Dumb and Dumbler

[dogears]

IMO, the magic of 102 is what the tranny does when pushed. Crazy bass textures. I'd be apprehensive not using the smallish Twin iron. The amp will not be the same.....

Hey Eric,

wasn't the Super Twin a 6x6L6 amp?
Suppose the impedance mismatch doesn't really matter...

Peace,

Markus

Hey Eric,

didn't mean to offend you
Just trying to learn...

Peace,

Markus

Dude, my lack of response wasn't due to offense just my own ignorance. My whole purpose in these builds is to learn more. OT and impedance / tube compliment is one of those areas where my knowledge is seriously lacking. Hence my silence.

You are right the super twin is a 6 6L6 amp and I'm building a 4 6L6, I don't know if the mismatch is important. Perhaps (tony) someone who's (tony) done this (tony) type of build (tony) could chime in with some clarification.

Thanks for your sincerity, no offense taken. (I'm kind of counting on the group to point out my mistakes)

Eric

[tubedogsmith]

After screwing around with this circuit I think the biggest parts driving the crazy way it catches notes and runs with them are the two 47uf caps on the first two stages. The big bright cap on the master accentuates it but you can take the cap out and it still does it some. Swap the big caps out and it sounds like a regular high plate ODS. There's a lot of magic in the power supply. The best sounding old Marshall I ever owned had a 32uf on the plates, a 16uf ea. on the screens and PI, and a 32uf ea on the two preamp stages. I've since put that set up in a bunch of Marshalls and it continues to bring back good memories.

[Max]

There's a lot of magic in the power supply.

Hi tubedogsmith,

the human sound perception system perceives many sorts of differences in the dynamics of the presentation of sound similar as it perceives differences in the frequency spectrum. And since the dynamic structure of the presentation of sound is of a similar importance for the perception of the timbre of an instrument as the structure of the frequency spectrum, an amp builder can of course achieve very different timbres just by altering the dynamic response of an amp. Applied psychoacoustics - no magic.

Cheers,

Max

[tubedogsmith]

Magic can be found anywhere, even in a guitar!!

[Max]

Magic can be found anywhere, even in a guitar!!

Of course! And no Dumble needed!

http://www.youtube.com/watch?v=IIzK8FHGZnM

[talbany]

There's a lot of magic in the power supply

No Doubt about it!!.. Here is a good example of this, where an experiment was done to try and eliminate power supply ripple yet at the same time keeping with the sag characteristics..Something most of us especially those EE want to try to eliminate(PS Ripple)..Clearly the experiment shows how PS ripple adds to the amps ability to generate harmonic content...Draw your own conclusions and perhaps we can discuss this further
One wold think here in the case of the Ford amp where V 1& V2 are filtered more would reduce PS ripple causing the amp to be more clamped but as we all know the Ford amp has no trouble running away on it's self.
Take a look.. Interesting experiment for sure..Keeping in mind an under filtered amp has it's issues as well..
Hope This Helps

Tony

[jelle]

Cool, so we need to design a 'Europe / US' intermodulation switch?

Or one with a controllable sine wave generator within the PS.....

[talbany]

Or one with a controllable sine wave generator within the PS

Jelle
Something controllable so you can locate the sweet spot for that particular amp/PS was what I was thinking..Workin on it
Cool Huh!!

Tony

[jelle]

[Zippy]

Magic can be found anywhere, even in a guitar!!

Of course! And no Dumble needed!

http://www.youtube.com/watch?v=IIzK8FHGZnM

Hmmm, what's the extra knob on that Strat???

[Structo]

Thanks Tony, that was a good read.

I too believe that everything from the primary of the power transformer to the speaker affects tone.

Here is an interesting read.

http://www.nutshellhifi.com/library/ETF.html

[talbany]

Thanks Tony, that was a good read.

I too believe that everything from the primary of the power transformer to the speaker affects tone.

Here is an interesting read.

http://www.nutshellhifi.com/library/ETF.html

Cool read Tom Thanks for sharing..

Tony

Sorry didn't mean to derail Eric's thread..

[stevlech]

Hmmm, what's the extra knob on that Strat???

Piezo pickup volume control

[David Root]

That was a very interesting read, indeed. You have to read it from a MI amp perspective not a hifi perspective, but I need to go thru that again.

[dreric]

I'm getting to the point where I am wiring up the power tubes and there's a few point where I am confused between 6L6 and EL34. (Remember that I am doing two tandem builds "dumb" a 6L6 102 and "dumbler" a HRM blues master with EL34s) Is the following correct pin out for EL34s?

EL34 (based on the HRM-102 version 1.8 schematic)

pin 1: to ground
pin 2: Heater
pin 3: Tube 4 & 5 to one OT lead, tube 6 & 7 to the other OT lead
pin 4: B+ into a 1K 5 watt (other side of resistor to pin 6)
pin 5: 5.1 k
pin 6: the other half of the 1K 5 watt from pin 4
pin 7: Heater
pin 8: 1 ohm 5 watt to ground and bias test point

I'm confused by as to the bias test point, pin 8? and the relationship between pins 4 and 6 ........... do I have these correct?

Also while we are here schematics always show the upper BLUE lead going to V4 , V5 and the lower BROWN lead going to V6, V7. Is this important? I think so but I'm not exactly sure why (phase?)

The transformer for "dumbler" is a Marshall / Dagnall with different color codes:

Brown______upper coil
White ______center tap
Red ______lower coil

Am I correct is assuming that the brown should go to V4, V5 and the Red to V6, V7?

I think the I have "dumb's" 6L6 pin out correct I will post photos of both once I get the EL34's correct.

Thanks for all the help!!!!

Eric