Pete wrote:I think for rock you may want to explore HRM but it will be necessary to use together with the PAB on. Think of the M in HRM. just my $0.02.
Monkey? (j/k)
As for the HRM not having quite the gain of the '80s style, I guess that depends on whether you've done a "pure" implementation. Scott will most likely bash me for saying this, but if you max out the trimmer and use a linear OD gain pot you can turn the HRM into a gain monster.
I was all set to disagree on the HRM being better for rock but then I realized that if your preference would be a Marshall sound the HRM is better. Personally for a rock gig using a HRM I'd miss the non-HRM.
Besides the added tone stack, how different is an HRM amp from a non-HRM circuitwise? If I wanted to experiment with adding the post OD tonestack to a non-HRM amp, would I be looking at a few component changes or a complete overhaul of the amp?
Last edited by TimS on Fri Aug 03, 2007 12:41 pm, edited 1 time in total.
Look in the files section at the Bassman and SuperReverb posts, ignore the reverb and/or loop parts and compare the differences. You could do the HRM layout but put a non-HRM on it rather than making the add on board like Dumble did.
heisthl wrote:any idea what the lower right resistor is doing? looks to be connected to the mid pot with a value of 1k8
Pre skyliner TS.
Amp is sn 118 (early 80's), then HAD rebuilded it to newer specs. HRM is retrofitted, new power supply (you can still see and old cap chassis hole), and V2 circuit it's changed (different green wires joined).
dogears wrote:I guess this means that the pic on the site is authentic. I have had it for a while. Funk is right btw. This is way different. Let's see what astute eyes point out.....
I see a very warm, cuddley PI long-pair tail (different from current schems, similar to a certain '60s amp)...and a happy NFB and Presence setup (again, different than current schems and similar to a certain '60s amp). One of the PI plates is at 91k, so I assume the other one is at 100k.
kleinm wrote:I see a very warm, cuddley PI long-pair tail (different from current schems, similar to a certain '60s amp)...and a happy NFB and Presence setup (again, different than current schems and similar to a certain '60s amp).
chris_sanford wrote:Don't think so. Tail resistor on the mid pot looks more like the Bluesmaster TS (think Marshall style).
I hope I'm not stepping on anyone's toes or violating some unwritten rule by asking this, but what exactly is the Bluesmaster? I keep seeing references to it but it seems to be somewhat of a taboo subject, or at least one that's kept very quiet.
If it's not cool to talk about here, let me know and I'll delete this post, but otherwise would someone mind filling me in? I'm not asking for circuit details (I'd love to know them if anybody would like to share, but they seem to be a closely guarded secret); I'm just curious about the history of the amp - when it was made, who used it, etc.
http://www.raw-sewage.net/jtm45ri_mods.html - scroll to the bottom of the page. There are several versions of the same basic schematic. I don't see anything with a mid pot tail resistor or .02 caps to the output grids.
chris_sanford wrote:Don't think so. Tail resistor on the mid pot looks more like the Bluesmaster TS (think Marshall style).
I hope I'm not stepping on anyone's toes or violating some unwritten rule by asking this, but what exactly is the Bluesmaster? I keep seeing references to it but it seems to be somewhat of a taboo subject, or at least one that's kept very quiet.
Thanks.
Hi Tim,
From the information I've been able to piece together, the Bluesmaster uses a traditional Marshall-style tone stack and PI values, but is otherwise similar to the HRM schematic found on this site. I have no idea when this circuit appeared, or who might have used it. Clearly though, the pic posted in this thread looks like one of these beasties, although the flipped overdrive stage input wires are a new twist.
chris
Last edited by chris_sanford on Fri Aug 03, 2007 5:55 pm, edited 1 time in total.
chris_sanford wrote:
Don't think so. Tail resistor on the mid pot looks more like the Bluesmaster TS (think Marshall style).
chris
Correct me if I'm wrong, but I don't ever recall seeing a Marshall tonestack with a fixed resistor to ground off the Midrange control. I'll look at my Doyle book again.
BTW - you can see in the picture that the Midrange pot is an Alpha 250k. Again, this isn't a Marshall-style midrange value that I'm aware of.
It appears its a Skyliner midrange value, and the 1k8 (assuming that's correct) is just connecting the resistor to ground, and not having much effect on the frequency knee or taper. Just speculation, though.
(j/k)
