Your title while does get attention but is not stated correctly "First Watt F4 beaten hands down by my class D amp, what's wrong?" would imply this is a product of First Watt and a product they produce does not compare, It should have been stated First Watt F4 clone. As a manufacture of products Mr Pass takes great pride in products he produces and is quite generous with his intellectual property, he was being kind to reply but in his placed my feathers would have been slightly ruffled.
Bill
Bill
with any kind of DIY amp construction there will always be problems
and making it even worse, possibility of 'commercial' clones not functioning properly
I'm sure this is a carefully considered 'calculated risk' from the very beginning
I think its due time to see some pictures of the actual build
and making it even worse, possibility of 'commercial' clones not functioning properly
I'm sure this is a carefully considered 'calculated risk' from the very beginning
I think its due time to see some pictures of the actual build
Dear OP,
Could you provide more info about
1. your audio system
2. music you listen using F4 and class D
3. measurement result of your F4 and class D
4. what other audiophiles say about your F4 and class D
5. yourself, how you would place yourself in terms of ability to objectively judge the sound quality of a hi-fi equipment
Thank you in advance,
Doug
Could you provide more info about
1. your audio system
2. music you listen using F4 and class D
3. measurement result of your F4 and class D
4. what other audiophiles say about your F4 and class D
5. yourself, how you would place yourself in terms of ability to objectively judge the sound quality of a hi-fi equipment
Thank you in advance,
Doug
No That's not a joke.. I'm prefectly serious.. When the phase is reversed... imaging will be blurred and the music will be kind of dead sounding and lifeless... Based on your description of your DIY amp.. that seems to be the problem.. Just try reversing the polarity on both spks terminals and see if the sound improves....
I don't think this is actually a Levinson design, for example I think this amp from memory uses an opamp to convert balanced to single ended. It may be based on a levinson design, but I would be surprised if it was a clone.
I Agree. As Nelson states this is the entertainment business, not every one prefers his sound. And that's before we even get into system synergy.
For the record I have an F4 HP amp, and whilst I have amps that do things better, I still like this amp alot
Guys,
sorry for not replying earlier, I've been busy with another project.
here are some pics of the thing. it may look weird for some with the oak front panel but I only call it different. those are not actually heat sinks but pieces of L profiles. kind of neat if you ask me, considering the price of a readily built heat sink. it may not ensure the perfect heat transfer at joints, surfaces not being 100% flat and all but the transistors stay below 65 Celsius for some 2-3 hours of uninterrupted service. it screams DIY and that's what we're here for
it weighs 21 kilos. there's no label for power rating on the tranny but it's 6 cm tall and 14 cm outside diameter. the thing sitting on top of it is a fan controller, you can see the green thermistor hanging near one of the output transistors.
there's 4x22000 uF of filtering per rail (label says Rubycon but nowadays that don't mean much).
near the back plate there are the BA1 front ends built by me. schematic is taken from here: http://www.diyaudio.com/forums/atta...4351063-f4-power-amplifier-pass-ba1-fe-f4.jpg
basically Burning Amp front end with the DC offset (at least I think that's what it is) circuitry removed.
the J109s and the 2SK170 were bought off eBay from some UK parts shop. I don't know if there is any way to to tell whether they're genuine or not. no "boutique" parts used, I ordered some Elna and Panasonic caps for the front end's feedback and output DC blocking but they arrived late. at any rate, I don't think caps may cause such a degradation. Mr. Pass himself once wrote that even the lowest grade ones are not that bad as some would have us believe.
one might notice the little 20pF ceramics but I wasn't able to source any other type of such low capacitance locally.
I tried to connect the front ends such that there is as little crosstalk as possible. the wires of the two channels don't cross and they don't hang around needlessly.
I don't have the layout of the PCB in PDF format right not but I can say that I didn't go for a balanced layout since I'm not using it as such anyway. it uses a ground plane.
I'm guessing by the shape and parts positioning that the layout of the F4's PCB is the one found in the users's manual on the First Watt website.
the testing was done with all sorts of music but mainly using high quality lossless recordings of jazz, classical and mostly acoustic music played by an Arcam rDAC connected a PC. speakers are Dynaudio Confidence 3's ($8000 new), extremely revealing. as mentioned before, on the Audience 52's ($800 new) the differences are not huge, and I would say that the only difference I can hear is that the F4 seems to output more bass. but with the C3's the deal is completely different.
as for my ability to judge sound... this is the kind of difference that is beyond subjective preference. everyone should know what I'm talking about. this the reason I'm reluctant about posting when it comes to sound impressions. many people get stuck on the "subjective preference" argument when it's not the case. there is subjective preference and there is bad sound.
sorry for not replying earlier, I've been busy with another project.
here are some pics of the thing. it may look weird for some with the oak front panel but I only call it different. those are not actually heat sinks but pieces of L profiles. kind of neat if you ask me, considering the price of a readily built heat sink. it may not ensure the perfect heat transfer at joints, surfaces not being 100% flat and all but the transistors stay below 65 Celsius for some 2-3 hours of uninterrupted service. it screams DIY and that's what we're here for
it weighs 21 kilos. there's no label for power rating on the tranny but it's 6 cm tall and 14 cm outside diameter. the thing sitting on top of it is a fan controller, you can see the green thermistor hanging near one of the output transistors.
there's 4x22000 uF of filtering per rail (label says Rubycon but nowadays that don't mean much).
near the back plate there are the BA1 front ends built by me. schematic is taken from here: http://www.diyaudio.com/forums/atta...4351063-f4-power-amplifier-pass-ba1-fe-f4.jpg
basically Burning Amp front end with the DC offset (at least I think that's what it is) circuitry removed.
the J109s and the 2SK170 were bought off eBay from some UK parts shop. I don't know if there is any way to to tell whether they're genuine or not. no "boutique" parts used, I ordered some Elna and Panasonic caps for the front end's feedback and output DC blocking but they arrived late. at any rate, I don't think caps may cause such a degradation. Mr. Pass himself once wrote that even the lowest grade ones are not that bad as some would have us believe.
one might notice the little 20pF ceramics but I wasn't able to source any other type of such low capacitance locally.
I tried to connect the front ends such that there is as little crosstalk as possible. the wires of the two channels don't cross and they don't hang around needlessly.
I don't have the layout of the PCB in PDF format right not but I can say that I didn't go for a balanced layout since I'm not using it as such anyway. it uses a ground plane.
I'm guessing by the shape and parts positioning that the layout of the F4's PCB is the one found in the users's manual on the First Watt website.
the testing was done with all sorts of music but mainly using high quality lossless recordings of jazz, classical and mostly acoustic music played by an Arcam rDAC connected a PC. speakers are Dynaudio Confidence 3's ($8000 new), extremely revealing. as mentioned before, on the Audience 52's ($800 new) the differences are not huge, and I would say that the only difference I can hear is that the F4 seems to output more bass. but with the C3's the deal is completely different.
as for my ability to judge sound... this is the kind of difference that is beyond subjective preference. everyone should know what I'm talking about. this the reason I'm reluctant about posting when it comes to sound impressions. many people get stuck on the "subjective preference" argument when it's not the case. there is subjective preference and there is bad sound.
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your reply pretty much sums up the reason I think 1000 times before posting pics. wanna know my opinion? I'm sick of those luxuriously looking clones of commercial products with readily built, very expensive cases. that has nothing to do with DIY. if one uses good parts, has soldering skills and doesn't skip anything important there's no reason for things to go wrong. and amp is a good amp no matter the look of the case. and TBH judging by the look of the solderings it is pretty well build, I've seen much worse.
as for bias, I didn't yet, will do so soon and post results.
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