I have used the 200uF 100V cerafines from Parts Connexion on the V1.7+ boards with no issues. They are a slightly larger diameter but there’s enough room for them (see photos of edge of board and placement near R10, a Z-foil). On V1.5 boards it may not fit but it fits fine on V1.05 boards as well.
Pete
Attachments
Yes
, i have used the KZs as well and hear no displeasing effects. Just don't use Elna Silmic IIs... they mute the sound
Pete
Thanks, I have made many purchases from Digikey and I am very hesitant to buy components on Ebay. If I can't find Cerafine I will get KZs.
I have extra Black Gates, the PK 4V variety. They do work and sound very good. The 4V rating seems awfully low, but many have used them without issue. The recommendation is to start with some other cap that you don't care about. If you don't have any faults in your build, you know shorts or wrong voltages, then you can remove the other caps and install the PK.
If you are interested, send me a PM.
Jac
You mean 220uF.
But yeah, the 100v 220uF Elan Cerafine's are 2mm wider and 15mm taller than the 50v 220uF Cerafine's, and should work out with the new boards I would assume. It's about impossible to find a reliable source for the 50v or 63v ones.
I have always used transformers rated a little higher than needed, but there is a law of diminishing returns.
The specs call for 160VA so I was looking at two Antek AS-2225 200VA, for a dual monoblock configuration. Would there be much, is any, benefit in going to the AS-3225 which is 300VA?
The AS-2225 is $32 each and the AS-3225 is $41 each.
The specs call for 160VA so I was looking at two Antek AS-2225 200VA, for a dual monoblock configuration. Would there be much, is any, benefit in going to the AS-3225 which is 300VA?
The AS-2225 is $32 each and the AS-3225 is $41 each.
I can't say from personal experience, but early in the development of this amp, Bob McDaniels compared2 levels of toroidal Antek transformers and, if I recall, found cleaner, better damped bass with the larger levels.
Some searching in the beginning of this thread or the thread below might turn up the posts.
My_Ref Fremen Edition - Beta build/Fine tuning
Dario has always loved his R-core transformers, but those are hard to get here in the US. I actually did use the 300VA Anteks for my main system based on Bob's comments, but it was my first build of this amp and I used almost every premium component I could get to make sure I had the best amp I could.
Some searching in the beginning of this thread or the thread below might turn up the posts.
My_Ref Fremen Edition - Beta build/Fine tuning
Dario has always loved his R-core transformers, but those are hard to get here in the US. I actually did use the 300VA Anteks for my main system based on Bob's comments, but it was my first build of this amp and I used almost every premium component I could get to make sure I had the best amp I could.
Hi all
I want to enhance once again the excellent work done by Dario and the effectiveness of the circuit of this amplifier!
I'm using a raspberry + USB DAC as source of my HiFi. The DAC is directly connected to My_REF. Sound is perfect and no noise or any disturbance is present.
Now I'm try to use a diy preampli and soon as put it between DAC and My_REF 2 problems appears:
1. USB interference from rasberry. It sounds like a prprprpr. I cannot hear this when the DAC is connected directly to My_REF.
2. 50Hz hum from preampli. It sounds as clissical power hum.
To come back to the original good quality of sound I have to power the raspberry with a power bank and the preapli with batteries.
So it seems that My_REF is very proof versus noise. The USB problem is not present and no noise from the power is captured.
I want to enhance once again the excellent work done by Dario and the effectiveness of the circuit of this amplifier!
I'm using a raspberry + USB DAC as source of my HiFi. The DAC is directly connected to My_REF. Sound is perfect and no noise or any disturbance is present.
Now I'm try to use a diy preampli and soon as put it between DAC and My_REF 2 problems appears:
1. USB interference from rasberry. It sounds like a prprprpr. I cannot hear this when the DAC is connected directly to My_REF.
2. 50Hz hum from preampli. It sounds as clissical power hum.
To come back to the original good quality of sound I have to power the raspberry with a power bank and the preapli with batteries.
So it seems that My_REF is very proof versus noise. The USB problem is not present and no noise from the power is captured.
Finding a good trafo
Hi all ! I'm just starting to follow this build thread, and thought I'd search out this question.
So ... At [p.104 post #1038], Bob says he could have shipped ApexJr 125 VA transformers ...
"but though it's been months, I remember feeling the 300 VA units made a significant improvement in the body of the sound. "
That's the only reference I've found. I am also trying to source an affordable pair of transformers, so if for example Antek's 200VA toroid is more than sufficient and the 300VA toroid doesn't make a startling difference, that's probably where I'd land.
Comments and suggestions welcome !
Hi all ! I'm just starting to follow this build thread, and thought I'd search out this question.
So ... At [p.104 post #1038], Bob says he could have shipped ApexJr 125 VA transformers ...
"but though it's been months, I remember feeling the 300 VA units made a significant improvement in the body of the sound. "
That's the only reference I've found. I am also trying to source an affordable pair of transformers, so if for example Antek's 200VA toroid is more than sufficient and the 300VA toroid doesn't make a startling difference, that's probably where I'd land.
Comments and suggestions welcome !
Choices
Thanks for the reply. This is helpful as I assess my project !
I've made surprisingly few changes to my audio set-up over the years -- neglected, I confess -- but I've been reading up on impedance matching and amplifier-to-speaker matching to try to determine if I'm getting it right.
At present, I just switched to a pair of low impedance speakers (4 ohm-- audiophile, circa 1995, with 10" woofer, 6" midrange, 1" tweeter). I'm not getting the sound I'm used to (instruments are now very distinct, versus the more blended sound I've had for ages). I'm not getting the musicality I want, but I continue to listen and test. It may be my turntable and/or cartridge that I need to adjust, as I just installed a new cartridge as well.
So ... I'm bi-amping these speakers, and my two amps each have a gain of approx 27db, so I think this is not too far off from the My_Ref FE gain of 30. I'm hoping to use the My_Ref FE in a bi-amp mode for the upper octaves.
Regarding transformers, the difference in price for 300VA versus 200VA Antek trannys isn't that much. IF it doesn't bump up my chassis cost, I may go with the 300VA version --- with the thought that my "current hungry" low impedance speakers may need it.
In addition, I like the idea of adding a soft start circuit to limit inrush current from possibly degrading any parts.
Are there any other major choices that I should consider before selecting a chassis and starting to source parts (when the new BOM is available, of course)..... ?
Best to all,
Paul B.
Thanks for the reply. This is helpful as I assess my project !
I've made surprisingly few changes to my audio set-up over the years -- neglected, I confess -- but I've been reading up on impedance matching and amplifier-to-speaker matching to try to determine if I'm getting it right.
At present, I just switched to a pair of low impedance speakers (4 ohm-- audiophile, circa 1995, with 10" woofer, 6" midrange, 1" tweeter). I'm not getting the sound I'm used to (instruments are now very distinct, versus the more blended sound I've had for ages). I'm not getting the musicality I want, but I continue to listen and test. It may be my turntable and/or cartridge that I need to adjust, as I just installed a new cartridge as well.
So ... I'm bi-amping these speakers, and my two amps each have a gain of approx 27db, so I think this is not too far off from the My_Ref FE gain of 30. I'm hoping to use the My_Ref FE in a bi-amp mode for the upper octaves.
Regarding transformers, the difference in price for 300VA versus 200VA Antek trannys isn't that much. IF it doesn't bump up my chassis cost, I may go with the 300VA version --- with the thought that my "current hungry" low impedance speakers may need it.
In addition, I like the idea of adding a soft start circuit to limit inrush current from possibly degrading any parts.
Are there any other major choices that I should consider before selecting a chassis and starting to source parts (when the new BOM is available, of course)..... ?
Best to all,
Paul B.
Hi Paul,
Not to rain on your parade, but a 3 dB difference is really pretty big. From a human perception point of view, something that is 3 dB louder sounds like about twice as loud. That means that you are probably going to have to trim the loudness of the FE's if you are going to bi-amp them with your existing amps.
One thing is that the My_Ref has lots of compensation and interactions that mean changing its gain internally is very difficult to do well. But the good news is that it should be fairly easy to change the sensitivity externally. A simple, 2 resistor voltage divider can drop the input voltage but, as always, there are complications. The impedance ratios of the output of your pre amp to the divider and again from the divider to the input of the amp need to be managed and can affect the sound. The divider could be high impedance and followed by an opamp as a buffer to lower its output impedance, but now you need a +/- power supply.
I know from our off-line conversation that you are thinking about building a second set of FE's if you like the first ones. One solution would be to build 2 FE's so that you can bi-amp both the top and bottom with FE power.
One other question that I should have asked earlier. What is about the speaker sensitivity specification? You might be able to power these speakers with the FE's not bi-amped. I believe I remember some people powering speakers with 86 dB per watt sensitivity without problems.
Hey guys, any other great suggestions for dealing with Paul's issue?
Jac
My understanding is a 3db increase doubles the sound intensity but it takes a 10db increase to double the "percieved " volume to human ears.
I stand corrected. Thank you.
Once upon a time, when younger, I could hear 1/2 dB difference in sound level, although that was a really small difference.
Jac
Thanks to Stream for reminding us. It is best if build related discussion comes in this thread. Over in the Completed Projects Thread, we got off topic and started talking about building older boards and the new board. That should have probably happened here and if you want to make sure you are caught up, please be sure to read that thread up to about post #34.
Fremen Edition My_Ref Amplifier – Completed Projects and Photos
Jac
Fremen Edition My_Ref Amplifier – Completed Projects and Photos
Jac