Pre Amp Out Pwr In and Buffered Effects

[JammyDodger]

Hey All,

There is a lot of talk on in the forum about the Dumbleator and Kleinulator. Question is.... Don't modern effects really buffer the signal themselves? I don't hear much unwanted signal change when I use a couple of effect in series in this loop.

Cheers, Mike

[talbany]

A break the chain serial loop with a decent rack mount unit with controllable in and out levels..work OK at lower volume levels.. It's when you really start to push the preamp that you begin loading the PI.. This boss pedal is pretty cool.. Ive used this with good results and am able to switch effects..
http://www.bossus.com/gear/productdetai ... arentId=95


Tony VVT

[heisthl]

True the Dumbleator is not a requirement with some FX units but even with those it adds to the tone in a positive way. Once used you never go back.

[Bob-I]

True the Dumbleator is not a requirement with some FX units but even with those it adds to the tone in a positive way. Once used you never go back.

I agree. Most rack effects are ok, until you crank it up and overload it. The Dumbleator prevent this an adds some nice harmonics as well. Sometimes I used the D-lator without effects just for the richness it adds.

[talbany]

The Dumbleator makes it feel like you are playing the amp in the middle of a football field filled with marshmallows..LOL Really not kidding..



Tony VVT

[Bob-I]

The Dumbleator makes it feel like you are playing the amp in the middle of a football field filled with marshmallows..LOL Really not kidding..



Tony VVT

Funny, I've never played in a football field filled with marshmellows

I'm confused, is this good or bad?

[talbany]

Excerpt from one of Dumbles interviews back in the 80's talking about one of his cabs..

Does that change the tonal quality?

Yes. The low end is absolutely luscious. You feel like you're floating on a football field filled with marshmallows. And it gives a singe to the midrange that puts solos right out there. It works great for chords and solos, but especially well for slide. It's the kind of enclosure that Lindley and Lowell George used.

What I hear when I use the loop is more compressed low end as well as a bit more low end Bloom.. Which sounds to me like what Dumble was implying in a corksniffer kind of term.. That's all
Sorry for the flyby

The whole article...http://www.roblivesey.com/dumble/

Tony VVT

[Fischerman]

lol I thought that was a strange metaphor too (from the orig HAD interview)...probably because I hate marshmellows and even the smell of them is kinda sickening.

Now...a football field filled with women's breats? I'm so there.

[Structo]

Well HAD certainly can lay claim to the most flowery metaphors I have ever heard when talking about tone and tubes.

Like that YouTube with HAD on it.

http://www.youtube.com/watch?v=iVTj08qTwGw

[Structo]

This quote from the interview puzzles me. Is the preamp section of the ODS really that high gain?

Like 1:1,000,000?

(Q) Why is the Overdrive so sensitive?

(A)
It's a different kind of signal handling. In the Overdrive, I approach gain levels that are extremely intense; within the linear region, I have a signal gain capability of one million. So if you stuck 10 microvolts in, you'd get 10 volts back. And I do it with stability, and it's still very musical. The best way to approach an Overdrive is real slow. Walk up to it, look at the knobs, have it turned down real low, and then get a feeling for it. Learn what to do with your fingers to make it respond well. If you walk right up to it, it has a tendency to absolutely frighten some people. The secret control on the Overdrive's panel section is the ratio control, which controls how much overdrive is fed back into the circuit. If you turn that up, it's Rock City.

[FUCHSAUDIO]

The preamp output is fairly hi impedance, and the cathode follower part of a Dumbleator lowers it to drive effects, especially solid state effects which have lower impedance inputs than a tube unit would have. The return portion of the D-lator raises the return signal level (to compensate for lower output from pedals etc.) and adds some sparkle and slight EQ to the signal as well.

You could plug effects right into the patch jacks without a D-lator type device, but it may work less than optimally or suck tone....

[glasman]

This quote from the interview puzzles me. Is the preamp section of the ODS really that high gain?

Like 1:1,000,000?

Probably, that is only 120dB. The first two preamp stages have about 32dB (or so) each so you already have 64db with the clean master and tone controls maxed out. Another 60dB would be possible, but the circuit throws gain away as a few critical stages so net gain probably is closer to say 60 to 65 dB for the amp under normal settings.

Given a 50mV (guesstimate) guitar signal and 100 watt amp @16 ohms you get

(40V rms / .05V) = Gain of 800 or ~58dB.

(40V RMS deliver 100W into 16 ohms)

[talbany]

This is something I have always wondered about.. Since frequency is impedance dependent.. (We know this to be true with output transformers) How does it effect the frequency when the impedance is lowered through the cathode follower buffer.. I am sure there is a mathematical equation that explains what it does but how does it effect feel and character is the real question?



Tony VVT

[rmb550]

This is something I have always wondered about.. Since frequency is impedance dependent.. (We know this to be true with output transformers) How does it effect the frequency when the impedance is lowered through the cathode follower buffer.. I am sure there is a mathematical equation that explains what it does but how does it effect feel and character is the real question?



Tony VVT

I think in fact the converse is true -- impedance is frequency dependent.

[talbany]

Sorry got em backwards.. Impedance is frequency dependent.. still you change one it still effects the other or am I wrong in assuming this..
Another words how does lowering the impedance effect frequency response

Tony VVT