High Plate Classic? Should We build it.

[ayan]

I've been slowly building parts for my next build to scratch my obsessive compulsive addiction of these amps and help get me out of this Covid slump

The only ODS I have not tackled yet is the High Plate Classic. I know most of you out there are Skyliner freaks and that's cool! I get it,Sky is a great stack no question although I really like my low plate classic with single coils and played at low volume levels and at times miss that High plate sound especially on the OD Side.I also know the mids will be a bit scooped (although there are ways around that). Anyway, I thought I would ask around first.(anyone play one?)
Here are a few H.P.C's in action..Would you build one?... Be honest?

Tony

Sure, do it! My second build ever back in maybe 2000 was a HPC, followed by quite a few others. A great amp, not at all finicky. Great with a Strat and great with a Gibson on the rhythm pickup as shown in Gregor's video. I think I always used a 150K slope, and this particular one had a 1uF bypass cap on the V1B cathode and an extra cap at the entrance of the OD. Super pretty sounding overdrive without a trace of buzz. With the mods described it was a rock sounding amp, more of a blues or fusion amp.

G.

[Guy77]

Beautiful looking build Gil. Thanks for the update.
Is that 500k trimmer used on the OD entrance?
I see you installed the treble bleed as well, nice!

Guy

[ayan]

Beautiful looking build Gil. Thanks for the update.
Is that 500k trimmer used on the OD entrance?
I see you installed the treble bleed as well, nice!

Guy

Thanks, Guy. BTW, that was my 6th build from circa 2006, I believe it found a new home that same year. The OD trimmer was 100K and yes, it had the infamous treble bleed on it too. If were to build another one of those again, like Tony will be, I'd pay closer attention to the parts used, ditch the treble bleed and probably ditch the additional pre OD cap as well.

G.

[Guy77]

Thanks for the update Gil. I also like the idea of the 100k trimmer. I would imagine a larger trimmer may make it hard to control the low end, though I have never built this model so will not know until I try.

[talbany]

Beautiful looking build Gil. Thanks for the update.
Is that 500k trimmer used on the OD entrance?
I see you installed the treble bleed as well, nice!

Guy

Thanks, Guy. BTW, that was my 6th build from circa 2006, I believe it found a new home that same year. The OD trimmer was 100K and yes, it had the infamous treble bleed on it too. If were to build another one of those again, like Tony will be, I'd pay closer attention to the parts used, ditch the treble bleed and probably ditch the additional pre OD cap as well.

G.

Thanks for the rundown Gil..I remember drooling over those pictures however,completely forgetting it was a H.P.C for some reason I thought it was a low plate.(long time ago) I am thinking the same as you that with the right combo of parts i will be able to ditch the bleeder..Hopefully. So a couple quick questions i am grappling with. First would be the size of the bypass caps?, another would be size of the OD entrance trigger,whether or not to increase it like 124?.The last one would be to up the value of the OD master to 250k (as long as the low end doesn't get too squirilley on me).Those are kind of things I am contemplating right now..Being the proud builder of one if you were to do another and looking back and knowing what you know now? would you set it up differently?
Last one?..If you did the same makeover on H.P.C as you did on the others,would it be an amp you could still want or use?..Just curious

BTW.The amp would be predominately Strat's/Tele's
Thanks Bud!

Tony

[Charlie Wilson]

Tony, Maybe(overly bright). I think more compressed sounding. The .02 HF taper, I think, is to scoop some of the mids. It does have "Larry Carlton" scratched in the chassis. My opinion, build it with all 100k in OD and bypass caps like Gil's.
CW

[talbany]

Tony, Maybe(overly bright). I think more compressed sounding. The .02 HF taper, I think, is to scoop some of the mids. It does have "Larry Carlton" scratched in the chassis. My opinion, build it with all 100k in OD and bypass caps like Gil's.
CW

Cool! Thanks. C.W

acrw6649larry3se5.jpg

BTW.Mine has Larry the Cable Guy scratched at the bottom

Tony

[ayan]

Thanks for the rundown Gil..I remember drooling over those pictures however,completely forgetting it was a H.P.C for some reason I thought it was a low plate.(long time ago) I am thinking the same as you that with the right combo of parts i will be able to ditch the bleeder..Hopefully. So a couple quick questions i am grappling with. First would be the size of the bypass caps?, another would be size of the OD entrance trigger,whether or not to increase it like 124?.The last one would be to up the value of the OD master to 250k (as long as the low end doesn't get too squirilley on me).Those are kind of things I am contemplating right now..Being the proud builder of one if you were to do another and looking back and knowing what you know now? would you set it up differently?
Last one?..If you did the same makeover on H.P.C as you did on the others,would it be an amp you could still want or use?..Just curious

BTW.The amp would be predominately Strat's/Tele's
Thanks Bud!

Tony

Tony, I don't know that I ever built a LPC... maybe later in life? Not originally, but I seem to recall turning one of my amps into a LPC and using a 100K slope, and thinking that fattened up the sound almost to Skyliner levels. To answer your specific questions: bypass caps were V1a 5uF, V1b 1uF, V2a and b, 5 uF. I was after a clean, sustainy overdrive OD tone back then. OD entrance was the usual 220K resistor and 100K trimmer. OD level and ratio were 100K, I never liked the higher values. The 1 uF at V1b was actually from an actual ODS, maybe a one of, some say that it kind of hurt the clean sound and I think that would be a valid comment. Before the 220K pre OD resistor, I used a my own 4.7M resistor in parallel with a .0047 uF cap. That is pretty radical, but it took all the harshness away from the OD. It'd be easy to put that on a switch, but as I've said many time before, the ODS is supposed to be a simple amp... That being said, I remember Brandon telling me that Larry Carlton had told him that whenever he switched guitars (he'd gone from the 335 to some Valley Art Strat and Tele types, then to an actual Strat, LP Special with P-90s, etc.), HAD would tweak the amp to better match the new guitar.

G.

[talbany]

Thanks for the rundown Gil..I remember drooling over those pictures however,completely forgetting it was a H.P.C for some reason I thought it was a low plate.(long time ago) I am thinking the same as you that with the right combo of parts i will be able to ditch the bleeder..Hopefully. So a couple quick questions i am grappling with. First would be the size of the bypass caps?, another would be size of the OD entrance trigger,whether or not to increase it like 124?.The last one would be to up the value of the OD master to 250k (as long as the low end doesn't get too squirilley on me).Those are kind of things I am contemplating right now..Being the proud builder of one if you were to do another and looking back and knowing what you know now? would you set it up differently?
Last one?..If you did the same makeover on H.P.C as you did on the others,would it be an amp you could still want or use?..Just curious

BTW.The amp would be predominately Strat's/Tele's
Thanks Bud!

Tony

Tony, I don't know that I ever built a LPC... maybe later in life? Not originally, but I seem to recall turning one of my amps into a LPC and using a 100K slope, and thinking that fattened up the sound almost to Skyliner levels. To answer your specific questions: bypass caps were V1a 5uF, V1b 1uF, V2a and b, 5 uF. I was after a clean, sustainy overdrive OD tone back then. OD entrance was the usual 220K resistor and 100K trimmer. OD level and ratio were 100K, I never liked the higher values. The 1 uF at V1b was actually from an actual ODS, maybe a one of, some say that it kind of hurt the clean sound and I think that would be a valid comment. Before the 220K pre OD resistor, I used a my own 4.7M resistor in parallel with a .0047 uF cap. That is pretty radical, but it took all the harshness away from the OD. It'd be easy to put that on a switch, but as I've said many time before, the ODS is supposed to be a simple amp... That being said, I remember Brandon telling me that Larry Carlton had told him that whenever he switched guitars (he'd gone from the 335 to some Valley Art Strat and Tele types, then to an actual Strat, LP Special with P-90s, etc.), HAD would tweak the amp to better match the new guitar.

G.

Great Thanks! Always appreciate your take on these amps. I think I will Start here (but use a
classic stack w/150k slope) and see where that leads..I would like to try and maybe change the value to the OD trimmer as an experiment. I'll draw up a parts list of the type of parts I would like to use and do a build thread.
Thanks everyone at the Garage for your input, always good to have a few opinions of things to try going in..Now the fun part starts collecting the Parts Arrrgg!!

094_schematic_12_132.pdf

Tony

[norburybrook]

I'm eagerly waiting for pictures.......I like pictures..... go Tony



M

[marcos]

I´m a little late to the party. Anyway, here´s my .02 cents: I did play a real Dumble High Plate Classic once. A long time ago, but I remember it as being very versatile, good with both single coils and humbuckers, and not too bright at all. In my own experiments, though, I never liked the 150k slope/.05 midcap that HAD used. Good results changing the cap to .033. Good luck and lots of fun with your build, Marcos

[talbany]

I´m a little late to the party. Anyway, here´s my .02 cents: I did play a real Dumble High Plate Classic once. A long time ago, but I remember it as being very versatile, good with both single coils and humbuckers, and not too bright at all. In my own experiments, though, I never liked the 150k slope/.05 midcap that HAD used. Good results changing the cap to .033. Good luck and lots of fun with your build, Marcos

Hey Marcos
Thanks for your input,always valued here! and .033 makes sense. So my options now for a mid cap are either 6PS/.033/716P my mid pot will be a linear and my slope will be a metal film MK'3..I think?..

Better late than never
Tony

I'm eagerly waiting for pictures.......I like pictures..... go Tony

Will do.

[marcos]

FWIW, Tony, although I cannot vouch for every detail, I believe in the amp I played the slope resistor was the usual Sprague Q-Line, 150k 2% tolerance. Hope this is helpful

[talbany]

FWIW, Tony, although I cannot vouch for every detail, I believe in the amp I played the slope resistor was the usual Sprague Q-Line, 150k 2% tolerance. Hope this is helpful

Yes it was!
Most of the Classics I've seen have a C.F/Q-line..The metal films seem to have better clarity in mids and focus the low end slightly...The 715's will really brighten and push the mids forward quite a bit..Classics are already scooped (vs Skyline) so a metal film slope can help pop the mids a little and tighter lows are always welcome especially in O.D. I assume the .033 won't scoop the mids as much as a .05 will..So lots of options So will see how the amp balances out and tweak it from there. For me Classics can be a bit more challenging to get balanced than the Skyliners are..IMO.


All the best!
Tony

[erwin_ve]

Tony, I was looking at the #94 pics and noticed something strange at junction of the od entrance resistor and the trimpot, there seems to be a wire connected in the eyelet, going to...? Is it possible this is a od entrance with some resemblance to a 2nd gen od entrance: 220k to earth, the 1M trimmer would be a voltage divider, maybe wired under the board? Green wire seems to be connected to the trimmer at the tube side of the board.
What do you think?