Some one knows if it is possible to apply the output stage of the Pass D1 to a CD player that it uses 4 BB pcm1702 in place of the BB pcm63?
The only difference between two me seems to be the output current that is 1,2 mA in place of 2 mA.
Thanks.
The only difference between two me seems to be the output current that is 1,2 mA in place of 2 mA.
Thanks.
i would expect it works, as it works also with AD1865
http://www.diyaudio.com/forums/showthread.php?postid=383625#post383625
http://www.diyaudio.com/forums/showthread.php?postid=383625#post383625
Hi,
Just scale R27 and R34 from original schematic to give you the wanted I/V conversion ratio :
2mA in 1K5 give you 3V FS, so use 2K5 for R27 & R34...
Just scale R27 and R34 from original schematic to give you the wanted I/V conversion ratio :
2mA in 1K5 give you 3V FS, so use 2K5 for R27 & R34...
Thanks guys.
To this point, if not mistake, task that they go replaced in agreement also cap.C15 and C16.
Still a question.
Thoughts that replacing ghi IRF 610 with of the MPV3306, or the 2sk389 can go the same one well? I ask, why of these transistors I have some in house already of the selected braces, therefore I would avoid to buy of others.
Thanks again.
To this point, if not mistake, task that they go replaced in agreement also cap.C15 and C16.
Still a question.
Thoughts that replacing ghi IRF 610 with of the MPV3306, or the 2sk389 can go the same one well? I ask, why of these transistors I have some in house already of the selected braces, therefore I would avoid to buy of others.
Thanks again.
pro said:
Oups ! Yes you're right, I just forgot about the LP filter.. Just recompute the cap's values accordingly 😉
Don't know the MPV3306. Same as Zetex' ZVN3306 ? If yes, it should work, but be careful about dissipation issues. I don't know either how it will sound with a 3306... Just test.
2SK289 should work too, but chose the right grade to withstand the bias current. In this case the gate voltage should be negative to achieve 0V at the source. Just check this thread for additionnal info :
http://www.diyaudio.com/forums/showthread.php?s=&threadid=34191
Hope this helps
One other question.
Because it's output will run in unbalanced mode, is a CCS needed in place of R26 and R33, or well therefore as it is.
Thanks.
Pro.
Because it's output will run in unbalanced mode, is a CCS needed in place of R26 and R33, or well therefore as it is.
Thanks.
Pro.
Works well as it is . CCS isn't necessary but you can try it . IMHO the CCS changes a little the sound character , and gives to it the sensation of more articulation, but very little.
I just tried the buffers with P-channel ZVP3306A and works fine.
I just tried the buffers with P-channel ZVP3306A and works fine.
The original D1 stage has a volume control between drains of Q3 and Q6 . I made a volume control by a chain of resistors 80R/160R/320R/640R/1,24k/2,49k/4,99k/10k each resistor with one relais that bypasses it when on.
Why is this volume control at the Drains of Q3/Q6 and what would be disadvantage to put it between the sources of Q2/Q5?
If i want more voltage, what about instead of Q2/Q5 source follower pair a differential pair like BZLS around Q3/Q6 ?
or would it be better to double all resistor values and use +-60V with the original circuit?
Why is this volume control at the Drains of Q3/Q6 and what would be disadvantage to put it between the sources of Q2/Q5?
If i want more voltage, what about instead of Q2/Q5 source follower pair a differential pair like BZLS around Q3/Q6 ?
or would it be better to double all resistor values and use +-60V with the original circuit?
till said:
I was looking for more voltage too.
I just tried - 2 days - the folded cascode , see the SuperSymmetry patent at
passlabs.com , and I am particulary enthusiast with the results , and more pleased than the source follower. I was suspecting that these dacs - 1541A in the case - was , soundwise , in need of more voltage swing and by listening it seems a correct finding.
I made it with ZVP3306A P-channel mosfet .Of course after the folded cascode is possible apply the buffer too.
Another BOSOZ gain stage is not going to deliver what you search for - probably.
Hi Stefano.
Have you a schematic for the 1541 D1 stage?
Actually I use passive I/V with a simple diy opamp made with a 2sk389 cascoded with 2n5486 and CCS always with 2n5486. The current is given by a zvn3306a with CCs 2n5486.
The all it seems to play much soft one and detailed at the same time.
I would like to try the active I/V.
Have you a schematic for the 1541 D1 stage?
Actually I use passive I/V with a simple diy opamp made with a 2sk389 cascoded with 2n5486 and CCS always with 2n5486. The current is given by a zvn3306a with CCs 2n5486.
The all it seems to play much soft one and detailed at the same time.
I would like to try the active I/V.
there are some circuits based on D1 stage but modified in the board, you only need to search them. The original circuit can be found at passlabs.com and will work with the TDA1541, as it does with the AD1865.
pro said:
I did not enjoy too much the passive I/V especially in the 1541A , a matter of taste , maybe .
I am enjoying the folded cascode a lot , instead . Spectacular , absolutely .😉
Hi,
I used the D1 DAC I/V stage on the PCM chip with the original resistors and caps. The output level is only a little lower than my cd player so I didn´t make any changes. I don´t have balanced out so I didn´t use the volume control that Nelson Pass has in the circuit.
I used the D1 DAC I/V stage on the PCM chip with the original resistors and caps. The output level is only a little lower than my cd player so I didn´t make any changes. I don´t have balanced out so I didn´t use the volume control that Nelson Pass has in the circuit.
Hi averybody.
I got it.
This is the folded cascode I/V with Zetec fets for my NONOS Philips CD582.
It seems to sound very dinamic with high frequency very smooth, deep and large soundstage. Really impresive.
The L/P filter is a second order and the two black tubes are full up aof silicon grease, so to stop the oscillation around the 0V of the folder fet.
Ciao.
I got it.
This is the folded cascode I/V with Zetec fets for my NONOS Philips CD582.
It seems to sound very dinamic with high frequency very smooth, deep and large soundstage. Really impresive.
The L/P filter is a second order and the two black tubes are full up aof silicon grease, so to stop the oscillation around the 0V of the folder fet.
Ciao.
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