however there are new parts from Sovtek.
You ask about the quality, are you aware the all number tubes are usually higher grade designed for industrial and audio use? Tubes designed for audio usually have lower microphonics and hum, among other things.
Most of the common tubes with alpha-numeric numbers are lower grade TV tubes.
Are you aware that the 7025 is a high grade 12AX7?
RCA app note about the 7199:
http://www.triodeel.com/7199.htm
And this about the 5881:
http://www.ginko.de/user/franz.hamberger/roehren/e5881.html
Pete B.
You ask about the quality, are you aware the all number tubes are usually higher grade designed for industrial and audio use? Tubes designed for audio usually have lower microphonics and hum, among other things.
Most of the common tubes with alpha-numeric numbers are lower grade TV tubes.
Are you aware that the 7025 is a high grade 12AX7?
RCA app note about the 7199:
http://www.triodeel.com/7199.htm
And this about the 5881:
http://www.ginko.de/user/franz.hamberger/roehren/e5881.html
Pete B.
navin said:
As I understood you were trying to keep it simple since you wanted to build several channels. Most pentodes EF86, 12BY7 come one to a package and it seems that twin triodes will get you the most bang. 6SN7 is a big tube, your not going for a lot of power, 12AU7 is a better choice for medium mu from what I see you trying to do.
Here's a reprint of the Van A. mod for the Dynaco, I don't agree with all his points or all his logic but you might get some ideas. He adds a 6dB/oct filter in front and poorly chooses the -3dB points in my opinion but he gives the equations since your asking about filters:
http://www.enjoythemusic.com/magazine/manufacture/0902/
Pete B.
Here's a reprint of the Van A. mod for the Dynaco, I don't agree with all his points or all his logic but you might get some ideas. He adds a 6dB/oct filter in front and poorly chooses the -3dB points in my opinion but he gives the equations since your asking about filters:
http://www.enjoythemusic.com/magazine/manufacture/0902/
Pete B.
PB2 said:
thanks for that link.
meanwhile I have been looking at quit a few ckts. see link below.
http://www.diyaudio.com/forums/showthread.php?s=&threadid=69042&pagenumber=2
I understand that the 6SN7 is a big tube. so I was really hoping for something like the HIF 87 with either a 12AX7, ECC83, 6SL7 for the input.
BTW what do you think of Memmo Van Der Veen's EL34 ckts on his website and on piltron.com.
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