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Dumble (Ford 2) again....

PacoCasanovas

Fractal Fanatic
And this is not happenening in Quantum right? :(

I wonder why the Non HRM model got worse. Maybe it's becasue at FW12.03b it was too ideal? And now that it's become more authentic, the flaws started to come out.?
I wouldn't go that far. The thing is here - but the amp lacks of gain..... I once misspell myself regarding the "fart" story. I have very much respect for Cliff's hard work and experience regarding amps. He inspired me a lot and I love his "Cliff Notes" section at the board! Who else in the industry does something similar? Yes - nobody else ;) - and beside that, Quatum is a big step forward. The nonHRM type amp is some kind of a strange animal at the moment......

The "plexi glass" is a HooVi Deeflexx Edition - Deflection System. It not only kills the annoying beam effect of a guitar speaker, the whole room became being inside the "listener's sweet spot" - it extends the "listening area" of a guitar speaker to the whole room. Unbelieveable but true.....
It makes things much easier for me when modifying amps on customers requests in realtime. Usually I sit on my work bench, customer is standing in the room playing and stays in direct conversation with me, so I can implying his thoughts and wishes right at the spot on his working amp (as told by Rotti in another thread - amps have letal voltages inside - don't try this at home!!! I have years of experience and made my special tools now being able to do such things) . Both of us, hear the amp exactly doing the same as we expected staying at the perfect sweet spot in front of the cabinet. What a great piece of gear! :D

PS: I use Celestion V30s inside the custom-audio cabinet. This is my reference cab for all type of amps and sounds. unless the customer brings his own cabinet or a combo ;)
 
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Raab90

Inspired
I wouldn't go that far. The thing is here - but the amp lacks of gain..... I once misspell myself regarding the "fart" story. I have very much respect for Cliff's hard work and experience regarding amps. He inspired me a lot and I love his "Cliff Notes" section at the board! Who else in the industry does something similar? Yes - nobody else ;) - and beside that, Quatum is a big step forward. The nonHRM type amp is some kind of a strange animal at the moment......

The "plexi glass" is a HooVi Deeflexx Edition - Deflection System. It not only kills the annoying beam effect of a guitar speaker, the whole room became being inside the "listener's sweet spot" - it extends the "listening area" of a guitar speaker to the whole room. Unbelieveable but true.....
It makes things much easier for me when modifying amps on customers requests in realtime. Usually I sit on my work bench, customer is standing in the room playing and stays in direct conversation with me, so I can implying his thoughts and wishes right at the spot on his working amp (as told by Rotti in another thread - amps have letal voltages inside - don't try this at home!!! I have years of experience and made my special tools now being able to do such things) . Both of us, hear the amp exactly doing the same as we expected staying at the perfect sweet spot in front of the cabinet. What a great piece of gear! :D

PS: I use Celestion V30s inside the custom-audio cabinet. This is my reference cab for all type of amps and sounds. unless the customer brings his own cabinet or a combo ;)
Oh, so the tone and feel is there, but it needs more gain?

That makes sense, since Cliff said at one point that his Dumble is particulary low gain compared to the average. Besides, things like this are only to be expected since these amps are almost each one a completeley different amp model, such thing as an ODS doesn't really mean anything.

Maybe you could get there using some preamp adjustments? Obviously playing with the input trim is not going to compensate for this, since according to what you said, the difference comes from non LTI load characteristics at the preamp stage.
 

PacoCasanovas

Fractal Fanatic
no, the differences were between clean preamp and the OD circuit. Different signal divider network.....this can't be compensated with input trim because the d-concept is a clean preamp into OD not a booster stage into a preamp circuit as all other amps were designed. The clean preamp and the divider network were the most important portions in the whole circuit design IMO.
Cliff's Dumble is a HRM amp.....Which is not the same amp as the Ford 2.....non HRM amps have always much more gain.....not just different models....and there were other tricks, such as the post OD hi cut filter, not shown in the schematics you can found at the interwebz......
 

austinbuddy

Fractal Fanatic
Agree, in sound, I would not call Cliff's amp a Robben Ford Dumble voicing. The BludoOjai is a Robben Ford voiced amp, but it was originally modeled sometime back with the "pre-amp boost" set to ON, pre G3 and pre Quantum era. It's my amp.

For lead or gain tones it is still pretty great (really cuts through a band at high volumes in voicing) but it means the clean channel is pretty gainy. So here are some tips, some of this is in the Amp Wiki too.

Paco would already know this, but for other thread readers, for the Bludo CLEAN amp, take the tone stack from "default" and replace it with either the Skyline or Skyline Deep tonestack.

Next, set the master volume to 5 (it has a brite cap on it, so the louder the master, the less trebly; Ford sets his around 5). Next, set the Drive control to literally 1 or 1.5 - pretty low, and the guitar input gain control to 0.5. (Think about how Robben constantly uses that volume pedal to control the amount of guitar signal going into the amp...this gives you some room).

Now you have a very nice sounding Dumble Fender on Steroids with mids clean, with Bass at 5, Mids at 3-5, treble at 5, presence at 3-5. Jack up the Level output volume to compensate for the lower gain settings. Pair it with a G12-65H speaker. Cab Pack 17 has many choices (full disclosure, I produced 5 of the 6 Cabs in that Cab Pack). The BludoMix Cab in factory firmware is a 1x12 Alnico dual port cab, and will sound good but perhaps a tad darker (great for Jazz) on clean sounds than the G12-65H will.

Now, if you like, put a Zen drive in front on the BludoClean amp....or a boost...and listen to how that clean channel wakes up fast for grittier leads and touch-responsiveness.

For BludoLead, take the Lead default amp values. Put the Master Volume on 5. Put drive at 4-5 and Overdrive at 4-5, and experiment with the tone stack swaps above. If you want the amp to feedback effortlessly on a note, raise the overdrive setting higher combined with the gain, provided you have sufficient volume coming out your speakers to hit your guitar pickups in a reinforcing loop, it will do it! Throw a boost or Zen drive on that, if you like...

Cliff is getting some more detailed, verified schematic-type info on Bludotone/other Dumble-style amps along with corresponding G3 measurements, and while he is super super busy with other more pressing things things these days, I am told one day he will put the BludoClean/BludoLead of regular Skyline, G3'd, into the firmware and perhaps a few other Dumble-style amp as surprises, we can look forward to that when he reaches it on his monumental "to do" list!

But we've never had it so lucky...all these boutique amps, awesome.
 
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FractalAudio

Administrator
Fractal Audio Systems
Moderator
The ODS-100 Ford 2 model is not based on the HRM model with the HRM tonestack removed. Whether or not the model matches any particular Dumble is unknown as we have not been able to procure a non-HRM Dumble yet. The model is based on schematics that were given to us that supposedly accurately represent Robben Ford's Dumble. Whether or not the schematics are accurate I do not know.

The voltage divider at the output of V1B is set to 0.078 which is based on the values that are indicated on the schematic for the set-point of the trimmer.

As no two Dumbles are identical it stands to reason that one person's interpretation of the ideal Dumble voicing may not agree with another's.

Since V1 is running clean you can get more gain by simply increasing Input Trim. It will have basically the same effect as increasing the trimmer.

I'm sorry you are unhappy with the model. We strive to make every model as accurate as possible but given the rarity of these amps, the lack of accurate schematics, and the wide variation from one amp to another it is virtually impossible to please everyone.
 

PacoCasanovas

Fractal Fanatic
Dear Cliff, thank you very much for your reply. If you like, I can send you a schematic of my interpretation - if you need more data, I can provide much more based on calculations and experiments over the past months. At the moment I'm unable to send an amp in for G3, since the prototype is already sold to a customer (which is a member of this community btw.) and the 2nd and 3rd amp were promised for other customers who want it after playing it at my workshop. If I sell one, I can order parts for the next - that is the situation right now.... ;) And I'm not making much profits with it - It was originally made just for my own pleasure having the tone I always dreaming of, without spending 50'000$. I don't care if it's a real d unless it feels right IMOO - if someone else wants this sound, they were welcome to try it first - but it's not something everyone need to have......

My first prototype features a single ended power amp - 6V6 based, the 2nd one was a 6V6/EL34 changable model. I also experimate with transformer mismatch by design, and safe-mismatching. People really get behind it and enjoy it :)
The 3rd amp will be the next prototype with a EL34 based push pull design and a single 6V6 together.....two switchable output stages....

V1 runs clean - I agree - it's basically a tuned fender style preamp. There are many types of voicings, low or high plate design. I'm not fully agree about the input trim thing - but for the moment this will keep me going.
My interpretation also features the local feedback thing on V1b which even give you approx. 8dB less gain if my calculation is correct. The signal divider between clean and drive section is to my interpretation 10.88 (220k + 70.6k for the trimmer pot between input and taper lug and taper to ground is set 26.7k - trimmer is a 100k type which has approx. 97.3k in reality. Btw...The trimmer was originally made by Mr. D to correct the differences of various preamp tubes - one more reason why it's not covered by the goop in so many gooped amps. All my resistors were MF50 types with 1% tolerances. The signal divider factor goes (220k + 70.6k)/26.7k - in reality something between 5Veff down to 0.498Veff), based on 100mV input).
The signal divider network also plays a role as the load for V1b which affects their AC load line.....

more to come....
 
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PacoCasanovas

Fractal Fanatic
oooh...and my interpretation is voiced to Celestion V30s, since most players prefer these speakers.....

Celestion K100 in a diezel oversized cab did an awesome job as well....not the typical d-style cabs, but they work ;)
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
The signal divider factor goes (220k + 70.6k)/26.7k - in reality something between 5Veff down to 0.498Veff), based on 100mV input).
The signal divider network also plays a role as the load for V1b which affects their AC load line.....

more to come....
A signal divider, which is more correctly called a voltage divider, is calculated by taking the resistance to ground divided by the sum of the resistances. In this case the voltage divider would be 26.7/317 = 0.084. This is very close to the values that we were given (which yield 0.078).

Our model also uses local feedback on V1B (which is about 2-3 dB less gain) and accounts for the voltage divider's affect on the AC load line. In fact all stages in a Dumble typically have an AC load-line that's different than the DC load-line due to the load resistance being significant in relation to the plate resistor.

Since V1A and V1B run clean (linear) Input Trim will accomplish the same thing as increasing the trimmer into the drive stages. This is because a linear system is commutative (see any introductory Signals and Systems text for properties of linear systems). The commutative property is where A x B = B x A. Therefore it does not matter if the gain is before or after the linear stages.

Frankly most of the Dumble stuff is complete BS. The amps are nothing special. Yes, they can sound good but there is nothing magical or mysterious or profoundly different than all other tube amps. A Carol-Ann is a much better sounding amp, better constructed and without the stupid high price.
 

Tex Axe

Experienced
Mine has Unicorn prints inside.. Magical black dragons appear when you try to unlock the magic power which Dumble clearly got from some other Schmendrick....or out of 1940 rca manuals according to another crook I worked for at one time..
That particular con man ripped Ken Fischer off one of the many reasons I quit working there...

I agree about Carol Ann amps..

I used to speak to Kenny alot on the phone he kept it real and would bust any bubbles I started to get about
unicorn horns and pixie dust on my crystal lettuce..



Cliff is it possible to add hi and lo filters to every amp ?
I think it is..
If you know what values to put there and which types to measure..

Why not have variable hi lo filters on every amp ?
For those that know what they want they can input that value there..

What about that Idea ?
hi lo filters on every amp ...
Such as the Steel String Singer had...

Cliff :
If you Pm me I will send you something you might find useful perhaps.

If you cant beat them then by all means level the playing field.


The very worst thing that will happen is you will be told the truth..
Im here all week...
xoxoxoxo
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
Cliff is it possible to add hi and lo filters to every amp ?
I think it is..
If you know what values to put there and which types to measure..

Why not have variable hi lo filters on every amp ?
For those that know what they want they can input that value there..
It's already there. See the Low Cut Freq and Hi Cut Freq parameters.
 

Tex Axe

Experienced
Stupid high price " Clapton paid 70k for his ODS im told....... which is a far cry from the hoof prints on Carlos Santana's back.
The SSS Ej and Srv got were nothing near that expensive I know what Eric and Stevie both paid and it was no where near what I paid for the Ultra phonic but the market determines price ..

When Stevie came into Rays to speak to Dumble on the phone I heard F U YOU CAN KEEP IT I DID NOT PAY THAT MUCH FOR THE FING AMP IN THE FIRST PLACE and watched Srv storm out of the place mad as hell..
What Stevie did not understand was Dumble charged regardless for time on the phone after 10 min so when he was told
$4500 for the repair bill he was mad as hell because he might have paid 1500-2500 for it at the time to begin with..

When Erics amp came back through town after being fixed it was years later and it never sounded the same
of course not the output transformer burned up ie caught fire while Ej was playing it.... The boards and transformer had to be replaced
when they were out went all that magic unicorn Dust sure the chassis and shell were still the same but not the sound that being my point.

That was worked out Srv got more amps after that from Dumble the point being a misunderstanding about how Dumble charged for time which in those days and now means money...
Stevie thought he was saving money by using Rays free long distance phone that had no effect on what Dumble charged after 10 min.
Eric did not pay that much for his SSS I know what he paid for it and wont repeat it and the only reason is he asked me not too.
I paid more for the ULTRA PHONIC then those guys paid for Steel String Singers..

I was at Rays more then my own house during those days I was glue there looking for vintage gear in 1980 and beyond through the golden Dumble era those guys played Steel String Singers and they sounded better to my ears then the ODS and too their ears at the time..
Each player after a different thing....

The only dog I ever had in this hunt was chasing tone..
I did not steal my amps I bought them..

Someone did not bring me an amp to fix an I in turn start making them for the public.
I invested in having these amps to learn more about them and to make some for myself...

But I did not give permission to anyone to take anything from my home and go start making amps for profit
that was never my intention though it has in fact happened.

What they stole wound up being nothing of what anyone thought it was to begin with
The only reason I would know the difference is I put my hand inside Eric's Dumble and touched the epoxy
and I know you cant remove epoxy without damaging parts.. or at the least making the biggest mess you have ever seen.

So in fact no actual Dumble knowledge was stolen from my home as I had not bought a real one yet at the time.
They in fact stole information on who knows what as it did not sound the same as when Eric owned it..

What bothers me is I was told when I bought the amp it was 1:1 and spot on the real thing just like Eric's and
though it sounded ok and all I know better because I happened to be there the day the amp was open on the bench.

I was listening too the conversation with Dumble and Bill Johnson about how to fix it laughing because I told Bill before hand
Dumble is not going to tell you all how to fix this... Bill said if you dont shut up you will have to leave ...
Ok I said smiling..
8 min later to the Second the phone call was over why ?
because after 10 min its very expensive to bother Dumble on the phone..

Again all this can be cleared right up with one phone call to Eric

Im still waiting on Brandon to put 4 known good tubes in that amp and bias it though and
also to call Eric personally and ask him if #5 had epoxy in it at the time he owned it..
Neither has happened to date that I know of..

I had to explain to Erics Tech why perhaps Dumble will not answer his calls anymore..
The truth always seems to hurt...


Before I had the Tech ask Eric what color the epoxy was in #5 I told him the color so he knew before Eric told him
that way he would have no doubt who is full of shit and who is not..
 

Anthony David

Experienced
If there is nothing special about a Dumble, why do people like EJ, CS, and Mr. ford love them so much? Surely they aren't just fooled by hype?
 

PacoCasanovas

Fractal Fanatic
A signal divider, which is more correctly called a voltage divider, is calculated by taking the resistance to ground divided by the sum of the resistances. In this case the voltage divider would be 26.7/317 = 0.084. This is very close to the values that we were given (which yield 0.078).
Accepted, my bad..... ;)

Regarding to your quote "the amps are nothing special" - so it goes for Marshall, Fender, Vox and all these amps which were just based on their legacy.....just as Bogner, Friedman, Matchless and so on and on and on.......so what? Some amp designer even copied the miss-interpretations of others (Soldano SLO vs. Mesa Rectifier) also based on so called nothing special designs, which became standards......
I never saw an amp that uses his clean preamp to get an almost guitar like but voiced signal into a hot dual gain stage - most amps pushed their 2nd gain stage into overdrive and much too much compression and so on.....

Obviously, you paid 50'000$ for a "nothing special" amp? - My sincerest condolences.......

I guess nothing will come around the corner in the near future if you call it BS. I can live with that. Doesn't mean a thing.......
 

FractalAudio

Administrator
Fractal Audio Systems
Moderator
If there is nothing special about a Dumble, why do people like EJ, CS, and Mr. ford love them so much? Surely they aren't just fooled by hype?
I didn't say they're bad amps, they just don't justify all the hype and ridiculous prices. $50K for a Dumble is stupid. They're good amps and the voicing appeals to a certain type of player. They aren't my cup of tea. I like the tone but don't care for the feel. IMO the AC load line is poorly chosen. The preamp tubes go too asymmetric for midrange frequencies. Again IMO. Also I don't like the tone stack design. And the fx loop design is among the worst I've ever seen in an amp. The mysterious "Dumbleator" is a hack to fix the poor fx loop design. The fx loop has so much output impedance that any cable more than a few feet long causes excessive high frequency roll-off. So he designed a buffer (in a 19" rack box), called it a Dumbleator and everyone rejoiced. The fact is the whole purpose of the Dumbleator is to compensate for a crappy fx loop.

Now let's open one up. They're full of Radio Shack and NTE parts. In other words: garbage. $50K for an amp using some of the cheapest, poorest quality components made. Uh, okay. Oooooh but there's black goop all over the Formica circuit board. Formica. You know, the stuff they used for countertops in the 70's. With all the money he was charging for the amps you'd think he could splurge for some real FR-4 rather than using a hunk of leftover Formica from when they remodeled his kitchen. At least mine has simulated woodgrain Formica. I'm sure that helps add mojo to the tone.

Oh, and if you get an EL-34 version make sure you wear oven mitts when handling the amp after use. The power transformer is incorrectly chosen which causes it to overheat due to the extra heater current. But it's okay because it's a Dumble and he doesn't make mistakes. The underspec'd power transformer is all part of the mojo.

He's also full of crap with his "fragile harmonics" nonsense. Alan Philips of Carol-Ann can design circles around the guy and won't spew any of the voodoo crap and secret handshake bs.

It's audiophile bs applied to amps. Oooooh these $500 power cords sound better because they "reduce micro-distortions". What's a micro-distortion? I asked a cable manufacturer the same thing. He said it was a distortion so small that it couldn't be measured. I'll let you think about the absurdity of that statement.
 
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