D-Lite Rebuild....

[Cliff Schecht]

I don't know who started all of the IC e-cap bashing but I think it's a bunch of bullshit. IC makes a good product, I'm yet to have the literally thousands of their caps (from 6.3V to 500V) fail on me in any way. Yes, Fender uses them in their amps because they are affordable. The caps are affordable because IC has been making the same units for 30 years and doesn't pay any tooling costs or anything, just basic materials costs, and they don't price their products like it's made out of platinum and gold (Sprague Atoms *ehrmmm*).

I'm always defending IC e-caps with the fact that Peavey has been using them extensively for many many years now. Peavey, if anything, knows how to design an amp that is reliable and easy to work on (all sound/tone opinions aside) and if they have no problem using IC caps, I really don't either. I'm yet to see a failed IC e-cap but I've seen my fair share of bad Atoms.. I think F&T's are too new to start seeing a lot of failures but these could turn out to be turds as well (although probably not).

[talbany]

FWIW.. Off the top of my head I can think of at least 2 later stock ODS (including 700v a Music Man) that was loaded with IC .. They are not my fave but I wouldn't necessarily consider it a bad sounding cap..The Ford of Caps..

Hope This Helps!!

Tony

[M Fowler]

Steve,

I hear what your saying but I have read the same thing about such brands as Mallory caps which are really expensive.

I have no history of having had bad caps or noting any affects from bad caps. I have had old caps that needed replacement in customers old relcic amps of course.

I just figured if Henry's Redplate amps can sound so good and sell like hot cakes using IC axial caps, it's good enough for me. I have seen two parts dealers web site's showing out of stock and have now started selling the new JJ axial caps.

Once again Steve I do appreciate your opinion the subject, thanks.

Mark

[dcribbs1412]

The one thing I would do, if not already done is to move a few of the supply grounds.

1. Move the ground for the Clean, Overdrive and PI to the star point at front right corner near the input jack.
2. Move the board grounds from the buss rail to the front star point.
3. Move the HV Cap ground to a point near the power input jack
4. Move the screen cap ground near the first power tube (I used the ground for the Bias tail resistor.
5. Rework the PI ground and move it from the buss bar to the ground connection on the speaker jacks. I drilled two hole in the board and installed two ne eyelets to mount the 390 and the 1uf presence cap.

They all add up in the end.

Thanks for the info Gary
will check and make these changes ASAP
much appreciated

Darin

[tonestack]

I don't use Polyprops film caps as to my ear they sound harsh.

A film cap is a film cap. Polypropylene caps do not sound any different than polyester caps. As long as the caps that are being compared are not microphonic, any perceived difference in tone is the result of the caps not having the same value (the measured value, not the value that is printed on the component) or psychoacoustics (a.k.a. "perceptual accommodation").

[tonestack]

I am always amazed that these types of builds do not hum like crazy due to ground loops. Heck, even the input jack has a ground loop because the jack is not insulated from the chassis.

Done properly, busbar grounding is not bad. It is used all of the time in the RF world. The problem with busbar grounding is that most people introduce ground loops by grounding the bus to the chassis at two or more places. For example, if one is using a non-insulated Switchcraft jack, that jack should be sole connection to the chassis for the entire DC circuit. The better way to ground the bus is to use a bushing to insulate the input jack or a Cliff jack and ground the bus at the power supply. If using non-insulated Switchcraft output jacks, there is no need to run a wire between the ground connections on the jacks, as they are connected via the chassis. Running wire between the jacks introduces a ground loop.

[jelle]

I don't use Polyprops film caps as to my ear they sound harsh.

A film cap is a film cap. Polypropylene caps do not sound any different than polyester caps. As long as the caps that are being compared are not microphonic, any perceived difference in tone is the result of the caps not having the same value (the measured value, not the value that is printed on the component) or psychoacoustics (a.k.a. "perceptual accommodation").

Have you compared these caps in a high gain circuit? I have and I certainly perceive a difference between different compositions caps. I even hear differences between different brands of polyester film caps.

Distortion changes all the old Hifi derived rules.

Jelle

[Bob-I]

I don't use Polyprops film caps as to my ear they sound harsh.

A film cap is a film cap. Polypropylene caps do not sound any different than polyester caps. As long as the caps that are being compared are not microphonic, any perceived difference in tone is the result of the caps not having the same value (the measured value, not the value that is printed on the component) or psychoacoustics (a.k.a. "perceptual accommodation").

You just opened a can of worms... Many of us have done tests on a variety of cap types and brands and find the it makes a significant difference in these amps. Even the orientation of the cap makes a difference. Some folks go so far as to use one type for the bass cap, and a different type for the mid cap.

Yep, there's a difference.

[tonestack]

You just opened a can of worms... Many of us have done tests on a variety of cap types and brands and find the it makes a significant difference in these amps. Even the orientation of the cap makes a difference. Some folks go so far as to use one type for the bass cap, and a different type for the mid cap.

Yep, there's a difference.

I will believe you when you show me spectral analysis plots from the same amp using two different sets of caps that have the same exact measured values. Any difference that cannot be measured doesn't exist. The difference is merely the result of acoustical phenomenon known as perceptual accommodation.

The orientation of a film-and-foil cap matters because the outer foil acts like a shield; therefore, it should be connected to the low-impedance side of the circuit to reduce coupling.

[talbany]

The orientation of a film-and-foil cap matters because the outer foil acts like a shield; therefore, it should be connected to the low-impedance side of the circuit to reduce coupling.

Perhaps one should pose this question?..What if you prefer the sound of a cap oriented with the outer foil facing the the higher impedance side..Should one sacrifice tone over functionality..I will keep my opinion to myself on this one..Just posing the question?

Tony

[tonestack]

Distortion changes all the old Hifi derived rules.

The harmonic spectra generated by distortion doesn't change the rules. What is causing any real difference is that the caps being used have different measured values. A capacitor has internal inductance in addition to capacitance. If one takes two different caps and matches their inductance, capacitance, working voltage values, there will be no tonal difference as long as the caps are not microphonic.

This argument is kind of silly. If the tonal differences in film caps were real, they would be completely unsuitable for use at RF frequencies.

[tonestack]

Perhaps one should pose this question?..What if you prefer the sound of a cap oriented with the outer foil facing the the higher impedance side..Should one sacrifice tone over functionality..I will keep my opinion to myself on this one..Just posing the question?

The only thing that connecting the outer foil of a cap to the high impedance side of a circuit does is increase the likelihood of a stage experiencing parasitic coupling. It is difficult enough to keep parasitics in check without making things more difficult for oneself. However, if that floats you boat, then do it.

[ToneMerc]

I will believe you when you show me spectral analysis plots from the same amp using two different sets of caps that have the same exact measured values. Any difference that cannot be measured doesn't exist. The difference is merely the result of acoustical phenomenon known as perceptual accommodation.

The orientation of a film-and-foil cap matters because the outer foil acts like a shield; therefore, it should be connected to the low-impedance side of the circuit to reduce coupling.

TS; I'm not trying to be a wiseass here, however I do have a very straight forward question and it requires only a simple answer. From purely practical experience, how many Dumble style amps have you built? The reason I'm asking is that many of these observations are in the context of amp builds relating to this forum.

TM

[talbany]

Since this is a Dumble forum and for those wondering if Dumble was concerned with outer foil orientation..

AFAIK.All the Dumbles I have seen (I have seen many) loaded w/ 6ps all seem to have the marked side of the Cap facing the PT except for the .02 at the entrance of the PI and NFB .1 in some cases
An SBE rep I spoke with told me that where the label is printed has never been an indication as to where the outer foil is located..I have also never seen a Dumble amp with a cap marked tested....If this is true then to me this is evidence that Dumble was not to concerned with cap orientation..
Of coarse your opinions will very..


Tony

[Bob-I]

You just opened a can of worms... Many of us have done tests on a variety of cap types and brands and find the it makes a significant difference in these amps. Even the orientation of the cap makes a difference. Some folks go so far as to use one type for the bass cap, and a different type for the mid cap.

Yep, there's a difference.

I will believe you when you show me spectral analysis plots from the same amp using two different sets of caps that have the same exact measured values. Any difference that cannot be measured doesn't exist. The difference is merely the result of acoustical phenomenon known as perceptual accommodation.

we disagree, caps DO make a difference, i can hear it, others can hear it, i'm sorry you cant because these amps are amazing to experience.