[George Papadi]

1)I'm rebuilding my Theta mono tube amps & need to buy quality,great sounding, moderately priced film & foil polypropylene 0.47uf 600/630 volt coupling & by-pass capacitors. Does anyone prefer the sonics of Audio Cap Theta series($12), Multi Cap PPFXS($13), Auricap ($22), Mundorf ZN series($11) or Sonicap Generation I ($5). Cap length can't exceed 1.3". For several reasons, leads must be solid, not multistranded. On a price performance basis, I'm thinking Honda & Lexus rather than Mazeratti or Ferrari quality. Only the Auricaps seem too costly. I realize that sonics are subjective but would appreciate your recommendations?

2)Need to replace resistors as well. Carbon film, carbon composition, & metal films are in original circuits. Any recommendations?

[Ian Bell[_2_]]

George Papadi wrote:
1)I'm rebuilding my Theta mono tube amps& need to buy quality,great
sounding, moderately priced film& foil polypropylene 0.47uf 600/630
volt coupling& by-pass capacitors. Does anyone prefer the sonics of
Audio Cap Theta series($12), Multi Cap PPFXS($13), Auricap ($22),
Mundorf ZN series($11) or Sonicap Generation I ($5). Cap length can't
exceed 1.3". For several reasons, leads must be solid, not
multistranded. On a price performance basis, I'm thinking Honda& Lexus
rather than Mazeratti or Ferrari quality. Only the Auricaps seem too
costly. I realize that sonics are subjective but would appreciate your
recommendations?


When used a coupling capacitors there is no sonic difference because they all
have zero signal across them. Use orange drops.

2)Need to replace resistors as well. Carbon film, carbon composition,&
metal films are in original circuits. Any recommendations?


Metal film every time.

Cheers

Ian

[Patrick Turner]

On Oct 21, 2:11*pm, George Papadi George.Papadi.
wrote:
1)I'm rebuilding my Theta mono tube amps & need to buy quality,great
sounding, moderately priced film & foil polypropylene 0.47uf 600/630
volt coupling & by-pass capacitors. Does anyone prefer the sonics of
Audio Cap Theta series($12), Multi Cap PPFXS($13), Auricap ($22),
Mundorf ZN series($11) or Sonicap Generation I ($5). Cap length can't
exceed 1.3". For several reasons, leads must be solid, not
multistranded. On a price performance basis, I'm thinking Honda & Lexus
rather than Mazeratti or Ferrari quality. Only the Auricaps seem too
costly. I realize that sonics are subjective but would appreciate your
recommendations?

Have you replaced all the caps and resistors in ONE channel only, and
then carried out an AB listening test?

One would set up the two amps each fed by a mono signal from a preamp
and then arrange ONE speaker in ONE position to be switchable to
either of the power amps so that the ONLY thing to change is the power
amp. I bet you don't hear a lot of sound change, and if you have a
friend try to trick you by saying he has switched from amp A to B but
maybe either really doing it or not. He records the exact switch
setting each time he says he has made a switch or not and each time
YOU should be able to identify the better sounding amp, and perhaps
after ten attempts your friend will show you his list of switch
settings and your corresponding choices for the best sounding amp. My
guess is that the amp which had original R&C parts is likely to get a
"score" of 5 and so is the amp where all R&C have been replaced. Or
perhaps the original amps are deemed to sound better.

Usually the amp which is 1dB louder will be prefered as being "more
detailed". So levels are very important for AB testing.

There is nothing wrong with changeing caps if it makes you feel better
even if you can't pick any sound change in a blind AB test - this has
been my experience dealing with audiophiles; they really cannot choose
correctly very often, or at all, but they still enjoy the expense, and
convince themselves that when both channels have had caps changed as
well as the caps in the preamp and speaker crossovers, recordings of
Joan Sutherland made in 1967 sound just that much better. BTW, Joan
died last week at 83, and I have to say that I have never ever heard a
better opera singer. Sure, her recordings deserve a good system, but
her singing is what mainly gets the music across the line for a true
audiophile, not the brand of polypropylene capacitors.
But I know ppl who don't like any opera and like most music produced
electronically, or with a casual 10% level of THD and IMD such as much
rythm and blues or rock'n'roll, and they like to change capacitors.
Just why is a mystery.

While carbon film resistors work fine while they remain in serviceable
condition they can mysteriously just go open circuit for no apparent
reason after some years. The worst offenders are plate load R with say
200Vdc across them. Even though they look fine after 5 years service
and have no sign of heat stress, they go open. I have seen so many
failures of carbon film R that I routinely replace all typical 1W CF
types with 3/4W metal film Welwyn types, or metal oxide 2W types, 5W
vitreous enameled wire wounds or white box wire wounds etc so that if
a tube short circuits the anode load R does not overheat and smoke
when conveying twice the normal Idc from B+ to 0V..

I doubt resistor changes can be detected by ear unless the R values
are changed drastically by intention or by carelessness.

What makes sound change in amps is more likely to be caused by changes
of brands of input or output tubes or changes to output transformers
or to the amount of NFB used or to the general amp topology.

I've seen ppl spend hundreds of bucks on caps to replace all existing
caps and then found the amp sounded worse, so they went back to the
original caps. I've seen audiophiles change all their caps without
making any AB comparisons, and seen how allergic some are about making
rational choices about subjective sound quality. Their allergy to
rationality is linked with their self esteem, need to be right,
feelings of control over destiny, self worth and numerous other mental
issues best left to a psychiatrist to work out with longe session
therapy. I've seen audiophiles change major components such as
speakers and amp types without any AB and sometimes I have had to be
very polite about their latest hi-end expense because I felt they
obviously have a worse system after such changes. I have also seen
audiophiles wax lyrical abour their latest speakers and the imaging
but pointed out to them that alas one tweeter has its cone "pushed in"
and deformed, thus ruining one tweeter's response and drastically
changeing high treble response between the two channels. But mostly
tweeters work over 5kHz, and large differences in channels above 5kHz
often go un-noticed. I have assisted audiophiles in setting up their
multi amp systems with active crossovers and choosing the best
location for the sub. Usually my measured work which they said they
liked so much does not last a fortnight because they CHANGE some damn
thing and don't bother measuring anything, so for example they move
the sub position, or alter the phase, and the bass gets response peaks
and troughs which were not there previously and this isn't hi-fi any
more. Its all innocent fun of course, but I work with precision on
gear and I rarely need to change anything in my own system. I'd like a
better CD player or a better turn table but one really does have to
spend a lot and go to exraordinary lengths to get a slight
improvement. I have not even mentioned the claims ppl make about
cables, but lemme tell ya, I need the gumboots, de-oderant,
wheelbarrow, shovel and broom when audiophiles talk about cabling, or
mains filters, and Shak-Ti stones on top of speaker cabinets.

The very best Oille De Le Reptille is obtained by a dude who has a
12yo virgin **** a little bit into the bottle at midnight when there
is a full moon. A little dab on speaker cones of this stuff will have
to entering the Gates Of Sonic Nivarna, only $2,369 for 50ml bottle.

Patrick Turner.


2)Need to replace resistors as well. Carbon film, carbon composition, &
metal films are in original circuits. Any recommendations?

--
George Papadi

[Engineer[_2_]]

On Oct 21, 4:47*am, Ian Bell wrote:
George Papadi wrote:
1)I'm rebuilding my Theta mono tube amps& *need to buy quality,great
sounding, moderately priced film& *foil polypropylene 0.47uf 600/630
volt coupling& *by-pass capacitors. Does anyone prefer the sonics of
Audio Cap Theta series($12), Multi Cap PPFXS($13), Auricap ($22),
Mundorf ZN series($11) or Sonicap Generation I ($5). Cap length can't
exceed 1.3". For several reasons, leads must be solid, not
multistranded. On a price performance basis, I'm thinking Honda& *Lexus
rather than Mazeratti or Ferrari quality. Only the Auricaps seem too
costly. I realize that sonics are subjective but would appreciate your
recommendations?

When used a coupling capacitors there is no sonic difference because they all
have zero signal across them. *Use orange drops.

2)Need to replace resistors as well. Carbon film, carbon composition,&
metal films are in original circuits. Any recommendations?

Metal film every time.

Cheers

Ian



Ian is quite right. Incidentally, coupling caps work by NOT charging
(on the AC signal that is.) I use orange drop caps and metal film
every time, if I have them. Else, whatever plastic caps of the right
specs I have to hand. Don't use ceramic caps in audio as they are
alleged to be nonlinear against voltage... or, since they don't
charge, is that current? I use them for RF only. Anyway, there's no
need to use them in audio as we have plenty of plastic cap choices.
Cheers,
Roger

[Fred[_12_]]

"George Papadi" wrote in message ...

1)I'm rebuilding my Theta mono tube amps & need to buy quality,great
sounding, moderately priced film & foil polypropylene 0.47uf 600/630
volt coupling & by-pass capacitors. Does anyone prefer the sonics of
Audio Cap Theta series($12), Multi Cap PPFXS($13), Auricap ($22),
Mundorf ZN series($11) or Sonicap Generation I ($5). Cap length can't
exceed 1.3". For several reasons, leads must be solid, not
multistranded. On a price performance basis, I'm thinking Honda & Lexus
rather than Mazeratti or Ferrari quality. Only the Auricaps seem too
costly. I realize that sonics are subjective but would appreciate your
recommendations?

The Multi Cap is out due to size - the 0.47/600V PPFXS is 1.8" long.

2)Need to replace resistors as well. Carbon film, carbon composition, &
metal films are in original circuits. Any recommendations?

Either Holco or PRP metal film w/ copper leads are excellent. Be sure
you grip resistor leads with needle nose pliers when bending - failure
to do so can cause open or noisy resistors due to damage to the
connection between the lead and the resistive element.

Fred


--
George Papadi

[Patrick Turner]

On Oct 22, 9:03*am, Engineer wrote:
On Oct 21, 4:47*am, Ian Bell wrote:





George Papadi wrote:
1)I'm rebuilding my Theta mono tube amps& *need to buy quality,great
sounding, moderately priced film& *foil polypropylene 0.47uf 600/630
volt coupling& *by-pass capacitors. Does anyone prefer the sonics of
Audio Cap Theta series($12), Multi Cap PPFXS($13), Auricap ($22),
Mundorf ZN series($11) or Sonicap Generation I ($5). Cap length can't
exceed 1.3". For several reasons, leads must be solid, not
multistranded. On a price performance basis, I'm thinking Honda& *Lexus
rather than Mazeratti or Ferrari quality. Only the Auricaps seem too
costly. I realize that sonics are subjective but would appreciate your
recommendations?

When used a coupling capacitors there is no sonic difference because they all
have zero signal across them. *Use orange drops.

2)Need to replace resistors as well. Carbon film, carbon composition,&
metal films are in original circuits. Any recommendations?

Metal film every time.

Cheers

Ian

Ian is quite right. *Incidentally, coupling caps work by NOT charging
(on the AC signal that is.) *I use orange drop caps and *metal film
every time, if I have them. *Else, whatever plastic caps of the right
specs I have to hand. *Don't use ceramic caps in audio as they are
alleged to be nonlinear against voltage... or, since they don't
charge, is that current? I use them for RF only. *Anyway, there's no
need to use them in audio as we have plenty of plastic cap choices.
Cheers,
Roger- Hide quoted text -

- Show quoted text -

Coupling caps do actually have an AC voltage across them. Their
reactance becomes high as frequency becomes lower, and so there is
some ac voltage always there although it is a negligible amount. If
the cap is a plastic type the amount of THD or IMD generated by the
cap being in the circuit is utterly negligible even at LF of say 20Hz
when the signal voltage across the cap becomes considerable relative
to the following grid biasing resistance.

AFAIK, plastic film or foil type caps have never been been the cause
of any significant or audible distortion that the most golden eared
audiophile can identify in a careful AB test. But some audiophiles
still say caps affect the sound and that different brands of the same
type of cap sound different, or better or worse, or whatever.

A change of input tubes in a preamp may cause a sound change even
though THD 0.01%, and artifacts of the tube should be entirely
inaudible if below -80dB below signal. Perhaps it is due to subtle
microphonic effects.
Just how plastic caps change the sound is not within my capability to
explain.
I just use generic 630V rated Wima polypropylene caps and nobody
complains (very much).

When a guitar amp is seriously overdriven the coupling caps do begin
to get a Vdc charge that is greater than the Vdc because of the grid
current flow. The increase is Vdc charge effectively increases the
output tube grid bias so much on big bashes of signal that the OP
tubes work in class C to make a near square wave to the speaker.
Usually low C values are used, say 0.01uF with say a following Rg =
220k, giving a quick recovery from overload. AFAIK, the presence of a
steady Vdc charge across coupling caps in amps well short of clipping
or overload causes negligible THD/IMD.
Electro coupling caps used on base circuits of bjts are regarded as
sonic poison though.....

Sure, use ceramics for RF bypassing. Their C value changes with
temperature. I've not seen significant THD caused by them though, but
I never use them in audio circuits unless I want to bypass something
at RF, and the presence of a ceramic cap has such high reactance at AF
that its loading/distortion effect on the AF is negligible.

Patrick Turner.

[Ian Bell[_2_]]

Patrick Turner wrote:
On Oct 22, 9:03 am, wrote:
On Oct 21, 4:47 am, Ian wrote:





George Papadi wrote:
1)I'm rebuilding my Theta mono tube amps& need to buy quality,great
sounding, moderately priced film& foil polypropylene 0.47uf 600/630
volt coupling& by-pass capacitors. Does anyone prefer the sonics of
Audio Cap Theta series($12), Multi Cap PPFXS($13), Auricap ($22),
Mundorf ZN series($11) or Sonicap Generation I ($5). Cap length can't
exceed 1.3". For several reasons, leads must be solid, not
multistranded. On a price performance basis, I'm thinking Honda& Lexus
rather than Mazeratti or Ferrari quality. Only the Auricaps seem too
costly. I realize that sonics are subjective but would appreciate your
recommendations?

When used a coupling capacitors there is no sonic difference because they all
have zero signal across them. Use orange drops.

2)Need to replace resistors as well. Carbon film, carbon composition,&
metal films are in original circuits. Any recommendations?

Metal film every time.

Cheers

Ian

Ian is quite right. Incidentally, coupling caps work by NOT charging
(on the AC signal that is.) I use orange drop caps and metal film
every time, if I have them. Else, whatever plastic caps of the right
specs I have to hand. Don't use ceramic caps in audio as they are
alleged to be nonlinear against voltage... or, since they don't
charge, is that current? I use them for RF only. Anyway, there's no
need to use them in audio as we have plenty of plastic cap choices.
Cheers,
Roger- Hide quoted text -

- Show quoted text -

Coupling caps do actually have an AC voltage across them. Their
reactance becomes high as frequency becomes lower, and so there is
some ac voltage always there although it is a negligible amount. If
the cap is a plastic type the amount of THD or IMD generated by the
cap being in the circuit is utterly negligible even at LF of say 20Hz
when the signal voltage across the cap becomes considerable relative
to the following grid biasing resistance.


Properly sized coupling capacitors will have practically zero AC across then at
the frequencies of interest by definition.

AFAIK, plastic film or foil type caps have never been been the cause
of any significant or audible distortion that the most golden eared
audiophile can identify in a careful AB test. But some audiophiles
still say caps affect the sound and that different brands of the same
type of cap sound different, or better or worse, or whatever.


For the latest on this check out Doug Self's new book which demonstrates that
some film/foil caps are measurably better than others though the difference is
tiny OHMO. The place you really need to take cars is in frequency sensitive
circuits like RIAA where there will be considerable AC voltages across caps.

Cheers

Ian

A change of input tubes in a preamp may cause a sound change even
though THD 0.01%, and artifacts of the tube should be entirely
inaudible if below -80dB below signal. Perhaps it is due to subtle
microphonic effects.
Just how plastic caps change the sound is not within my capability to
explain.
I just use generic 630V rated Wima polypropylene caps and nobody
complains (very much).

When a guitar amp is seriously overdriven the coupling caps do begin
to get a Vdc charge that is greater than the Vdc because of the grid
current flow. The increase is Vdc charge effectively increases the
output tube grid bias so much on big bashes of signal that the OP
tubes work in class C to make a near square wave to the speaker.
Usually low C values are used, say 0.01uF with say a following Rg =
220k, giving a quick recovery from overload. AFAIK, the presence of a
steady Vdc charge across coupling caps in amps well short of clipping
or overload causes negligible THD/IMD.
Electro coupling caps used on base circuits of bjts are regarded as
sonic poison though.....

Sure, use ceramics for RF bypassing. Their C value changes with
temperature. I've not seen significant THD caused by them though, but
I never use them in audio circuits unless I want to bypass something
at RF, and the presence of a ceramic cap has such high reactance at AF
that its loading/distortion effect on the AF is negligible.

Patrick Turner.

[NX211]

On Oct 20, 11:11*pm, George Papadi George.Papadi.
wrote:
1)I'm rebuilding my Theta mono tube amps & need to buy quality,great
sounding, moderately priced film & foil polypropylene 0.47uf 600/630
volt coupling & by-pass capacitors. Does anyone prefer the sonics of
Audio Cap Theta series($12), Multi Cap PPFXS($13), Auricap ($22),
Mundorf ZN series($11) or Sonicap Generation I ($5). Cap length can't
exceed 1.3". For several reasons, leads must be solid, not
multistranded. On a price performance basis, I'm thinking Honda & Lexus
rather than Mazeratti or Ferrari quality. Only the Auricaps seem too
costly. I realize that sonics are subjective but would appreciate your
recommendations?

2)Need to replace resistors as well. Carbon film, carbon composition, &
metal films are in original circuits. Any recommendations?

--
George Papadi

Capacitors of today are of such high quality that virtually any
capacitor of the correct value / voltage rating made by a reputable
manufacturer will work perfectly well. (Especially when you compare
them to capacitors made 40 or 50 years ago.) The differences are so
subtle at audio frequencies that no one can hear the difference. They
might think so - but I could easily fool them.

There's so much hype connected with consumer component sales that
people will pay HUGE prices just to get that worm fuzzy feeling. It's
unbelievable to see people pay $8 or $10 (or more) for some foil /
wax .01 mfd capacitor just because some "expert" told them otherwise.

Purchase one of those orange drop capacitor kits from AES or someplace
similar for about $70 and be assured that they will work great and
last longer then you will.