Love my Sonic frontiers sfl2 preamplifier in stock form apart from a recent replacement of all electrolytic capacitors. I would really like to replace the original 3uf multi caps with Mundorf supreme silver gold oil's but due to size constraints only a 2.2uf will fit. The only over cap I have in mind is a v-cap odam 3uf. Any advice from someone with experience living with this unit and trying these and other caps would be fantastic. Thanks in advance
You won't listen, but I would strongly recommend you do not do that.
I know Chris (one of the owners of that company) and my late wife worked there during that time period. The capacitors they used were excellent and do not degrade over time. I've serviced audio equipment professionally almost 50 years.
I know Chris (one of the owners of that company) and my late wife worked there during that time period. The capacitors they used were excellent and do not degrade over time. I've serviced audio equipment professionally almost 50 years.
While I don't have your preamp I do have some experience with both of the caps you mentioned. Of the 2 I prefer the V Cap ODAM over the Mundorf.
The V Cap is more neutral while the Mundorf has slightly highlighted treble.
Depending in the input capacitance of your amp you may be able to get buy with a smaller value cap. See the Vcap website for capacitor calculator.
Scott
The V Cap is more neutral while the Mundorf has slightly highlighted treble.
Depending in the input capacitance of your amp you may be able to get buy with a smaller value cap. See the Vcap website for capacitor calculator.
Scott
One thing for everyone to consider seriously. If the capacitor you are thinking of using is too large, you can't use it. If the leads are too large for the existing holes, do not enlarge the holes.
Oil capacitors are old technology and unreliable compared to today's much better capacitors. They are also larger. They are also not as good as a capacitor, so anyone who says they like an oil-filled capacitor actually likes distortion if that part is in a place where it can create it. Later they won't like it.
Oil capacitors are old technology and unreliable compared to today's much better capacitors. They are also larger. They are also not as good as a capacitor, so anyone who says they like an oil-filled capacitor actually likes distortion if that part is in a place where it can create it. Later they won't like it.
I am listening honest, I've just joined a DIY site that advises not to do it 🙂🤣 I do love it in stock as I said and have no intention of ever letting go. I wish Sonic frontiers still produced Beautiful Audio. I've lived with Sonic Frontiers products since 2000. I think your wife may have worked on my preamp as it's Beautifully put together. cheers
Hi bedomes,
She was in the office.
Anyway, I'm just tired of people wrecking equipment. Tired of cleaning up after, or knowing they wasted money. The "capacitor club" is like a religion, zero science involved. That doesn't bode well. We'll certainly advise to help you make something better or repair an item. You will find members who firmly believe coupling capacitors make a difference. That answer is - it depends. Mostly it does not.
Good equipment is generally well engineered. From experience, those folks will not allow a cheaper component degrade performance, they won't normally waste money either. On the flip side, they will install over-priced parts if it means sales. That's the marketing department and the audiophile fashion side of the business. Those things belong on the outside of the unit, not the inside.
She was in the office.
Anyway, I'm just tired of people wrecking equipment. Tired of cleaning up after, or knowing they wasted money. The "capacitor club" is like a religion, zero science involved. That doesn't bode well. We'll certainly advise to help you make something better or repair an item. You will find members who firmly believe coupling capacitors make a difference. That answer is - it depends. Mostly it does not.
Good equipment is generally well engineered. From experience, those folks will not allow a cheaper component degrade performance, they won't normally waste money either. On the flip side, they will install over-priced parts if it means sales. That's the marketing department and the audiophile fashion side of the business. Those things belong on the outside of the unit, not the inside.
I completely Understand and only usually work on what needs to be addressed. Circuit board tracks are very delicate and in my mind only the best tools are up for the job ( no destroyed tracks and only beautiful clean solder joints were aloud in this project) . When I received this pre amplifier quite a few of the electrolytic capacitors had leaked and were way out of tolerance and needed replacement immediately. The gain switch was also not working this was due to a dry solder joint next to one of the relays at the back of the preamp . You will be pleased to know This unit Tests perfect and should be good to go for another 30 / 40 years. From experience this is a very reliable pre amplifier of excellent design.
Those 0.022uF capacitors can be removed without any effect on sound at all. Another example of people imagining non-existent problems, which affected manufacturing.
If you consider the frequency range we are dealing with, and characteristics of the parts involved, those small caps do absolutely nothing. In fact, if the output coupling capacitors were electrolytic (which have leakage issues), adding those wouldn't change a thing. Nor could you hear or measure any difference in the audio band or slightly beyond.
If you consider the frequency range we are dealing with, and characteristics of the parts involved, those small caps do absolutely nothing. In fact, if the output coupling capacitors were electrolytic (which have leakage issues), adding those wouldn't change a thing. Nor could you hear or measure any difference in the audio band or slightly beyond.
Either way, they don't improve anything. They exist for audiophile approval only.
You can leave it stock of course. I would just recommend against the idea of adding parts like that if they weren't there. If you had a bad one, I would recommend simply removing them.
You can leave it stock of course. I would just recommend against the idea of adding parts like that if they weren't there. If you had a bad one, I would recommend simply removing them.
The original circuit diagram shown above seems to state 2.2uf being used but on production models I've only ever seen 3uf used. I would presume sonic frontiers decided to use 3uf on the final production.
You will often see running production changes. Part availability is one factor, and this is not a critical value at all.
Keeping service information up to date is a full time job on both ends. We would get ECO's (engineering change order) for many brands, others simply didn't say anything at all. Notifications came in the way of changes in later paperwork, or service bulletins. That and manuals / schematics can easily have errors.
Keeping service information up to date is a full time job on both ends. We would get ECO's (engineering change order) for many brands, others simply didn't say anything at all. Notifications came in the way of changes in later paperwork, or service bulletins. That and manuals / schematics can easily have errors.
No it's a much smaller cap and still a multi cap but possibly a higher specification. personally I haven't seen it but I know it's there sitting under the board. possibly a multicap ppmfx or RTX im not sure.
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It's just another small capacitor.
Think of dropping a big rock. Then adding (gluing) a small rock to it and dropping it again. Ask someone what difference there is. The characteristics of the larger capacitor will dominate, even if the two are vastly different (as long as the smaller one isn't completely terrible, or a short).
We use smaller capacitor in parallel in power supplies to address high frequency impedance. We are talking RF frequencies and it is for circuit stability. This concept does not hold for audio frequency coupling capacitors. Also look at the impedance levels of the two circuits.
Think of dropping a big rock. Then adding (gluing) a small rock to it and dropping it again. Ask someone what difference there is. The characteristics of the larger capacitor will dominate, even if the two are vastly different (as long as the smaller one isn't completely terrible, or a short).
We use smaller capacitor in parallel in power supplies to address high frequency impedance. We are talking RF frequencies and it is for circuit stability. This concept does not hold for audio frequency coupling capacitors. Also look at the impedance levels of the two circuits.
As can you see, the -simulated- output impedance (and FR behaviour too) of SFL-2 with 3uF or 3u22 (fixed ESR values with frequency change) almost identical (with infinitive capacitance it's 120R), so the designer use this 0.22uF for other purposes.
Usually use this technique to decrease (and possibly hold steady) output impedance (with better, and lower ESR smaller value capacitor) when with increasing frequency the "larger" capacitor ESR grooving.
Usually use this technique to decrease (and possibly hold steady) output impedance (with better, and lower ESR smaller value capacitor) when with increasing frequency the "larger" capacitor ESR grooving.
Hi euro21,
Sorry, no.
ESR means absolutely zero with coupling capacitors for one thing. Tell me, what is the ESR of the 3uF? The smaller cap? They are in parallel. Now, what is that circuit impedance? Probably 10,000 ohms minimum, compared to the ESR of even an unreasonably high but realistic capacitor? Right.
What you need to be concerned about is the dielectric, and where that capacitor is situated along with the impedances in that circuit. So ... not a coupling capacitor. A filter element is a different story, but coupling caps are not those by definition.
These myths and misapplication of data has to stop.
Sorry, no.
ESR means absolutely zero with coupling capacitors for one thing. Tell me, what is the ESR of the 3uF? The smaller cap? They are in parallel. Now, what is that circuit impedance? Probably 10,000 ohms minimum, compared to the ESR of even an unreasonably high but realistic capacitor? Right.
What you need to be concerned about is the dielectric, and where that capacitor is situated along with the impedances in that circuit. So ... not a coupling capacitor. A filter element is a different story, but coupling caps are not those by definition.
These myths and misapplication of data has to stop.
I was under the impression that bypass capacitors were to speed things up a little especially in power supplies and also taking on some characteristics of the smaller higher specification cap.
Nope. Not at all.
A high frequency bypass capacitor lowers impedance at high frequencies well beyond the operating frequencies of the total circuit. Individual transistors will operate at MHz frequencies. Audio circuits may operate to the 200 kHz area max, and we then filter the input so they do not amplify RF. Bad things happen when you amplify RF along with your audio.
So in a power supply, bypass capacitors are there for circuit stability, period. Nothing is "sped up", you just avoid ringing and oscillations which may cause things you can hear in the audio band. High frequency bypass capacitors should be placed near the circuit using the power, or to attenuate noise in the power supply.
In an extreme case, say you place a small fantastic film cap across an electrolytic capacitor. If you fire a pulse through there with and without that capacitor, the pulse gets through at the same time (barring high inductance). So at best case, these are really high frequency effects well above the audio band. Best case. That added fantastic (and expensive I bet) has done zero for you. Besides, the characteristics of the larger capacitor will dominate.
When people look at characteristics and effects far removed from the audio band, and apply those to audio, it doesn't do anything at all. Nothing except to sell some expensive parts. It is audio fashion, people sit and think of things and apply those things to situations where they do not apply.
Every part has a set of characteristics that will best match a circuit location and frequency range. Leakage may be an issue as well. There is no "best capacitor" or "best resistor". There are only various parts well suited to certain applications. Also, it is a part type and material that matters, not the brand or model. Big shock to people, industry doesn't really care about audio. We can order parts labeled a certain way and market them. Or, if we make them ourselves, they will not be as good as a high quality industrial part. A signal is just a signal, whether it be audio or a servo signal - whatever. Physics does not change the rules just because we are dealing with audio.
A high frequency bypass capacitor lowers impedance at high frequencies well beyond the operating frequencies of the total circuit. Individual transistors will operate at MHz frequencies. Audio circuits may operate to the 200 kHz area max, and we then filter the input so they do not amplify RF. Bad things happen when you amplify RF along with your audio.
So in a power supply, bypass capacitors are there for circuit stability, period. Nothing is "sped up", you just avoid ringing and oscillations which may cause things you can hear in the audio band. High frequency bypass capacitors should be placed near the circuit using the power, or to attenuate noise in the power supply.
In an extreme case, say you place a small fantastic film cap across an electrolytic capacitor. If you fire a pulse through there with and without that capacitor, the pulse gets through at the same time (barring high inductance). So at best case, these are really high frequency effects well above the audio band. Best case. That added fantastic (and expensive I bet) has done zero for you. Besides, the characteristics of the larger capacitor will dominate.
When people look at characteristics and effects far removed from the audio band, and apply those to audio, it doesn't do anything at all. Nothing except to sell some expensive parts. It is audio fashion, people sit and think of things and apply those things to situations where they do not apply.
Every part has a set of characteristics that will best match a circuit location and frequency range. Leakage may be an issue as well. There is no "best capacitor" or "best resistor". There are only various parts well suited to certain applications. Also, it is a part type and material that matters, not the brand or model. Big shock to people, industry doesn't really care about audio. We can order parts labeled a certain way and market them. Or, if we make them ourselves, they will not be as good as a high quality industrial part. A signal is just a signal, whether it be audio or a servo signal - whatever. Physics does not change the rules just because we are dealing with audio.