Now that is a very good tip! Thank you!
Being a greedy Dutchman, I will write to them in English. I hope they will answer...
Has anyone ordered with them from abroad? How smooth went the transaction?
would you get a quote
I like to buy toroid for F5 as well Aleph XJ
I did not receive an answer yet (It's weekend in Poland) ,but I will let you know when I hear from them.
BTW, I have got some large an new toroids with 30V on the attick.
I bought them for some extra Alephs (I did build an Aleph5 - splendif amp!), but never found the time to built those extra pairs.😱
If anyone is interested in buying these, drop me a mail...
Regards,
Lucas
Nelson, did you have a preference for a certain type of diode?
Was the difference in sound quality obvious?
Regards,
Lucas
I used this
Hyperfast
and fast recovery, which I didnt know about back then 😱
Appears to work ok though, since amp sounds nice, and beats many around
But now I wonder if I should try "soft recovery" types
https://www1.elfa.se/data1/wwwroot/webroot/Z_DATA/07023393.pdf
Bridge is mounted on sides of heatsink
I would NOT do that with classA
Hope picture will change to F5 next time😛
Hyperfast
and fast recovery, which I didnt know about back then 😱Appears to work ok though, since amp sounds nice, and beats many around
But now I wonder if I should try "soft recovery" types
https://www1.elfa.se/data1/wwwroot/webroot/Z_DATA/07023393.pdf
Bridge is mounted on sides of heatsink
I would NOT do that with classA
Hope picture will change to F5 next time😛
Attachments
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Nothing to be ashamed of - maybe both are quite good at it.
I was wondering whether the MUR 860 (I have got bunches around) is up to the task for 2 channels of F5. They are specified with 8 A maximum. Is that enough safety margin for this application?
I have also got spare PCBs of the CarlosFM PSU here that uses these MUR 860s. I could use them together wit Civiller PSU boards in a CRCLC configuration, if they could stand the current draw. Can anyone advice on this?
The IR 30EPH06 used by Tinitus is of a totally different caliber. It is rated with 30 A. Has anyone else experience with these?
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I used this
Hyperfast
Appears to work ok though, since amp sounds nice, and beats many around
But now I wonder if I should try "soft recovery" types
https://www1.elfa.se/data1/wwwroot/webroot/Z_DATA/07023393.pdf
Bridge is mounted on sides of heatsink
I would NOT do that with classA
Hope picture will change to F5 next time😛
Hi Tinitus,
In the PDF it says:
"State of the art Hyperfast recovery rectifiers designed with optimized performance of forward voltage drop,
Hyperfast recover time, and soft recovery."
So maybe you have made a better choice than you realize
BTW, do they get warm?
I didnt see the soft recovery, so you saved me there, thanks
No, they dont get hot
Or, as hot as the heatsink the outputs are mounted on
I have driven a 1ohm speaker, but it definately liked 2ohm better
Its a 50wat, so could ad up to considerably amount of current
I dont know, but F5 is not designed to deliver huge amounts of current
Might help if you use double bridge on each channel
May depend on the heatsink, or whatever you choose to mount them on
Maybe power-up is the worst possible situation
But really, I dont know how much current flows in each diode of a bridge
But basicly it shouldnt be much more than bias current, and use the original curcuit with limiters
And maybe save a bit an trafo size
And, depending on your speakers
But again, power-up could be the most critical situation
But personally, that may not be where I would save money
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I'm wondering if the F5 would be up to the task of driving Strathearns
one half ohm resistance if the amp only high passed 300-500 Hz ?
First order input filter on F5.
Anybody?
F5 on higher voltage?
I've seen lots of debate about the power rating of the transformer for the F5 and I know the right answer is 18V-18V at >300VA.
But has anyone tried a higher voltage? I have a nice big 25V-25V I would like to try.
Thanks.
I've seen lots of debate about the power rating of the transformer for the F5 and I know the right answer is 18V-18V at >300VA.
But has anyone tried a higher voltage? I have a nice big 25V-25V I would like to try.
Thanks.
And I was thinking about 15V trafos, with raised bias 
Wasnt there something with input driver stage being at the limit with the original supply
Wasnt there something with input driver stage being at the limit with the original supply
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I have simulated the circuit with +/- 35 Volt rails, and it runs quite happily.
However you have about 280mW dissipating through each Jfet. I have no idea how long these devices would last, at that level of power dissipation.
The data sheet says they are rated for 400mW maximium each.
Just one more thing I hope you a have a preamp with enough gain to make use of the extra voltage headroom.
Also, you will need bigger heatsinks if you want to maintain the same level of bias current.
If you are prepared to experiment and blow a few jfets, then give it a go.
However you have about 280mW dissipating through each Jfet. I have no idea how long these devices would last, at that level of power dissipation.
The data sheet says they are rated for 400mW maximium each.
Just one more thing I hope you a have a preamp with enough gain to make use of the extra voltage headroom.
Also, you will need bigger heatsinks if you want to maintain the same level of bias current.
If you are prepared to experiment and blow a few jfets, then give it a go.
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You can always build SY's ImPasse preamplifer which was designed for bridged F4's.
The gain of the F5 can be tweaked up -- I did this when I used lateral mosfets.
🙄 No, I am not. My thought is at that xvr point and above the
F5 would not be required to output a lot of power, yes/no?
The N.Pass F5 article states
"It will drive a 2 ohm load without burping, and 1 ohm without misbehaving."
Now that would be full range.
If not, then a paralleled set of outputs, or an X'd F5?
Hi ichiban,
I've been lurking here while I start to collect my F5 bits, but your post causes me to write. Have you heard of using autotransformers for speaker impedance matching? Your Stratherns might be well served with these:
http://www.zeroimpedance.com/Zero-New.html
Regards,
John
I've been lurking here while I start to collect my F5 bits, but your post causes me to write. Have you heard of using autotransformers for speaker impedance matching? Your Stratherns might be well served with these:
http://www.zeroimpedance.com/Zero-New.html
Regards,
John
Thanks for the reply. 🙂 I use the torroidial transformer that came with the Strats for matching to 4 8 16 ohm amp outputs. However, I've read that a direct amp feed, if the amp is up to it, results in better sound. As I recall the Eagle? & the big Thresholds and Krells were said to be up to the current, pun intended, task at hand. 😀
do they all have multi-paralleled output stages?
I know the Krells have.
The F5 is a single pair.