First Post!!! (Clean blues master EQ question)

[richon]

Hi,

I've build like 10 amps sofar , fenders, marshall and all in between ( I just build a 183 50W with 6L6 which sound awesome, but it was for a friend)

Now I want to build my last one!!! , so I was thinking in the blues master, after seeing a lot schematics from brown note, ceriatone, etc, etc

I really like the fender clean with a twist into more mids, tweed-esque and blackface all mixed and sofar the 183 sounded good, but I see the blues master has a different eq

what should I expect from a clean side , blues side of sound from the blues master eq?

[Teleguy61]

Many many posts in the files on the BM type amps.
Click "Search for all terms", start in Dumble Files, and the move to
Dumble Discussion.
Search also for "Ripper" style amps, they are a nice twist.
Good luck.

[richon]

I've been reading a lot lately of the EQs in the different versions of Dumbles vs Fenders


so far I don't know what to expect beside words "more articulate" and so on

I want to understand why use the bluesmaster (390p, 22n, 22n, 250K treble, 500K bass, 25K miss) over the Vibroverb/Twin (250p, 100n, 47n, 250K treble, 250 bass, 10K mids)

more mids? (as I saw in the TONESTACKCALCULATOR)

but would this blues master EQ work better for getting clean/bluesy sounds of a strat (no OD channel) instead of the "strange" Dumble EQ: (390n, 100n, 10n, 250k treble, 500k bass, 250K mids, with the mids working apart from bass

[Teleguy61]

The Dumble topology in the preamp section is much more than just the caps and resistors. The various voltage and bias combinations have a great deal to do with the tone, also the pot values and tapers.
Pick one and build it as a good schematic here shows, play it awhile and then start tweaking.
Very rewarding experience.

[mhartman]

I haven't played them all, but I can tell you that I didn't love the bluesmaster tone stack for dumble style, blusey cleans. If I were building that style of amp, I would probably start with a low plate classic or skyliner and then tweak from there. This, however, is just one guy's opinion, however, so YMMV.

[talbany]

I personally like the BM cleans..The BM stack really should not be compared to a Marshall type stack in terms of tone, since the Marshall stack is cathode follower driven it has a lower driving impedance which effects gain and frequency response...
You can't really compare them to a Fender stack because of the lower .022 Bass/mid caps and 47k slope..So it kind of is it's own sort of thing..
The BM stack can be a bit bass heavy and mid scooped and does't seem to carry the losses like the Skyliner (the need for the low gain OD entrance on the BM)..So it's a bit more lively..A big part of the BM (bluesy tone) comes from the hotter higher gain less GNFB output section..If you like pedal driven OD type tones a BM stack and output section would be a cool single channel blues based amplifier..

Tony

[boldaslove6789]

I dig the BM cleans too... particularly with the "Mega Boost" PAB. I think even a Skyline Stack with FTSW'abe PAB ("Mega" Boost) is the perfect recipe for Blues tones for someone that plays a wider variety of guitars.

Tip on modding your amp:

Mod the Normal Ch tonestack to a Skyline (high or low plate) or BM (high plate), add a relay Pwr supply for a relay or two and add a PreAmpBoost boost. Make sure you tweak the Dropping string to get the plate B+ just right (use the B+ voltages on the Layout/scheme's in the files section), and you'll have an amp that is mucho more versatile than what it is now.

[richon]

low plate is 190V and high plate is more 260V ???

I play only single coils (and telecaster)

[mhartman]

I would listen to TAlbany and BoldAsLove over me -- they are way more experienced. Mine (a temp build to see if I liked it) was too bassy for my strat in position 4 (where I like to hand out most of the time). I played with it a bit and then decided to tear it out and do something else. I could have had something wrong with that build that I missed.

[Teleguy61]

low plate is 190V and high plate is more 260V ??

Low plate refers to 100K plate resistors in V1 and V2, high plate refers to 220K/150K plate resistors in V1 and V2, with corresponding cathode resistors.

[talbany]

low plate is 190V and high plate is more 260V ???

I play only single coils (and telecaster)

I have never seen or heard of this..
Plate voltages on V1 are always around 200v on both..I've seen them as high as 210 and as low as 131v..
The 131v was on an ODS with the RF mod and had a RP/RK setup similar to ODSR#60
260-270 is more like Twin/Showman voltages!!

Tony

[Teleguy61]

260-270 is more like Twin/Showman voltages!!

Exactly. Hearing the "high plate/low plate" tossed around sounds like voltage levels. It's not, it's plate/cathode resistor combinations to set operating bias etc.
D style preamps typically operate at much lower voltages than stock Fender style preamps.
The higher voltage is a harder cleaner feel. The lower voltages, when set up right, are a little softer feeling, and have a surprisingly different touch sensitivity.

[richon]

So I Get it, low plate voltage would be my path

Now using 220k/3,3k instead of the "classic" 100k/1,5k would get me in the cleanest way?

[Teleguy61]

It is not really quite that simple.
I strongly recommend you do some research in the forum archives,
read comments, listen to clips, examine schematics and layouts.
There is not a quick fix answer.
It's worthwhile time spent, you will learn a lot.
Good luck!

[richon]

well well well

I put the voltages down in the preamp section (big improvement)

then changed the caps in the EQ to the bluesmaster ones (22n 22n) but after a test with 47K (for slope resistor) went for the 68K

and WOW big improvement... although the gain in the stage increased ... so now I know I have two things to test:

a cleaner PI and power stage

or increase the NFB resistor


so far sounds EXCELENT... but I know I can make it better

with 470R in PI and a 12AT7 works fine but I guess a 820R would do better for cleaner power stage

The bass is a lot, should a 47n (instead of the 100n in the power stage) work better for taming the excess sub bass notes?

the NFB resistor is 4,7K which is kinda fizzy with the 470R in the PI, and a classic fender vibroverb (820R) works better... any thoughts?