Steve Farris ODS #075

[Max]

Is our understanding in regard to what is called a "classic" tonestack the same?

Max
My info concurs...Would you say the the 1 constant he used throughout the life span of the classic era stack that separates or identifies the Classic from following generations would be the 100k mid pot and could be used as the determining factor here.. My info says it does..Thanks!!

Tony

Tony,

what I think has been referred to as beeing a "classic" tonestack here on ampgarage is this:

Treble: 300/330pF, 250k
Middle: 47/50nF, 100k
Bass: 100nF, 250k (no capacitors soldered directly to the pot)
"Deep" switch (no "Mid" switch)

For my current understanding this "classic" tonestack is the one you will find in all the "transition generation" and "4th generation ODS" until the introduction of the "Skyliner" tonestack (5th generation ODS).

The Farris amp #075 is one of the very first (maybe the very first) ODS with a version of this "classic" tonestack. The last ODS amps originally built with a "classic" tonestack can be found in the 16X series # range. The first ODS amps originally built with a "skyliner" tonestack can be found # in the 15X range. So the transition from the "classic" to the "skyliner" stack will have taken place in the 15X - 16X series # range.

The "silverface" ODS amps up to approx. series #070 did not yet have this "classic" tonestack. But some of these have been updated later on by Alexander with a "classic" stack just as some of the ODS amps originally built with the "classic" stack have been updated later on with a "skyliner" stack.

Am I right?

Have a nice Sunday,

Max

[talbany]

Max
Thanks for the insight!!

Tony

[talbany]

Max

One other thing..Looking back through some schematics of some of the first ODS (Gen 1) 1-8 I have.. These bear very similar specs to that of the classic
Treble: 250/500pF, 250k
Middle: 47/50nF, 100k
Bass: 100nF, 250k (no capacitors soldered directly to the pot)
"Deep" switch (no "Mid" switch)
Bright switch 250pf
100k Slope..

Striking similarities don't you think and don't believe the sonic differences were that different (looking at it from my chair)..I am just speculating here but it looks to me like he went back to the earlier stacks and tweaked them a bit.. Do you think it may be possible the transition or classic stacks were a slightly tweaked version and were more custom voiced or part of the evolution?...I am trying to find a common theme or set of parts that would identify it as such and don't see it... Sorry for all the questions.. But you can see where it gets confusing at times..

Tony

[marcos]

Hi Max and Tony,
maybe we should start a new thread covering the topic of the different
tonestacks.
One more question: Does the tonestack with 250K Treble and Bass pots,
100K mid but with a 150K slope resistor qualify as a "Classic"?
Quite a difference in tone to the version with the 100K slope, and it seems
that there is a good number of amps with this tonestack.

Have a nice day Marcos

[bluesfendermanblues]

Hi Max and Tony,
maybe we should start a new thread covering the topic of the different
tonestacks.
One more question: Does the tonestack with 250K Treble and Bass pots,
100K mid but with a 150K slope resistor qualify as a "Classic"?
Quite a difference in tone to the version with the 100K slope, and it seems
that there is a good number of amps with this tonestack.

Have a nice day Marcos

I tried a version of the classic stack with a 1k resistor at the bottom end of the bass pot (inspired by Ayan's posts about #124 mods). It seriously lowered the amp volume, and sounded very close to a basic Fender Blackface tonestack. However, I reversed to the Skyliner which is much more flexible and powerfull. Just my two cents.

[Max]

Max

One other thing..Looking back through some schematics of some of the first ODS (Gen 1) 1-8 I have.. These bear very similar specs to that of the classic
Treble: 250/500pF, 250k
Middle: 47/50nF, 100k
Bass: 100nF, 250k (no capacitors soldered directly to the pot)
"Deep" switch (no "Mid" switch)
Bright switch 250pf
100k Slope..

Striking similarities don't you think and don't believe the sonic differences were that different (looking at it from my chair)..I am just speculating here but it looks to me like he went back to the earlier stacks and tweaked them a bit.. Do you think it may be possible the transition or classic stacks were a slightly tweaked version and were more custom voiced or part of the evolution?...I am trying to find a common theme or set of parts that would identify it as such and don't see it... Sorry for all the questions.. But you can see where it gets confusing at times..

Tony

Tony,

are you sure from the date codes on the pots and the kind of parts used etc., that these 1st generation amps with some sort of "classic" tonestack have not been updated by Alexander to "classic" specs?

Have fun,

Max

[Max]

One more question: Does the tonestack with 250K Treble and Bass pots,
100K mid but with a 150K slope resistor qualify as a "Classic"?

Hi marcos,

in this thread you find the schematics of #094 („transition generation”) and #123 (4th generation):

https://tubeamparchive.com/viewtopic.ph ... 94&start=0

Both schematics show 150k slope resistors, and as far as I remember, both amps always have been referred to on the ampgarage site as still having a "Classic" and not yet a "Skyliner" tonestack.

In the "Dumble Files" section you find a schematic of #124 before the Skyliner update. This schematic of the "classic" version of #124 shows a 100k slope resistor.

That is why I thought up to know, that the term "classic tonestack" - as used here on the ampgarage site - does not depend on the fact, that it has a 100k and no 150k slope resistor.

Is this wrong?

Cheers,

Max

[talbany]

Max

One other thing..Looking back through some schematics of some of the first ODS (Gen 1) 1-8 I have.. These bear very similar specs to that of the classic
Treble: 250/500pF, 250k
Middle: 47/50nF, 100k
Bass: 100nF, 250k (no capacitors soldered directly to the pot)
"Deep" switch (no "Mid" switch)
Bright switch 250pf
100k Slope..

Striking similarities don't you think and don't believe the sonic differences were that different (looking at it from my chair)..I am just speculating here but it looks to me like he went back to the earlier stacks and tweaked them a bit.. Do you think it may be possible the transition or classic stacks were a slightly tweaked version and were more custom voiced or part of the evolution?...I am trying to find a common theme or set of parts that would identify it as such and don't see it... Sorry for all the questions.. But you can see where it gets confusing at times..

Tony

Tony,

are you sure from the date codes on the pots and the kind of parts used etc., that these 1st generation amps with some sort of "classic" tonestack have not been updated by Alexander to "classic" specs?

Have fun,

Max

Max
Thanks again!!.. The layout I have is I am sure very accurate.. Although I cannot say for certain if the amp had ever been upgraded and layout modified.. may have been.. So there you go.. Thanks Again for the reply's.. Be Well!!

Tony

[Structo]

On the pre-#124 ODS amps, there appears to be a OD tone control on the output of OD2 shown on the schematics.

Was this pot adjustable on the front panel? Or only as an internal trimmer?

I know there was an Accent switch on early ODS amps but that was a Presence or a brite switch, no?

Not sure when he switched to blackface chassis but I have pictures of what appears to be #84 that is a blackface with a small Presence (Accent) pot.

Then by the Beach Boys #97 the Presence pot has a full sized knob.

So somewhere between Gregor's #94 and #97 HAD gave the amp the full sized Presence control.

[erwin_ve]

On the pre-#124 ODS amps, there appears to be a OD tone control on the output of OD2 shown on the schematics.

Was this pot adjustable on the front panel? Or only as an internal trimmer?

Treble bleed. internal pot. Probably for amps without a dumblelator.

[Max]

On the pre-#124 ODS amps, there appears to be a OD tone control on the output of OD2 shown on the schematics.

Hi Tom,

here you can see the "data sheet" of the 4th generation ODS:

http://www.berkleemusic.com/assets/disp ... dumble.pdf

In the line that starts with "Overdrive Controls" you can read:

"level, ratio, with internal trigger & h.f. taper"

As you can see from the internal pictures of #094 you find this "h.f. taper" in at least some of the "transition generation" amps, too (as far as I know, all "transition generation" amps have the "trigger" control).

My question:

Why do you think, that you do not find the "h.f. taper" in all the 4th generation amps but only up to #124 ("On the pre-#124 ODS amps...")?

Was this pot adjustable on the front panel? Or only as an internal trimmer?

In most ODS you’ll find the "trigger" and "h.f. taper" controls inside the amp. But there are some where you can find them on the back or front, too.

Here you can see a picture of an amp (#0121), with external "trigger" and "h.f. taper" controls originally placed on the front (the silver ring in the "Level" position is the "trigger" control, the Marshall knob in the "Level" position is the "h.f. taper" control, the silver ring in the "Ratio" position is the level control and the Marshall knob in the "Ratio" position is the ratio control). Btw: Rather useful to have these on the front to get the best out of the special 7247 OD circuit of this amp:

http://personalpages.manchester.ac.uk/s ... e71_12.jpg

I know there was an Accent switch on early ODS amps but that was a Presence or a brite switch, no?

1st, 2nd and 3rd generation: Most (all?) of these originally built with an "Accent" switch.

transition generation: Some with an "Accent" switch (#084), some with a small "Presence" control (#094), some with a full sized "Presence" control (#075).

4th generation: All with a full sized "Presence" control.

In this Dumble catalogue you can see pictures of two "transition generation" ODS, a "silverface" (#075) and a "blackface" (# unknown to me). (BTW: I doubt, that this catalogue is indeed from 1978 as it displays the "Lankershim Bl., N. Hollywood" address):

http://personalpages.manchester.ac.uk/s ... gues/1978/

Not sure when he switched to blackface chassis but I have pictures of what appears to be #84 that is a blackface with a small Presence (Accent) pot.

Yes, #084 is one of the first "blackface" ODS, perhaps the very first.

Then by the Beach Boys #97 the Presence pot has a full sized knob.

So somewhere between Gregor's #94 and #97 HAD gave the amp the full sized Presence control.

The earliest ODS known to me originally built with a full sized "Presence" control is not #097 but #075, the Farris amp. "Presence" is on the front, "Ratio" is on the back and because of this the "effects loop" is a stereo jack. Look at these pictures from the "Maverick Music" site:

http://www.maverick-music.com/scripts/v ... oduct=1968


Tom,

just in case you don't know this branch of research and therapy already:

http://nccam.nih.gov/health/heart-disease/

http://www.heartmath.com/

http://www.heartmath.org/research/scien ... heart.html

http://www.youtube.com/watch?v=CMQipX-hIDs

http://www.youtube.com/watch?v=jT5kHw3D ... re=related

http://www.amazon.com/Instinct-Heal-Dep ... -2-catcorr

http://www.amazon.com/Healing-without-F ... -3-catcorr

http://www.anticancerbook.com/

Perhaps you find something useful - I did.

I wish you all the very best!

Max

[brewdude]

What exactly is the "trigger" control? Is that the pre-OD trim pot?

[Max]

What exactly is the "trigger" control? Is that the pre-OD trim pot?

Yes.

[Structo]

Thanks for the links Max.

It is overwhelming how CAD has changed my perspective and outlook on life.

[Max]

A memeber here did send me a PM and asked, what I would recommend for a 70ies build: a "pre-classic" tone stack or a "classic" tone stack.

My advise:

First decide (perhaps from some records or trying some originals, if you have the opportunity) what you are after - the tone of one of the "pre-classic" ODS (up to around # 070) or the tone of one of the "transition" or "4th generation" amps (starting around # 07X, like the Farris amp).

If you are not sure, what kind of amp is played by a certain player, you could ask the members here. Perhaps someone will know.

When you have made up your mind, that you like a certain amp best, I would recommend to find out as much about its circuit specs as possible (with the help of the members here) and then build a clone in accord with what is known about the circuit of this original Dumble amp you liked best (or one at least similar to this, same" generation" e. g.).

If the clone comes out at least a bit similar to what you like about the original, I would play it for at least three months or half a year and try to find out, if you two find a way to one another or not. If yes, you're there, if not, I would start tweaking.

While tweaking the amp, I think it is most important, to always give a tweak a chance for at least some weeks. Our hearing depends a lot on our emotions, on our state of mind, on how tired we are and so on. So what may sound like shit today will perhaps be better tomorrow and great in a month (vice versa).

If you don't succeed, even with the help offered here at ampgarage, I would recommend to approach the comercial amp builders, and ask them to built you a custom made amp, that will suit your personal taste. With some patience (and some money to pay them for their know how and labour!), you will end up for sure with an amp, that you will like.

What I think is important too, is, that IMHO a "good" clone has not to sound exactly or even very similar to a certain original Dumble amp. In the end it should be a great tool for a certain player - not more, not less. If this is the case - who cares in the end, if it is a clone of a certain Dumble amp?

Perhaps you start with a clone in mind and find out while tweaking, what rythm beats in your own heart and what tone drives you to tears. That is IMHO far more important than if your amp does "Poli" like Dumble #XYZ.

My 2cents.

Cheers,

Max