that fits with:
Attenuate interference at source.
It may also be the reason for the stringent regulations on EMI which are requiring all manufacturers to minimise interference from the source.
Thanks Andrew,
but I don't like the case of these, and I search for a JFET with Gfs > 30mS. Any equivalent for i.e. an ZVP3306 in N-Channel version or any other suggestions?
Yes it's a MOSFET but I don't compare it with a JFET, I only used it as example for the data Gfs etc... so, any suggestion?
Help Desk
Hello Salas,
Let’s see if I have this correct? 2N5459 Q7 in the DT CCT sets the current for the LED string and should be somewhere between 5 and 6 ma Idss. Matching the BC550C’s is not critical.
I tested 100 2N5459’s they all fall between 6 and 8ma most are very close to 7ma Idss. This is too high for the target 5 to 6 ma. Will 5.4 ma 2sk170GR’s work for setting the current for the LED string.
Still waiting for RIAA capacitors to arrive.
DT
All just for fun!
Hello Salas,
Let’s see if I have this correct? 2N5459 Q7 in the DT CCT sets the current for the LED string and should be somewhere between 5 and 6 ma Idss. Matching the BC550C’s is not critical.
I tested 100 2N5459’s they all fall between 6 and 8ma most are very close to 7ma Idss. This is too high for the target 5 to 6 ma. Will 5.4 ma 2sk170GR’s work for setting the current for the LED string.
Still waiting for RIAA capacitors to arrive.
DT
All just for fun!
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I prefer the 5459 due to more Vpinch, plays a role. But possibly academic after the filtering. The thing to do is make your 5459s of choice G&S and feed a 3 green leds string on the breadboard. See the total Vf across the leds, match another triplet. Use 15V B+.You got headroom to bias the cascode's base a little high in yours, helps. BC550s just keep them same hfe zone 5-10%.
Hello Salas,
5459’s it is. I located a test / calculation procedure for matching BC550C hfe at Transistor matching
Thank you for the LED testing procedure. I like the actual 5459 to be included in the CCT being used to select the LED’s
DT
All Just for fun!
Mundorf Silver Gold Oil are really a word apart: is not coarse like teflons, is not harsh like silver, is delicated when needed & strong too also when needed, it is very very tridimensional & transparent, do a sound that never tires, is a whole change not only like other caps that seems more transparent or things like this, if a resume in only one word I say: native sound
Mine advice: buys without doubting it if you can afford & enjoy.
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Now that WAF is much improved, see attached before and after, I can continue with the v1.2 build....
Not an optimal set-up yet since my media room is under construction and will be for some time. But is much better than before..
The Salas RIAA fits perfectly under turntable.
Not an optimal set-up yet since my media room is under construction and will be for some time. But is much better than before..
The Salas RIAA fits perfectly under turntable.
Attachments
Hello
I have picked the lowest Idss pair of 2N5459’s I could find, 6.6ma for Q7. I am thinking that R7 2.2K should be 1 watt maybe ½ watt not ¼ watt? I^2*R=watts. The other resistors look ok at ¼ watt.
Thank you Salas for tossing out the RIAA and B1 projects, they are food for thought. JFET’s are new for me to chew on.
I pulled out a copy of The Art of Electronics by Horowitz and Hill and getting up to speed on emitter followers, buffers, cascodes and the like. Transistor Man (Figure 2.5) is cool. Things like the wide range of Idss values for the same JFET is curious odd.
DT
All Just for Fun!
I have picked the lowest Idss pair of 2N5459’s I could find, 6.6ma for Q7. I am thinking that R7 2.2K should be 1 watt maybe ½ watt not ¼ watt? I^2*R=watts. The other resistors look ok at ¼ watt.
Thank you Salas for tossing out the RIAA and B1 projects, they are food for thought. JFET’s are new for me to chew on.
I pulled out a copy of The Art of Electronics by Horowitz and Hill and getting up to speed on emitter followers, buffers, cascodes and the like. Transistor Man (Figure 2.5) is cool. Things like the wide range of Idss values for the same JFET is curious odd.
DT
All Just for Fun!
Looks impressive, the arm is an original Schroeders? wich cart are you using? the base is Silestone or Corian?
Compared your TT vs ours TT, ours TT seems toys!!!!!
A little big the TV
The speakers are Proac future diy clons, wich drives & specs, how sounds?
About tube preamps are also diy, wich tubes, topology are you using?
Joaa,
My wife would be very un happy bringing in the boulder you have your turn table setting on. It would be the ultimate TT stand, however. Nice TT by the way;-)
Merlin,
The speakers are my own design based on my experience with Thiel's back in the days. Drivers are Scan Speak Revelators. I am very happy with the sound. "Quasi" first order crossovers. Very hard on the tweeter. +/- 2db down to about 32hZ. What is interesting and happened quite by accident is that they have a very nice impedance characteristics for tube amps.
The Preamp is a 12b4. CLCLC filter regulated by series 0D3. It is in flux right now. Currently using a ccs load with LED bias. I am very happy with sound of 12b4, however, they tend to be feedback prone and noisy. Currently using GE JANs. I have in the works several experimental boards to optimize the design and operating points including discrete CCS and a Gyrator load.
P.S. Am now only missing 2 resistors to complete the V1.2 Build. Mouser has an error in their online catalog. When ordering 0.49R resistors, they send 6.49R resistors. Made the mistake twice now. Should have remaining parts in Wednesday or Thursday.
My wife would be very un happy bringing in the boulder you have your turn table setting on. It would be the ultimate TT stand, however. Nice TT by the way;-)
Merlin,
The speakers are my own design based on my experience with Thiel's back in the days. Drivers are Scan Speak Revelators. I am very happy with the sound. "Quasi" first order crossovers. Very hard on the tweeter. +/- 2db down to about 32hZ. What is interesting and happened quite by accident is that they have a very nice impedance characteristics for tube amps.
The Preamp is a 12b4. CLCLC filter regulated by series 0D3. It is in flux right now. Currently using a ccs load with LED bias. I am very happy with sound of 12b4, however, they tend to be feedback prone and noisy. Currently using GE JANs. I have in the works several experimental boards to optimize the design and operating points including discrete CCS and a Gyrator load.
P.S. Am now only missing 2 resistors to complete the V1.2 Build. Mouser has an error in their online catalog. When ordering 0.49R resistors, they send 6.49R resistors. Made the mistake twice now. Should have remaining parts in Wednesday or Thursday.
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