New 100w/HRM build-problems solved

[moj067]

DocZ I checked that outer jacket and I'll be damn if that stuff carried a resitance value (what is that stuff made of?). So I got an exacto out and trimmed away little pieces that may have contact w/ solder points and voila! instant firebreathing dragon amp. All better same tonal chacteristics I was griping about except more gain. Much better and lesson learned, thanks for the input, that was most invaluable to my build. Now I've just got to dial in this HRM tonestack and enjoy.

['67_Plexi]

Yep, I checked those resistor values aaaaand you were right Alan, I owe a pint or something. Thanks aplenty, I put in what to my crappy eyes at the time looked to be 2.7k when as you summized was 27k. I'm still finishing up the streamling of my power section arrangement ( I like it better already) and will follow up w/ what should be positive results. I'm now filled w/ guarded optimism, I think my P.I. dropping resistor will have to come up in value though, as Scott recommended. I will listen first before changing the 180k to 150k on the OD2 resistor, but I'm sure Scott is probably right on.
Thanks to all for your interest as I muddle through this fun build.

You're welcome bro !!

Glad it got cured. Thats why I kept insisting you recheck them. Been there and done that a few times.

['67_Plexi]

looking at the pics I see a potential issue with the shielded cable that could cause many of the problems you describe, it has a conductive black jacket over the center clear insulation (not the shrink sleeve). You must double strip that cable so that the black jacket does not touch the hot conductor or you will have added resistance going to ground like around 2K~5K, that internal black jacket is very conductive it is an extra shield and I see many places where it looks like it could be touching the hot connection, this is not enough resistance to shut the amp down just to load the circuits and make you loose gain and high end. You should not have that black jacket near the tip(center) you should only see the clear insulation 1/8" from the end.

You aren't using George L's are you ? That cable is probably THE worst chice you could use in there. I ask because that has the black conductive jacket.

In a well laid out HRM amp you can actually get away with only using 2 screen cable runs. One from the input jack and one from the wiper of the gain pot. It's all I use in the OD2 amps. It does require diligent lead dress and a sturdy grounding scheme though. I would rather filter highs out in a controlleable manner at a later stage than have crappy cable filter them out for me much earlier in the circuit. Personal preference. Dumble used several more screened cables.
Having gone through many different types of screened cables I've settled for a high quality/low cap RG58/U from a local supplier. It is very flexible, has a good sturdy 22awg center core, strips awesome with the correct tool and the braid solders real easily without melting the inner core. Yes there are cables with slightly lower capacitance, but 24 and 26awg inner core gets too fragile for my liking. I actually think that the 8 to 10 pF from these cables is barely noticeable.

[moj067]

No, it's the Lava ELC, supposed to have capacitance of 15pf/ft.
I chose it over the Gepco purple stuff because it doesn't have the foil outer shield. It's good stuff and Mark is very quick about turnaround on orders. He's in N.C. and I'm here in S.C. so it's quick too. I try to support good people and he's good people.
Thanks again for your help, it takes a village as they say.