After letting the reg settle for 15 mins and come up to temperature I measured:
Vout = 24.95 V
Vr4 = 56.0 mV
This is with the pres connected and open circuit audio inputs and outputs.
Also, I am using R4=10R as per the pdf schem.
The cabling to the MOSFETs are a product of having a tight layout, which I hadn't visualized as being quite so tight... I was planning on mounting them on sinks that run parallel to the board, using stand-offs to mount the sinks. What problems do I cause by having leads to the MOSFETs? Are there other components than the gate R's that I could mount directly on the Mos's to help?
Thanks.
Tani.
Substitute the Zener with a 4K3 1/2W resistor. Has a noise benefit VS normal quality non TC comp Zeners (usually unobtanium in low quantity, aerospace spec, expensive), and its audible in my experience, adding resolution. If it will not hit 25V exactly since my calculation with your local CCS current shows it should overshoot the stock 4K3 value a bit, either add a small trim value in series (68R maybe), or forget about it, no big deal. Let me know if you could hear this change.
You may be cutting some reg bandwidth because of the cable's inductance but you are lucky it did not oscillate. Thankfully its a tolerant design. The least length to Mosfet's gate and pin attached gate stopper are the only worthy parameters to take care of.
You may be cutting some reg bandwidth because of the cable's inductance but you are lucky it did not oscillate. Thankfully its a tolerant design. The least length to Mosfet's gate and pin attached gate stopper are the only worthy parameters to take care of.
Did you consider the Grado DJ carts? They are supposed to back cue, don't know how well they will scratch though. DJ pro fora must have more info about durability and uses. There is also an AT model that some say has some sonics and the durability ATP2-xN. Amazon bargain on the AT. I don't think they will handle anywhere near an ORT Nightclub E though.
Scratching is not an issue as it's not really my style and certainly not the style of this project... it'll be a rotary mixer without cross-fader, making fast cuts impossible.
I wasn't aware of the Grado carts and although I knew of the AT's, I didn't know that they were regarded highly. That offer from Amazon is good enough to get them and see for myself... thanks for the link.
I wasn't aware of the Grado carts and although I knew of the AT's, I didn't know that they were regarded highly. That offer from Amazon is good enough to get them and see for myself... thanks for the link.
If the Grados suffice must be the better ones for sonics. The AT has the better durability. Now with the trimmer stuff, maybe it can fair better than they think. Because the Grado has very low inductance and loads flatter on all mixers. Xone to Gemini it will come across as smoother easier.
Sorry Salas, I'm not following exactly. Given I can adjust the input loading with a trimmer, which do you think would be the best cart to try first? Are you recommending that more could be gotten from the AT due to the trimmer compared to the Grado? That is, the Grado won't react as much to input load changes due to it's lower inductance... ?
Yep, I say maybe the AT is better than they think by just slapping it on 47K mixers when the Grado has a benefit to shine easier. Its moving iron, not moving magnet, hence the low inductance. The AT is not for the DMC championship either but the Grado looks like taking only the odd back cue. The AT is certainly steadier.
P.S. Got to find trip mats! Way cool.
P.S. Got to find trip mats! Way cool.
Finally my phono is working like a charm. :-D I'm so happy and obligated.
I tried 15nF and after an additional 470pF but i dunno i need more hearing experience and some burning time for the components i guess. i have an r-core structured Tx with 4 pair wires and two of them in company provides ~37V so i can easily set Vout to DC 37V in shunt. I will measure voltage you asked for further biasing but i was impressed at least with the music i got. That is why i went to buy some good lp to our fleamarket. 50th anniversary with a lot of good stuff for cheap price.
Hence the week passed with listening.
Examining the phono pcb location and trying to rotate an move it , i find a place where i got only a very low hum. But after it will be on a box and grounded properly i hope hum will fall dead. Next is to make up a good collection of brand of capacitor for riaa stage and coupling caps and order it.
I will post further progress and measures that i will made.
Thanks for your (Salas and the Riaa troops
) help.
I tried 15nF and after an additional 470pF but i dunno i need more hearing experience and some burning time for the components i guess. i have an r-core structured Tx with 4 pair wires and two of them in company provides ~37V so i can easily set Vout to DC 37V in shunt. I will measure voltage you asked for further biasing but i was impressed at least with the music i got. That is why i went to buy some good lp to our fleamarket. 50th anniversary with a lot of good stuff for cheap price.
Hence the week passed with listening.
Examining the phono pcb location and trying to rotate an move it , i find a place where i got only a very low hum. But after it will be on a box and grounded properly i hope hum will fall dead. Next is to make up a good collection of brand of capacitor for riaa stage and coupling caps and order it.
I will post further progress and measures that i will made.
Thanks for your (Salas and the Riaa troops
) help.
Hi Salas,
At postin 4141 you calculates schematics for my Lyra dorian.
At the weekend i measured a lot of sk170bl and i thought of
building the circuit you postet in 4945 instead ´cause it´s simpler.
Will this work too? I think so.
I chose jfet-pairs as follows:
8,16/816
8,45/8,50
8,23/8,20
8,39/8,37
for Q7 and Q2 at PSU i´ll use 6,61 Pairs
Do you see any advantages or should i just stick with circuit from
4141?
And i measured like 30 3mm green LED´s. They are 1,99V each
Greetings Ulf
At postin 4141 you calculates schematics for my Lyra dorian.
At the weekend i measured a lot of sk170bl and i thought of
building the circuit you postet in 4945 instead ´cause it´s simpler.
Will this work too? I think so.
I chose jfet-pairs as follows:
8,16/816
8,45/8,50
8,23/8,20
8,39/8,37
for Q7 and Q2 at PSU i´ll use 6,61 Pairs
Do you see any advantages or should i just stick with circuit from
4141?
And i measured like 30 3mm green LED´s. They are 1,99V each
Greetings Ulf
Hi Salas,
you´re to kind...thanks. But still some questions.
Okay, i´ll stay with circuit 4141 for 6,61mA fets.
Will the 8,16mA pair be a good match for Q7?
Do i need any matching for bc550c?
Should i stay with the PSU you recommended in posting 4141?
Cause the psu at 4945 is slightly different what about use of Q2.
BF245A instead of 2sk170gr 2,94 and 2,98mA IDSS at PSU 4141?
As i understand, shunt reg (with irfp9540) has to be as close as
possible to the circuit. What about the CCS (irfp9510) part?
hopefully last question: how many VA for the transformer?
Greetings and thanks a lot
ulf
And...do you have a picture of PCB downside from Picture at Posting 4628?
you´re to kind...thanks. But still some questions.
Okay, i´ll stay with circuit 4141 for 6,61mA fets.
Will the 8,16mA pair be a good match for Q7?
Do i need any matching for bc550c?
Should i stay with the PSU you recommended in posting 4141?
Cause the psu at 4945 is slightly different what about use of Q2.
BF245A instead of 2sk170gr 2,94 and 2,98mA IDSS at PSU 4141?
As i understand, shunt reg (with irfp9540) has to be as close as
possible to the circuit. What about the CCS (irfp9510) part?
hopefully last question: how many VA for the transformer?
Greetings and thanks a lot
ulf
And...do you have a picture of PCB downside from Picture at Posting 4628?
Yes it can be good for Q7.
+/- 20 hfe between channels will suffice as for 550C.
Yes stay with that PSU, BF245A is there on the general because of dissipation its going to impose on its BJT underneath when over 40V, yours is 36V, hence less total dissipation and more mA from 2SK load is beneficial.
There is 4 wire remote sensing depicted, if you are not to use it, only then the shunt portion has to be near the consumption nodes. The reg must be tightly laid out as a whole though.
50VA.
Photo from a doubled Jfet 58dB (4628). The little caps and one resistor are to bring some values to 100% nominal & matching. The whole phono is 100% matched everywhere. Active & passive parts, plus THD, Riaa curves and gain. Much work, crazy left over volume for Jfets and Riaa caps.
+/- 20 hfe between channels will suffice as for 550C.
Yes stay with that PSU, BF245A is there on the general because of dissipation its going to impose on its BJT underneath when over 40V, yours is 36V, hence less total dissipation and more mA from 2SK load is beneficial.
There is 4 wire remote sensing depicted, if you are not to use it, only then the shunt portion has to be near the consumption nodes. The reg must be tightly laid out as a whole though.
50VA.
Photo from a doubled Jfet 58dB (4628). The little caps and one resistor are to bring some values to 100% nominal & matching. The whole phono is 100% matched everywhere. Active & passive parts, plus THD, Riaa curves and gain. Much work, crazy left over volume for Jfets and Riaa caps.
