DCB1 TURBO BUILD @600Ma

[ijrussell]

Like wise, I'll do a bit of googling too.
Something I've not heard of but always open minded.

Just out of curiosity where are they from ???

S.

https://diyaudiostore.com/products/whammy

[Macca]

Listening to this Chinese relay preamp daily and it's pretty good for £100 but it suffers the same issues as all the other passive pres I've tried. It lacks pace.

.

The Spotify interconnects are not a good match with my passive either so you might want to take that into account. I guess it might be to do with impedance.

[Bigman80]

The Spotify interconnects are not a good match with my passive either so you might want to take that into account. I guess it might be to do with impedance.

Yep, tried some RG316u, Sommer and some Shark cable.

SPOTFIRE are better than those. Shouldn't have to wait long mate, the pre is nearly finished!!!

[STD305M]

https://diyaudiostore.com/products/whammy

Hi Ian
Thanks for the link
Will have a look !!!!

S.

[keith1962]

Salas who designed the DC version of Nelson's B1 also has a preamp with gain if needed. I don't need the gain so the DCB1 suits me fine.
So to get to 600 ma it just requires 4 rectifier be changed from MUR820 to MUR860 and 2 resistor values to be changed and the unit will operate with more juice without any further adjustment needed?
Are the 4 rectifier the black ones across the end of the board next to the 4 caps? Any links for where to buy 4 x 860?
Which 2 resistors need changing and to what value? Is it the 2 that run parallel to the short length of the board right next to the 4 caps. If so mine are Dale 10 R 6.5w (black Dale). Any close up pics of the resistors in question?
Currently having a play with mine to rearrange in the case and try different attenuator. I have a TKD 601 in there and have some alternatives to try. TKD 2501, Alps Black Beauty, Khozmo Shunt, Acoustic Dimension and a DACT which is in there at the minute and is a huge step up over the TKD. My money is on the DACT or the Acoustic Dimension.
Some nice looking builds there chaps!
Keith.

[STD305M]

Salas who designed the DC version of Nelson's B1 also has a preamp with gain if needed. I don't need the gain so the DCB1 suits me fine.
So to get to 600 ma it just requires 4 rectifier be changed from MUR820 to MUR860 and 2 resistor values to be changed and the unit will operate with more juice without any further adjustment needed?
Are the 4 rectifier the black ones across the end of the board next to the 4 caps? Any links for where to buy 4 x 860?
Which 2 resistors need changing and to what value? Is it the 2 that run parallel to the short length of the board right next to the 4 caps. If so mine are Dale 10 R 6.5w (black Dale). Any close up pics of the resistors in question?
Currently having a play with mine to rearrange in the case and try different attenuator. I have a TKD 601 in there and have some alternatives to try. TKD 2501, Alps Black Beauty, Khozmo Shunt, Acoustic Dimension and a DACT which is in there at the minute and is a huge step up over the TKD. My money is on the DACT or the Acoustic Dimension.
Some nice looking builds there chaps!
Keith.

Hi Kieth

You need to use mur820 or 860, if you have MUR 820 already fitted they will be fine.
the 2 resistor that need changing are just below the 4 power caps change to 1.8ohm 3watt, Approx...
[IMG][/IMG]


You can get MUR820 or 860 from ebay or Farnell
Also change the 8 resistors around the relay to better quality such as Audio Note or similar if you
want an increase in resolution.
Make sure your Tx is big enough to cope.
Steve...

[Firebottle]

Altering to run at 600mA does involve lowering the value of the 2 resistors you mention.

You do need to meet the criteria I stated in https://theartofsound.net/forum/show...63#post1035463

From tests the value needed is around 1.8 ohms or a little less. You could try 2 off 3.3 ohms in parallel giving 1.65 ohms. A 3 watt resistor is a large enough rating.
The difficulty with specifying the exact resistor value is that the relationship with increasing current is not linear, as it's dependant on the characteristics of the first FET.

[keith1962]

Thanks chaps, they are the resistors I was thinking about. Mine are 10R 6.5W so will try some as Alan suggests.
How Do I tell which rectifier I have fitted. There is nothing to see on the 4 that go across the width of the board at the cap end.
Fets are mounted to floor of case as has been done in the recent builds on this thread, will check the tx.
1M and 220k resistors are Riken Ohm and the 220r are Shinkoh so as good as it gets already unless going to z-foils or AN silver. Nick at Hificollective said not really worth it.
Keith

[Bigman80]

Thanks chaps, they are the resistors I was thinking about. Mine are 10R 6.5W so will try some as Alan suggests.
How Do I tell which rectifier I have fitted. There is nothing to see on the 4 that go across the width of the board at the cap end.
Fets are mounted to floor of case as has been done in the recent builds on this thread, will check the tx.
1M and 220k resistors are Riken Ohm and the 220r are Shinkoh so as good as it gets already unless going to z-foils or AN silver. Nick at Hificollective said not really worth it.
Keith

Not much needs doing in that case. The resistors are fine!!

Alan and I are going to do some resistor value tests to get to 1.2A so as soon as we have them in place I'll update the thread.

As Alan said, this is going to largely be guesswork due to the slightly differing relationship with the FET.

[STD305M]

Thanks chaps, they are the resistors I was thinking about. Mine are 10R 6.5W so will try some as Alan suggests.
How Do I tell which rectifier I have fitted. There is nothing to see on the 4 that go across the width of the board at the cap end.
Fets are mounted to floor of case as has been done in the recent builds on this thread, will check the tx.
1M and 220k resistors are Riken Ohm and the 220r are Shinkoh so as good as it gets already unless going to z-foils or AN silver. Nick at Hificollective said not really worth it.
Keith

Hi Keith,
My assumption was that you had a standard build, didn't realize you had Riken and Shinkoh already fitted!!
as for not being worth doing, i changed dale resistor to Audio Note Tantalum and there was quite a difference.
My assumption would be the 4 rectifiers you already have fitted are Mur 820 or 860 but cant say for definite,

S.