"70ies circuit Bludodrive"

[Max]

https://tubeamparchive.com/viewtopic.php?t=398

Hi tubedogsmith,

thanks for the link to this "1977" schematic. This is indeed a very good example for such a kind of "mixture" schematic of ingrediences of different Dumble amps that in reality never existed together in any real Dumble amp, at least not in one I had my nose in or have seen on gut pics:

- mid pot value and cap of a transition or 4th generation "classic" ODS tone stack
- bass pot value and the single cap of a 5th generation skyline ODS tone stack
- treble pot value and cap of a 3rd generation ODS
- some kind of "mid switch", a feature that in reality never existed in any Dumble ODS before the 1988 5th generation skyline amps
- LNFB at V1b that never existed in any real 1977 ODS (the first ODS with a LNFB at V1b - but of a different kind - are the 1979 transition generation "classic" amps)
- trigger trim pot that never existed in any 1977 ODS (a new feature in the transition generation, too)
- snubbers with a value (500pF) that I have never seen in any Dumble ODS and that have not been in any ODS at all before the first transition generation "classic" amps
- a master volume "bright cap" I have never seen in any Dumble ODS before the 1988 skyline amps
- and so on and on...

But please don't take me wrong now, of course I will not say, that the tone of such a kind of "weird mixture" guitar amp may not please some people. But such a kind of guitar amp, at least IMO, is for sure no "tonal replica" of any real "1977" (1977 = 2nd generation) or whenever else Dumble ODS. At least not, if Scott is right (and he is IMO), and even small technical differences - like those between a usual skyline ODS amp and those of a skyline ODS with the RF amp "Ojai tweeks" as an example - make it impossible from a technical point of view that a usual skyline amp replica sounds anyway close to the RF green light green switches amp, that has these "Ojai tweaks" - as Scott posted here: https://tubeamparchive.com/viewtopic.ph ... 983#134983

Have a great weekend and lots of fun!

Max

[tubedogsmith]

Hey Max, my only reason for posting that is there seemed to be a question as to what Brandon was thinking about the '70's circuit and from what he said in that thread i'd guess this was it at the point in time anyway.

[Max]

Hey Max, my only reason for posting that is there seemed to be a question as to what Brandon was thinking about the '70's circuit and from what he said in that thread i'd guess this was it at the point in time anyway.

Hi tubedogsmith,

yes, I did understand it in this way as you have meant it, but I thought it is really a perfect example of such a kind of "cocktail" schematic. So thanks again for the link to what Brandon thought concerning this in 2006.

Cheers,

Max

[tubedogsmith]

Ya, it's not so much a cocktail as a blender drink!!

[Max]

Hi Max,

Thanks for posting the chronology with pics. It really helps to have it set out like that. Ultimately it would be great to have a separate thread started, with sound clips (choice examples from the real Dumble clips thread) included and then put up as a sticky.

Cheers,

Paul.

Hi Paul,

I’ll post some links here to the "tone examples" in the reference thread. Because The Amp Garage forum has no wiki - like this forum as an example http://www.l-camera-forum.com/leica-wik ... /Main_Page - there will probably be no other possibility than such a kind of "generations" or "history" or whatever kind of "sticky". If someone should get the permission of the administrator for such a kind of sticky (in the "Dumble Files" section?), I would of course contribute.

Until such a kind of sticky exists all those interested could perhaps just save copies of some info they may deem to be of interest on their hard discs and organize their own "Dumble database". I would highly recommend anyway investing some bucks and downloading some HQ mp3 files of those tone references in the "reference thread" you should perhaps like to listen to in a better quality. I’ll start here now with some "references" for the

1st generation "pre-classic" ODS tone:

Slide: most of the live stuff of David Lindley. All the FET. His settings for slide you find on the pictures of his amps here in this thread.

Usual guitar into the clean channel of a 1st generation ODS: https://tubeamparchive.com/viewtopic.ph ... 437#131437

Usual guitar into the OD channel of a 1st generation ODS: https://tubeamparchive.com/viewtopic.ph ... 857#130857

I’ll post more examples for the 1st generation tone in the "reference thread" and then I'll post more links to these here.

And I'll post links to some examples of the tone of the other generation ODS in future posts here.

Paul, all the best and have a nice weekend,

Max

[ampcrack]

Hi guys,
I love this thread, but most of this has been discussed in earlier threads,
the last time in the "Pre-Classic Tonestacks" thread in the files section.
One thing to consider: A batch of about ten amps were (SrNrs. 30s/40s)
were made for the german importer at the time, Applied Acoustics in Bochum
Germany, the guys who later on manufactured Kitty Hawk amps:These amps
were very similar, made for sale in their shop, not voiced to the player
or tweaked or anything.#40 may well be one of them.One typical feature of these amps is the export power transformer.
There are many inaccuracies in the #40 schematic, which has never been updated so far.Most of the corrections can be found in Tony´s 70s layout.
How do I know? My personal amp is from that batch, but there are slight variations from amp to amp, I´ll send some more info on this soon.

Marcos

Hi Marcos,

I know for a fact that it was not just SrNrs: 30/40s, but actually from the SrNrs: mid 20's to the late 60's!
And there was also another importer next to Applied Acoustics as well.
And I completely agree with Max. Mr. Dumble never let any amp go until it was 1000% the way it was supposed to sound.
Of course some of these amps were later "tweaked" and "customized" with some very strange electronics...
And the special tuning for a player and his instrumenet is just that.
Best,
John

[Structo]

DKT

[Max]

I know for a fact that it was not just SrNrs: 30/40s, but actually from the SrNrs: mid 20's to the late 60's!
And there was also another importer next to Applied Acoustics as well.

Hi ampcrack,

this is correct, the first of these has been #019 (2nd generation), the last one #070 (3rd generation). AFAIK their total number has been somewhere around 25. AFAIK the other importer has been a music store in Germany called "Spiecker & Pulch".

Have a nice Sunday,

Max

[Max]

2nd "classic" > "skyline" transition generation ODS pictures

These 2nd kind of "transition generation" ODS amps you’ll meet in the #014X - #016X series number range. Robben Ford’s second chassis, which currently resides in his black cabinet, is one of these amps. AFAIK its original chassis is the tan one, in which now his old "green light, green switches" chassis resides.

All of these I know of still have the "deep" label above the EQ switch in the middle of the three EQ switches. But at least some of them are known to have skyline tone stacks. If these have been originally equipped with a skyline tone stack or have been later updated with such a skyline tone stack, I don’t know precisely. There are some of these with a small 4-step rotary switch instead of a deep or a mid switch. I don’t know which function precisely these 4- step rotary switches have.

All of them are already in a 5th generation kind of cabinet with the tolex/suede covered cross bar between chassis and grill cloth. Some with a four bolts fastening systems (two at the front panel, two at the back panel), some, like Robben Ford’s as an example, with an 8 bolts fastening system (four at the front panel, four at the back panel).

My database for these 2nd "classic" > "skyline" transition generation ODS amps is rather small at this point. So if someone here has some info concerning these amps and their features, a post here would be appreciated.

Have a nice weekend,

Max

[talbany]

I don’t know which function precisely these 4- step rotary switches have.

Max
I have never seen pics or the inside of one of there so called modified mid selector switches however If I had to make an educated guess as to what they are I would say the switch is loaded with several different treble caps.. >(002 cap mounted on the board)... This way way you could select the appropriate treble cap values for taste..
Values I would pick would be 250pf,,390, 500 and bypassed for .002 on the board.. he might have chosen other values but these are the most popular ones he used..

Hope this helps..

Tony

[Structo]

What I find interesting appearance wise, is HAD's choice for grill cloth.

Knowing that VOX really doesn't like other companies to use this cloth as I believe it is trademarked.
Also the fact that the ODS amps are basically hot rodded Fenders, the choice in grill cloth is puzzling.

On the other hand, it may just be that he thought it looked cool in which case I concur.

Interestingly, he has the cloth running vertically compared to VOX speaker cabinets since they weren't intended to be placed vertically.

[Max]

I don’t know which function precisely these 4- step rotary switches have.

Max
I have never seen pics or the inside of one of there so called modified mid selector switches however If I had to make an educated guess as to what they are I would say the switch is loaded with several different treble caps.. >(002 cap mounted on the board)... This way way you could select the appropriate treble cap values for taste..
Values I would pick would be 250pf,,390, 500 and bypassed for .002 on the board.. he might have chosen other values but these are the most popular ones he used..

Hope this helps..

Tony

Hi Tony,

I once have been told that the effect of one of the four positions of these rotary switches is a bit similar to the usual "mid" boost and the effect of another position is a reduction of the amount of mids.

Nice Sunday!

Max

[marcos]

Hi Marcos,

I know for a fact that it was not just SrNrs: 30/40s, but actually from the SrNrs: mid 20's to the late 60's!
And there was also another importer next to Applied Acoustics as well.
And I completely agree with Max. Mr. Dumble never let any amp go until it was 1000% the way it was supposed to sound.
Of course some of these amps were later "tweaked" and "customized" with some very strange electronics...
And the special tuning for a player and his instrumenet is just that.
Best,
John[/quote]


Hi John,
I know that the amps imported by Applied Acoustics started with #19,
their showroom amp that I tried at their shop in 1978, and ended with #68 AFAIK.I was referring to a qoute from the Dumble Book where HAD
states that he completed "ten amps in ten days that were to be shipped to
Germany".Although I am not 100% sure, this might refer to the amps I believe to be from this shipment.Assuming that HADs statement is correct,
that would not leave him much time to perfect the tone of each individual amp, would it?
What I do know for sure is that many of these amps were changed later on.
The amps sold by "Spiecker & Pulch" (hope I got the name correct)
in Ratingen, Germany, are a different story.The Roys told me that
these,too, were imported by them, this may or may not be true.
FWIW at the time (!978/79) other shops in Germany ran ads for Dumbles
as well, if I remember correctly a place called "Music Market" in Cologne
and "Bochen&Härle" in Munderkingen.
Hope this makes a bit clearer, enjoying everybody´s contributions

Marcos

[Max]

6th generation "skyline HRM" ODS pictures

AFAIR the first of these 6th generation "skyline HRM" ODS amps have been build around 1995, but maybe some already in '93 or '94. I am no longer sure 100% after 15 years. AFAIR they start with the series #200.

At first glance they look a bit similar to the 4th generation "classic" ODS amps. But at second glance the "mid" switch, the "drive" and "volume" overdrive controls and the gold script "By Dumble" are obvious differences. Their features and circuits have often been discussed here. Pictures of these 6th generation ODS amps are easy to find in the internet. Here are three of them:

Cheers,

Max

[Max]

Interestingly, he has the cloth running vertically compared to VOX speaker cabinets since they weren't intended to be placed vertically.

Hi Tom,

All those of these 2x12" Dumble cabinets I know with just one set of feet are obviously intended to be placed on their long bottom side. But some of these 2x12" cabinets have two sets of feet. So these you can position either with the handle on top or with the handle at one site. Their dimensions are chosen in the way that an ODS fits precisely on top of one of the short sides and a DL, SSS or ODS 150W fits precisely on top of the long side with the handle (see the attached picture). If you use this kind of cabinet in combination with an ODS, I would recommend to try both ways to place the cabinet, because IMO the feel, the tone and the sound dispersion character will be different - depending on the location, the position on stage in relation to the position of the player etc.

Cheers,

Max