Revamped the riaa filter.... replaced the 15n teflons by some small ICL, the russian polystyrenes (47n) replaced by the obbligato... simplified the resistors and now it really sings.
BTW, the russian polytyrenes are very good for bypassing "plain" mkp on the output and on the BiB vref.
BTW, the russian polytyrenes are very good for bypassing "plain" mkp on the output and on the BiB vref.
Only workable scheme is MM phono + pre-pre stage from the PDF versions. With those you can select direct to phono or through pre-pre. This is not a loop feedback phono so to can just set a loop gain switch for MM/MC with exactly the same PSU and 1st stage set-up. I.e. not behaving like a discrete op-amp.
I suggest any switch at the cartridge signal input will degrade the sound (compared to if it wasn't there). So if your gain is MM only (40dB), it's best to use a head amp or SUT before the phono stage.
However, if your gain is up around 55dB (as my phono stage is), this will be able to handle most LOMCs and also MMs ... you just have to turn your preamp volume control up more, for LOMCs. (I use both my 0.28mV Benz LP and my 4mV Grado Reference Reference1 with my 55db phono stage.)
Regards,
Andy
It can be also done by just defeating the MC pre-pre power rail while having a dedicated set of MM RCAs permanently connected to the next stage.
I did something like that for a friend (long ago)... my build had two pairs of inputs, one for high output MC ~ MM and another for very low output MC.
I used a sut instead of the prepre
I used a sut instead of the prepre
AIUI, having the 2 pairs of input RCAs (for HOMM & LOMC) means that the extra circuitry for the LOMC interacts with the circuit for the HOMM ... which is undesirable?
Sure, you may not have heard much of a difference - but, to do the comparison properly, you need to have 2 separate, almost identical phono stages inputting to your preamp ... one for the HOMM directly (without the extra gain stage for the LOMC), the other with the parallel LOMC inputs.
Regards,
Andy
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Dual inputs. one for MM and one for MC.
Then switch in the output of the MC pre-pre to the input of the MM.
Very few would have the need for a quickly swappable MC MM.
They may have two decks set up with alternative MC/MM. Two inputs would better suit this.
If one had only one deck and an arm that happened to suit both MM & MC, then a quickly swappable input is not required. A single input would suit this re-arrangement of the deck.
Then switch in the output of the MC pre-pre to the input of the MM.
Very few would have the need for a quickly swappable MC MM.
They may have two decks set up with alternative MC/MM. Two inputs would better suit this.
If one had only one deck and an arm that happened to suit both MM & MC, then a quickly swappable input is not required. A single input would suit this re-arrangement of the deck.
I am gathering parts for a new pair of V12R and I must choose between IRF9140 and IRF9240... appart from the voltage differences 100v to 200v, I see that 9140 have lower Ciss Coss and Crss.... is this benefitial for the folded ?
The irf240/9140 make a better complementary pair than either irf140/9140, or irf240/9240.
This is stated many times in this Forum.
But using a 9140 limits the supply rail voltages to +-50Vdc.
This is stated many times in this Forum.
But using a 9140 limits the supply rail voltages to +-50Vdc.
I really do not need a complementary pair here.
I will use IRF960 for the CCS and 9140 or 9240 for the shunt....
I will use IRF960 for the CCS and 9140 or 9240 for the shunt....
If you want or need similar performance from dual polarity supplies then complementary selection may be an important consideration.
For a single polarity supply, complements are completely irrelevant.
But others will already have learned why 9140 is maybe better than 9240.
For a single polarity supply, complements are completely irrelevant.
But others will already have learned why 9140 is maybe better than 9240.
Come on Andrew.... why others and not me ? I know 9140 is better but I do not really know why... is it faster ? On resistance is lower as well as capacitances but in this application what is relevant ?
HF performance at the shunting current is important.
If a 510 would take the heat then provided it can be stabilised then it is likely to perform better.
But so much around the circuits interact with other components and parameters that I cannot predict which combinations will perform at HF.
I think it is the HF performance of these Salas Regs that gives them the good results that we hear.
If a 510 would take the heat then provided it can be stabilised then it is likely to perform better.
But so much around the circuits interact with other components and parameters that I cannot predict which combinations will perform at HF.
I think it is the HF performance of these Salas Regs that gives them the good results that we hear.
Hehe... found it: http://www.diyaudio.com/forums/powe...-voltage-shunt-regulator-157.html#post1992251
And here it starts: http://www.diyaudio.com/forums/powe...-voltage-shunt-regulator-156.html#post1991947
So more gm and more current does it
And here it starts: http://www.diyaudio.com/forums/powe...-voltage-shunt-regulator-156.html#post1991947
So more gm and more current does it
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