VFET no. 33 up and running again with new KE-33 and so far no "flicker noise".
I adjusted voltage to 36 VDC on VFET amp board.
It is very quiet.
Less "harsh" than ACA and more 3D I would say.
S-sounds on voice less pronounced.
I have never heard "pops" from heat expansion.
Chassis with white alu-front at the bottom shelf is PSU for VFET.
I organized wires so 230 VAC wires a away from signal and speaker wires.
I have no hum etc. with ear close to speakes.
The VFET setup is more silent than with ACA but both very silent.
I adjusted voltage to 36 VDC on VFET amp board.
It is very quiet.
Less "harsh" than ACA and more 3D I would say.
S-sounds on voice less pronounced.
I have never heard "pops" from heat expansion.
Chassis with white alu-front at the bottom shelf is PSU for VFET.
I organized wires so 230 VAC wires a away from signal and speaker wires.
I have no hum etc. with ear close to speakes.
The VFET setup is more silent than with ACA but both very silent.
Attachments
PSU is based on a Connex 2kW SMPS (audio-grade) which has nice specs. Low noise etc.
PDF attached. Depending on configuration the module can look different. In my case it is a single 36 VDC PSU. It had to be pre-ordered from factory. I then added filter caps at the output and an output fuse. The chassis is just one I found on ebay. The onboard primary fuse is 15A (230 VAC) so I put a 1A T fuse at the IEC inlet to protect a bit. Output fuse is a 4A F fuse.
The filter caps I used was some I had (4-pole Jensen). 2 x 8200 uF / 63V as I remember. No problem at all starting up with this cap load.
I think it would work fine without caps (as indicated in spec) but I measure a bit lower noise after caps than at direct SMPS output. I think it was 9 mV at direct SMPS output and 6 mV after caps. It is just with a DMM (not a scope). Now with closed chassis etc. it might be less.
I just cut the wire from SMPS brick so I saved time playing with these connectors as there are really many parts and wires. It is a screened cable (double screened). It has some alu-foil inside and a normal "mesh" screen.
VFET is a very light load for the SMPS so I just glued some small heatsinks to it. Normally it should be attached to a large heatsink. Heatsink gets around 55 C or so. Some components inside are around 65 C.
PDF attached. Depending on configuration the module can look different. In my case it is a single 36 VDC PSU. It had to be pre-ordered from factory. I then added filter caps at the output and an output fuse. The chassis is just one I found on ebay. The onboard primary fuse is 15A (230 VAC) so I put a 1A T fuse at the IEC inlet to protect a bit. Output fuse is a 4A F fuse.
The filter caps I used was some I had (4-pole Jensen). 2 x 8200 uF / 63V as I remember. No problem at all starting up with this cap load.
I think it would work fine without caps (as indicated in spec) but I measure a bit lower noise after caps than at direct SMPS output. I think it was 9 mV at direct SMPS output and 6 mV after caps. It is just with a DMM (not a scope). Now with closed chassis etc. it might be less.
I just cut the wire from SMPS brick so I saved time playing with these connectors as there are really many parts and wires. It is a screened cable (double screened). It has some alu-foil inside and a normal "mesh" screen.
VFET is a very light load for the SMPS so I just glued some small heatsinks to it. Normally it should be attached to a large heatsink. Heatsink gets around 55 C or so. Some components inside are around 65 C.
Attachments
Thanks for that!
It is good to have other options for power supplies. My experience indicates that the right amount of external bulk capacitance is beneficial to both SMPS and capacitance multiplier PSU. The Jensen 4-pole caps that you used look good for this application. I wanted to keep the kit SMPS intact for testing purposes, so I built a new cable for my external PSU. There are certainly a lot of parts to that external cable connector, and nimble fingers are needed to keep them all in place.
Edited to add:
I didn't use any shielding for my umbilical. I just twisted two channels worth of 18ga stranded wire together (dual-mono PSU). No issues with noise either.
It is good to have other options for power supplies. My experience indicates that the right amount of external bulk capacitance is beneficial to both SMPS and capacitance multiplier PSU. The Jensen 4-pole caps that you used look good for this application. I wanted to keep the kit SMPS intact for testing purposes, so I built a new cable for my external PSU. There are certainly a lot of parts to that external cable connector, and nimble fingers are needed to keep them all in place.
Edited to add:
I didn't use any shielding for my umbilical. I just twisted two channels worth of 18ga stranded wire together (dual-mono PSU). No issues with noise either.
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I would also just have made a cable without screen if I should make my own.
Screen is also connected to V- if my memory is correct so I connected screen to chassis / PE via a NTC in PSU unit.
I just raised the IEC inlet fuse to 2A T as the 1A T broke 10 min. ago during power on. Prototypes needs some final "adjusting". SMPS has softstart but seems not "soft enough" for the 1A T fuse. Probably 1.5 A T could have done it.
Screen is also connected to V- if my memory is correct so I connected screen to chassis / PE via a NTC in PSU unit.
I just raised the IEC inlet fuse to 2A T as the 1A T broke 10 min. ago during power on. Prototypes needs some final "adjusting". SMPS has softstart but seems not "soft enough" for the 1A T fuse. Probably 1.5 A T could have done it.
Does anyone know the part number for the on off switch? When trying to push those connectors on, really tight, one pin pushed in. Still works but I would like to replace it.
Played for a few hours without any problems over weekend. When I had the loud pops due to heat expansion the top was off. With top plate secured no pops so all is good. Sound much like my better SET tube amplifiers. SE tube sound in a SS amplifier. Sound did improve over startup with a few hours burn in. Not that is was bad on start up but then could be my imagination.
I mentioned to Nelson on this forum many years ago for a SE V-fet amplifier and with a promise I waited patiently. Finally glad to build and listen to this amplifier. After reading some on the N channel build thread I am glad to own this P one not that there is any significant difference but more complaints of pops on startup and down.
Played for a few hours without any problems over weekend. When I had the loud pops due to heat expansion the top was off. With top plate secured no pops so all is good. Sound much like my better SET tube amplifiers. SE tube sound in a SS amplifier. Sound did improve over startup with a few hours burn in. Not that is was bad on start up but then could be my imagination.
I mentioned to Nelson on this forum many years ago for a SE V-fet amplifier and with a promise I waited patiently. Finally glad to build and listen to this amplifier. After reading some on the N channel build thread I am glad to own this P one not that there is any significant difference but more complaints of pops on startup and down.
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So let me guess they’re totally useless do not even close to the original VFET and the circuit won’t work or are these a Good option Or should I try to get my money back or is there a possibility that someone has a set fets for sale
I almost put a Mouser and Digikey order in last night. about 40 some capacitors diode’s Zenor trimmers pots and A whole slew of resistors. I opened it this morning to take a look at everything not one service mod has been done for the suicide diode‘s but it does have some generic chips in it.
Cancel your order, ask you money back from Mouser and the seller.
Or at least, ask your money back from the seller, and find another amp to mod
Or at least, ask your money back from the seller, and find another amp to mod
They are not VFETs for sure but they are not fake VFETs, as they are not labeled as VFETs. Someone has replaced the VFETs with ECG 180 and ECG 181 transistors (PNP and NPN). So it is no longer a VFET amp.
VFETs for sale, some of them are brand new in sony package.
I am planning to sell my 2SK60 and 2SJ18 at the swap meet very soon. 20 pieces in total, but I have more K60 than J18 (these were all purchased from a sony repairman here in brazil).
I'm not keeping any for myself, in fact I want to let go of most of the unobtanium I have (not just K60 J18). Over the following weeks/months. The money is much needed at this time so don't expect bargains.
I have seven pieces of the ultra-rare 2SJ19 by nec that has never shown up for sale in the non-japanese speaking world afaik. How these ended up in a drawer in an electronic parts shop in Sao Paulo is a bit of a mistery, but I assume it has something to do with the japanese people that have been living in that city for decades, there are plenty of them.
Give me a week
-Alex
edit: I don't have a good idea about shipping and insurance prices at this time, will be looking into all of this very soon.
I am planning to sell my 2SK60 and 2SJ18 at the swap meet very soon. 20 pieces in total, but I have more K60 than J18 (these were all purchased from a sony repairman here in brazil).
I'm not keeping any for myself, in fact I want to let go of most of the unobtanium I have (not just K60 J18). Over the following weeks/months. The money is much needed at this time so don't expect bargains.
I have seven pieces of the ultra-rare 2SJ19 by nec that has never shown up for sale in the non-japanese speaking world afaik. How these ended up in a drawer in an electronic parts shop in Sao Paulo is a bit of a mistery, but I assume it has something to do with the japanese people that have been living in that city for decades, there are plenty of them.
Give me a week
-Alex
edit: I don't have a good idea about shipping and insurance prices at this time, will be looking into all of this very soon.
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Just posted above, before you sell your amp in despair... I need to sell these. End of next week in the swap meet. I will post pictures of course, and basic measurement as well.
-Alex
OMG I’m not gonna lie I got a little teary when I saw your post.
Thank you so much for thinking of me. Today has been a horrible day with the retailer that I’m dealing with. He pretty much told me no get lost.
This is the exchange today between he and me.
(Me)Good morning Ron,
I’m sorry to hear that we won’t meet today when I show up to the store and bring the amplifier in.
I think the right thing for me is a refund and we can partner ways on this particular amplifier. Here’s why.
1. I asked about this amplifier before I purchased it, if it was original and it’s condition. You replied back in an email stating that it was unaltered and in working condition. That is not the case. You also allude as it was also unmodified which led me to think that you were very well informed about this amp.
2. The amplifier does not function properly after start-up. There's no output for a bit and I’m not talking about the speaker relay delay, maybe the relay is bad. You can hear the click of the relay and there is still no sound for a bit.
3. The speaker selector switch is inoperative and only works on one position.
4. With source audio there is some kind of motorboating popping sound coming from the left channel. It leads me to think that there are some kind of capacitor problems, mostly in the Preamp section.
5. And the main problem of them all is that it is not original. I took off the bottom plate (the two small screws) of the amp to look at the V-Fets. Only to see that someone had replaced them with a non sony v-fet chip. This is the whole reason I purchased your Sony Ta-4650. These chips are unobtainable and therefore it will not be able to be repaired. This is why I'm requesting a full refund.
(Store)You voided your guarantee by removing the cover. You were told not to do that. All you had to do was ask to see it and we would have done that for you.
(Store)I was surprised to see that you had dropped this off an hour and 20 minutes after I told you that you had voided your guarantee by removing the cover. I am not going to touch this unit. You have 30 days to come pick it up.
********* i’m crafting an email right now to send to him. It was right at 52 minute drive for me to get to his location and drop it off one way He never said not to bring it it’s almost like he knows that this was a fraudulent sale I’m just trying anyway and every way to get out of it. Prior to purchase I asked him if it was altered or upgraded anyway and he says it’s not been altered or upgraded and he’s telling me I can’t remove a cover and take a look to see if he’s being honest*******>
Wow, what a crook. At least give him a Yelp bomb.
And those subs are BIPOLAR output transistors, not V-FETs.
If you still have his email, you could really annoy him by taking
your case to small claims court. If he doesn't show, you'll get a
default judgment. No lawyer needed.
And those subs are BIPOLAR output transistors, not V-FETs.
If you still have his email, you could really annoy him by taking
your case to small claims court. If he doesn't show, you'll get a
default judgment. No lawyer needed.
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