I have that issue here. It is a killer one coz along with the Bulb amp, it also has Self on distortion, Hiraga on distortion, AND an article on a horn system. Of all the stuff, the Hiraga article is really remarkable along with the unique bulb amp.
Dear Mr. Pass,Attached is the document detailing the DIY Sony VFET OS2 output stages.
These are revisions of the previous efforts for the N channel 2SK82 and P channel 2SJ28 design but intended to accommodate people who have those VFET or other Sony VFET transistors, notably 2SK60 and 2SJ18 or even other power Fets in TO-3 packages, including Mosfets.
The biggest differences are in the current sources. Where the originals used constant current sources, for the P channel design we have a mu follower and for the N channel a novel variation. Both of these are constant current for DC, but can be adjusted to supply a percentage of the output current in support of the smaller VFET chips.
The diyAudio store will be making its announcement shortly with an initial stock of both output stage kits, which are compatible with original and new kits for front ends and power supply filters, especially Mark Johnson's efforts. I have been asked to assure you that there will be plenty to go around, no problems, and even if you don't have the VFETs you will be able to make Mosfet versions for TO-3 and also TO-247 plastic packages, so don't fret. Also the ever benevolent 6L6 has agreed to do build guides.
So here we go. Stay in line, no crowding....
please help in choosing an amplifier for Fidelio Lowther EX3. I’ve made ACA 1.8, it’s better and I feel like I’m on the right track. Maybe Aleph J? The sound is too bright, midrange intrusive with a bit of bass.
Thanks in advance from Croatia.
How about a Pass single ended 100w/ch with Tokin 2SK183H SITs and a Godzilla power supply? That ought to satisfy the edifice amplifier pyramid builders.
task old as Continent - find an amp to rectify Lowther flaws?
to simplify things - did you ever tried an amp, with which you got your Lowthers dialed to your liking?
if yes, it could ease answering to your question
send me pair of those and you'll get it
(it will be just augmented Singing Bush but, hey, let's ignore that for purpose of this rotten treaty :rofl)
Ordered EX3 drivers, expensive, I think, must be good, made boxes according to the original schemes and now I intend to make an amplifier that will look like something in the lamp version. And maybe not.?
task old as Continent - find an amp to rectify Lowther flaws?
to simplify things - did you ever tried an amp, with which you got your Lowthers dialed to your liking?
if yes, it could ease answering to your question
I believe you'll need first to work on some phase plugs , and then to look for most helpful EQ filter for them
yes, blasphemy, but for shouty Lowthers only way (not all of them are, but not-ones rare as hen-tits, and equally expensive )
I believe Pa did some experiments , even made table of filter for several FR drivers needing help
was it related to F1 or F2 amp, can't remember
yes, blasphemy, but for shouty Lowthers only way (not all of them are, but not-ones rare as hen-tits, and equally expensive )
I believe Pa did some experiments , even made table of filter for several FR drivers needing help
was it related to F1 or F2 amp, can't remember
Here's the link to Pa's Current Source Amps With Sensitive Drivers article.
https://www.passdiy.com/download.php?download_file=/images/uploads/project/cs-amps-speakers.pdf
In the past I've put some fluffed up cotton behind the wizzer cone to tame it.
https://www.passdiy.com/download.php?download_file=/images/uploads/project/cs-amps-speakers.pdf
In the past I've put some fluffed up cotton behind the wizzer cone to tame it.
Thank you. I have a lowther phase plug. I need to make a current source amplifier then EQ. There is no other.
Tried hooking up the internal SMPS to test, Mean Well 150/36/4.3W. Led wouldn't light up when I connected L and ground to 120V AC line. Tested wires for continuity, 120V AC was fine. I guess I got a dud, no LED and no V+ or V- DC. I have to wait until another one comes in, but I have other wiring and internal tasks to the 4650 chassis in the mean while.
You want to see if the supply is dealing with what it thinks of as a short, often as a lot of filter capacitance on start up, or trying to develop a v- supply and thinking that a v- is isolated from ac ground.when it's not.
Thank you. It is hooked up to the same powered outlet in the chassis as the smaller smps 20v that powers the preamp, and that one seems fine with the led lighting up and providing DC. I'll check it again later, but have another on order just in case. Maybe I'll disconnect the small one and try the larger one again, although I can't see how they would interfere with each other. Maybe two smps need to be connected in series from the outlet rather than parallel?
Pa was thinking that you tried it with heavy load, and said to check isn't it too much heavy
if you tested it unloaded and there is no voltage nor led lit, Iznogood
if you tested it unloaded and there is no voltage nor led lit, Iznogood
I think it is a bad sample, too. It was unloaded when tested with wall voltage to L and ground. Lucky me.
Figured out my layout, soldered wires from the transistors on the heat sinks so harnesses ready to hookup to cards. I need to wait for a working SMPS and some ordered odds and ends and pieces, and final assembly should be done a few days after July 4 or so (I hope).
I am at the point in the build where I start testing and would appreciate some guidance. Should I test the output board with voltage applied and without the VFET to be safe? If so, what are test points and expected voltage levels should I see if assembled correctly? This is an n channel version, IRF250 installed. Thanks!
I had planned to build an Alpha J, but since there have been no boards available for months, I decided to try to build this version of the Sony VFET. This will be my second amp build so I am an a newbe to this hobby. I completed two ACA,s with no issues and love them, but need another challenge. I have located a pair of Sony 2sj18s VFETs on the swap meet page, and they are on the way. When they arrive I will order the other parts on the BOM. Since the original chassis is no longer available in the DIY store, which Chassis should I get for this project. I am thinking of using one of Mark J’s front ends.
I spent some time reading the threads this morning and found my answer…the 4U chassis will be fine for this build. I also came to the realization that this build may be a bit over my head as a second amp build. Fortunately the 4U chassis will also fit the Alpha J, so I will order that chassis and go from there. Perhaps by the time the chassis arrives the alpha boards will be available, or I will be more confident about atempting the sony vfet build.