Hey guys,
nice amp you´ve built yourself.
Please do us and yourself a favour and use a lab-powersuply to first start up your amp. Once you´ve powered it with lowest current slowly allow it to draw more power. If something should go wrong, you will not burn beyound recognition...
Cheers
Chris
nice amp you´ve built yourself.
Please do us and yourself a favour and use a lab-powersuply to first start up your amp. Once you´ve powered it with lowest current slowly allow it to draw more power. If something should go wrong, you will not burn beyound recognition...
Cheers
Chris
Hey Thomas,
very nice work!
It seem you used the same case I did for my Aleph 30 (4U 300mm deep).
http://www.diyaudio.com/forums/showthread.php?postid=1019336#post1019336
Zen V9 was my favourite project but my ls 3/5a are 82 dB!
Take a look to the temp too, I got 35° C above the ambient with 104 Watt per channel.
Ciao
Peppe
very nice work!
It seem you used the same case I did for my Aleph 30 (4U 300mm deep).
http://www.diyaudio.com/forums/showthread.php?postid=1019336#post1019336
Zen V9 was my favourite project but my ls 3/5a are 82 dB!
Take a look to the temp too, I got 35° C above the ambient with 104 Watt per channel.
Ciao
Peppe
Finally I powered the amp and ................ it works 
But it was not so simple because I had some problems that maybe others can have. For the first test I used an old CDP, cheap speakers and, overall, a 200W light bulb: this saved one channel from a first short.
Here the circuit for the light bulb:
The bulb light up on powerup, then turns immediately off and, after a few seconds appears a constant weak light. If there is a short on the amp, the bulb doesn't turn off, but remains lit with its normal light.
This was the case for the right channel. I dismounted the amp, checked components, soldered again mosfets and cleaned the board with a toothbrush. On next try both channel worked.
Then I "cooked" the amp for an hour to fix the voltage trhough the pot P1 when heatsinks are hot: nice trial if you don't have a multimeter with small clips like Steen. I found that R18 (the side toward center of the board) and R7 (toward the edge) are good sites where to anchor ordinary "crocodiles".
With 35Vac I get 45Vdc at amp input, so I fixed the voltage measured as above at 22.5V.
Finally I mounted again the chassis and on a final test without light bulb............ again a short on the right channel, whith smoke coming trough cover holes.
Well, I discovered that tha cause of the shorts are the standoffs of the PS. The smoke came from the for 3w resistors that now are baked. The amp would be save.
Now I've to wait monday to buy new resistors and PLASTIC standoffs.
But it was not so simple because I had some problems that maybe others can have. For the first test I used an old CDP, cheap speakers and, overall, a 200W light bulb: this saved one channel from a first short.
Here the circuit for the light bulb:
The bulb light up on powerup, then turns immediately off and, after a few seconds appears a constant weak light. If there is a short on the amp, the bulb doesn't turn off, but remains lit with its normal light.
This was the case for the right channel. I dismounted the amp, checked components, soldered again mosfets and cleaned the board with a toothbrush. On next try both channel worked.
Then I "cooked" the amp for an hour to fix the voltage trhough the pot P1 when heatsinks are hot: nice trial if you don't have a multimeter with small clips like Steen. I found that R18 (the side toward center of the board) and R7 (toward the edge) are good sites where to anchor ordinary "crocodiles".
With 35Vac I get 45Vdc at amp input, so I fixed the voltage measured as above at 22.5V.
Finally I mounted again the chassis and on a final test without light bulb............ again a short on the right channel, whith smoke coming trough cover holes.
Well, I discovered that tha cause of the shorts are the standoffs of the PS. The smoke came from the for 3w resistors that now are baked. The amp would be save.
Now I've to wait monday to buy new resistors and PLASTIC standoffs.
I'm proud to present to you my Zen v9 nicely playing his first string quartet 
Stickers are there for a try and will be replaced by a serigraphy.
The problem was solved empirically. The short had to do with mosfets, not standoffs. By unscrewing mosfets from heatsink, the short was away. So I just put on ceramic insulators and the amp works. Is there something to know on how properly fix mosfets to heatsink? I'd like this amp to last
Now the sound.
It's playing his first hour of music so it is not yet at its best, but it is .... incredible.
The first surprise is the absolute silence at power up. With volume all open there is no noise. Drivers look like dead at 50 cm and have real weak hum with the ear at 10 cm. Star ground works. The source is a PC with EMU1212M through an external Wolfson dac: if I had a doubt that the PC is noisy this is a nice evidence that it is not.
What is incredible with the first music playing is the bandwidth: in a simple string quartet there are more sounds on violins highest harmonics and cello lowest string. And more sounds in the middle in a fascinating detail.
With my Fostex FE206 96db, I can play the quartet at live volume with the pot at 2 o'clock, so the power is enough. Tomorrow I'll try big orchestras
Next days I'll post more detailed impressions on sound with my reference recordings, but with what I listened today I can say already that this was really an experience to do, for us coming from Class D.
May I risk an evaluation? This amp overshoots largely my UCD180 on its best qualities: clarity and exacteness of sounds. Funny is that I spended half the money with this Zen
.
Stickers are there for a try and will be replaced by a serigraphy.
The problem was solved empirically. The short had to do with mosfets, not standoffs. By unscrewing mosfets from heatsink, the short was away. So I just put on ceramic insulators and the amp works. Is there something to know on how properly fix mosfets to heatsink? I'd like this amp to last
Now the sound.
It's playing his first hour of music so it is not yet at its best, but it is .... incredible.
The first surprise is the absolute silence at power up. With volume all open there is no noise. Drivers look like dead at 50 cm and have real weak hum with the ear at 10 cm. Star ground works
. The source is a PC with EMU1212M through an external Wolfson dac: if I had a doubt that the PC is noisy this is a nice evidence that it is not.What is incredible with the first music playing is the bandwidth: in a simple string quartet there are more sounds on violins highest harmonics and cello lowest string. And more sounds in the middle in a fascinating detail.
With my Fostex FE206 96db, I can play the quartet at live volume with the pot at 2 o'clock, so the power is enough. Tomorrow I'll try big orchestras
Next days I'll post more detailed impressions on sound with my reference recordings, but with what I listened today I can say already that this was really an experience to do, for us coming from Class D.
May I risk an evaluation? This amp overshoots largely my UCD180 on its best qualities: clarity and exacteness of sounds. Funny is that I spended half the money with this Zen
.
Congrats, Thomas. Nice that everything worked out. I agree that its amazing, how good sound one gets from the ZenV9 for the invested $$. Mr Pass is the greatest gift for the DIY community, ever I am in the process of making a pair of efficient speakers at the moment, when they are finished; the ZenV9 will be pulled out again. I will try it without feedback also. Interesting stuff
How did you make that nice "ZenV9" sticker?
Thomas, your amp will look good in any livingroom. Well done.
Steen
I am in the process of making a pair of efficient speakers at the moment, when they are finished; the ZenV9 will be pulled out again. I will try it without feedback also. Interesting stuff As long as they are bolted tightly to the heatsink with a locking washer under the screw-head, you should be fine. Thats assuming that the ceramic insulators are good enough, which they probably are.
How did you make that nice "ZenV9" sticker?
Thomas, your amp will look good in any livingroom. Well done.
Steen
Transistor mounting
I believe this (below) is a good article about transistor mounting and heatsinks in general. Though I agree that a screw and a washer will work just fine, you might increase reliability and life span of the transistors if you use some more elaborate way of mounting the transistors.
http://www.sound.westhost.com/heatsinks.htm
A really nice work by the way. I myself am just in the planning stage right now. I envy each and everyone that have a working Zen 1-9.
I believe this (below) is a good article about transistor mounting and heatsinks in general. Though I agree that a screw and a washer will work just fine, you might increase reliability and life span of the transistors if you use some more elaborate way of mounting the transistors.
http://www.sound.westhost.com/heatsinks.htm
A really nice work by the way. I myself am just in the planning stage right now. I envy each and everyone that have a working Zen 1-9.
steenoe said:How did you make that nice "ZenV9" sticker?
Steen
Hi Steen.
Thanks. Here attached is the file for stickers with enough resolution for a serigraphy. The yellow "Zen" would be gold colour, but with your aluminium front plate I would go with Black or dark grey.
What speakers are you planning?
Mjjg, thanks for the link and for the envy
.
Thanks for the PDF Nice work on that logo.
), so that was an easy decision
For starters it will be those, but future plans might include some other cabinets like the BIB or maybe backloaded horns.
Steen
Nice work on that logo.Some of the DIY'ers around here has got together, and are working on some Abby clones, with Fostex FE166E drivers. I was offered to join them for a pair of cabinets and ofcourse said yes. I dont have to do any work (for a change
), so that was an easy decision For starters it will be those, but future plans might include some other cabinets like the BIB or maybe backloaded horns.
Steen
That really looks very good! I've decided to start building mine.
I'm going for four channels but I only have two PSU cards, so I would like to use 15000 uF caps. These are the ones I'm choosing from
Panasonic TUP
Panasonic THA
United Chemi Con
Cornell Dubillier
Any suggestions or should I just pick the cheapest?
/Trango
I'm going for four channels but I only have two PSU cards, so I would like to use 15000 uF caps. These are the ones I'm choosing from
Panasonic TUP
Panasonic THA
United Chemi Con
Cornell Dubillier
Any suggestions or should I just pick the cheapest?
/Trango
Hi,
As promised I'm back with some sonic impressions about ZenV9 after some hours of listening. I can confirm that power is enough in a "Zen" system configuration without pre: SPDIF from PC (truly Toslink, so there is not a ground in common) => DAC => ZenV9 => Fostex FE206E.
Nevertheless a 5W T-Amp sounds louder in this system, what disappointed me at the beginning. So, as I'm an ugly guy, I selected the third movement of Mahler's 2nd symphony to see how ZV9 would behave. The T-Amp can't reproduce it well, because if you set volume so that weakest sounds are well audible then, when it comes with the big orchestra, with all double basses and brass reinforced by kettledrums, the amp starts emitting confused and distorted sounds.
Here arrived the surprise with ZV9. With the big orchestra came out thick sounds and deep double basses together with crystal sounds of bows and trumpets, in a very clear image. Not so loud to shake windows, but enough to feel basses in the chest. So I comprised: Zen amp spreads the power in a natural way, while I'm used to amps that boost the middle range (many recordings too do that) to give the impression of a louder sound.
This leads to another impressive character of this Zen: the coherence of sound. With this I mean only the relative loudness of each instrument with respect to others. Good example of incoherent sounds are many recordings of concerts for violin and orchestra, where the violin sounds louder than all the bows together. If you want a thick sound of double bass in a small room then a flute must sound weak. That's what Zen9 does, but without any sacrifice in detail and resolution.
To test an amp detail I'm used to play voices "a cappella": the test is easy, just count the voices. But this task was too easy for Zen9, so I went to Liszt's Etudes trascendentales for piano solo (Arrau). These are always boring if you don't listen to a live piano, because there is nothing to listen but only the beauty of all sound you can get out from a piano.
Here another surprise, for what I think is the best character of Zen9: the beauty of each single sound. It has so much detail that you can enjoy all resonances and reverb of each single note, which is what is needed to enjoy Liszt studies. I repeated the experiment with similar boring studies for solo violin (Ysaye) and solo cello (Shostakovic) and I couldn't stop listening. I think ZenV9 is a jewel to use like a 12 years old cognac, in silent nights, when you want to savour rich sounds, instead of just listen.
As promised I'm back with some sonic impressions about ZenV9 after some hours of listening. I can confirm that power is enough in a "Zen" system configuration without pre: SPDIF from PC (truly Toslink, so there is not a ground in common) => DAC => ZenV9 => Fostex FE206E.
Nevertheless a 5W T-Amp sounds louder in this system, what disappointed me at the beginning. So, as I'm an ugly guy, I selected the third movement of Mahler's 2nd symphony to see how ZV9 would behave. The T-Amp can't reproduce it well, because if you set volume so that weakest sounds are well audible then, when it comes with the big orchestra, with all double basses and brass reinforced by kettledrums, the amp starts emitting confused and distorted sounds.
Here arrived the surprise with ZV9. With the big orchestra came out thick sounds and deep double basses together with crystal sounds of bows and trumpets, in a very clear image. Not so loud to shake windows, but enough to feel basses in the chest. So I comprised: Zen amp spreads the power in a natural way, while I'm used to amps that boost the middle range (many recordings too do that) to give the impression of a louder sound.
This leads to another impressive character of this Zen: the coherence of sound. With this I mean only the relative loudness of each instrument with respect to others. Good example of incoherent sounds are many recordings of concerts for violin and orchestra, where the violin sounds louder than all the bows together. If you want a thick sound of double bass in a small room then a flute must sound weak. That's what Zen9 does, but without any sacrifice in detail and resolution.
To test an amp detail I'm used to play voices "a cappella": the test is easy, just count the voices. But this task was too easy for Zen9, so I went to Liszt's Etudes trascendentales for piano solo (Arrau). These are always boring if you don't listen to a live piano, because there is nothing to listen but only the beauty of all sound you can get out from a piano.
Here another surprise, for what I think is the best character of Zen9: the beauty of each single sound. It has so much detail that you can enjoy all resonances and reverb of each single note, which is what is needed to enjoy Liszt studies. I repeated the experiment with similar boring studies for solo violin (Ysaye) and solo cello (Shostakovic) and I couldn't stop listening. I think ZenV9 is a jewel to use like a 12 years old cognac, in silent nights, when you want to savour rich sounds, instead of just listen.
Thomaseliot,
I had a similar listening impression when i compared by gainclone (LM3875) to mt T-amp. I found the t-amp had more thrust, ecspecially in the bass but lacked teh seperation and clarity that was immediatley apparent from the gainclone. Over time i forgot or got over my need for oomph and have truly begun to appreciate the honesty of the gainclone. It is so revealing that i have all but given up listening to old MP3 (recorded at bit rates less then 196kbs) as the msuic lack so much seperation.
From your impressions i really want to hurry up and finish up my zen (man this chassy i staking for ever). I sounds wonderful.
Good job
I had a similar listening impression when i compared by gainclone (LM3875) to mt T-amp. I found the t-amp had more thrust, ecspecially in the bass but lacked teh seperation and clarity that was immediatley apparent from the gainclone. Over time i forgot or got over my need for oomph and have truly begun to appreciate the honesty of the gainclone. It is so revealing that i have all but given up listening to old MP3 (recorded at bit rates less then 196kbs) as the msuic lack so much seperation.
From your impressions i really want to hurry up and finish up my zen (man this chassy i staking for ever). I sounds wonderful.
Good job
Hi Neil,
I used the T-Amp comparison only for perceived SPL out of a 5W amp. I know some people have done good mods to it but, as is, it is impressive for size and price.
Another world are more powerful Tripath amps. My reference are a couple of amps based on TA2022 (50W, 150W bridged) and one on TA0102A (100W).
Not yet done a direct comparison to point out differences, I just discovered something never heard in this Zen. Even in some renowned tube amps I know well. Yes, I confess, timbers and clarity are not the best characteristics of Tripath amps, though there is still much to experiment.
I never heard to a gainclone, but I'm sure you'll find something magic in ZenV9, if you have efficient speakers (what is that in your avatar?).
I used the T-Amp comparison only for perceived SPL out of a 5W amp. I know some people have done good mods to it but, as is, it is impressive for size and price.
Another world are more powerful Tripath amps. My reference are a couple of amps based on TA2022 (50W, 150W bridged) and one on TA0102A (100W).
Not yet done a direct comparison to point out differences, I just discovered something never heard in this Zen. Even in some renowned tube amps I know well. Yes, I confess, timbers and clarity are not the best characteristics of Tripath amps, though there is still much to experiment.
I never heard to a gainclone, but I'm sure you'll find something magic in ZenV9, if you have efficient speakers (what is that in your avatar?).
My avatar is a pair of Jordan VTL's that i made several years ago. I have a blog which describes most of my DIY projects. It can be found here:
http://web.mac.com/noteldov/iWeb/Neil' Site/Welcome.html
Just click on audio projects.
I recently replaced the the Jordan's with a pair of Zu Druids. Since most of the amps that i have built are under 30w i needed a pair of pseaker that were more efficient.
I am very happy with the Druids.
http://web.mac.com/noteldov/iWeb/Neil' Site/Welcome.html
Just click on audio projects.
I recently replaced the the Jordan's with a pair of Zu Druids. Since most of the amps that i have built are under 30w i needed a pair of pseaker that were more efficient.
I am very happy with the Druids.
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