Resistors. Max voltages in ST70.

[mugsy]

Hi!

Can somebody please tell me what the max voltages resistors are likely to see for the following resistors on the driver board please:

R3 & R4 - 1M5

R23 / R24 / R25 / R26 - 270K

R5 / R6 - 620R

R9 / R10 - 47R

R11 / R12 - 10R

R13 / R14 - 18K

They are listed as needing to be half watt types, but what is the working voltage please? There are some 0.6w metal film ones in my local Maplins store, but max. voltage here is 250v. Are these suitable?

Many thanks! Yellow_Light_Colorz_PDT_06

- John

[Uncle Ned]

Hi! Can somebody please tell me what the max voltages resistors are likely to see for the following resistors on the driver board please:R3 & R4 - 1M5 R23 / R24 / R25 / R26 - 270K R5 / R6 - 620R R9 / R10 - 47R R11 / R12 - 10R R13 / R14 - 18KThey are listed as needing to be half watt types, but what is the working voltage please?

That list isn't of resistors on the DIYtube board, but I can tell you none have more than a 250V drop across them. AFAIK the voltage rating should refer to the insulation on the outside of the resistor, so the actual rating shouldn't be an issue unless the resistor is next to the chassis or on top of a PC board trace (or if you touch it!)

There are some 0.6w metal film ones in my local Maplins store, but max. voltage here is 250v. Are these suitable? Many thanks! Yellow_Light_Colorz_PDT_06 - John

Maplins, yuk, those guys nicked me for over $30 for a little adapter for my phone box! I'm sure their resistors are fine though like everything in the UK probably a bit overpriced... Yellow_Light_Colorz_PDT_09

[mugsy]

Thanks for that Uncle Ned!!

Yeah Maplins (and the UK) is a complete rip off, but those Phillips resistors are pretty good so I'll go for those then.

Those resistor numbers are from the dynakitparts dynaclone board BTW. Sorry didn't realise they weren't numbered in the original guide (which I have just had a wee look through).

Cheers,

- John

[EWBrown]

These values look to be the same as those in the original 7199 driver board, or perhaps its 3-tube EF86 / 12AU7 equivalent.

The original Dynaco schemtaic diagrams can be found here:

http://www.geocities.com/vintageaudio/

The actual operating voltages should be listed on Page 2.

The entire assembly manual is here: (6.1 MB PDF file)

http://www.dynakitparts.com/store/manuals/Dyna-ST70.pdf



/ed B in NH

[mugsy]

Yes those are indeed the original values - the dynakit board is a replacement for the original board - no changes.

Thanks for those links Yellow_Light_Colorz_PDT_12

- John