R-Core has minimal stray field, not the toroid. The toroid is very offensive in same box with MC preamps for harmonic noise. Its most offensive side is the secondary wires exit area. I am pretty sure because I have tried those things together many times. It takes a grounded copper shield around it and/or a grounded ferromagnetic container to tame it if it must be in the same box. Maybe you talk encased toroids as low stray field?
I agree.... I have built some riaa amps with a r-core tx inside the case without trouble.... also did the same with toroids and could never get rid of induced noise... I could silence one channel but the other picked up like an antena.
Turning the toroids one against the other somehow minimizes the problem but never cures it alltogether.
Heavy screening is needed.
Anyway ... r-cores sound so much more effortless... it is incredible
What i wanted to say is that toroids have low stray field in one direction and high stray fields in other.
Anyway, i always put the transformers in a separate box anyway.
I use R-Core sometimes too and get them from Japan.
For my own builds i use Block Spit Bobbin. They are economical and work well.
As a said many times, i am not a great PSU builder, nevertheless i get my builds super quiet.
In September i plan a Paradise Fest at my home and then we can compare.
Anyway, i always put the transformers in a separate box anyway.
I use R-Core sometimes too and get them from Japan.
For my own builds i use Block Spit Bobbin. They are economical and work well.
As a said many times, i am not a great PSU builder, nevertheless i get my builds super quiet.
In September i plan a Paradise Fest at my home and then we can compare.
Split bobbin are a good economical solution if in different box. Because they make the primary/secondary separation. Its the right angled corners of the iron frame that still emit field VS the rounded R-Core. But the capacitance is lower VS the toroid that has the primary and secondary windings on top of eachother. Even the EI has plastic formers that provide some little separation. EI has its less stray field to its side by the way. Some EI are excellent for audio but need kept separate box for low signal high gain too. Heck, even the mains primary wires are offensive to a point. Best is two box far away, anyway.
Just placed an order for a pair of AN-0220 :
Antek - AN-0220
25VA - 2x20V - 4.096cm High - $40 shipped
Thank you Joachim about the hint concerning stray field.
Antek - AN-0220
25VA - 2x20V - 4.096cm High - $40 shipped
Thank you Joachim about the hint concerning stray field.
Just placed an order for a pair of AN-0220 :
Antek - AN-0220
25VA - 2x20V - 4.096cm High - $40 shipped
Thank you Joachim about the hint concerning stray field.
This is what I like, the correct voltage and slightly over powered
Put them in their own box, iron not aluminum or copper, and you will have adequate power. The boxed transformers may be placed in the same box as you paradise but then I would advise to box the paradise also, copper not aluminum or iron. Like here http://www.diyaudio.com/forums/anal...t-all-dc-coupled-riaa-preamp.html#post2163002 #4
AWG, what’s that? used for washing machines or locomotive’s?
AWG conversion table It seems a bit thin, but I like to oversize, 23 AWG (or 0.25 MM2) is to thin, use 1 MM2 (or 17 AWG) and thicker (for external wiring connecting the boxes).Or go extreem, use 4 times RG214
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Why didn't I think of that.
http://www.diyaudio.com/forums/soli...l-shielded-cable-input-wiring.html#post782635
Ricardo, when you do not have access to bigger sized cables you can run some in parallel.
By the way i have the Paradise R2 now on for some days constantly and it is very hot weather. Under this conditions the heatsinks get very hot, but not extreme.
Plus-Minus 30V in is still safe but a little less would be better. Under my condittions running the CCSs on more current is certainly not a good idea.
By the way i have the Paradise R2 now on for some days constantly and it is very hot weather. Under this conditions the heatsinks get very hot, but not extreme.
Plus-Minus 30V in is still safe but a little less would be better. Under my condittions running the CCSs on more current is certainly not a good idea.
That's handgun calibre coax.
It's what I use for my amplifier interconnects
http://communications.draka.com/sites/eu/Datasheets/hf27e.pdf
Thank you.. I will use double klotz
After some hours burning, everything is coming into place... detail is awesome but not overdone... there is harmony... voices are incredibly real... this build has real potential gentlemen.. just match the riaa caps between channels the best you can and use a preamp with double volume or a "balance" and reach paradise.
I use only a 25watt amp with monitors and can hear really deep bass.
This buil majors in diferentiation but in harmony...
Just a last question.. this is so promissing I am planning to demo it to a friend that uses a goldenote tuscany (0.15mV cart)
I must eliminate input offset... can I use a 20k trimpot with two 40k resistors (one on each side) instead of the usual 100k trimpot ?
I want to use vishay bulk metal trim pots and mouser only has 20k ones
I must eliminate input offset... can I use a 20k trimpot with two 40k resistors (one on each side) instead of the usual 100k trimpot ?
I want to use vishay bulk metal trim pots and mouser only has 20k ones
Thanks you Ricardo for this nice mini review. We will get more.
Just for learning, this is a mathematical analysis of a differential pair. I calculated my last Matrix over 30 years ago !The mathematical symmetry of the differential pair - ElectroYou
Just for learning, this is a mathematical analysis of a differential pair. I calculated my last Matrix over 30 years ago !The mathematical symmetry of the differential pair - ElectroYou
On the other hand a 0.15mV cartridge should also have a low DC impedance. That also lowers input offset. Your DENON103 with 40 Ohm creates more offset. DC offset in the Paradise can be calculated. It is the NON cancelled base current times the DC impedance to ground. Under an ideal situation the NPN and PNP transistors at the input have the same Ube and the same Hfe. Then the input would be on zero volt. The current that flows out of the NPNs flows exactly into the PNPs ( conventional notation, in fact the current flows from minus to plus ). In reality there is a small difference in Ube, say the NPN have 0.65V and the PNP have 0.6505V, that is a mismatch of 0.0005V. This value alone does not tell us the DC offset. We also need the DC impedance of the cartridge plus the ballast resistor in parallel. The Denon DL103 plus 1kOhm ballast resistor gives 40//1000 = 38.46 Ohm. With transistors of Hfe = 500 and an idle of 20mA
we have a base current of around 40uA. How much DC offset do we get if the Ube´s are mismatched by 0.5mV ? I think Hesener did the calculation. i am too tired at the moment. We simply can work backwards by putting a 50 Ohm resistor to ground at the input ( cartridge non connected ) and measure across that resistor. We can also now measure each transistors Ube ( 4 x positive/ 4 and 4 x negative / 4 ). The transistors Ubes appear in parallel per polarity. We have taken some measures so that the Ube difference remains small. One is to use the BC327 and 337 transistors. They are very symmetrical concerning Ube. The other is the rather high emitter degeneration resistors. They lower the amount of Ube mismatch by current feedback. That works this way : the un linear Ube diode ( between base and emitter ) gets a series resistor.
That series connection of Ube diode plus emitter resistor makes the whole chain more resistive.
we have a base current of around 40uA. How much DC offset do we get if the Ube´s are mismatched by 0.5mV ? I think Hesener did the calculation. i am too tired at the moment. We simply can work backwards by putting a 50 Ohm resistor to ground at the input ( cartridge non connected ) and measure across that resistor. We can also now measure each transistors Ube ( 4 x positive/ 4 and 4 x negative / 4 ). The transistors Ubes appear in parallel per polarity. We have taken some measures so that the Ube difference remains small. One is to use the BC327 and 337 transistors. They are very symmetrical concerning Ube. The other is the rather high emitter degeneration resistors. They lower the amount of Ube mismatch by current feedback. That works this way : the un linear Ube diode ( between base and emitter ) gets a series resistor.
That series connection of Ube diode plus emitter resistor makes the whole chain more resistive.