No it isn't, line stage especially with zero gain is easy to make inaudible for hum.
The rcore I bought with two other units and the seller did combined shipping. The total cost for the unit ended up being about $53, an equivalent toroid with shipping would've run at least $25. I can always use transformers for other projects, so to me the "extra expense" was not that much, since I needed to buy a new transformer anyway. I don't think I've read anywhere in this thread that you should be spending extra money on a rcore, that was my personal choice, just like it was to change caps and resistors. I believe that's why it's diy, so you put into your equipment what you believe makes a difference, if it makes no difference then you are the wiser not to do that again! 
While encapsulated toroid are not too noisy and sounds very good I always prefer R-Cores for even lower noise, radiated field, better regulation and fuller sound.
My Selectronic 120VA R-Cores in the My_Ref loose only one volt under load Vs the 225VA Noratel toroid which looses more than 2V.
And the difference could be clearly heard: the 120VA R-Core sounds louder, fuller, more refined and absolutely silent.
My Selectronic 120VA R-Cores in the My_Ref loose only one volt under load Vs the 225VA Noratel toroid which looses more than 2V.
And the difference could be clearly heard: the 120VA R-Core sounds louder, fuller, more refined and absolutely silent.
Simple... you measure with a voltmeter (multimeter) AC voltage on secondaries not connected to load and after you connect them to load.
If I remember correctly this voltage variation is called transformer regulation.
Not transformer regulation.
That is defined as the [{measured output voltage on no load divided by the measured voltage when the secondary/ies are loaded with resistors to draw rated current for each winding (*)} - 1] * 100, when fed with the rated supply voltage.
If you measure the unloaded AC voltage while while connected to the rectifier and smoothing, you will get a reading very close to the unloaded condition.
The loaded AC voltage as you described cannot be the rated output voltage, it is feeding a capacitor input filter.
In addition, to get a fair comparison for the test you suggest both transformers should start with specification for equal regulation. I would suggest that the VA should also be equal to make the test comparison more valid.
(*) where the secondary total VA, is more than the maximum rated VA the current in each secondary should be reduced as specified by the manufacturer so that total draw during test does not exceed the rated maximum output VA.
eg, two secondaries each rated at 5Aac and 50Vac with a transformer that is rated as 350VA is permitted. Each secondary alone can supply 250VA while the total VA draw at any moment does not exceed the maximum transformer VA. i.e. one winding can supply 2Aac the other 5Aac and still operate within specification.
That is defined as the [{measured output voltage on no load divided by the measured voltage when the secondary/ies are loaded with resistors to draw rated current for each winding (*)} - 1] * 100, when fed with the rated supply voltage.
If you measure the unloaded AC voltage while while connected to the rectifier and smoothing, you will get a reading very close to the unloaded condition.
The loaded AC voltage as you described cannot be the rated output voltage, it is feeding a capacitor input filter.
In addition, to get a fair comparison for the test you suggest both transformers should start with specification for equal regulation. I would suggest that the VA should also be equal to make the test comparison more valid.
(*) where the secondary total VA, is more than the maximum rated VA the current in each secondary should be reduced as specified by the manufacturer so that total draw during test does not exceed the rated maximum output VA.
eg, two secondaries each rated at 5Aac and 50Vac with a transformer that is rated as 350VA is permitted. Each secondary alone can supply 250VA while the total VA draw at any moment does not exceed the maximum transformer VA. i.e. one winding can supply 2Aac the other 5Aac and still operate within specification.
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Thanks Andrew for the clarification.
Probably you're right on how to make a more fair comparison, nevertheless the fact an inferior VA rated R-Core seems to perform better than an higher rated Toroid is a possible hint of R-Core superiority.
Both, or you misread the scale? Else its too much offset if all is correctly done on first look. Are the Jfets certified originals?
hi, i think i should post my question here.
i have my DCB1 runs normal for a long time, but suddenly some problem happen on positive side: the resistor at 2x68r is so hot that cannot be touch and the 3 leds has very small light
It is no problem on the negative side and the output voltage was normal at +10.3v / -10.6v
what may be wrong?
i have my DCB1 runs normal for a long time, but suddenly some problem happen on positive side: the resistor at 2x68r is so hot that cannot be touch and the 3 leds has very small light
It is no problem on the negative side and the output voltage was normal at +10.3v / -10.6v
what may be wrong?
Good soldering is key. Given the opportunity to mention: Use leaded solders 0.6mm (Kester 44 is best), clean boards by rubbing softly with pure alcohol moist rag before soldering. Use soldering station at 350C. Hakko FX-888 or alike. Use chisel tip ~ 2mm. Solder in 2 secs, if 2 secs does not do it, use bigger tip, flux, up the station's power. Only shiny well set soldered points are healthy in the long run.
DCB1 SELECTOR SWITCH?
Hello guys.
I just ordered the board for a DCB1, and needless to say, am quite eager to get started! Only I am not to experienced in DIY, so I have a few noob questions.
I wanted a TOCO DPDT switch, but PERCY is sold out. He does have single pole double throw, though. Can I use two or three of a SPDT to switch between two or three inputs? Or can I use the rotary from Broskie with the DCB1?
What benefits from matching the LED's?
Have anyone tried the stepped attenuator diy kits with vishay dale resistors from ebay, are they difficult to solder?
I also wish to have a subwoofer out, is this as easy as hooking up a second set of outputs, or use a Y- connector?
I think thats all, for now
Hope someone can find the time to explain
Kenneth
Hello guys.
I just ordered the board for a DCB1, and needless to say, am quite eager to get started! Only I am not to experienced in DIY, so I have a few noob questions.
I wanted a TOCO DPDT switch, but PERCY is sold out. He does have single pole double throw, though. Can I use two or three of a SPDT to switch between two or three inputs? Or can I use the rotary from Broskie with the DCB1?
What benefits from matching the LED's?
Have anyone tried the stepped attenuator diy kits with vishay dale resistors from ebay, are they difficult to solder?
I also wish to have a subwoofer out, is this as easy as hooking up a second set of outputs, or use a Y- connector?
I think thats all, for now
Hope someone can find the time to explain
Kenneth
I think I have read every single one. Well not completely all of it, but I will go through them again, cover to cover.
What about the function of the SPDT vs DPDT ?
Thanks, but I don't think you understand. Does the SPDT switch work like I can use three switches to turn on and off three inputs? Like three in a row, say the left one os line one while down, and the rest of them is up. And to switch to line two, I pull nr one up and nr two down and so on.....it looks lile Peter Daniels does this on his Patek switchbox... See?