ampage Tube Amps / Music Electronics	For current discussions, please visit Music Electronics Forum.

ampage archive

Vintage threads from the first ten years

previous: rooster The sheetmetal work is not a proble... -- 7/26/2004 8:04 PM

Re: TSL with OEI?

7/27/2004 3:46 AM
Eth	Re: TSL with OEI? Hey! Let me know how it goes on the tranny swap. I was thinking if it would be possible to take the bell covers from the stock one and swap it too a jcm800 tranny. ? Is that what you mean by OeI, the 800? I own a tsl100 myself and I play metal and thrash. I bought it based on scott ians endorsement.... And I am basically pretty happy with it....or something... My home made amp with jcm800 trannies definitely has the balls on that one.... I do play live with my tsl often though, it sounds heavy as hell with an eq in the effects loop. I use one that I built up based on the eq section(s) of the boss mt-2. Which is basically a resonant boost at 100hz, a sweepable mid, and a resonant peak somewhere between 2.5K and 5khZ. Let's assume there is no eq box in the feedback loop! From now On.... All the time, I play with the "deep" switch out/off. That circuit is an op-amp based gyrator in the feedback loop of the power amp. A gyrator is a silicon simulation of an inductor. So they paired that with a cap and ... inside the feedback loop got a resonant bass boost. So the feedback loop is decoupled in the bass region. Darn! I just erased the theoretical argument for it I have never done the math for the frequency, but I will bet $, the gyrator / cap is set for ~ 100Hz... I don't use it because I can't get over the theoretical argument that: by useing this switch the damping factor in the 100Hz region is super low, bass distortion is probably pretty high, and the effect of a change in volume will be more drastic with it in/ON than OFF. The reason that volume changes will drastically effect the bass is because Marshall 4x12's resonance is ALSO at 100Hz....The best ones are, at any rate.... Any way, so now as the speakers get moving and the cab starts to get resonant...That perfect threshhold arrives and is gone! It is so narrow because the poweramp can't keep that frequency range dampened. Usually the cabinet gets going and the damping of the power amp still can dampen those speakers for a few more decibels before it is blown out and muddy.... Not to mention that the power amp is resonant at this same frequency! O.K. more rambling... I don't find that the tsl lacks bass. I run the bass control at 4! (mid3, treb5). The minimum bass setting before it goes away keeps the bass clear. And I actually changed my slope resistor to 47k, because otherwise you have to crank the treble in order to get the midrange dip to be in the right place (low enough on the frequency spectrum) The eq is a way to totally blow minds... O.k. so that is one way to get there. And maybe something to try. And I really am playing frickin metal Too! So I hope maybe some of this helps, and I am all ears on the tranny swap!!!!! later, Eth (guitarist for SMYT)

7/27/2004 3:46 AM

Eth

Re: TSL with OEI?

Hey!
Let me know how it goes on the tranny swap. I was thinking if it would be possible to take the bell covers from the stock one and swap it too a jcm800 tranny. ? Is that what you mean by OeI, the 800?

I own a tsl100 myself and I play metal and thrash. I bought it based on scott ians endorsement.... And I am basically pretty happy with it....or something... My home made amp with jcm800 trannies definitely has the balls on that one....

I do play live with my tsl often though, it sounds heavy as hell with an eq in the effects loop. I use one that I built up based on the eq section(s) of the boss mt-2. Which is basically a resonant boost at 100hz, a sweepable mid, and a resonant peak somewhere between 2.5K and 5khZ.

Let's assume there is no eq box in the feedback loop! From now On....

All the time, I play with the "deep" switch out/off. That circuit is an op-amp based gyrator in the feedback loop of the power amp. A gyrator is a silicon simulation of an inductor. So they paired that with a cap and ... inside the feedback loop got a resonant bass boost. So the feedback loop is decoupled in the bass region. Darn! I just erased the theoretical argument for it

I have never done the math for the frequency, but I will bet $, the gyrator / cap is set for ~ 100Hz... I don't use it because I can't get over the theoretical argument that: by useing this switch the damping factor in the 100Hz region is super low, bass distortion is probably pretty high, and the effect of a change in volume will be more drastic with it in/ON than OFF. The reason that volume changes will drastically effect the bass is because Marshall 4x12's resonance is ALSO at 100Hz....The best ones are, at any rate.... Any way, so now as the speakers get moving and the cab starts to get resonant...That perfect threshhold arrives and is gone! It is so narrow because the poweramp can't keep that frequency range dampened. Usually the cabinet gets going and the damping of the power amp still can dampen those speakers for a few more decibels before it is blown out and muddy.... Not to mention that the power amp is resonant at this same frequency!

O.K. more rambling... I don't find that the tsl lacks bass. I run the bass control at 4! (mid3, treb5). The minimum bass setting before it goes away keeps the bass clear. And I actually changed my slope resistor to 47k, because otherwise you have to crank the treble in order to get the midrange dip to be in the right place (low enough on the frequency spectrum)

The eq is a way to totally blow minds... O.k. so that is one way to get there. And maybe something to try.

And I really am playing frickin metal Too! So I hope maybe some of this helps, and I am all ears on the tranny swap!!!!!

later, Eth (guitarist for SMYT)

Replies:

rooster Hi, Eth.By OEI, I am referr... -- 7/27/2004 1:34 PM