Bluesmaster - getting rid of excessive bass - SOLVED= D'lato

[bluesfendermanblues]

Having recently finished a Bluesmaster 100w with EL34s, I must confess that it took me a LOT of tweaking time to get the amp trimmers dialed in.

I'll post some pictures and clips soon, even if my amps looks fairly cramped.

Compared to skyliner amps (of which I have 3) the Bluesmaster should really be labelled; BASSMASTER Its a mystery to me why HAD used a 1M pot or 500K Bass pot in those amps. Maybe because the Dumble bluesmasters are converted Skyliners, where he just kept the original pots. Same goes for the Bassmaster HRM Bass trimmer, that must have been an old habit from the skyliner HRM's.

I like to have usable OD tones with both OD mode and OD+PAB mode, which is a time consuming challenge, trying to find a (front panel) bass pot setting, that works for both clean sounds and OD (without PAB).
It takes a lot of back and forth between one bass pot setting and how high you can set the OD trim and the HRM trims. HRM were set like this: Treble trim at 100k, Bass trim at 40k to ground and middle trim at 4k.

If you look at pictures of Matt Schofields or Larry Carlton's Bludo BLUESMASTER settings, you will see that both players have the (front panel) tone control settings close to:

- treble at '5' (12 o'clock) (120k between center and 'ground' wiper)
- mid at 3 (9 o'clock) (6.4K between input wiper and center)
- BASS at 2½ (8:30 o'clock). (25k between input and center wipers)

You might argue that Scott Lerner (who I believe use Bluesmaster amps from Glaswerks and Bludotone) has his tone controls at noon in many of his youtube clips? Yes, but Scott plays lead guitar on those clips (e.g. in the 'kitchen' clip) - with OD and PAB on.

And I have seen Scott mention somewhere, that his amps use MEGA BOOST (22M resistor from mid pot to ground), which in effect means that the tone controls are not active in those clips.

BTW I ended up with a 75k PAB resistor.

Since I like to see my tone control pots at noon, a setting that usually works on Skyliner amps, I ended up changing the Bass pot to an alpha 50K logaritmic (that gives 25k at noon) and the mid pot became a liniar 25K alpha (that give 6.4 at noon). You have to check a few pots to find the suitable ones.

I hope this info is helpfull to other Bluesmaster builders who have had bass issues. My BM would have caused earth crakes with the pot values as per the recent schematics.

I am very gratefull to a lot of you fellow forumites, who have posted a lot of your knowledge about the Bluesmaster and other Dumble amps. Wtihout your info and input, I wouldnt have 4 nice Dumble clone amps. THANK YOU!! Dogears, Ayan, Tony, Henry, Johan, Max, Steven and a lot of others kind people. I really am gratefull - Happy holidays.

[bluesfendermanblues]

Matt Schofield and Larry Carlton amp settings

[Structo]

Man, unless Larry is running his amp through a device that tames the volume, that must be a very loud sucker.

On my 100w I can barely get the volume and master above 8:00 before it is way too loud.

I use my Dumbleator to tame the volume and get the controls up into the usable settings.

My amps bass response is pretty huge as well and I usually have the mid and bass pots 9:30 and 9:00 respectively.

[tubedogsmith]

He doesn't use the OD side though does he.

[FUCHSAUDIO]

According to my discussions with Matt (who had Larry's Bludo on loan for a time), he said "I could dial in some sweet tones, but the knobs were sure in weird positions when I did". Not sure what to attribute that to, but I've heard it before. Lots of people running around setting their amps with the knobs "just like X player" and not understanding why things don't sound right....

[Guitarman18]

I believe that Larry's Bludotone amp is in fact a Ripper configuration, which has rarely been discussed on this forum. The Bludo that Matt uses is Larry's spare AFAIK.

Looking at posts that mention the Ripper topology, I get the impression that it is a modified BM, but with 22uF cathode bypass caps, based on comments that Gary made.

'The amp started life with 22uf's across the board (ripper configuration), it now has 4.7uf on all stages'

This would go some way to explaining the extreme bass settings used by both LC and MS.

Hope this helps.

Cheers,
Paul.

[FUCHSAUDIO]

22uf explains the "buttload of bass" issue....lol

[David Root]

The "bob" syndrome! I love it!

I just finished wiring up my Bloozman HRM, which is a Bluesmaster HRM pretty much as per Henry's schematic but with Normster's 12AT7 buffered onboard loop, in a Bassman chassis/head, and no FET input.

It has bob syndrome in Spades, I think. I cranked it up this afternoon with my reference cabinet, which is a 2x15 JBL E130. Yeah, I know, so 15" speakers, but they are guitar speakers not bass speakers, and damn good ones too.

I had to turn the HRM bass pot almost off to fix the OD tone. The clean is not bass shy either. I am thinking of changing the HRM bass pot to 250K from 1M and maybe the Clean bass pot to about 300K from 500K.

Are there any potential negatives to doing that? I understand the gain and impedance issues I think.

[Normster]

FWIW, I've been using 250KA pots for bass since my first BM build. 500KA was over the top. You might also try a 68k slope resistor to tighten things up.

[David Root]

Thanx for confirming that. I will do it.

[jelle]

Check your PM.

[Cliff Schecht]

I still have some NOS NIB 250k log taper AB pots, normal shaft length if you guys are interested. I think David used a few a while back..

[David Root]

I did indeed. Early Hecho en Mexico, look and feel very good, work fine, five out of six within 10% spec, but on the high side, mostly 265K up to 285K or so.
Great if that is what you need, but if you are hoping for on the low side of 250K, maybe not in this batch.

[Cliff Schecht]

Yeah those pots are sorta goofy like that. I can Ohm out the collection and try to set aside a few low ones if they show up too. Just trying to cut down on my unused stock of parts really .

[bluesfendermanblues]

Guys I just like to point out, that all the above mentioned Bluesmaster issues are solved by using a Dumblelator. As Mark said in another post the Dumblelator is the secret sause.

Yes you can use a Dumble amp as a stand alone, but its much better to consider a DUmble amp as part of a rig consisting of amp + dumblelator.

I've 'wasted' a lot of tweaking time - not realising that I needed a Dlator in order to get the sounds.

Now I can have the OD trimmers in my amps much higher. I didn't know just how people could get usable sounds with the OD trimmer above 20k, but the D'lator is the ticket.