Which resistors to use???

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HVfanatic

Member
Joined 2008
Hi,

I'm currently getting started with building my Pass family (F3, F5, Aleph J).

All boards are Peter Daniel boards.

My problem:

I can't find the resistor recommendations. If I remember correct:

F5: All low power resistors Dale RN55D
F3, Aleph J: All low power resistors Dale CMF-55

Is this correct?

Where do you source them from???

Thanks, Dirk
 
h_a

h_a

Member
Joined 2006
Hi Dirk,

from what I know the RN55D are military grade, so their power rating IMHO is only half of what is standard (for this size) for even higher reliability. I think the CMF-55 have the same dimensions, just twice this power rating. If so, you can use CMF-55 everywhere.

Anyway, the resistors usually run far below these ratings.

I think in Nelson's original schematics he is using 1/4 W resistors througout, with the exception of the usual source degeneration resistors which are 3W Panasonic types.

Have fun, Hannes
 
EUVL

EUVL

Member
Joined 2003
xen-audio.com
RN55 and CMF55 are the same. While use for military you have to lower the power rating.

The CMF55 you can get from Schuro has non-magnetic end caps. Expensive but 0.1% so no matching required.

You can also get PRP 9372 which is also non-magnetic but has a slightly higher tempco, e.g. from

PRP Quarter Watt Resistors

Not sure about source in DE. Pls google.

Beyschlag and Welwyn both have magnetic end caps and are not much cheaper.


Patrick
 
LucasAdamson

LucasAdamson

Member
Joined 2009
EUVL said:
If I am not wrong you can also use Caddock MK132 instead of CMF50 ?
Available from Mouser.


P.
Click to expand...

Jeez. If you're simply made of money. I'm being quoted £12 each for some of these from Farnell, the UK's cheapest supplier. It seems that both Caddock MK132 series and Dale/Vishay CMF 50 series are all imported from US per order, at vastly greater cost.

I notice that you are using a whole host of different types in your monoblocks Peter.

Can anybody else recommend resistors for the Peter Daniels F5 boards please? Are 1% metal film resistors so different from manufacturer to manufacturer? I have some from Hong Kong that I've used in the past without ruining projects, but I'm wondering if I should be fussier with the F5 and use more exotic ones, as the project is costing me so much anyway.

Many thanks
Lucas
 
A

Andy5112405

Banned
Joined 2006
What kind of resistors would you recommend for the source resistors of the output devices? High power resistors are usually Wire-Wound which are inductive and will influence the sound. Non - Inductive Wire-Wound are available but are expensive. It would be relatively easy to make the resistors out of Metal Film resistors but then the rating becomes an issue. How much power do the Source resistors dissipate ? 10Watts is easy in wire-wound, but would need 20(ish) x 0.6W metal film resistors. Would the track impedance between all the metal film resistors completely negate their use against wire-wound? Do I just have to sell the wife to buy non-inductive wire-wound resistors?
 
LucasAdamson

LucasAdamson

Member
Joined 2009
Panasonic 3w metal film resistors, available from Digikey (US) and nowhere else I've found in UK. Vishay Dale 1/4w metal film resistors are available there too (and also not in UK) - they're good for the signal circuit.

Digikey charge $30 delivery to UK, but free if order is over $100. I have $60 in my Digikey shopping list at the minute - perhaps we can team up for a $100 order?????

Let me know
Lucas
 
LucasAdamson

LucasAdamson

Member
Joined 2009
Yes, of course, and Farnell, but can you get 3W metal film resistors from either of them? Do you mean these? BI Technologies | Passives | Resistors | Through Hole, Fixed | Non-Inductive - Through Hole Package because if so, they're £1.32 each.

I am struggling with heatsinks.

I am building a Pass F5 using CViller's BOM, which lists the Panasonic and Dale resistors, which are of excellent quality and perfectly suited to the task, excepting tailored esoteric and expensive alternatives. As I will be also making a DC - B1 buffer, and buying the resistors for a friend's F5 too, I could very well soon get to the $100 mark, making it actually CHEAPER than buying from RS or Farnell, and meaning I could get tried and tested stuff I can't source in England for love nor money.

I'm sure those non-inductives will be fine though.
 
LucasAdamson

LucasAdamson

Member
Joined 2009
Peter, is there any theory about which might sound better between 1/4W and 1/2W resistors? I ask because I have a feint memory of reading that the lower wattage are nicer sounding...the smaller CMF50s also fit your boards properly, without standing soldier.

Are there any reasons not to use 1/4W resistors?

Thanks
 
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