So I get a call from Larry Carlton last night........

[norburybrook]

Update;

Well Larry has flown off to Spain now. My gear arrived back at my house a 2:45 am yesterday morning! I was gigging last night so just I'm just putting everything back in the studio.

So the cabinet dimensions:

in inches: 21x17x10.

it has two of these ports:

Ports 2.jpg

ports 1.jpg

and a EVM 12 speaker.

here are Larry's setting on the amp, Interesting that he has the deep(mid) switch in. But what was most interesting was when I looked at the back, he'd mismatched the cab impedance. It's an 8 ohm cab but was running it from the 4 ohm tap. I presume he could hear a difference and preferred the sound, it was definitely changed as I use it set on 8 ohms.

IMG_20181007_123251.jpg

IMG_20181007_123430.jpg

thoughts?


M

[martin manning]

Thanks, Marcus! Those are the outside dimensions?

I think you are right about the impedance miss-match (he preferred the resulting sound), but maybe following HAD’s recommendation too. The engineer in me says that’s going to be hard in the power tubes, but it seems they are able to take it. The master is not up very high, either. Maybe you’ll want to experiment and see what the tones are like both ways? Your impressions would be welcomed, I’m sure.

BTW, is the 50/100W switch just filling the hole, or does it do something?

[norburybrook]

Thanks, Marcus! Those are the outside dimensions?

I think you are right about the impedance miss-match (he preferred the resulting sound), but maybe following HAD’s recommendation too. The engineer in me says that’s going to be hard in the power tubes, but it seems they are able to take it. The master is not up very high, either. Maybe you’ll want to experiment and see what the tones are like both ways? Your impressions would be welcomed, I’m sure.

BTW, is the 50/100W switch just filling the hole, or does it do something?

outside dimensions, chosen to match the head cabinet in depth and width, the height was an estimation based on a photo.

The 50/100w is just to fill the hole, same reason I put the ground switch in. I may remove that as it's not really a good thing these days. I need to think about what to put in the hole? maybe a switchable LNFB in out. Would a long cable run be an issue?

Yes, I'm going to give it a go with these settings and see if I can hear/feel a difference.

M

[martin manning]

You could probably run coax for a LNFB defeat, ground the shield near V1, and connect the center conductor to the FB loop between the resistors on the grid side of the cap. The switch would ground the loop by connecting the center conductor to the shield.

[norburybrook]

Just pulled the covers off the Bluesmaster.

must be Larry's default settings the impedance wasn't mismatched on this. He did say it sounded a bit sterile to him compared to the cream amp. I wonder if it was the HRM thing, they do sound better with the boost and OD so you only have one tone stack in line IMHO. The Bluesmaster has vintage iron which I think makes the map a little softer than the one I built with new transformers. I'm still to know what makes and amp really great

IMG_20181007_144727.jpg

Anyway I think we can safely say these are the 'LC' settings.

M

edit; Thinking about the 'sterile' statement, could it be the precision power supply? I've often wondered about the difference with the classic and precision, would Larry's amp have a classic power supply? I think so. Perhaps it takes someone with Larry's 30 years intimate knowledge of the dumble to be able to feel/hear this straight away. Just a thought.

I also decided I didn't like the coloured knobs...so it's back to default. The coloured knobs are in a sealed bag now complete with Larry's DNA...I can clone him in the future

IMG_20181007_152531.jpg

[martin manning]

I don’t believe the precision power supply is much of a factor as long as the capacitance at each node is the same. The balance resistors will definitely draw a bit more current at each node and pull the voltages down a bit differently. I don’t think that adds up to “sterile,” but one could easily compensate for that by altering the dropping resistor values.

[talbany]

Thinking about the 'sterile' statement, could it be the precision power supply? I've often wondered about the difference with the classic and precision, would Larry's amp have a classic power supply? I think so. Perhaps it takes someone with Larry's 30 years intimate knowledge of the dumble to be able to feel/hear this straight away. Just a thought.

This is the main reason why I don't use the "Precision" power supplies (connected to metal film plate resistors) and am really picky about filter caps in all of my personal amps!

Tony

[Bombacaototal]

Excuse the ignorance but what is precision power supply? Do you mean precision resistors on bias and plates?

[martin manning]

The version with pairs of radial caps on the screen and preamp nodes.

[Bombacaototal]

Thanks Martin!

[martin manning]

I don’t believe the precision power supply is much of a factor as long as the capacitance at each node is the same. The balance resistors will definitely draw a bit more current at each node and pull the voltages down a bit differently. I don’t think that adds up to “sterile,” but one could easily compensate for that by altering the dropping resistor values.

Following up on this, 470k balance resistors result in about a 10 volt reduction at the preamp supply node, assuming constant HT. ESR for stacked filters should be the same as for a single cap if the total capacitance is the same and the loss factors are similar.

[norburybrook]

I don’t believe the precision power supply is much of a factor as long as the capacitance at each node is the same. The balance resistors will definitely draw a bit more current at each node and pull the voltages down a bit differently. I don’t think that adds up to “sterile,” but one could easily compensate for that by altering the dropping resistor values.

Following up on this, 470k balance resistors result in about a 10 volt reduction at the preamp supply node, assuming constant HT. ESR for stacked filters should be the same as for a single cap if the total capacitance is the same and the loss factors are similar.

Thanks Martin,

so are you saying there's very little difference capacitance and resistance wise then between the two power supplies? It's interesting that my 50w has the extra 100w filtering on the reservoir caps and that doesn't seem to have any negative effect.

I've just tidied up the BM front panel today so had it out of the head case. I'd forgotten that I'd ordered Tube town's own 6L6's for this amp, it was a mistake as I always use JJ's , I might have a play around with some old valves and see how it sounds. It's still very new so needs to get some miles under the belt. Looking at those new orange drop caps and the smaller resitors...it doesn't look right....I might have to get some 1w and some old drops to put i there......I'm starting to get a bit anally retentive about this now......I sawed 2 mm off the front panel today so the line at the bottom of the chassis was at the correct height......it had been bugging me.

IMG_20181009_164556.jpg

M

[martin manning]

Yes, the capacitance at each node is nominally the same for both supplies.

[Synchu]

I never had any luck with Tube Town branded tubes.
I’m using Tube amp doctor, TAD, 6L6WGC (short bottles), with my BM 50 and I’m loving it.
Niki

[skyripper2]

awesome story. way too cool.