I'll try 'em & let you know the results.
Just to be clear on something...the Drain of Q1 sees the positive voltage rail, and the Source (and Gate) of Q2 sees the minus, correct?
I'm asking because of this sentence in Nelson's description of his circuit (Q101/201 is equivalent to Q2 in yours): "Q101 and Q201 are constant current sources formed by simply attaching the Gate pins of the JFETs to the Drain pins" (my emphasis). That's a typo, right? It should be the Source pins.
One more question...has anyone used this circuit as a buffer for a DAC's output? (Either voltage or current style) This is where I will probably try it (without the volume pot, of course)
Thanks!
Just to be clear on something...the Drain of Q1 sees the positive voltage rail, and the Source (and Gate) of Q2 sees the minus, correct?
I'm asking because of this sentence in Nelson's description of his circuit (Q101/201 is equivalent to Q2 in yours): "Q101 and Q201 are constant current sources formed by simply attaching the Gate pins of the JFETs to the Drain pins" (my emphasis). That's a typo, right? It should be the Source pins.
One more question...has anyone used this circuit as a buffer for a DAC's output? (Either voltage or current style) This is where I will probably try it (without the volume pot, of course)
Thanks!
Some types are 100% symmetric, others are nearly, depends on their internal geometry. The 2SKs will work both ways but slightly different as you can see I take advantage in the DCB1's regs, in the audio part tie G,S, of the Jfet that goes to -V. Looking at Nelson's schematic, should be a typo.
About moving the board closer to the back... I have tried to cram things into spaces too small in the past and won't likely do that again. Those leads are less than 2 inches. If 2 inches of Cardas or Tara Labs RSC is going to degrade the sound appreciably, we all have other issues to look into. like our heads.
Really don't sweat it, I say. In the end you won't hear it, and it will save you heart burn when you need to pull things apart to upgrade those parts in the future.
The sound of it has been well described in the past, but I am constantly amazed at how much better this is than the preamp I was running before. For less money and a little bit of effort this thing is a giant killer.
Thanks for the compliments on the box. Made from an antique dresser top that was on a free pile on the side of the road. Chestnut according to a friend. All I know is it was easy to work with, and took on a beautiful shade with a couple generous coats of tung oil. Also it smelled like old basement when I cut it. Oh well, now all that aged mildew and mold is encapsulated in a hard coat of oil.
I have now ordered up Takman resistors to replace the Dale Vishay's I used as well as the needed RCA's and a stepped attenuator. Should be even better when that stuff is done.
Really don't sweat it, I say. In the end you won't hear it, and it will save you heart burn when you need to pull things apart to upgrade those parts in the future.The sound of it has been well described in the past, but I am constantly amazed at how much better this is than the preamp I was running before. For less money and a little bit of effort this thing is a giant killer.
Thanks for the compliments on the box. Made from an antique dresser top that was on a free pile on the side of the road. Chestnut according to a friend. All I know is it was easy to work with, and took on a beautiful shade with a couple generous coats of tung oil. Also it smelled like old basement when I cut it. Oh well, now all that aged mildew and mold is encapsulated in a hard coat of oil.
I have now ordered up Takman resistors to replace the Dale Vishay's I used as well as the needed RCA's and a stepped attenuator. Should be even better when that stuff is done.
Hypnotize Production PCB
I just finished a Hypnotize build using the production pcb. It is playing music. Voltages are fine. DC offset is minimal. The music is already shockingly good.
I used final BOM parts where it was important. All connectors fit together. The TQ2-12V relay delay works just fine.
It seems that at least for the Hypnotize pcb nothing bad happened between prototype and production.
I just finished a Hypnotize build using the production pcb. It is playing music. Voltages are fine. DC offset is minimal. The music is already shockingly good.
I used final BOM parts where it was important. All connectors fit together. The TQ2-12V relay delay works just fine.
It seems that at least for the Hypnotize pcb nothing bad happened between prototype and production.
Grufti, good news, and Korben_69 did a great job on the BOM then. I think I can hear Tea-Bag's sigh of relief from the southern hemisphere (that the Hypno PCB's are good).
My proto build always sounded good from the start, but the last few days, or maybe last week, the sound has suddenly improved further, woo up there, sounds like even more detail, really clean. Very interesting and enjoying every bit of it. Maybe the burn-in time is longer than I expected, since there is a definite improvement on top of what was already very good.
My proto build always sounded good from the start, but the last few days, or maybe last week, the sound has suddenly improved further, woo up there, sounds like even more detail, really clean. Very interesting and enjoying every bit of it. Maybe the burn-in time is longer than I expected, since there is a definite improvement on top of what was already very good.
Try it with two BC550. My prototype Mez worked just fine with 12V relais and two BC550C.
You can always find and substitute a Darlington, if it doesn't work. The proto builders who ran into trouble heard "chatter" from the relay.
You can always find and substitute a Darlington, if it doesn't work. The proto builders who ran into trouble heard "chatter" from the relay.
Hi salas
I live also in Greece and I have some questions for your project
Can you email me at *****?
Thanks
manolis
I still think this chatter problem is not what you think it is.
I still believe you have suggested the wrong solution.
I await my boards and will experiment to try to replicate the "fault". I bet an extra capacitor will solve the imagined problem. There is space on the PCB for it. Just to the left of the resistor labeled "note". The extra cap will fit across the left end of the same "note resistor" and the -ve of the 100uF capacitor.
Add it to your schematic of the Hypnotize and you'll see I have referred to this cap in this and other threads.
If you get problems, its either addressed by the 100-150nF comp cap across c,b of the relay coil sink transistor, or use BC517.
Hi salas
I live also in Greece and I have some questions for your project
Can you email me at *****?
Thanks
manolis
Read the forums, ask here. There are 602 first round boards out there, you don't want me to have people telling me I give personal guidance and why not to all. I must be fair. Cheers.
P.S. No full emails online, there are spam mailbots scanning the web. Therefore I will take out yours, not to be exposed.
I think its due to marginal current gain of the coil NPN Andrew. Thus the 517 worked. But then again not sure, bcs I never got it in my build so to research.
I will certainly try
Someone talked about making some kind of assembling manual
I dont know, would it be possible to collect all the most important information/posts in some kind of file
Maybe not all at once, just bit by bit
Well, maybe I should just start reading thread again
Someone talked about making some kind of assembling manual
I dont know, would it be possible to collect all the most important information/posts in some kind of file
Maybe not all at once, just bit by bit
Well, maybe I should just start reading thread again
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