• Disclaimer: This Vendor's Forum is a paid-for commercial area. Unlike the rest of diyAudio, the Vendor has complete control of what may or may not be posted in this forum. If you wish to discuss technical matters outside the bounds of what is permitted by the Vendor, please use the non-commercial areas of diyAudio to do so.

OLD THREAD DAC End by Andrea Ciuffoli

Status
Not open for further replies.
Jump to Latest
#444
Hi Quang Hao, why are you using all the resistors in parallel?
So two paralleled 2k gridresistors should be 1K, gridstopres. could
be 110ohm output to ground would be 50K then....
Or what´s the reason for paralleling?
And power rating at these three points could´t be the reason

Greetings Ulf
 
#445
le´flu said:
Hi Quang Hao, why are you using all the resistors in parallel?
So two paralleled 2k gridresistors should be 1K, gridstopres. could
be 110ohm output to ground would be 50K then....
Or what´s the reason for paralleling?
And power rating at these three points could´t be the reason

Greetings Ulf
Click to expand...

Using multiple parallel resistor and reverse auction together to create a pure resistance only. Against the phenomenon of inductance.
 
#447
defec said:
Guys, what would be the negative of using a JJ 50/50 500v in place of the Jensen cap? It's a lot easier to get etc.
Click to expand...

Hard to say, if someone compared the two and prefer the Jensen you might still choose the JJ because you have different taste and system.
This is the great complex freedom of DIY at the contrary of many commercial products where convenience and marketing have significant influence.
Anyway Jensen is not hard to find and I trust Andrea's judgment. If money is not a problem buy both and choose what you like most.

Here is where you can find original Jensen
Jensen 47uf + 47uf 500V Electrolytic Capacitor - eBay Capacitors, Electronic Components, Electrical Test Equipment, Business Industrial. (end time 26-Feb-10 21:40:23 AEDST)

or search Jensen 47uF on ebay.
 
Last edited:
#455
sugden said:
I'm also not sure whether i can find dale resistors in Singapore, because i was newbie in DIY. My last resource was eBay.
Click to expand...

I have the same problem to find Dale RN55 resistors. I will get them from ebay but need to buy 25pc for $2.81. I have no choice.

Note the CCF-55 series cannot get close to the wanted values
RN-55 are 1/4W
RN-60 are 1/2W
The final letter can be B, C, D and indicates the tollerance grade. Mostly are D (1%) but some values are C which are a little more expensive.

In the I/V tube PCB all the resitors lined up vertically in the centre between the tubes can be 1/2W. The BOM indicates 1/4W but better put 1/2W.

Find Dale resitors at
eBay Australia Shop - bigsmythe74: 1 4w Metal Film Resistors, Allen-Bradley 2 watt CC Res

Also the seller has got some best Carbon Composition resistors if you need one day to play with the valve amplifier.
 
#459
flocchini said:
Should these resistors be non-inductive like the Mills?
Thanks
Click to expand...

I put 2 good wirewound WELWYN - WP4S-2R2JA2 4W (Farnell), I don't think in this position and purpose is important non-inductive.
Also in this position the resistors are subject to surge everytime you switch on the DAC. Wirewound handles that really well. An alternative you can try is carbon ceramic (RS Components), or thick film that are non-inductive.
 
Last edited:
#460
Hi all! I tested the all PCb of DAc-end is Ok!

The sound is good , near my Dac-end use out put tranformer sill, tube 6c45PI
There is one change about the filament of 5687!
Some image!
 

Attachments

  • DAC1.jpg
    DAC1.jpg
    453.7 KB · Views: 467
  • Dac3.jpg
    Dac3.jpg
    547.8 KB · Views: 450
  • BT.jpg
    BT.jpg
    679 KB · Views: 443
Last edited:
Status
Not open for further replies.
Top Bottom