mudihan said:
It is a very good buffer.
It has even got Cascoding with 2SC2240 and 2SA970.
You should be able to use some other JFET pairs, too.
2SK246 + 2SJ103 is not the easiest to find everywhere.
Here is link + The JFET Buffer Circuit as attachment.
http://cgi.ebay.co.uk/STEREO-FET-BU...12050QQcmdZViewItemQQ_trksidZp1742.m153.l1262
Attachments
Re: Re: Re: STEREO FET BUFFER on ebay
Great, Andy
If I could afford it and had some payment method for use in other country,
I would buy 10 pieces of that Audio Kit .. right way!!!
Such a good STEREO FET BUFFER with complementary 2SK246 / 2SJ103
is very useful, in many cases. When we are into diyaudio.
In UK the seller of this stuff at ebay is tubeshunter
http://stores.ebay.co.uk/tubeshunter
poynton said:
Great, AndyIf I could afford it and had some payment method for use in other country,
I would buy 10 pieces of that Audio Kit .. right way!!!
Such a good STEREO FET BUFFER with complementary 2SK246 / 2SJ103
is very useful, in many cases. When we are into diyaudio.
In UK the seller of this stuff at ebay is tubeshunter
http://stores.ebay.co.uk/tubeshunter
Ebay FET buffer
Has anyone tried one of these? Any comments on the schematic?
I've ordered one to try as a buffer after a pot (a la Pass B1).
The price is $9.99 plus $5 delivery to the UK
Has anyone tried one of these? Any comments on the schematic?
I've ordered one to try as a buffer after a pot (a la Pass B1).
An externally hosted image should be here but it was not working when we last tested it.
The price is $9.99 plus $5 delivery to the UK
The circuits are not quite identical, but there has been a bit of discussion on something similar here: http://www.diyaudio.com/forums/showthread.php?postid=1549507#post1549507
I received two of these buffers and installed one in my dac/preamp.
The system had been TDA1541A S1 > 2x LM49710 > 3.3uF Epcos MKV > 10K stepped attenuator > 75cm interconnect cables > UCD180HG (input cap bypassed).
I added the buffer after the stepped attenuator and a second pair of coupling caps after the buffer (if I don't have a DC offset after a few days I'll remove these caps).
My system had sounded very good before adding the buffer. As the UCDs have a 100K input impedance, I hadn't worried about using a 10K attenuator as a passive pre. After adding the buffer the sound became slightly richer with better resolved lower mids & upper bass. There is less HF sparkle, which I don't mind. Voices sound more real and everything seems a bit more solid and weighty. The slight loss in detail seems very acceptable given the increased body and real-ness of the the sound.
I ran the buffer from the same (over-spec'd) +15/-15V supplies feeding the opamps. I added a 22uF conductive polymer cap on each rail on each channel of the buffer.
Well worth a play for $10
The system had been TDA1541A S1 > 2x LM49710 > 3.3uF Epcos MKV > 10K stepped attenuator > 75cm interconnect cables > UCD180HG (input cap bypassed).
I added the buffer after the stepped attenuator and a second pair of coupling caps after the buffer (if I don't have a DC offset after a few days I'll remove these caps).
My system had sounded very good before adding the buffer. As the UCDs have a 100K input impedance, I hadn't worried about using a 10K attenuator as a passive pre. After adding the buffer the sound became slightly richer with better resolved lower mids & upper bass. There is less HF sparkle, which I don't mind. Voices sound more real and everything seems a bit more solid and weighty. The slight loss in detail seems very acceptable given the increased body and real-ness of the the sound.
I ran the buffer from the same (over-spec'd) +15/-15V supplies feeding the opamps. I added a 22uF conductive polymer cap on each rail on each channel of the buffer.
Well worth a play for $10
Re: Re: Re: Re: STEREO FET BUFFER on ebay
Good luck if you want to deal with this "tubeshunter". I have received half the part listed in one of its kits and after 2 months he does not even bother to respond to me anymore after using all kind of excuses. Finally I never got the missing parts and this seller is out of my list forever!
lineup said:
Good luck if you want to deal with this "tubeshunter". I have received half the part listed in one of its kits and after 2 months he does not even bother to respond to me anymore after using all kind of excuses. Finally I never got the missing parts and this seller is out of my list forever!
Re: Re: 2sc2240 & 2sa970
Sorry, I'm not understanding yet. Without bipolars those FETs are also in the same "constant voltage mode" as drains are connected to a voltage source, or not?!
Personaly, I'm thinking that this is not a cascode at all because is not used as intended. If you make good decoupling of the V+/- sources with some good capacitors, bipolars could be taken out with no problem.
Thanks.
Zen Mod said:
Sorry, I'm not understanding yet. Without bipolars those FETs are also in the same "constant voltage mode" as drains are connected to a voltage source, or not?!
Personaly, I'm thinking that this is not a cascode at all because is not used as intended. If you make good decoupling of the V+/- sources with some good capacitors, bipolars could be taken out with no problem.
Thanks.
Yeah, a little strange part choices; low noise bipolars for cascode, but no low noise jfets. I see it the same as Dorin, the cascode is of little use here. Also it seems - although the point in the schematic is missing - that the cascode is output-modulated for which I also don't see much reason here.
Nevertheless I don't see a reason why the buffer shouldn't perform well.
Have fun, Hannes
Nevertheless I don't see a reason why the buffer shouldn't perform well.
Have fun, Hannes
Hi All
Well just got the buffer today from china on a slow boat again I have been sent an updated version in that the board is now double sided now it seems to me that the screen print is wrong in the power supply pin ID from left to right -15volt 0v +15volts which seems the wrong way round plus the + 15v is connected to 0V
i have emailed the seller on this but he denies this and said the board is same as the old one and refuses the help this image is the old board the one I was expecting to get
And this is the new double sided board
And the underside of new board you can see that the -15volt connects both channels and the +15volt connects to ground
Here is the old schematic
can anyone help me get the supply wiring correct thanks
Well just got the buffer today from china on a slow boat again I have been sent an updated version in that the board is now double sided now it seems to me that the screen print is wrong in the power supply pin ID from left to right -15volt 0v +15volts which seems the wrong way round plus the + 15v is connected to 0V
i have emailed the seller on this but he denies this and said the board is same as the old one and refuses the help this image is the old board the one I was expecting to get
An externally hosted image should be here but it was not working when we last tested it.
And this is the new double sided board
An externally hosted image should be here but it was not working when we last tested it.
And the underside of new board you can see that the -15volt connects both channels and the +15volt connects to ground
An externally hosted image should be here but it was not working when we last tested it.
Here is the old schematic
An externally hosted image should be here but it was not working when we last tested it.
can anyone help me get the supply wiring correct thanks
Yep that’s the second time this seller has refused to help after he has been paid second change an all that he won’t get my money again that’s for sure
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