ERO foil caps? replace or keep?

[ke4mcl]

just got a fisher x100 integrated. its loaded with ERO foil caps. i dont have much experience with those caps. do those fall under the same rules as wax caps? replace them all?

 

[sloober]

Yep, yank em.

 

[jaymanaa]

File 13:thumbsdn:

 

[ke4mcl]

but they look soo purty!

oh well.. ah re-capping we will go!

 

[audiodon]

ke4mcl,
That amp can stand better than orange drops as ero-foil replacements. That is, do better and you will hear the difference.

 

[ke4mcl]

i dont use orange drops except on vintage radios. its getting PIO's as do all the tube amps i rebuild. i wish i had not gotten rid of all the 7189's i liquidated on the 'bay a few years back because i could have used a set on this fisher.

i think i have a set of tele 12ax7's for it, will have to look around. i have an mc225 on its way and an mc240 on the shelf. the teles will be in the fisher temporarily and then will take up permanent residence in my mac tube amps.

 

[jaymanaa]

If you are keeping the circuit mostly stock, Fisher is the only amp I would ever recommend Solen Fast-caps for. Not all mind you, maybe 2 or 4 mixed in among the oilers. Just my 2 cents though.

 

[audiodon]

Yeah, and save three of those 5751s for it. Use three close ones for the preamp and tone circuit. You won't be sorry you did. Any good solid 12AX7s in the phase inverter positions will be fine.

I bought a set of new Mullard 7189s. I don't recommend them in this amp. I like Sylvania 7189s, but i haven't tried them all.

The absolute phase on that one is reversed, so hook your speaker positives to the com output. i'm not sure if that's typical of any tube amp with a single tube for the tone control section, but it's true with this amp.

 

[jaymanaa]

Yeah, and save three of those 5751s for it. Use three close ones for the preamp and tone circuit. You won't be sorry you did. Any good solid 12AX7s in the phase inverter positions will be fine.

I bought a set of new Mullard 7189s. I don't recommend them in this amp. I like Sylvania 7189s, but i haven't tried them all.

The absolute phase on that one is reversed, so hook your speaker positives to the com output. i'm not sure if that's typical of any tube amp with a single tube for the tone control section, but it's true with this amp.

RCA made a very "rugged" 7189, but I haven't compared them soundwise to any others. They take the current though, and ask for more.:yes:

 

[BrokenHill]

The ERO Foil caps in my Fisher 400 sounded better then other caps that I
had tried in this receiver, I had tested the ERO Foil caps on my Eico 950B
capacitor tester and they checked out very good so I had been using them
for about three years.
I did not like the way orange drops sounded in the 400 although I have had
great success in other tube amps with them, and I did try the various different
types of orange drops that are available.
It is my understanding that Mylar film caps do not go bad if unused or have
low usage on them, it is the amount of hours in active service that takes the
toll on them, if anyone knows different please explain more on this.

About four months ago I finally got some Russian teflon caps of various
value's and by themselves I did not like the way they sounded in the 400,
when I combined a K72n-6 .022 500volt teflon in parallel with a
K42y-2 .033 500volt PIO I got very good results with them together.
I really like the way the teflon & PIO combo sounds in the Fisher 400 and a
similar combination might work good in other Fisher models?

 

[Patrice B]

The absolute phase on that one is reversed, so hook your speaker positives to the com output. i'm not sure if that's typical of any tube amp with a single tube for the tone control section, but it's true with this amp.

I have an X-100A here with 1 tube in the tone control...

Do I have to do as you said (the phase reversal thing)?

Thanks.

Patrice

 

[Patrice B]

It brings me to another question: how would someone notice this phenomenon? I'm aware of what it does when one of the speakers is out of phase in relation with the other, mainly no imaging and lack of bass.

Also, several amp maker back then built phase reversal switches to prevent users to suffer from misphasing the speakers. I have an Heathkit and an Harman Kardon with this feature.

The HK doesn't even have the back terminals identified (negative and positive), only two taps identified "speakers". So in this case, I'm not sure the absolute phase is respected...

I take a guess and imagine that when the absolute phase is reversed, the two speakers "pull" when they're supposed to "push" and the reverse.

Thanks.

Patrice

 

[soundguy]

I take a guess and imagine that when the absolute phase is reversed, the two speakers "pull" when they're supposed to "push" and the reverse.

thats correct. the old trick was putting a battery on the woofer and seeing which way it moved to tell he absolute polarity. People of course will tweak on this, but there are few out there in a blind test that will likely hear a difference. Its obvious critical that speakers are in phase with each other, but so long as they are, you should be fine.

 

[Patrice B]

Thanks Soundguy,

What you've mentioned is to test a speaker for phasing I imagine.

I guess one could send a signal (like a pulsating bass drum) on the amp to see if the absolute phasing is respected in this case...