Too bright non-HRM

[LPSGME]

Yes, I have a d'lator (with a bypass switch). It compresses the tone a bit but doesn't roll the highs all that much. But I'm also using very short and expensive cables. Perhaps I should try some cheaper longer cables.

This amp was originally an HRM. So guess I can also put the HRM board back in to see if that helps.

[kd]

From another thread, here is a suggestion from Gil Ayan concerning taming a bright amp:

Another very simple way to address a bright OD is to raise the output cap from .0047uF to .01uF. Higher than that will not make too much of a difference, but .01uF sounds good. The treble bleed is to help impart a certain chartacter that one would be hard-pressed to achieve by tweaking before the output of the overdrive. Another common solution is to increase the output resistor to 180K, which will decrease the available overdrive volume.. or to eliminate the output resistor all together and replace the output 100K pot with a 500K pot. More volume available and less brightness. I have recommended this to some folks who have used it with success.

[LPSGME]

The last problem I noticed when recording (a buzzy sound) ended up being the microphone (an EV); also a particular speaker seemed to emphasis it, so I also changed that. The shrillness I'm getting now has to be coming from something else in my recording chain that I'm not noticing, 'cause the amp seems OK otherwise.

[Luthierwnc]

I don't think my problem is technical -- its that I think I ought to be a non-HRM player but my HRMs always sound better. A quick 12-step recovery program followed by redoing that part of the board and life will be good.

My favorite tone with any of the "D" amps I've built is clean/loop/boost. I do the PAB with a trimmer on the first lug of the middle pot. This one is dialed down to about 180k -- so not as big a kick as the treble-to-bass disconnect. It also leaves the mid switch relay useable. That circuit is paralleled with a normally-closed relay switch to ground.

Thanks for all your help. I'm feeling better now

[LPSGME]

I don't think my problem is technical -- its that I think I ought to be a non-HRM player but my HRMs always sound better. A quick 12-step recovery program followed by redoing that part of the board and life will be good.

My favorite tone with any of the "D" amps I've built is clean/loop/boost. I do the PAB with a trimmer on the first lug of the middle pot. This one is dialed down to about 180k -- so not as big a kick as the treble-to-bass disconnect. It also leaves the mid switch relay useable. That circuit is paralleled with a normally-closed relay switch to ground.

Thanks for all your help. I'm feeling better now

Your alternate PAB wiring sounds interesting, but I don't follow how you are connecting the signal from the 180k trim in conjunction with the normal wiring of the PAB relay. Could you please explain more.

[heisthl]

Your OD coax is not cheap enough, seriously, the cheap stuff gets rid of a lot of highs, and a lot of times eliminates the need for a fizz filter, just my 2 cents (a foot) comment.

[Max]

Robben Ford's loop cables: http://www.youtube.com/watch?v=fBBOLeNA60k

Cheers,

Max

[boldaslove6789]

Max,Or anyone,

Does anyone have any info on the cable's ,or how much µF they are? After testing a few I came to the conclusion that the OD was (somewhat) pleasing but, I couldn't get a good balance with the clean ala the high's were rolled off too much to justify using them. My HRM OD can be quite bright even with a d-lator and both bright switches (bright switch on amp & bright switch on send of D-lator) are DIS-engaged. My D-lator only has a send bright switch (no return switch) BTW.

[Max]

Does anyone have any info on the cable's ,or how much µF they are?

AFAIK capacitance is only one of the many parameters that all have more or less influence on the transferred signal.

Here you find some information concerning all this: http://www.st-andrews.ac.uk/~www_pa/Sco ... nalog.html

Concerning Robben Ford’s loop cables in this video:

They seem to be some kind of white Teflon cable, similar in looks to those Alexander uses in his post Columbia / Tandy era amps.

But here the problem starts: AFAIR he used different types of Teflon cables (gauges, conductor materials etc.) in his post Columbia / Tandy era amps over the years. I even saw as much as three or four different types of Teflon cables in the very same Dumble amp.

Concerning the specs of all these different types of Teflon cables he used over the years I only remember that many years ago someone once has measured the capacitance of some of the (different types, too) Teflon cables he used to connect his amps with the reverb tanks. AFAIR the capacitance values of these "reverb cables" all have been in a range between 50 and 100pF/ft and they have been some kind of shielded control wire and no NF or HF cables AFAIR.

But as you will know, RF did/does not always use these white Teflon cables, as you can see here (BTW: don’t overlook the fact that in this picture the bright 1 of the Dumblelator is "on", on some other pictures it is "off"): http://personalpages.manchester.ac.uk/s ... 202002.jpg

From my own experience I can only say this: Up to now I could only try 3 different Dumblelators, so my personal data base is far too small for any generalisation. I always used them in such a kind of 19" cabinet on top of the amp (more U of course when needed): http://www.thegearpage.net/board/showpo ... ostcount=8

Width is the same as the width of the amp cabinet and by this it doesn't look that bad IMO in a matching colour (matching: your boots of course!).

So the Dumblelator cables I have used have never been any longer than perhaps 1 or 2 ft. I adjusted amp, effects and Dumblelator always in a way that, with everything in the loop but all effects bypassed, I got more or less the same tone as without anything in the loop. And to do so was never a problem with one of these Dumblelators and with the Dumble amps I am familiar with.

My own impression was always this: Without the Dumbleator and only with the TC2290 in the loop of the amp (as an example), the sound was perhaps a bit more "sterile" and "colder" as without the TC in the loop. But with the Dumblelator in the loop and all effects on bypass, I could get more or less the same kind of timbre again as without anything in the loop.

And because up to now I have never played a Dumble amp that was too bright in the OD mode for my personal taste, I don’t have any personal experience in regard to your problem with the bright OD channel.

Last time I’ve played with a Dumblelator and effects in the loop of an ODS, I’ve used around 1ft of Teflon RG195 and couldn’t notice any obvious difference between amp without anything in the loop and with effects and Dumblelator in the loop and all effects set for "bypass".

But please be cautious with my comments, as perhaps my own "Dumble taste" may not be the "mainstream" one.

I personally like bright ODS tones very much as an example. Like this one here (solo starts around 2:30): http://www.youtube.com/watch?v=UQsayvE6_Pc

But concerning "…knows tone" it is perhaps recommendable anyway to always remember this:

http://www.youtube.com/watch?v=Zjz16xjeBAA

Cheers,

Max

[erwin_ve]

Max,Or anyone,

Does anyone have any info on the cable's ,or how much µF they are? After testing a few I came to the conclusion that the OD was (somewhat) pleasing but, I couldn't get a good balance with the clean ala the high's were rolled off too much to justify using them. My HRM OD can be quite bright even with a d-lator and both bright switches (bright switch on amp & bright switch on send of D-lator) are DIS-engaged. My D-lator only has a send bright switch (no return switch) BTW.

Use 200-300pF per side. That should give you the needed HF roll-off.

[boldaslove6789]

Thanks guys

[dogears]

Max,

I agree that when using a Dumble with no bright cap, or small 15-20pf cap, then 1-2ft cables is the ticket.

I can say with certainty (recall the Millers Son video of Dumble 183 on YouTube) that if using 200pf cables with an amp with no bright cap, the tone is dead and dull. On that clip we engaged the recovery bright switch to compensate. The cables were set up for use with my Ojai (68pf bright cap). So, bottom line for me is that using 4-6ft cables with the loop should be reserved for amps with the big bright cap on the master. Smaller cables for amps with less or no bright cap. Fwiw, I have recorded and experimented extensively (hundreds of hours) with loops/bright caps/cable length and the results are that it is impossible to achieve the tone of the big bright cap and long cables with no bright cap and short cables. Apples and Oranges. Different tastes. So, they long cables are not a bandaid for brightness but in fact part of the system that contributes to the unique tone.

So the Dumblelator cables I have used have never been any longer than perhaps 1 or 2 ft. I adjusted amp, effects and Dumblelator always in a way that, with everything in the loop but all effects bypassed, I got more or less the same tone as without anything in the loop. And to do so was never a problem with one of these Dumblelators and with the Dumble amps I am familiar with.

My own impression was always this: Without the Dumbleator and only with the TC2290 in the loop of the amp (as an example), the sound was perhaps a bit more "sterile" and "colder" as without the TC in the loop. But with the Dumblelator in the loop and all effects on bypass, I could get more or less the same kind of timbre again as without anything in the loop.

And because up to now I have never played a Dumble amp that was too bright in the OD mode for my personal taste, I don’t have any personal experience in regard to your problem with the bright OD channel.

Last time I’ve played with a Dumblelator and effects in the loop of an ODS, I’ve used around 1ft of Teflon RG195 and couldn’t notice any obvious difference between amp without anything in the loop and with effects and Dumblelator in the loop and all effects set for "bypass".

But please be cautious with my comments, as perhaps my own "Dumble taste" may not be the "mainstream" one.

[Max]

Max, I agree that when using a Dumble with no bright cap, or small 15-20pf cap, then 1-2ft cables is the ticket.

Hi Scott,

this is a most interesting topic (at least from my perspective): Let me try to explain, how I did adjust these amps with a 68pF master cap that I’ve played. And it would be great if you could perhaps comment my procedure from the perspective of your own experiences.

With these 68pF master cap amps (I have personal experience with only three of them and all three have been skyline amps) I always did it like this:

The TC2290 has an Input control, the Dumblelator a Drive control and the amp the Master control with the cap. In order to get a reasonable signal level into the TC (low noise, no overload) you can use these three controls. Now the master cap’s influence on the tone was dependent on the master setting AFAIR.

So I used the master control of these amps a bit like an overall "brightness control" and adjusted it just to my personal "brightness taste" in the given setup, band, room etc. Then I used the Drive control of the Dumblelator and the Input control of the TC to adjust them for an appropriate overall signal level at the entrance of the TC and the Recover control to adjust for overall volume.

With this kind of procedure I always got a result that I liked in the end, even with low capacitance cables of a length of perhaps around two feet at that time. One of these amps I played very often and for a longer period of time with a Dumblelator and a TC2290 and I was always very happy with the overall sound like this. But indeed I had to turn the master volume rather high (at least between 10:00 and 14:00) to get satisfying results.

But I liked this kind of setup, as it provided me with a kind of additional "overall brightness" control (master with cap). And Scott, you are right, two of these amps I did not like that much without a Dumblelator in the loop, because you need of course an additional kind of volume control (drive and recover) to set the master control of the amp high enough to reduce the influence of the master cap to a usable level.

Because I met these master volume caps only in variants of the skyline amps and never in still all original classics or pre-classics, I've always thought, that they may perhaps be a part of the "skyline system". But this was/is only a guess of course. I don’t know for certain why Alexander implanted these caps in some (not all!) of the skyline amps I am familiar with, but AFAIR never in a classic or a pre-classic ODS. I know of at least two '84 classic amps that have been ordered and delivered with a Dumblelator, and these too didn't have such a master cap.

What could you find out and now think about all this, Scott?

All the best and a nice day off,

Max

[Luthierwnc]

LPSGME -- Attached is a rough stack bypass. Not a true "D" version but pretty effective for these or anything with a TMB tone circuit. My trimmer is actually 250k but I'd put in a 500k if I was building it on faith. This is really a next step from disconnecting lug one of the middle pot on a Blackface. On this amp, the trimmer comes directly off that lug so I don't clutter the relay board. You could also let the mid pot go directly to ground and only have the relay control the bass ground reference.

I dial in the Boost relative to how much volume increase I want over pure clean. The stock set-up usually was too much of a slam and I wanted to set it so I didn't have to fiddle with the guitar volume knob. Your experience may vary but I set the OD so it doesn't add very much more volume than whatever else the amp is doing at the time so the PAB does the heavy lifting there too.

On HRMs I've always tied the OD footswitch so it activates the PAB (if it isn't already on). On this amp I didn't -- but doubt I'll use the OD by itself even so.

Thanks all and I'll get some different cables, sh