Loose low end

[Guitarist]

You could try a .0022 off the plate of V1.

You may think this cheap, esay and cheeky but... in the past I very gradually headed there (.047--> .022 --> .01 --> .0047) but found it works amazing. The low end roll-off curve seems to work well for the rapid palm muting riffs that this much distortion affords.

This may be why Malmsteen uses that DOD driver, it spits out leaned lows? And he uses single coils.

You could solder in a quick effects loop insert cable off the master and try an EQ for kicks. I did this for a guy with an 800 and he was very, very happy.

[daz]

Thanks, but i tried that several times. It's all moot now tho because the amp no longer has a bass issue.

[mooreamps]

The 0.022uF coupler at the input to the phase splitter is letting sub lows through, because that 1M grid feed resistor is bootstrapped by the nfb of the long tail pair. Makes the equivilant resistance that the cap sees much higher, maybe 10M. So try reducing it's value, try 4n7 in the first instance.

http://www.schematicheaven.com/newam...ge_otr_120.pdf
Peter.

The 0.022uF coupler at the input to the phase splitter is letting the sub lows go through. In fact, all the 22nF couplers are letting the sub lows go through.
So, do what this guy suggests. Also, you can put a 10 nF or a 4.7 nF coupler, on the input of the first gain stage.




-g

[daz]

But why? The issue no longer exists.

[Bruce / Mission Amps]

The 0.022uF coupler at the input to the phase splitter is letting the sub lows go through. In fact, all the 22nF couplers are letting the sub lows go through. ...

-g

What are sub lows? I see this mentioned quite a bit.

[daz]

I think thats a rhetorical question, yes? Because i'm sure you know they mean lows that are too far down the freq range for guitar and therefore cause muddiness. I know it's said that the low end on a guitar only extends so low, but it can extend lower than is desirable in some amps. That was part of my issue....it wasn't just flabby bass, but the lows were so far down the spectrum that it was an issue because if i turned the bass down to get rid of it, along with those "sub lows" went the bass i WANT too. If i turned it up to get the lows i wanted, along with those came the sub lows too, muddying up the tone. I was never able to remove then with tone stack values or coupling cap changed. What did it was changes to the PSU and a few changes in what places withing the preamp the most and least gain boosts were taking place.

Anyways, i still think you were being tongue in cheek, but if not thats what i think is meant by sub lows.

[Chuck H]

Yeh, I see that alot too. Because of context I've always figured it to mean anything below about 50hz. Which is, by some, supposed not to be reproduced by a guitar amp. But in practice you can actually hear the difference between a .047uf and a .022uf decoupling cap off a standard gain stage. There must be at least some fundamental interaction due to LF response in the amp that affects the final tone even if the your not getting much below 70hz out of the speaker. So the idea that just chopping off the "sub lows" will only eliminate non audible frequencies, and not be noticable otherwise has to be wrong. I have noticed that anything above about a .0047 cap feeding the input of a standard LTP PI seems to make no difference. But that's because of the impedance relationships in that circuit.

Chuck

[guitician]

You have to realize that the roll-offs of each coupling cap add up to become sharper. Working with one cap is just -3db per octave, but four stages with the same caps will be -24db per octave. This will let you take out the lows below 50hz without effecting the guitars fundamentals.