0.22 ohm caddock bulk purchase for AX PCB ver 1.0

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grataku

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#1
If you want high quality 0.22 ohm metal film resistors in your AX and you have been struggling to locate anything but the inductive wirewound this maybe the thread for you.
There are three choices for the output resisors in question: the classic wirewound, the aryton-perry non inductive wirewound, and the thick film To220 type.
Non inductive wirewound have a larger form factor and are somewhat difficult to locate, the inductive type may do but they are sort of an inferior choice, the Caddock To220 (Type MP930) are very nice, can be mounted on the AX-ver1.0 board but they can be expensive. Mouser appears to have just begun stocking these resistors.
Since there are about 1000 boards out there, and 8 resistors are needed/board,
the possibility exist to source the part for a substantial price discount.

I have started a wiki page, feel free to sign up with NO STRING ATTACHED. Nothing will happen unless we can get the right price.

What I mean by that? Type MP930 on the Mouser catalog is $4.15 for 1 and $2.91 for 50. I expect on a 1000 pieces to be less than $1 each.

I will call Mouser and try to get a few quotes for different quantities (500, 1000, 1500, 2000). Will post them later. If need arises I could try the manifacturer directly.

Thank you!
 
#5
grakatu:
sorry to be a pain - just where is the wiki sign up for the resistors. I couldn't find it? Yep, call me a dunce .... :clown:
thanks,
mlloyd1
grataku said:
... I have started a wiki page, feel free to sign up with NO STRING ATTACHED. Nothing will happen unless we can get the right price.
Click to expand...
 
#6
I have used the 820s/821s before with nice results. I have not used the 930 before but doubt there is much if any sonic difference between the two. Is there much of a cost difference between the two? If the 20watt 821 is cheaper maybe we can save a little more using it instead of the 30 watt 930s. As far as the resistance goes maybe some of the ohter beta builders can shed some light on an optimum value.

mlloyd, here the wiki:
http://www.diyaudio.com/wiki/index.php?action=find&find=Caddock+0.20+ohm+TO220
 
#11
Peter Daniel said:
What about Mills wirewounds? Some people claimed they would be the best choice for that location (I think it was Fred😉 ).
Click to expand...

Yes Peter, I think you can get those bifilar wound with almost no inductance. The problem with the Caddocks is that they have a very low max-to-average current ratio, i.e. they give up life after overload relatively quickly. Wirewounds take a lot of abuse and will survive amp shorts.

Jan Didden
 
#12
:att'n:

Here is the quote I got form Caddock:

From: __________Andrea Bernard, Caddock Electronics, Inc.
Subject: _______Request for Quotation ___

Hello,

This quotation does not include the cost impact of
requirements which may be imposed by the addition
of purchase order attachments or purchase order notes
which have not been previously agreed to. _Any additional
requirements may affect price, delivery, and potentially the
acceptability of the purchase order.

Caddock does not recommend the Model MP930 resistor
for use in military or space applications. This model
is recommended by Caddock for use only in
commercial/industrial applications. Caddock has
qualified this device, for its intended use, to perform
according to catalog specifications. Caddock
does not maintain a military and/or space level
reliability program for this device. Caddock will not
provide reliability support, for use of the device,
in military and space applications.

#1) _MP930 0.20 ohm 1%


Please note I have quoted the 1%
tolerance. _20% and 5% tolerance is also
available with a 100 piece minimum.

250 - 999 ____= __$2.14 ea. _
1,000 - 2,499 __= __$1.66 ea.

We have approximately 3,870 pcs. available to ship from
final inspection ONE week after receipt of order (subject to change).


Normal Lead Time: _FIVE (5) weeks after receipt of order.

FOB: _____________________Shipping Point
Terms: __________________Net 30 days on approval of credit.
Prices quoted are valid for 60 days.

(MP900) ___In quantities of 50 pieces or more, the parts must be
purchased in 50 piece increments. _For increments of less than 50
pieces, the parts can be purchased as a separate line item at the
appropriate price break.

Caddock Electronics is a manufacturer of resistive components. _
We do not manufacture our product in commodity quantities for stock. _
Parts for this order may be custom manufactured. _Products specifically
manufactured for your order will be non-cancelable and non-returnable.

Thank you for your interest in Caddock Electronics resistor parts.

Best Regards,
Andrea Bernard,
Sales Technician
Tel. {909} 788-1700 ext. 2212
Fax _{909} 369-1151 or 369-5199
 
#15
caddock

grataku said:
Peter and Janneman,
I got a quote for the Caddock, I could get one for the Mills.
Could you please give me the exact part number for the Mills resistors? Who sells them?

Janneman
by 'bifilar' you mean aryton-perry non inductive?
Click to expand...

Grataku,

I am not familiar with this brand. I was referring to the manufacturing process, which either winds the resistor with 2 wires that are then connected in parallel but opposite phase, or, I understand, there is another proces with a single wire but winding first left-to-right on the resistor body, then right-to-left. The idea, anyway, is zero or at least very low inductance and the ruggedness and reliability of a wirewound resistor. Most manufacturers of power resistors have them.

Jan Didden
 
#17
:att'n: :att'n: :att'n: :att'n: :att'n: :att'n: :att'n: :att'n:

ALL:

From Mills directly, NEW QUOTE FOR MRP3 3 WATTS 0.22 OHM 1% tolerance with aryton-perry non inductive winding

500 pieces $1.06/each
1000 pieces $.95/each

The size for these is 0.562 length (body, no leads) and 0.17 diameter (inches)

Lead time 4 weeks.
Above 500 the price is basically down to labor.

This maybe the better way to go. The caddocks are really only 2.25w if not properly heatsunk and the fact that the Mills are non inductive tips the balance decidedly toward them. Price seems to be great as well which is always good.

There appear to be requests for around 500 pieces at this time,
Given the small size of the order I should be able to handle it NO PROBLEM.

Please decide whether you are OK with the MILLS, update the WIKI PAGE, and send me an email with the final number and your information. I will tell you about payment later.

Since there is a long lead time I would like to get definite numbers within a week and place the order ASAP.
 
#18
Peter Daniel said:
What about Mills wirewounds? Some people claimed they would be the best choice for that location (I think it was Fred😉 ).
Click to expand...

I think they are the best. Mother nature, non inductive, pure sound. Those 5W are small for that watage comparing to other brands. Just my two cents.😉

Trigon
 
#20
Peter Daniel said:
Checking with the PCB it seems that 5W version would be a better fit at .650" length. If the price difference is not that big, maybe that would be a better choice?
Click to expand...

I can never make you happy Peter, can't I? 😉 I don't have the pcb with me.
I don't see the a .650 long resistor, the 5W are .78 long check it out.

http://www.millsresistor.com/prod01.htm

One thing is for sure, the price will be higher.
 
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