Yup, that's the PSU board (with eight 33000uF caps) from the store, they're very versatile and very heavy duty. The preamp is a DCB1 followed by a DCB1XO (line level crossover). So far it seems like there's enough gain in total. I'm currently working on a BA-3 preamp, just because. My tweeter amp is a mini Aleph J. The two amps go very well together.
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Variac posted the updated BOM here:
http://www.diyaudio.com/forums/pass-labs/276711-sony-vfet-amplifier-part-2-a-277.html#post4991406
Congratulations on the build and result!
How hot are your heatsinks running, what size are they?
Thank you! One more question:
Is it possible to use a smaller/less expensive enclosure than Deluxe 4U?
like this:
DISSIPANTE 3U
Dissipante 3U – diyAudio Store
thanks!
Is it possible to use a smaller/less expensive enclosure than Deluxe 4U?
like this:
DISSIPANTE 3U
Dissipante 3U – diyAudio Store
thanks!
If using the 3u you might want to go for the 400mm depth one to ensure you have proper dissipation area. Don't forget that only the deluxe cases have the heatsinks predrilled so if you've never done this before and don't have the proper tools it might become more expensive in the end.
dissipation is also better when Transistors/ Alloybracket is mounted in the lower third of the heatsink. heat tends to go upward not downward. 300mm x 120mm could be enough than.
With the VFET Bracket/PCB construction, reaching 10 cm to the inner of the amp the Problem is that you have to put transformer and PSU in the middle of the two facing PCB when mounting the PCB´s low. If PCB´s have to on top over the Tranny/Caps you´ll have to mount them (too?) high.
With the VFET Bracket/PCB construction, reaching 10 cm to the inner of the amp the Problem is that you have to put transformer and PSU in the middle of the two facing PCB when mounting the PCB´s low. If PCB´s have to on top over the Tranny/Caps you´ll have to mount them (too?) high.
Actually hot air tends to rise due to buoyancy, because it less dense that colder air, and is an example of convective heat transfer. Heat transfer through a solid is conductive heat transfer and is non-directional, goes is all directions at the same rate. The transistor mounting and mounting bracket operate in this mode. Mounting the bracket in the middle of the sink would be optimal. The finned side of the heat sink operates in convective transfer mode and needs proper clearances to allow for a circulating air current through the fins to carry the heat away.
I do not think Hypex has one with suitable output voltages.
Also, a transformer + caps is not that much more expensive.
Many audiophiles would cry if they would see an SMPS in this fine amp
I have also been thinking about the mounting to the heat sink.
I will for sure need to mount my boards close to the top.
Heavy transformers will go on the bottom of the enclosure.
Mine will have so wide heat sinks that space will be tighter than in the modushop enclosures.
Also I do have 3 Consonance Calaf enclosures, I might use one of those while testing.
I agree that heat will go in every direction in the metal and hot air will rise upwards.
So which is better. Top or bottom being hotter?
Hot air flowing will tend to make the top part hotter if FETs are in the middle I guess.
Not a game changer probably anyway.
And thanks to the people helping me with the JFETs.
I will consider paralleling them.
I also asked for an offer from linear systems, but no reply yet. (100 pairs)
Also, a transformer + caps is not that much more expensive.
Many audiophiles would cry if they would see an SMPS in this fine amp
I have also been thinking about the mounting to the heat sink.
I will for sure need to mount my boards close to the top.
Heavy transformers will go on the bottom of the enclosure.
Mine will have so wide heat sinks that space will be tighter than in the modushop enclosures.
Also I do have 3 Consonance Calaf enclosures, I might use one of those while testing.
I agree that heat will go in every direction in the metal and hot air will rise upwards.
So which is better. Top or bottom being hotter?
Hot air flowing will tend to make the top part hotter if FETs are in the middle I guess.
Not a game changer probably anyway.
And thanks to the people helping me with the JFETs.
I will consider paralleling them.
I also asked for an offer from linear systems, but no reply yet. (100 pairs)
Hi
only little message: Big Thanks for all the great work doing for us greedy Boys- assembling Parts! in the Store.
Supplemental Kit is arrived on last Weekend- now long time to wait for Essential Parts.
So i will enjoy listening to M2 actually with Toshibas on Output.
A Genius Stroke Amp.
Next step in that direction is the DEF- i follow- but is difficult to find a matching depletion
N_JFet....but very funny stuff presented by Antoinel.
only little message: Big Thanks for all the great work doing for us greedy Boys- assembling Parts! in the Store.
Supplemental Kit is arrived on last Weekend- now long time to wait for Essential Parts.
So i will enjoy listening to M2 actually with Toshibas on Output.
A Genius Stroke Amp.
Next step in that direction is the DEF- i follow- but is difficult to find a matching depletion
N_JFet....but very funny stuff presented by Antoinel.
warning - don't use a transistor tester for checking these V-fet
Good evening gentlemen,
it happened today that I wanted to finish my V-fet amp. The first channel was up and running when it happened that I thought, I'd ruined a V-Fet. I took it out of the amp and connected the my small transistor-tester which I often use to identify and check all kind of actice devices.
What happened was that the tester showed N-Fet for a quarter of a second and showed short between two legs afterwards. This means it has died.
So, my advise, don't try this!
So my problem now is, I lack in a V-Fet for my amp. If anybody has got a spare 2SK82 and is willing to sell it, I'd be absolutely happy.
Cheers Ernst
Good evening gentlemen,
it happened today that I wanted to finish my V-fet amp. The first channel was up and running when it happened that I thought, I'd ruined a V-Fet. I took it out of the amp and connected the my small transistor-tester which I often use to identify and check all kind of actice devices.
What happened was that the tester showed N-Fet for a quarter of a second and showed short between two legs afterwards. This means it has died.
So, my advise, don't try this!
So my problem now is, I lack in a V-Fet for my amp. If anybody has got a spare 2SK82 and is willing to sell it, I'd be absolutely happy.
Cheers Ernst
Did you try to turn the FET off afterwards? FETs have very high impedance gates and so can be turned on or off by applying a voltage during testing on a transistor tester. Quite often when turned on, they will stay on by themselves as there is path to change the state of the gate.Good evening gentlemen,
it happened today that I wanted to finish my V-fet amp. The first channel was up and running when it happened that I thought, I'd ruined a V-Fet. I took it out of the amp and connected the my small transistor-tester which I often use to identify and check all kind of actice devices.
What happened was that the tester showed N-Fet for a quarter of a second and showed short between two legs afterwards. This means it has died.
So, my advise, don't try this!
So my problem now is, I lack in a V-Fet for my amp. If anybody has got a spare 2SK82 and is willing to sell it, I'd be absolutely happy.
Cheers Ernst