Two-Rock Resistors?

[rccolgan]

Hello! I'm re-drawing a JM Sig layout based on the information I've been capturing over the last couple of years. One thing I keep getting stuck on is figuring out what resistors that Two-Rock uses (or something close to). From my observation, Two-Rock used metal film resistors in most of the audio circuit circa 2006-2007 like in the blue chassis Sterling Signature. Shortly after, they started using tan resistors (carbon film?) however the odd thing is that their color band indicated weird values that are only seen with precision metal film. For example, 121k, 68.1k, 1.54k, etc (see attached picture).

Did they likely custom order these resistors based on the originating precision metal film circuits? Any guesses on the manufacture, resistance material, & wattage specs? Seems to be a light epoxy finish as well..

Thanks in advance!
-Ryan

[ijedouglas]

They look like Draloric LCA Carbon Film. Jelle is selling a bunch of them and may know the strange values.

[martin manning]

Yes, they do have the look of Sprague Q-Line/Draloric CF. It's the markings that are strange, specifically the last band being gold, which suggests they predate the current 6-band standard. Otherwise, I'd say they are E96 series and the upper one is 1540Ω, 2%, and the lower one is 1MΩ, 2%.

[talbany]

It does look to be some kind of Draloric resistor (end caps).These look to be older than the later ones jelle has. I dont think they are the Q-lines those (yellow band) are flameproof. Dralorics can sound pretty different from all the different ones Ive tried given their voltage, series, age and tolerance values however this is getting granular.If you want to get close Jelle's LCA's would do fine.. I've seen pics of some Older NOS of Rocks but this is the 1st one loaded Dralorics.
I've seen those "blue" bypass caps before I think those are the NOS Spragues so if you are trying to get close to the sound of that amp you may want to try and hunt those down too.I've seen those pop up on E-bay from time to time.
Do you have pictures of the rest of that amp for my collection.
As far as having someone custom make their resistors? It's possible they had their own PS6 Series caps custom made I believe they were 'Blue..

Thanks

Tony

[rccolgan]

Thanks, everyone, for your input! @TAlbany, the blue sprague caps are likely custom epoxy since they also say "K&M" right on them. Highly interesting about the unique sound these resistors could produce compared to similar spec resistors. I'm working on getting more pics of the amp All these D-type secrets under every rock it seems.

@MartinManning - The markings are definitely weird. I used a 5 band calculator instead of the 6 band to get the values correct. I disregarded the extra red band (50PPM?) with the 5 band calculation.

I'll reach out to Jelle to see if there is some values and similar spec available. Again, thank you! The search continues..

[talbany]

Thanks, everyone, for your input! @TAlbany, the blue sprague caps are likely custom epoxy since they also say "K&M" right on them. Highly interesting about the unique sound these resistors could produce compared to similar spec resistors. I'm working on getting more pics of the amp All these D-type secrets under every rock it seems.

Are you talking about the "bypass" caps? I cannot find it marked on most of the old pics I have in my Two Rock files (A picture would be great!). I know the tone caps have K&M on them.
BTW. As Far as the Metal films go (Light Blue ones) Two Rock used NTE's on the older builds

Tony

[Synchu]

Blue electrolytics look like standard Vishay axials.

Niki

[ChopSauce]

Maybe it is, but it rather looks like a Philips cap to me.

[rccolgan]

Yes, the bypass caps are BC/Philips 4.7uf/63v and a 10uf/63v

[talbany]

NTE's Metal Films/ Phillips axial's
NTE's are a clear sounding resistor with a flat top end and work especially well in a clean style amp IMO..
Somewhere I have a Two Rock 102 loaded with Q-Lines
Can't seem to find it.. I think it was one they built for Robben to use at one time
Will keep lookin

[Synchu]

Excellent info
I have exactly the same looking Vishay electrolytics like the pictured ones. Great catch that these are Phillips.

Niki

[rccolgan]

I played dress-up with some resistors and Philips/BC caps this morning. Top section top resistor is Amplified Parts 1/2w 350v, the bottom resistor in the top section is 1/2w Royal Ohm (Tayda electronics) 350v More food for thought. The .6 watt LCA 0414 that Jelle has definitely seems to be in the ballpark visually. Interestingly, the specs on the LCA 0414 says it's 500v rated whereas that voltage is seen mostly in 1W carbon film resistors I've found have been 500v and 1/2w are 350v Maybe this plays into the tone reports of higher wattage/voltage = larger resistance surface area = "brighter" contact noise? (Going deep down the rabbit hole). The NTE 1/2w metal films are 350v.