yup ; every path have it's own compromises .....
anyway - here is just as illustration - HK725 , discrete OP with Jfet input ;
possible to use whatever is in drawer
another option - Jfet XblahCSblah BOSOZ ......
again - choice for parts is ...... even BF245C , or my fave J309/310,,cascoded with any TO92/TO126/TO66 critter from drawer ........
I know that all these ideas needs optimisation .... but I'm lazy these days ;
anyway - here is just as illustration - HK725 , discrete OP with Jfet input ;
possible to use whatever is in drawer
another option - Jfet XblahCSblah BOSOZ ......
again - choice for parts is ...... even BF245C , or my fave J309/310,,cascoded with any TO92/TO126/TO66 critter from drawer ........
I know that all these ideas needs optimisation .... but I'm lazy these days ;
Attachments
juma said:(entering Michel Caine mode)
Parts count, old chap, parts count .....
(exiting Michel Caine mode)
You really like LTP, don't you ?
(not a big fan of D. Self type of circuits myself)
me likey there good old SN7 , PSU either shunt reg or without reg but with heavy bleed , da toob scorched with bias ........ with hard cathode degeneration ...... for F5 we don't need mucho gain
or same with both halves of 6DJ8 , with even more miliamps than 6SN7
or make few tricks with J310 :
first stage source resistor biased , then current mirrored drain to next vertical current mirror string .
output in a middle of string .
plenty muscles to drive even Zen amp ,not sissy F5 Jfet input
juma said:Here is another idea that I've been playing with. It's based on J. Broskie's Aikido tube design. I used FETs that are cheap and abundant.
--------
no P-channel FETs needed, and IMHO, it sounds good
Heve you ever tried using JFET like Tubes, but in SRPP arrangement ?
It uses almost the input stage of your posted circuit.
But Instead of upper NJFET is pure current source, CCS,
it should be coupled as SRPP ( Shunt Regulated Push Pull ).
SRPP is frequently used in Tube Preamplifier stages.
They are a kind of PUSH-PULL, but with two N-polarity devices.
Because of the similarity between JFEts and Valves
we can try Shunt Rgulated Push Pull for JFET, too.
See my Attachment of a line amplifier.
The bottom 2 tubes are in SRPP.
This gives lower distortion than using your circuit.
But only if you can find one SWEET SPOT, for Shunt Reg Push-Pull.
This sweet spot should be arranged and setup while condering The Load impedance as one parmeter.
At least this is what I read about it
Lineup
Attachments
No actually NOOOOO!
You do not have to read about it at all.
Just setup your circuit using 2 N-JFET and use the SRPP way.
Then you listen to the sound and compare.
Forget about reading all stuff !!!!
But be open to try all good ideas.
you may find a goldmine of nice things, if you are LUCKY
am I right or .. Zen Mod
Less reading and more learning by doing. Pleeeeeeeeeeeeeeeeeease
Bored by a rainy day I decided to try JFET-CCS-BOSOZ (schematics in attachment) as a preamp for F5. Yes, it has 1k Zout, but that's without significance when driving F5 (100k Zin).
2SK170 are of V type (12mA Idss). CCS gives 20mA. Gain is 6dB (2V/V).
+/- 18V PS is made from F5's PS by means of 7818 and 7918.
Output cap is 1uF MKP + 100nFMKS and it doesn't leave any imprint that I'm aware of.
Preamp is very neutral, nothing is changed in music presentation compared to F5 without preamp, signal is just amplified to level that drives F5 to full power.
I don't know if I like this preamp more than previous one, it's in nuances, so it will take more listening to make a decision. Anyway, circuit is simple, parts are easily obtainable, topology is nice, F5 is light load, it's simple enough to make it p2p, and this preamp sounds better than its' cousin with MOSFETs - what more could a man want to give it a try ?
2SK170 are of V type (12mA Idss). CCS gives 20mA. Gain is 6dB (2V/V).
+/- 18V PS is made from F5's PS by means of 7818 and 7918.
Output cap is 1uF MKP + 100nFMKS and it doesn't leave any imprint that I'm aware of.
Preamp is very neutral, nothing is changed in music presentation compared to F5 without preamp, signal is just amplified to level that drives F5 to full power.
I don't know if I like this preamp more than previous one, it's in nuances, so it will take more listening to make a decision. Anyway, circuit is simple, parts are easily obtainable, topology is nice, F5 is light load, it's simple enough to make it p2p, and this preamp sounds better than its' cousin with MOSFETs - what more could a man want to give it a try ?
Attachments
Oh, common guys, be serious about this. My ESLs sound like a Nokia without a preamp... (of course, if you listen to them over a mobile )
I know there are simpler solutions, but from a stupid's point of view, how about placing BOZ at input to get some gain and go with B1 after it. Then fit a selector between them and either use just the gain stage or just the buffer or use the buffer with added gain. Huh? Eighties recordings were made with a huge minus 12dB (early days of CD) and anything coming from the last couple of years has at least 6dB more gain added to it if not more... So, to avoid wasting the signal on the pot, just pass through the buffer or add some gain to Brothers in Arms...
)I know there are simpler solutions, but from a stupid's point of view, how about placing BOZ at input to get some gain and go with B1 after it. Then fit a selector between them and either use just the gain stage or just the buffer or use the buffer with added gain. Huh? Eighties recordings were made with a huge minus 12dB (early days of CD) and anything coming from the last couple of years has at least 6dB more gain added to it if not more... So, to avoid wasting the signal on the pot, just pass through the buffer or add some gain to Brothers in Arms...
juma said:
Smrcilo se nebo od Zemuna k'o da ce g....a da padaju
that's self-censorship, certainly
anyway - thunder was sommewhat faster than me - I have few hardware thingies ...... hm ....... "fused "
stein2 said:Oh, common guys, be serious about this. My ESLs sound like a Nokia without a preamp... (of course, if you listen to them over a mobile
I know there are simpler solutions, but from a stupid's point of view, how about placing BOZ at input to get some gain and go with B1 after it. Then fit a selector between them and either use just the gain stage or just the buffer or use the buffer with added gain. Huh? Eighties recordings were made with a huge minus 12dB (early days of CD) and anything coming from the last couple of years has at least 6dB more gain added to it if not more... So, to avoid wasting the signal on the pot, just pass through the buffer or add some gain to Brothers in Arms...
whazzat - serbo-hungarian forum
?you forgot to say that your cat-teasers are hybrids in fact ........... still without lower boxes
we can make any of two Juma's proposals - they're both good enough and - with proper PSU and implementations , more than just better than 95% of FiFi preamps ........
patience , my wackoo Stipan friend ......
juma said:
What, he plays a guitar or something...?
Neha...
OUaT "young Steiny" tried playing bass guitar and had a group called "The Drama!" but it turned out to be a "Tragedy" at the end, so, instead of making, he rather tries to enjoy listening...
Looking at a preamp simple yet efficient and not spoiling the virtues of the F5 plus making it capable of driving a pair of electrostatics with enough gain in the preamp stage. The pot itself simply isn't enough because it just wastes the already low output level of the CD303 and similar devices. F5 can easily push around the weenie FE126E in it's hybrid enclosure but for those there is the Stradivari SE with EL34's, the F5 has to be capable of providing enough rush to make the panels shiver if it's required. Just yesterday, I was trying to give some more volume to Vaya Con Dios when I realised that the pot was already turned all the way and the volume was low enough to be able to talk over the phone a few steps from the panels...
Edit: So, one question about this one: http://www.diyaudio.com/forums/attachment.php?s=&postid=1613044&stamp=1221762706
Do I have to match the SK170 to pairs for this... ?
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