The REAL DEAL Dumble Shootout!

[Funkalicousgroove]

Last night I was invited over to a fellow's house who just happens to own not one, not two, but THREE Mid/late 80's 100W Overdrive Specials. He told me to bring the best of my best (Honestly I just brought one that I had handy) and he was going to let me listen and compare to his real ones.

His amps:
1. A fairly squishy skyliner non-HRM 100W
2. A REALLY STIFF skyliner non-HRM 100W
3. An HRM that kinda fell in-between feel wise

all 3 amps had sovtek 5881 outputs, Beijing production 12ax7's and the serial# were within 20 of eachother.

The first one we played was the "Pinnacle" it had the lowest serial, and was the classic NON HRM sound, but VERY responsive to touch and pick attack, very 3-d indeed.

The second one had a music man OT, and was quite stiff, it sounded ALOT like Robben ford's Mystic Mile tones. The response was lightning fast and the bass was quick and "thumpy" there was no "Give" to this amp at all.

The third was my favorite, and closest comparison to the one I brought as far as circuitry. It was the standard HRM, and judging by the response I'd be willing to bet that it had the 20K OD trimmer.

Each of the 3 were TOTALLY different from eachother, but all cut from the same cloth.

MY AMP:
100W HRM with my own personal OD entrance network, and the Bluesmaster PI. JJ 6L6's , a beijing PI, New Sensor Mullard pre's.

The owner of the Dumbles was GREATLY impressed with the amp I brought, and although it was slightly different in voice and feel, was equally as magical, there were a total of 7 of us there, and at least half of then actually preferred the amp that I brought because it was a tad more agressive with the blues master PI. Feel and response between the HRM ODS and my amp were almost identical, so was note bloom, and string-to-string balance.

I will say that the broken-in amps had a little nicer vibe than the new amp that I brought, but other than that they all sounded like they were from the same family.

Guys, we're on the right track, and quite frankly I DID NOT hear a $30K price difference.

[chris_sanford]

A REALLY STIFF skyliner non-HRM 100W

Mr. Funk,

Great story... thanks for sharing! Did the amp with the MM OT also have the standard MM power tranny? Any piccies?

chris

[Funkalicousgroove]

I was not allowed to take pics, but down the road I may be allowed to get inside one or two of them, he was quite happy to know that I could service them!

The one with the Music Man OT had a 4-130 OT, and what looked like a MM PT (Which makes sense with the sovtek 5881's because they will take 700 plate volts if you run the screens around 350), but where they were sitting I really couldn't see inside very well, I was just really honored that he had me over and let me play with his $30K amps! I really tried not to overstep my boundaries.

One of the amps still had a little note from HAD inside it, but I couldn't see to read it.

The HRM had an OT that I didn't recognize, but it could have been another MM, it had the brackets like the MM OT's but this one was REALLY thick-maybe a 150W MM?

[chris_sanford]

The one with the Music Man OT had a 4-130 OT, and what looked like a MM PT (Which makes sense with the sovtek 5881's because they will take 700 plate volts if you run the screens around 350), but where they were sitting I really couldn't see inside very well

Choke or no? I'm curious as to where you thought the stiff feel was coming from? Stiff power-supply? Bypass caps on the master? ?? Anyway, thanks for the info! Hopefully you will get to spend some more time with these amps in the future!

chris

[Funkalicousgroove]

The story is:

When the owner ordered the second amp he asked Howard for more of the "Robben Ford" thing, and he also requested that his new amp not "Ghost note" as much. I'd Imagine that it probably has BIG caps on the first stage, and might very well have 700 volts on the plates.

THe amp was smooth as glass, just REALLY stiff.

[chris_sanford]

The story is:

When the owner ordered the second amp he asked Howard for more of the "Robben Ford" thing, and he also requested that his new amp not "Ghost note" as much. I'd Imagine that it probably has BIG caps on the first stage, and might very well have 700 volts on the plates.

By big caps of the first stage, do you mean the main ps filter caps?

THe amp was smooth as glass, just REALLY stiff.

I *want* THAT! (or at least, I want to know how to make my amps do that)

chris

[Funkalicousgroove]

If it did in-fact have the MM PT then it would have been running 700 Volts on the plates, so really having a total of 100uf (2x200uf) on the first filtering stage would probably have the desired effect of making it stiff and tight.

[chris_sanford]

If it did in-fact have the MM PT then it would have been running 700 Volts on the plates, so really having a total of 100uf (2x200uf) on the first filtering stage would probably have the desired effect of making it stiff and tight.

Well, all things being equal, the screen voltage controls a pentode much moreso than the plate, so with 350 on the screens, I would think the amp might actually be a little squishy. Of course, the overall preamp voltages might end up higher. Hmmmm.

chris

[Funkalicousgroove]

Honestly, that amp is his least favorite of the 3, and possibly the best candidate for letting me scope it out, If he agrees to let me crack her open I'll give ya all the juicy details.

[chris_sanford]

Honestly, that amp is his least favorite of the 3, and possibly the best candidate for letting me scope it out, If he agrees to let me crack her open I'll give ya all the juicy details.

That would be sweet! I'll keep my fingers crossed.

chris

[Funkalicousgroove]

For privacy purposes the owner wishes to remain anonymous

Send me an email and I'll give ya tha details.

[glasman]

700v on 5881's? What keeps them from melting down.....

[chris_sanford]

700v on 5881's? What keeps them from melting down.....

350 volts on the screens, dude.

chris

[glasman]

missed that....

[Funkalicousgroove]

I was kind of surprised that all 3 had them, I honestly expected to see STR's or 7581A's.