What the hell is this?

[talbany]

So going through some old shots I ran across this?
It appears to be an original "high plate "classic" with 150k slope, standard OD entrance, snubbers, and LNFB on V1B OD level added on the back. Caps dated 75. Other strange things are Q-line CF's on one side of the plates and some kind of (red) precision MF's on the other and CF's on the cathodes. It also has both flex foam and RGU-59 coax and a 220P Difilm on V1b coupler?
All on a 2nd generation chassis with slide switches. I don't remember when or where I got the shot but have never seen anything like it!
Anybody know the ser # or any other info on it.Specs look similar to the Ferris amp #075
BTW.Shot looks like it could be taken @ Two Rock.

I'll bet it sounds great!

Tony

109-0924_IMG-1.jpg

[M Fowler]

I don't have that particular photo Tony but it looks similar to the one I have marked as 70's Dumble.

70 Dumble.JPG

[Charlie Wilson]

Interesting amp Tony. Yeah that further confirms my suspicion that mismatched resistors on the plates and sometimes cathodes is done on purpose. I now know what those Q-Line 1w resistors sound like and it is probably not what you would think. They are very dull and thud like. So he has a clear, probably TI Instruments metal film going in, and a thud like resistor going out. I wanted to say that it may have been a 2nd Gen with replaced boards but the dates on the filter caps and the converted funky OD entrance on the preamp board seem to be the original boards. Maybe a very early idea for a high plate(pre Roderstein Mk3 resistors) and the use of formica for boards.
CW

[talbany]

Interesting amp Tony. Yeah that further confirms my suspicion that mismatched resistors on the plates and sometimes cathodes is done on purpose. I now know what those Q-Line 1w resistors sound like and it is probably not what you would think. They are very dull and thud like. So he has a clear, probably TI Instruments metal film going in, and a thud like resistor going out. I wanted to say that it may have been a 2nd Gen with replaced boards but the dates on the filter caps and the converted funky OD entrance on the preamp board seem to be the original boards. Maybe a very early idea for a high plate(pre Roderstein Mk3 resistors) and the use of formica for boards.
CW

CW
Thanks for the shout out Yeah! So based on the parts in this amp It looks like this one was voiced more for the OD side and going for a scooped 80's thing darker 2nd order heavy and very smooth and compressed. This would all be due to the "thud/dull" sounding Q-lines along with the 220P Difilm and ceramic cap, .047 mid cap and the 1-watt Phier being the main culprits and of course the LNFB/Snubbers. The 150k slope and to some extent the LNFB on V1B to cut back some of the low-end thump the high plates generate makes sense The clean on this thing won't have much sparkle (vs the stock 2nd gen) so you would have to keep the bright cap in if that's what you were after. Do you concur with this?


BTW. I didn't notice the funky OD convert on the board. The PI balance pot also appears to have been rigged in there as well with just the 1 eyelet the pot sits in and the resistors floating on the other 2 lugs Pretty slick
This also helps confirm my suspicion that he went to a ceramic cap when he converted over from the funky OD to the 220k/100k trigger
Tony

[Charlie Wilson]

I agree Tony. This thing is probably has a very flat sounding clean. Although I wonder how good the OD sounds. The question I have for you is, have you ever seen Formica boards in a 2nd Gen amp? I really think this amp is one of the early prototypes for the High plate classic and was a rebuilt 2nd Gen. Here is a picture of what I think those funny little red resistors are. Dumble sometimes used those for the 220k grid on V1.
CW

[talbany]

CW
No I have not seen a 2nd Gen with formica this would be the 1st. (looks like he kept the original blackboard on the bottom) Yes it definitely looks like some kind of transition generation amp (rebuild). I always thought Steve Ferris amp (#075) was the platform for the high plate convert. Both Steve and Dumble spent allot of time tweaking that amp and the OD ratio was placed on the back and the specs are similar?

Ferris #075
- amp was build in 1981
- for a while SF visited HAD nearly weekly for tweaking the amp to his wishes
- amp was kind of a prototype for the later black chassis version
- tone stack has been modded for a wider tonal range and richer OD-sound (whatever that means)
- Overdrive and FX-loop footswitchable
- PAB only via Jazz/Rock-switch in middle position (SF didn't use it much)
- first ODS with ratio control, pot placed backsides at the hole for the poweramp-in jack
- therefore FX-loop on preamp-out via stereo jack (needs Y-cable)
- first ODS with regular presence pot (instead of accent switch)
- first ODS with internal ‘Trigger’-pot
- first ODS with internal PI-balance trimmer
- 100 W switchable to 40 W, LED indicator
- 4 Ohm output with 8 Ohm EVM12L connected (so a bit mismatched)
- cabinet is made of mahogany
- first amp with creme tolex
- 3 x 7025 (1 x Mullard, 2 x GE); 4 x 7581A Philips/Sylvavia
- SF used that amp on countless studio jobs (even for Tori Amos and MADonna)
- it was lent (amongst others) to Eric Clapton and Marc Knopfler for recording

The Ferris amp was considered one of the "Grail amps" and was on many famous recordings.Andy Brauer had a Silverface high plate classic (similar to this one)I believe was #104 Looking around I think this might be that amp but I don't know for sure if it was a 50 or 100w. (Calling Andy Fuchs!!)

BTW.Come to think of it I do remember seeing those resistors on the V1 grids on some amps. I see a lot of amps where Dumble puts MF's in that spot?
Why do you think that is? Perhaps to try and not color the natural sound of the guitar too much and preserve its clarity on the clean?

Those resistors look similar to the Dales? how do they sound? Also IYO do the 2W Q-lines sound different than the 1 W?
Thanks in advance

Tony

[Charlie Wilson]

Tony, I am pretty certain he does it to tighten the bass and scoop the mids a little. I have only seen it in high plate amps, sometimes in bluesmasters. Using a metal film as a slope has a similar effect a la #124. Tony I just bought some of those TI in 200k. Close enough to see what they sound like. I'll report back. As far as Q Lines. The 1/2w have somewhat of a high end, the 1w a bit less, so..., I think you get the idea. You could make a Thud City with those.
CW

[talbany]

Tony, I am pretty certain he does it to tighten the bass and scoop the mids a little. I have only seen it in high plate amps, sometimes in bluesmasters. Using a metal film as a slope has a similar effect a la #124. Tony I just bought some of those TI in 200k. Close enough to see what they sound like. I'll report back. As far as Q Lines. The 1/2w have somewhat of a high end, the 1w a bit less, so..., I think you get the idea. You could make a Thud City with those.
CW

Cool! I would be interested to hear how the TI's work out for U
Thud City I've made plenty of those amps in my early days of amp building.Ha Ha!

BTW. I have a set of Black gates coming. Looking forward to checking those out here in a few days

Tony