Hi John,
yes, it sound better
Sadly no, maybe you could ask if one of the Release Candidate partecipants that buyed spare boards wants to sell them.
In the next months, though, there will probably be a group buy.
Damn I'm always too late to these things haha!
I'll wait for the next group buy then - will give me time to save up for some HQ components
- John
Nothing serious, just some holes enlarged (DR1, DR2) or reduced (C13) and, maybe, a final choice on C9/R10 arrangement.
Maybe that means you have gotten mighty close to "Perfection".
It is my view that this group will be unlikely to get involved in this experimental build.
Andrew, Please.
I was referring to the several people with good equipment who have already contributed to the FE development. Some of them have personal situations you may not be aware of, so please don't make such blanket statements.
You are of course welcomed to your view of this and any project. I believe the "Experimental" nature of the entire diyAudio forum is at the core of its attractiveness. For those not willing to experiment and make modifications, the entire retail market for someone elses work is fully available.
I think any valid adjustments and/or constructive commentary from you will and should be accepted as an attempt to further what has been a very "positive" and enjoyable experience/experiment for many.
We are all keeping our heads up with great anticipation for the posting of your finished design that optimises the potential of the LM3886 family.
Keeping the faith........
Bob
I was referring to the several people with good equipment who have already contributed to the FE development. Some of them have personal situations you may not be aware of, so please don't make such blanket statements.
You are of course welcomed to your view of this and any project. I believe the "Experimental" nature of the entire diyAudio forum is at the core of its attractiveness. For those not willing to experiment and make modifications, the entire retail market for someone elses work is fully available.
I think any valid adjustments and/or constructive commentary from you will and should be accepted as an attempt to further what has been a very "positive" and enjoyable experience/experiment for many.
We are all keeping our heads up with great anticipation for the posting of your finished design that optimises the potential of the LM3886 family.
Keeping the faith........
Bob
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Before connecting my partly rebuilt pcb and trying with music I tried it just connected to the transformer; everything appeared ok 4.8mv output offset +-14.5v and a couple of mv on the input.After 10 mins I went to check things and the led was off so I checked the voltages to find 26.9v on the output;-9.5v on the input and +14v but -7.5v.Anybody any ideas? Tia
Capacitor Auditions
Thanks Bob.
Bob is a gent. Bob is a peach. Bob is a diamond in the DIY rough. Bob was nice enough to lend me his Audyn True Copper and Mundorf ZN capacitors for a comparison listening on C13. Did I remember to say, “Thanks Bob!”
To those I added K71-4 Russian polystyrene and DC coupled (no capacitor at all).
Since Dario and Bob have been our project experimenters, I have been well served by just following their lead. In this case, I will try to summarize Dario's comments by saying that True Copper are very detailed and neutral and the best, ZN are full sounding, full detail, just a touch hard, and K71 is neutral and detailed, but a little cold. My results follow the characteristics that Dario and others have noted from these capacitors but remind me that we are combining the sound signature of the capacitor with the sound of the speaker, room, and listeners preference. In particular, I learned that certain capacitors and speakers combine better than others.
Let me start with the capacitors. These are my impressions from a comparison of each capacitor with DC coupled.
The True Copper have an extended high frequency response with just a touch of higher amplitude at high frequency. The mid-range appears neutral, but the bass is clearly boosted.
The ZN are neutral in bass, but boosted in mid-range. The high frequency is neutral and gives the impression of slightly less extension to the highest frequencies.
The K71 appear to be neutral in the bass and mid-range, but high frequency is both extended and boosted.
Now my poor homemade speakers are pretty good, but far from perfect. They use a Dynaudio D28 soft dome tweeter which while clear and well damped, tends to roll off slowly above about 14k Hz. In other words, they could use some help on the top end. As for the rest, the bass has a good solid feel and is well damped. No help needed here. The mid-range is also just fine as it is. Comparing Dario's comments, I suspect that my speakers have a slightly warm sound overall. Note that in this evaluation, I am evaluating the satellites without the subwoofer, directly powered by the FE and controlled with only a bare potentiometer for volume.
Combine my speakers and room with the True Copper and the sound is clear, the image is great, and they sound very smooth except for the extra bass that doesn't belong. I tried to like them, but the extra bass kept interfering with listening enjoyment. Most speakers and most rooms would benefit from a little more bass, so I can understand how the True Copper would be an excellent choice in most cases, just not mine.
Moving on to the ZN, the initial impression is very good. They sound very smooth, even liquid. The image is forward but clear. The bass is natural and the image is almost as good as the True Copper. I like the ZN, but the longer I listened, the more I became aware of the strong mid-range. In the end, it was a case of nice, but second best for me.
The K71 seem to be the most neutral in my system. The higher treble level that may contribute to Dario describing them as sometimes cold. It might make them seem a little thin sounding on other systems. With my speakers, the K71 enhance the top end and make the sound neutral and natural. The K71 give my speakers that help that they need on the top end. The image is the same as with the True Copper. The detail is the same or a touch better than the True Copper. Although they don't boost the bass, the bass extends to very low frequencies. Using my system, the K71 sounded the closest to DC coupled of the 3 top capacitors. That is a great result for me because I already own some K71. See, Bob even saved me some money.
One of the neat things about this experiment is that I realized one of the great benefits of DIY. Because I can match the sound choices of the amp to my room and speakers, I get the best overall choice for me. When I decide to build new speakers, my current choices probably won't be the best, but I can audition the sound again and find the best sound for me with the new speaker. The unfortunate soul that buys hi-end commercial audio equipment doesn't easily have that choice. They can't possibly know the speakers that the amp designer used when making his choices.
After selecting the K71 for my system, I realized that I would have more than one capacitor in the signal path to the FE because I am using an active crossover between the satellites and the subwoofer. Just to see what happens, I put 2 K71 in series before each FE channel. The result was quite interesting as the sound became a little more punchy and warm than with one K71. Overall, a very small change, but slightly closer to DC coupled in sound.
I realize that in developing the crossover, I will do this again, combining component sound for the best result. I will probably buy some ZN for the crossover as they might be a nice combination with K71 or other capacitors in the crossover.
So my recommendation is to try a few things on your own, especially when you get close to the sound you want. All of these capacitors are fine quality and will give any system a very nice sound. But you might as well get the combination that suits you best.
Jac
Thanks Bob.
Bob is a gent. Bob is a peach. Bob is a diamond in the DIY rough. Bob was nice enough to lend me his Audyn True Copper and Mundorf ZN capacitors for a comparison listening on C13. Did I remember to say, “Thanks Bob!”
To those I added K71-4 Russian polystyrene and DC coupled (no capacitor at all).
Since Dario and Bob have been our project experimenters, I have been well served by just following their lead. In this case, I will try to summarize Dario's comments by saying that True Copper are very detailed and neutral and the best, ZN are full sounding, full detail, just a touch hard, and K71 is neutral and detailed, but a little cold. My results follow the characteristics that Dario and others have noted from these capacitors but remind me that we are combining the sound signature of the capacitor with the sound of the speaker, room, and listeners preference. In particular, I learned that certain capacitors and speakers combine better than others.
Let me start with the capacitors. These are my impressions from a comparison of each capacitor with DC coupled.
The True Copper have an extended high frequency response with just a touch of higher amplitude at high frequency. The mid-range appears neutral, but the bass is clearly boosted.
The ZN are neutral in bass, but boosted in mid-range. The high frequency is neutral and gives the impression of slightly less extension to the highest frequencies.
The K71 appear to be neutral in the bass and mid-range, but high frequency is both extended and boosted.
Now my poor homemade speakers are pretty good, but far from perfect. They use a Dynaudio D28 soft dome tweeter which while clear and well damped, tends to roll off slowly above about 14k Hz. In other words, they could use some help on the top end. As for the rest, the bass has a good solid feel and is well damped. No help needed here. The mid-range is also just fine as it is. Comparing Dario's comments, I suspect that my speakers have a slightly warm sound overall. Note that in this evaluation, I am evaluating the satellites without the subwoofer, directly powered by the FE and controlled with only a bare potentiometer for volume.
Combine my speakers and room with the True Copper and the sound is clear, the image is great, and they sound very smooth except for the extra bass that doesn't belong. I tried to like them, but the extra bass kept interfering with listening enjoyment. Most speakers and most rooms would benefit from a little more bass, so I can understand how the True Copper would be an excellent choice in most cases, just not mine.
Moving on to the ZN, the initial impression is very good. They sound very smooth, even liquid. The image is forward but clear. The bass is natural and the image is almost as good as the True Copper. I like the ZN, but the longer I listened, the more I became aware of the strong mid-range. In the end, it was a case of nice, but second best for me.
The K71 seem to be the most neutral in my system. The higher treble level that may contribute to Dario describing them as sometimes cold. It might make them seem a little thin sounding on other systems. With my speakers, the K71 enhance the top end and make the sound neutral and natural. The K71 give my speakers that help that they need on the top end. The image is the same as with the True Copper. The detail is the same or a touch better than the True Copper. Although they don't boost the bass, the bass extends to very low frequencies. Using my system, the K71 sounded the closest to DC coupled of the 3 top capacitors. That is a great result for me because I already own some K71. See, Bob even saved me some money.
One of the neat things about this experiment is that I realized one of the great benefits of DIY. Because I can match the sound choices of the amp to my room and speakers, I get the best overall choice for me. When I decide to build new speakers, my current choices probably won't be the best, but I can audition the sound again and find the best sound for me with the new speaker. The unfortunate soul that buys hi-end commercial audio equipment doesn't easily have that choice. They can't possibly know the speakers that the amp designer used when making his choices.
After selecting the K71 for my system, I realized that I would have more than one capacitor in the signal path to the FE because I am using an active crossover between the satellites and the subwoofer. Just to see what happens, I put 2 K71 in series before each FE channel. The result was quite interesting as the sound became a little more punchy and warm than with one K71. Overall, a very small change, but slightly closer to DC coupled in sound.
I realize that in developing the crossover, I will do this again, combining component sound for the best result. I will probably buy some ZN for the crossover as they might be a nice combination with K71 or other capacitors in the crossover.
So my recommendation is to try a few things on your own, especially when you get close to the sound you want. All of these capacitors are fine quality and will give any system a very nice sound. But you might as well get the combination that suits you best.
Jac
Jac,
In the spirit of the season, If I ever decide to run for President I know who to select as my campaign manager
Actually I'm very happy that you took up the offer and produced such a thorough review - thanks.
I couldn't agree with you more. Once the essential construction of the FE is completed, we move on to what is closer to tuning for personal preference and system architecture rather than an attempt to perfect the amp itself. I have identified a weak spot (for my tastes) at the top of the mids in my Sunflower speakers and am convinced the solution will be exactly as you describe - proper combination of crossover and amp components. I also moved the Leap designed mains (Morel MDT30 1" soft dome + 2 Vifa 5" MTM) that I used for +15 years back into the room to help key in to the process you suggest. Hopefully that will help determine the best baseline for the FE amps.
If I am reading correctly, it sounds like you prefer the output quality of no cap at C13 over any other option. Is that what you are implying? The mailman should deliver a pair of the PE Audyn Plus 1uf caps later today and I will throw them into the mix. You also have me thinking about the extra bottom produced by the True Copper caps, as on some program material - not all - it is a tad excessive. I had considered adding some stuffing to the SF bass cabinet but will now consider your approach.
Looking forward to trying the K71-4 caps you are offering and will post a review.
Thanks again
In the spirit of the season, If I ever decide to run for President I know who to select as my campaign manager
Actually I'm very happy that you took up the offer and produced such a thorough review - thanks.I couldn't agree with you more. Once the essential construction of the FE is completed, we move on to what is closer to tuning for personal preference and system architecture rather than an attempt to perfect the amp itself. I have identified a weak spot (for my tastes) at the top of the mids in my Sunflower speakers and am convinced the solution will be exactly as you describe - proper combination of crossover and amp components. I also moved the Leap designed mains (Morel MDT30 1" soft dome + 2 Vifa 5" MTM) that I used for +15 years back into the room to help key in to the process you suggest. Hopefully that will help determine the best baseline for the FE amps.
If I am reading correctly, it sounds like you prefer the output quality of no cap at C13 over any other option. Is that what you are implying? The mailman should deliver a pair of the PE Audyn Plus 1uf caps later today and I will throw them into the mix. You also have me thinking about the extra bottom produced by the True Copper caps, as on some program material - not all - it is a tad excessive. I had considered adding some stuffing to the SF bass cabinet but will now consider your approach.
Looking forward to trying the K71-4 caps you are offering and will post a review.
Thanks again
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My application and evaluation of these caps was in the MyRef C, so perhaps the sound of the amp itself contributed to it.
Very nice evaluation, but focused almost entirely on broad tonal qualities. You make scant mention of the spatial characteristics, and that's where I found the True Coppers to excel beyond any others I've tried, in addition to providing a warm, dynamic sound with realistic midrange tonality and depth. You found the bass excessive, but I didn't notice that because my amps drive only the mids/tweets.
Perhaps I should give those K71-4's a try. Are there any commercial dealers, or must they be purchased from private parties at places such as eBay?
Perhaps you should give the TC's another listen for the layering of depth that I detected: subtle spatial and tonal characteristics of the music that no other cap provided. That, to me, differentiates the illusion of real music from an electronic reproduction. If the bass is too distracting, try moving your speakers.
You also failed to mention whether the caps you tested are the same value. We know how much influenece that has on the bass response of the MyRef amps.
Personally, I thought the DC coupled amp sounded pale and thin, and I preferred the musicality of almost any cap to the sound of no cap. That goes against prevailing opinion about caps in general, but, perhaps in this case, the amp was designed to sound best with some cap in the circuit, and listening without one gives a false reference. I suggest comparing caps to the sound of high quality commercial products or live acoustic music.
I never heard anyone mention a roll-off of Dynaudio tweeters. You certainly have some nice drivers there. Do you think there is much information above 14k to roll-off, and can you even hear it? I suspect the additional brightness you're hearing is much lower than that. What I have found is that brightness, good or bad, is often produced by the upper limits of a midrange driver, not the tweeter. I agree that the ZN cap does not have the extension to reproduce adequate detail in the highest frequencies, and the midrange is somewhat forward.
As you say, these caps provide the final flavoring to these wonderful little amps, and each person will optimize for their system and taste.
Peace,
Tom E
Very nice evaluation, but focused almost entirely on broad tonal qualities. You make scant mention of the spatial characteristics, and that's where I found the True Coppers to excel beyond any others I've tried, in addition to providing a warm, dynamic sound with realistic midrange tonality and depth. You found the bass excessive, but I didn't notice that because my amps drive only the mids/tweets.
Perhaps I should give those K71-4's a try. Are there any commercial dealers, or must they be purchased from private parties at places such as eBay?
Perhaps you should give the TC's another listen for the layering of depth that I detected: subtle spatial and tonal characteristics of the music that no other cap provided. That, to me, differentiates the illusion of real music from an electronic reproduction. If the bass is too distracting, try moving your speakers.
You also failed to mention whether the caps you tested are the same value. We know how much influenece that has on the bass response of the MyRef amps.
Personally, I thought the DC coupled amp sounded pale and thin, and I preferred the musicality of almost any cap to the sound of no cap. That goes against prevailing opinion about caps in general, but, perhaps in this case, the amp was designed to sound best with some cap in the circuit, and listening without one gives a false reference. I suggest comparing caps to the sound of high quality commercial products or live acoustic music.
I never heard anyone mention a roll-off of Dynaudio tweeters. You certainly have some nice drivers there. Do you think there is much information above 14k to roll-off, and can you even hear it? I suspect the additional brightness you're hearing is much lower than that. What I have found is that brightness, good or bad, is often produced by the upper limits of a midrange driver, not the tweeter. I agree that the ZN cap does not have the extension to reproduce adequate detail in the highest frequencies, and the midrange is somewhat forward.
As you say, these caps provide the final flavoring to these wonderful little amps, and each person will optimize for their system and taste.
Peace,
Tom E
Bob,
I effectively created a cap of 0.5 uF when I put 2 1 uF K71 caps in series. It shouldn't cause any big issue and it didn't in my case. It will shift the corner frequency of any My Ref from about 1.6 to about 3.2 Hz. This is effectively the DC blocking filter, so anything below 5 or 10 Hz should be pretty hard to hear.
Jac
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Bob,
That is a little hard to say. With no input cap, I found there was the most information. I guess there is a small bias in the back of my head that no cap should be what the recording engineer intended. No cap is interesting, even tempting, but I'm not sure that the ZN and K71 are a little easier to listen to.
In the end, I'm not quite ready to go there for safety reasons, but it does make a good way to understand what a capacitor is adding or subtracting to the sound.
Jac
Mmh... did you changed also the LM318?
Do you have spare BC639/BC640?
If you turn off, let things cool and then power on again it measures right?
Thanks Jac for the interesting post
Bass boosted... compared to DC-coupling, right?
Nearly all caps have the same effect, in my experience.
In fact the DC-coupled My_Ref sounds a bit thin, according the designer the amp is designed to work with a 1uF input cap which interacts with LM318 inputs.
The strange thing is that you heard such 'boost' only with True Copper...in your tests did you try the different orientation of caps?
From 0.68uF and up it will be fine.
But the amp is designed to work as intended with 1uF.
if your pre has 0 mV DC offset you can try without fear.
But I would not permanently use the My_Ref DC-coupled.
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