18W "D" type project

Discussion in 'Shock Brother's DIY Amps' started by dogmeat, Apr 11, 2019.

  1. dogmeat

    dogmeat Tele-Holic

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    kinda leaning toward pulling the signal for the OD from V1A, before the 1st pre-amp tone stack. that seems to make more sense. as far as making a true Dumble clone... I remember someone posting somewhere that they had built the amp in one of the schematics and that it was really good, and musical, an had some wow, but played next to the real thing.... not even. anyway, I'm going to re-cut/paste. I'll post it but it might be a while. feel free to add your thoughts
     
  2. L.A. Mike

    L.A. Mike Tele-Holic

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    I've played a couple of real Dumble ODS amps and a Dumble ODR. I also heard David Lindley's old SSS being played at Carter's Vintage.
    They all sound very 3 dimensional to me. I don't know how else to describe it.
    It's like the difference between listening to music on a good stereo system, then putting on a good set of headphones. All of a sudden there are all these other frequencies dancing around.
    I've played some clones. They sound like great amps on their own but don't sound like Dumbles.
    Personally I prefer a Mesa Mark I to any Dumble clone I've ever played. I bought one new in the late 70s mail order from Boogie and still own it.
     
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  3. Teleguy61

    Teleguy61 Friend of Leo's

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    I would strongly suggest you join
    https://ampgarage.com/forum/
    and pick the brains there.
    That is where the correct info is on D types, from folks who own, work on, and build them.
    It is a great resource.
     
  4. Lynxtrap

    Lynxtrap Tele-Holic

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    It's not like he is the only guy copying and selling Dumble clones, several brands have established themselves on the market selling such amps for "boutique" prices.

    His models should be pretty much based on those that have been blueprinted over at Ampgarage, and that seems to be the problem some people have with him, not least the guys on that forum. Anyhow, in that regard they should be pretty accurate.

    AFAIK he came up with the 20W himself, although others might have done the same before him. I imagine almost every conceivable configuration based on these amps has been built by someone at this point.

    Well, enough said about that. But visiting the Ampgarage is a good advice, the combined knowledge on Dumble there probably covers anything worth knowing about these circuits.
     
  5. L.A. Mike

    L.A. Mike Tele-Holic

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    Ceriatone doesn't just sell Dumble clones. I didn't say that. They copy and sell anything that is popular and will sell. Whether is a new model or classic design. He does cleverly modify the name but it's obvious what it is.

    As far as blueprints of amps being available at Ampgarage, as far as I know and correct me if I'm wrong, the originators of most of those designs didn't post them there.
    I don't see how something being on Ampgarage means it is now in the public domain and fair game to anyone who wants to copy the design.
    If something is posted there then the originator loses all rights to ownership?
    Seems wrong to me.
     
    Last edited: Apr 15, 2019
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  6. Lynxtrap

    Lynxtrap Tele-Holic

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    I certainly agree on some of that!
    Still, most of Ceriatone's amps/kits are models that lots of companies sell as kits and even as their own expensive boutique amps, at least in the case of Fender and Marshall.
    While every other pedal manufacturer seem to sell their own Klon clones these days, cloning the enclosure seems unnecessary.

    As to Ampgarage, that's no easy question. People post schematics online without the designers permission all the time, and we feast on them in forums such as the one we are posting in right now.

    Seems like at least half of the threads here has a Fender schematic in it, and I doubt that Leo Fender would have liked the idea of his amp designs being globally available for anyone to copy. Fender still make some of those amps. Same goes for Vox, Marshall, Hiwatt, Orange and you name it.

    I guess my point is that nobody seems to think that is a problem. But copying circuits from certain small builders who might not even be alive or making amps anymore, with originals being unobtainable to mere mortals, is controversial.

    Having said that, I would think twice about buying a Ceriatone Matchless kit. But I dind't feel bad about buying a D-clone from Ceriatone instead of, say, a Fuchs or a Two Rock for 3 times the money.
     
  7. L.A. Mike

    L.A. Mike Tele-Holic

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    Fuchs? Check out the circuit boards on his "boutique" amps.
     
  8. sds1

    sds1 Tele-Holic

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    What specifically do you take issue with regarding Fuch's boards? Just the fact that they are PCB?

    PCB (and PCB assembly) is not inherently inferior to turret board / point-to-point construction techniques.
     
  9. L.A. Mike

    L.A. Mike Tele-Holic

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    They are priced like hand made boutique amps
    A question for Fuchs, if you are interested, would be who makes the boards for him and where are they made?
    Andy and his assistant may have added some features to the Dumble style amp, and some of that switching may be easier accomplished by using PCBs. But his amps are assembled in his factory. They are the equivalent of a Mesa Boogie amp in construction (Mesa makes their own boards) but are double what a Boogie costs.
     
  10. Nickfl

    Nickfl Tele-Afflicted

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    A lot of what Leo (and most of those other guys) did came straight out of the tube amp design manuals published by RCA and other tube manufacturers. Furthermore it was pretty standard practice back in the day for manufacturers of amplifiers (radios, hifi and instrument amps included) to slap a schematic on the inside of the cabinet somewhere (or in the manual) for the convenience of repairmen. I don't think they really looked at it the way some people do now.

    I think the idea of closely guarded, special secret mojo 7 herbs and spices designs may have originated with Dumble pouring epoxy on his circuit boards to keep his "secrets". His amps may sound great, but he's clearly a little bit eccentric and the real secret is that there isn't anything all that special going on under there... if anything its the fine tuning he did for each individual player not the overall circuit topology that makes the amps special (and the fact that they mostly ended up in the hands of already world class players).
     
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  11. Lynxtrap

    Lynxtrap Tele-Holic

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    Please don't get me going on that guy... I think the circuits, the look of the amps and the price tag tells enough.
     
  12. Lynxtrap

    Lynxtrap Tele-Holic

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    I you look at for instance the schematic of Deluxe Reverb AB763 it contains three pending patents.
    A modern Fender schematic states clearly that it may not be published or reproduced in any way without their permission.

    When they slapped schematics inside the cabs in those days, it was not thought that users would even open the amps. And there was no internet to upload a copy to and share the schematic with the world.
    Those who really wanted to copy a circuit, like Marshall did with the Bassman, could do it with or without a schematic. I doubt there were many hobbyist building their own Fender amp in the garage.

    Not much is new in the world of tube circuits. But when guys like Dumble and Randall Smith started out, the idea of actually designing a circuit for distortion was quite novel.

    Secret or not, IMO the ODS series amps have certain characteristics that even come across in clones and copies of the amps. It's not magic, just components put together in a certain way that happens to make a pleasant sound.
     
  13. Nickfl

    Nickfl Tele-Afflicted

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    FWIW, those patents would have expired 40-50 years ago.
     
  14. L.A. Mike

    L.A. Mike Tele-Holic

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    First of all,
    The Urei 1176 compressor/limiter made in 1970 had a new LN (low noise) circuit added to it which was developed by Brad Plunkett. They encapsulated it in epoxy to stabilize the components and more importantly, protect the circuit until their patent was approved.
    So, we can see Mr. Dumble wasn't the first to use this process.
    The reason Mr. Dumble started epoxy the circuit was because of Kitty Hawk Amps. A company in Germany that imported Mesa Boogie and Dumble amps to Europe for a short period of time.
    There is a story about why this came to be if you're really interested. Kitty Hawk wanted more Dumble amps than he was able to produce, so they had someone copy (try to) his circuit and cloned his amp. They actually used a counterfeit nameplate for a while that said Dumble on it.
    The amps sounded terrible and were unreliable. Mr. Dumble found out about this, didn't know what to do, so he started putting epoxy over the preamp circuit area to try and protect his design. It was a kneejerk reaction. Eventually. it didn't matter because all the Dumble cloners started removing the epoxy so they could copy his design. And then some genius "blueprinted" the amp and put it on the internet. Places like Ampgarage. Where people think since the plans are posted there, it's ok to steal the design.
    As far as his amps "there isn't anything all that special going on under there... if anything its the fine tuning he did", that's your opinion not mine. I've played a few of them. For a tube amp like a Dumble ODS nothing comes close. No matter what the cloners state in their ads. And they get people to buy them because the only Dumbles their customers have ever heard were on Youtube or maybe at a concert.
    Stand in a room with a real DUmble and a clone and you will know what all the fuss is about.
    You may not realize it but Mr. Dumble started out selling the ODS at music stores in L.A. and from ads he put in Guitar Player magazine. It wasn't until people started realizing how great they sounded, and his orders were exceeding his capabilities to fill, that he decided to limit who he would build one for. Before that anyone with a couple of thousand dollars could own one.
    The price for them on the street is nothing more than supply and demand. He certainly doesn't charge anywhere near the amount they go for second hand.
     
  15. Lynxtrap

    Lynxtrap Tele-Holic

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    The question was what manufacturers might have been thinking about giving away their circuits back in those days.
     
  16. Nickfl

    Nickfl Tele-Afflicted

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    Actually, the OP's question was more like "what do you think of this build idea" and at some point the answer became "I don't know, let's just argue about the morality of clone building"...

    So to actually answer the OP: I think you are definitely going to want smaller cathode bypass caps, 25uf is way too big for a high gain design, I'd use 4.7uf or smaller.
     
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  17. sds1

    sds1 Tele-Holic

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    I'm pretty sure that's not an opinion, he's specifically referring to the technical aspects of any Dumble circuit -- there are no unknowns, nothing that cannot be replicated. We know everything there is to know about Dumble. Or so I thought.

    I don't doubt that you've yet to hear a clone that impresses you, but can you provide any technical discussion for why clones cannot even come close to a made-by-Dumble amp?
     
  18. L.A. Mike

    L.A. Mike Tele-Holic

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    Not technical. I don't design or repair amps.
    I've played some so there is that.
    I don't know why they sound better, just that they do.
    It's like one chef can out cook the other using the exact same ingredients.

    I spoke to Mr Dumble back in the 1980s about building me an amp. He explained what he normally did at that time which was build a basic ODS and then maybe do some mods for that buyer if he had time and if he thought it was really necessary.
    He had a lot of parts that have been individually measured and tagged. New parts and old junky looking stuff. He also tests them as he's building the amps so that they "fit" better electronically with the other parts in that amp. He didn't just take stuff out of packages and install it in the chassis because of what it was supposed to be. He measures everything.
    The same thing with transformers and speakers and tubes. He rejects more than he uses. I saw a pile of new EVM speakers that he'd bought from Mesa Boogie that he was sending back. He said he only found a couple that were any good.
    A few people have commented that he hears things (frequencies) that other people ignore. Things that may discolor the sound and make it less appealing. I think that is a big part of it.
    If you see a few ODS amp chassis you may notice that they are not all the same. I think he makes them himself, forms them. His wiring layout is also very interesting. Sometimes it looks almost perfect and then you'll see one or two wires that look like they were just added on at the end. Almost haphazard. I also saw a photo of one of his amps that had wood paneling that he'd used to construct a circuit board. I guess he drilled it out himself instead of using perf board.
    Ben Harper said he took his lap steels to Mr. Dumbles house when his Dumbles were being built. He said Mr. Dumble measured things in the amp while Ben played. Then would change a couple of things and test the results. Over and over until he was satisfied.

    Sometimes we just have to accept that some people are better at things that others.
     
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  19. FenderLover

    FenderLover Friend of Leo's

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    I wonder if a technically competent person has ever published a conversation with Mr. D, or if it's just musicians and non-technical people recounting his process and eccentricity. Not much different than reading an advertisement if one does not know the significance of what is being done. I don't doubt Mr. D's tech ability, but I don't recall one of these stories coming from a technical person who would know the difference.

    I've read many accounts by technical people repeat many of the non-technical things LA Mike just mentioned, but none of those things are barriers in achieving excellent sound, much less being on par with one that Howard built. It's pretty obvious that some builders are better than others. But that doesn't necessarily exclude hype and BS, or why what has been learned from the design already cannot be met or surpassed by anyone.

    Need we link the discussion about crystal lattice and atomic structure, or does a real technical discussion with Howard actually exist?
     
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  20. Mr Ridesglide

    Mr Ridesglide Tele-Afflicted Gold Supporter

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    I think most reasonably seasoned players will usually adjust an amp, every amp to get more or less the sound they hear themselves wanting/needing to get. Having said that, does it make sense to say that given more options within one amp could also make it more difficult to find that sound on any given day in any given room?
    Certainly not technical here but I do like the idea of some one making slight tweaks so that it is easier for player x to get their deal dialed in faster. I played a ef86 amp (Sampson) with a tone control offering 6 settings. It worked every time in every room that I used it in for about 5 years. I always found that sound/tone I desired. Sometimes I think it’s just that easy. Make it the way you like it with known values as options and let the jammer jam. :) now - shouldn’t we get this thing built?
     
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