Mid-90s Skyline HRM w/EL-34

[jfs322]

Sorry, I tried the search function but could not find anything. I'm looking for a schematic and/or layout for a mid-90s Skyline HRM w/EL-34 tubes.

Is there a verified schematic and/or layout for that series Overdrive Special?

Thanks!

[pompeiisneaks]

I t hink you may be talking about the #183 5th gen style (this one has 6L6's but you just need to swap out the OT and adjust the bias circuit to use for EL34's instead).

https://ampgarage.com/forum/viewtopic.php?f=5&t=13095

The #183 didn't have the HRM, but that's a known layout/schematic on other builds you'd have to apply here. That's part of the dumble methodology, he's got many recipes he also tweaks them, and you can do the same.

The above, 5th Gen is a skyliner, and just needs you to adapt to the HRM and EL34's

~Phil

[Charlie Wilson]

#183 does have EL34.
CW

[jfs322]

Thanks! More specifically, what I am looking for is I believe Dumble did a small run of ODS amps for a dealer, I want to say in the late 90s or so. These were Skyline HRMs with EL-34s, much later in time than #183. I'm guessing the serial number range is like #220 - #240. I was hoping someone has had access to one of these amps and did a schematic / layout, but failing that, I suppose I could use #183 and adjust for EL-34s and add HRM -- but I'm not sure if that'll get be 100% there. However, failing anyone having a schematic / layout for those late 90s amps, I guess it's the best I'll have to do. I heard the Two-Rock Emerald Pro is based on a '97 Skyline HRM, but not sure how close it is.

[norburybrook]

#183 DOES USE EL34's!!!!!

Sent from my Nexus 6 using Tapatalk

[erwin_ve]

You can use this one and do the output section of #183. I built this one with 6L6GC, lovely amp still have it after almost 10 yrs!

[jfs322]

Thanks, guys. I'll use #183, I just wasn't sure if the 80s Skyline EL-34 amps were comparable to the late 90s Skyline EL-34 amps. Any significant changes to those eras (aside, of course, from the addition of HRM)?

[erwin_ve]

Fwiw, the schematic I posted is very close to a Emerald pro: Emerald pro had 100k slope with 0.047 mid cap.
Biggest change to #183 is probably the feel. Non hrm amps have a looser feel and are more forgiving imo.On the HRM you have those pots to shape your tone. You can make them a little more mid scooped on the Od which can give a more modern sound.
Having said that: put them side by side and they are unmistakeably Dumble DNA.

[talbany]

Thanks, guys. I'll use #183, I just wasn't sure if the 80s Skyline EL-34 amps were comparable to the late 90s Skyline EL-34 amps. Any significant changes to those eras (aside, of course, from the addition of HRM)?

No!.. Apples and Oranges!. The only common features between the 2 being the tone stack (Skyliner) and output section (Fender Twin/ Showman style PI) #183. You could certainly use the Bluesmaster (Plexi Marshall) with the 34's for a more aggressive (rock) sounding amp!. This all depends on where you want to take it.
Btw..Dumble also used the #183 style PI in his Musicman Skyliners (non HRM) loaded EL-34's as well,

Tony

[pompeiisneaks]

#183 does have EL34.
CW

DOH

~Phil

[jfs322]

Thanks, guys. I'll use #183, I just wasn't sure if the 80s Skyline EL-34 amps were comparable to the late 90s Skyline EL-34 amps. Any significant changes to those eras (aside, of course, from the addition of HRM)?

No!.. Apples and Oranges!. The only common features between the 2 being the tone stack (Skyliner) and output section (Fender Twin/ Showman style PI) #183. You could certainly use the Bluesmaster (Plexi Marshall) with the 34's for a more aggressive (rock) sounding amp!. This all depends on where you want to take it.
Btw..Dumble also used the #183 style PI in his Musicman Skyliners (non HRM) loaded EL-34's as well,

Tony

Thanks, Tony. I'm guessing there isn't a verified schematic / layout for these late 90s Skyline HRMs, then? If not, would I get closer to it by working off of your Bluesmaster layout with slight tweaks to the tonestack, rather than working off of #183?

[talbany]

Use the schmo Erwin posted since it has the basic HRM topology,ie channel switch wiring (clean master) and the OD entrance,HRM stack and Rp/Rk values for V1 and V2.
You can then use the 183 layout to help wire up the tone controls on the front as well as the sockets (flying the grids) on the output tubes to accept the 34's.
Both layout and scmo have the same PI values..
That would be the easiest way to do it IMO!
Let us know if you have any questions!

Tony

[jfs322]

Will do. Thanks!

[Guitarman18]

Hi jfs322,

This is a schematic of an actual 90's HRM w/EL34, observed by ic-racer, so it is well documented and has everything you need.

https://ampgarage.com/forum/files/ods_102_hrm_158.pdf


Follow his build here:

https://ampgarage.com/forum/viewtopic.p ... +hrm+build

I see that a number of his Photobucket pictures are no longer available, but I can assure you that the quality of ic-racer's work and his meticulous attention to detail for all his projects, means that this is dead nuts accurate to the original.


Also, FWIW, a very popular post (1 response!) that I created at the time, for the BOM. Many of the links are probably no longer active, but it should get you started.

https://ampgarage.com/forum/viewtopic.p ... 942#p65942

Have fun!

Cheers,

Paul.

[jfs322]

Awesome, thanks!