I substituted C2 = 0.33 uF and C3 = 1 uF (Marked in RED in the schematic below) in an QUAD Power amp's Input LPF stage using much recommended Obbligato Gold Premium 630V Film caps. The stock caps in the QUAD were standard metalized stacked films of the same values.
The obbligatos' have not been bypassed at all - BUT just left on their own to function. Its now well past 60-70 hrs use and I find the results as under-mentioned:
(1) The Tone is quite robust with "very analog & roundish fullness" but its quite dry. Easily noticeable on Piano, strings, Sax etc. Lacks extension.
(2) Earlier, there used be a spacious airyness in the tone though not as thick sounding as with the Obbligatos (esp. noticeable in the midbass region) but this spaciousness effect has totally disappeared - making the overall presentation rather very Flat and 2-Dimensional. The reverberation is all gone.
After-thoughts
Squeezing the large, heavy & bulky Obbligatos in place of standard films was quite a challenge & a hell-of-a-task but now the net results ain't bringing any smiles - meaning do I need to revert back to the way things were earlier? i.e. removal of the "mighty Obbligatos" ?
Your suggestions will be most appreciated.
Thanks in advance . . .
The obbligatos' have not been bypassed at all - BUT just left on their own to function. Its now well past 60-70 hrs use and I find the results as under-mentioned:
(1) The Tone is quite robust with "very analog & roundish fullness" but its quite dry. Easily noticeable on Piano, strings, Sax etc. Lacks extension.
(2) Earlier, there used be a spacious airyness in the tone though not as thick sounding as with the Obbligatos (esp. noticeable in the midbass region) but this spaciousness effect has totally disappeared - making the overall presentation rather very Flat and 2-Dimensional. The reverberation is all gone.
After-thoughts
Squeezing the large, heavy & bulky Obbligatos in place of standard films was quite a challenge & a hell-of-a-task but now the net results ain't bringing any smiles - meaning do I need to revert back to the way things were earlier? i.e. removal of the "mighty Obbligatos" ?
Your suggestions will be most appreciated.
Thanks in advance . . .
An externally hosted image should be here but it was not working when we last tested it.
Bah, at a 1st look, 330 nF looks a little small on the input.
You may give it a try with a of-the-shelf Polyester or polipropilene say 1 to 4.7 uF, 100V rated is more than enough. I mean , common brands Wima, Evox-Rifa, Vishay. The experiment won't cost you more than a couple of Euro and you might be surprised.
effebi
You may give it a try with a of-the-shelf Polyester or polipropilene say 1 to 4.7 uF, 100V rated is more than enough. I mean , common brands Wima, Evox-Rifa, Vishay. The experiment won't cost you more than a couple of Euro and you might be surprised.
effebi
@ effebi
The Stock 0.33 & 1.0 uF were the regular Wima/Vishay/Evox-Rifa types and the results were quite good. I wanted it even better so tried genuine Film like the much touted Obbligato Gold Premium. BUT - after the work, it is not sounding good.
Maybe someone suggested that the Obbligato Caps are very tightly wound with thick film, so will need long break-in. Logically thinking, maybe this could be true.
The 0.33 & 1.0uF values are not the problem, the Obbligato Cap is the problem right now!
The Stock 0.33 & 1.0 uF were the regular Wima/Vishay/Evox-Rifa types and the results were quite good. I wanted it even better so tried genuine Film like the much touted Obbligato Gold Premium. BUT - after the work, it is not sounding good.
Maybe someone suggested that the Obbligato Caps are very tightly wound with thick film, so will need long break-in. Logically thinking, maybe this could be true.
The 0.33 & 1.0uF values are not the problem, the Obbligato Cap is the problem right now!
C3 can not have any measureable nor audible effect at all. it's in the feedback stage of DC-servo...
C2 can benefit from bigger value (or utlimately from change to PP type - I guess it is MKS or something alike).
C1 should bother you too - put there some decent ordinary film cap if it's ceramic.
just put there something from Vishay/Rifa/Wima and don't care about it anymore - in your search for "better sound" you will probably need a better amp caps really don't do the magic.
C2 can benefit from bigger value (or utlimately from change to PP type - I guess it is MKS or something alike).
C1 should bother you too - put there some decent ordinary film cap if it's ceramic.
just put there something from Vishay/Rifa/Wima and don't care about it anymore - in your search for "better sound" you will probably need a better amp
caps really don't do the magic.
hmm - seems no one wants to answer here.
Guess will keep the break-in on "strong mode" and hope for the best.
Ain't giving up on those Obbigatos so fast . . .
They gotta sound good - sooner or later
They have to have sound good because they are "mighty Obligatos"??? Come on, are you serious? I think you are a victim of aggressive marketing common for products targeted at audiophools.
Do you know what kind of dielectric is used inside the cap? (Do you know what a dielectric is at all?) Obviously the manufacturer doesn't tell and hides other important information about the product as well. Maybe for good reason. Maybe the caps don't spec well despite being hand rolled by blonde virgins in a clear full moon night. Don't let you fool by the golden sticker and what the manufacturer claims about the sonics.
Better give up here, use an ordinary film cap with standard metallised polypropylene dielectric, increase the value of C2 like effebi suggested, follow the advice of Lukas87 who got it absolutely right as well and buy some overly expensive audio voodoo cables instead or maybe a magic stone to put on top of you speakers to improve the sound or any other audiophool product that makes you happy.
I have changed to obbligato gold a coupling caps of DAC and have same impression as you - warm and heavy and slow sound and thick bass
did you get them to work correct after serious burn In
The Obbligatos totally changed to stand out as very superior caps after a very severe burn-in that's as long as 1 year of good, healthy use.
Now, the same warmth exists while top octaves have opened up completely, and the beauty of these caps is the big time "heft" in the bottom octaves that they provide.
In short - a class apart with zero regrets !! Most recommended.
One year to burn caps in - are you serious?!? Absolute crazy talk! More likely that you got used to the sound in that period of time...
And using them in the Quad in the positions you mention must have entailed the caps having much longer leads than the otiginal pcb mounted items, to fit in to the small space. Those leads are undoubtedly picking up RF so probably sound worse than the original 'cheap' components...
The problem with using the Obbligatos in either the Quad or a Dac is that they see practically nil dc across themselves. Not a good thing, especially for high voltage caps. Maybe some forced break in while being connected to a dc source close to their working voltage would help. Or a 220v ac outlet...
There are ways to innovate for these types of mods AND that's what I exactly did which may be outside your comprehension.
Any way - each to his own...
BTW - no RF or whatsoever so goodbye to such theories.
the bottom end developed exactly the texture that's reminiscent of a typical European highend amp. Indeed it was detailed, pitch accurate, just the right amount of damping and fast.
No bypass as Obbligatos don't like them. It spoils the goodies in them.
1000 Hrs of burn-in.
I rather think that a cap taking a year to break in (and for you to notice this a year later with any certainty) is probably outside most people's comprehension... But each to his/her own...
At any rate, enjoy - it's a terrific amplifier!
Obbligato - nothing but frustration
I'm glad you were able to get the Obbligato caps. I've had nothing but frustration. Paid for and ordered the matched pair of Gold, and received the black film oil. They said they would correct it, but stopped responding to my emails after I asked for the shipping tracking info. In the future, I will only go with a reputable company.
I'm glad you were able to get the Obbligato caps. I've had nothing but frustration. Paid for and ordered the matched pair of Gold, and received the black film oil. They said they would correct it, but stopped responding to my emails after I asked for the shipping tracking info. In the future, I will only go with a reputable company.
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