I'm following along, as I also use the AKG sextette at home, and have an interest in this design.
jeff
jeff
Yeah, I didn't say "I don't like capacitors", it's more a statement of the complaints aired here frequently. OTL circuits aren't typically the place for capacitor-phobia.
Hi
I’ll wait a few more days and if there’s no more comments / changes or further recommendations I’ll start ordering the components.
Thanks everyone
Eric
I’ll wait a few more days and if there’s no more comments / changes or further recommendations I’ll start ordering the components.
Thanks everyone
Eric
I always love it when some people say that they do not like capacitors in the signal path.
I say, what are those B+ caps doing in the output stage loop?
How about the the self bias bypass cap?
How about the fixed bias supply caps?
They are all in the signal loop.
Bypass all of them with quality non-electrolytic caps, if you prefer to (I do not prefer).
I am not going to build my amplifiers with all non-electrolytic caps.
I do not have that kind of real estate on the chassis.
I do not have that kind of money $$$.
I gave up using interstage transformers years ago (my bad).
I used to use battery bias in series with the grid stopper resistor & gave that up years ago.
I am not going to complicate my amplifiers by using DC coupling all the way from input to output.
I use good quality non-electrolytic coupling caps.
Just my bad decision of how to build a [bad?] practical amplifier.
I say, what are those B+ caps doing in the output stage loop?
How about the the self bias bypass cap?
How about the fixed bias supply caps?
They are all in the signal loop.
Bypass all of them with quality non-electrolytic caps, if you prefer to (I do not prefer).
I am not going to build my amplifiers with all non-electrolytic caps.
I do not have that kind of real estate on the chassis.
I do not have that kind of money $$$.
I gave up using interstage transformers years ago (my bad).
I used to use battery bias in series with the grid stopper resistor & gave that up years ago.
I am not going to complicate my amplifiers by using DC coupling all the way from input to output.
I use good quality non-electrolytic coupling caps.
Just my bad decision of how to build a [bad?] practical amplifier.
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I've wanted to make a 6AS7 headphone amp since I started this hobby a year ago. All the audiophile hype around the Bottlehead Crack (essentially the same circuit) got me going back then into DIY, not wanting to just build kits. My first purchase was for 20 NOS GE 6AS7's which are still in the cabinet. Seeing this thread now I'll be building this one as well, so following along too.
Awesome
Looking forward to see your build. I like to take my time and really enjoy the building phase so I’m pretty sure we’ll see pictures of your finished product before mine...lol
BR
Eric
Hope it's ok, I've never managed to get into a build thread on the ground floor of the discussion. I'm always the schmuck trying to figure out a 3,000 post project thread years later spending two days figuring out what schematic to start with, then giving up! I'm not fast either but do have all the parts for this already.
Can the headphone output on this circuit be used as-is for a line level output? So this circuit can serve as either a headphone amp or a pre amp? I wanted to use a switched headphone jack where when you unplug the phones the signal will be routed to RCA jacks on the back, when you plug in the phones those jacks disconnect (or short).
Would I need to attenuate the headphone level down to be a 2v line level with a few resistors?
Would I need to attenuate the headphone level down to be a 2v line level with a few resistors?
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one reason to avoid electrolytics is limited life expectancy, especially in the hot environment of a tube amp or high current psu SS amp, but it can be designed around.
Member
Joined 2009
Paid Member
Hi
Can I have some recommendations for the 6SN7, I’ve never heard that tube. So far I’ve been happy using the 6N1P-EV on all my other amps
I would prefer not to go NOS as the price is too steep for me.
Thanks
Eric
Can I have some recommendations for the 6SN7, I’ve never heard that tube. So far I’ve been happy using the 6N1P-EV on all my other amps
I would prefer not to go NOS as the price is too steep for me.
Thanks
Eric
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Well I did some online research since I’ve never heard a 6SN7 and many reviewers consider the brand Sylvania as a great value vs price. I guess I’ll buy a Sylvania...lol
BR
Eric
BR
Eric
A balance control?
In planning for another headphone amp... In the past I've had bad experiences with head amps without a balance control when the tubes are slightly out of balance. So for this one I do want a balance control. Rod Elliot (Elliot Sound Products) has some great info but which one of these would you implement for this particular project? A simple single linear pot or a dual linear-dual-pot-center-balanced arrangement? I know there will be some loss, but this amp will be used with my DAC so its not like I need a whole lot of gain.
Your preference? Simple or Dual weighted (or something entirely different)?
In planning for another headphone amp... In the past I've had bad experiences with head amps without a balance control when the tubes are slightly out of balance. So for this one I do want a balance control. Rod Elliot (Elliot Sound Products) has some great info but which one of these would you implement for this particular project? A simple single linear pot or a dual linear-dual-pot-center-balanced arrangement? I know there will be some loss, but this amp will be used with my DAC so its not like I need a whole lot of gain.
Your preference? Simple or Dual weighted (or something entirely different)?
Attachments
When you say out of balance you mean that the gain from L and R are not the same?
I’ve never tried adding a balance control so I guess I won’t be able to help based on experience...
On my last tube amp I’ve used 2 mono log. pot., 1 pot per channel so once but channels play with the same output level I then leave it alone and use my phone to control the volume through my DAC.
BR
Eric
I’ve never tried adding a balance control so I guess I won’t be able to help based on experience...
On my last tube amp I’ve used 2 mono log. pot., 1 pot per channel so once but channels play with the same output level I then leave it alone and use my phone to control the volume through my DAC.
BR
Eric
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That plan does nothing if the source impedance is zero, and near-nothing for low source impedance.
It can make sense in some all-tube systems, but you need to think about it.
