Some speculation could be maybe because VSSA have technical high pass in form of feedback caps that big value input cap bypassed or not is invinsible don't no, but on my pure DC coupled old Sansui amps adding a input cap no matter the brands i tried out is audioable.
Joy in Mudville
Fooled about some more .. and gotten One PCB to work on my assumed to be dead SMPS. A lashup mess but...
Stan Rogers provided the inaugural tunes. Hey! it was handy And I Am a Canadian!
On a waljkman type CD gizmo, thru the headphone plug (volume wheel) Into a Sole Mark Audio 4" full range driver.
Damn If it doesn't sound good.. Clear and V detailed, surprisingly so.
Not harsh either...Even thru all the junk gear.
You guys were absolutely right. Was worried there as the Praise was Very Canadian: ie Faint and Modest
No ideas re bass as One channel / a 4" driver isn't conducive to bass.
SMPs Will Not power the "other board'.
Clearly then, it's a Board (me 😱 issue.
More sleuthing for the hidden bungle.
Then there's the 'flame the resistors' SMPS.. which still meters identically to the 'working' one... Electrotrickery ?
Interestingly the SMPS is outputting 23.1 V, both rails, under use/load with One PCB energized. Possible problem when it has Two boards..?.. Dunno yet
Interestingly Volume is More than enough.
Burst the pore 86db driver enough.
Likely Could do same with my 94db Tannoys.
No joke that, they use Far Less amp power than the wee full rangers for a Lot more sound.
This amp will get a Volume pot.
Makes me wonder What? are people using for speakers that the power of 45+ V is appropriate? Concert Stage Gear ?
As I'm embarking on the CM PS adventure.. I'm wondering if ~30V at/to the modules is More than enough
or if a 300va Tx is actually required, necessary or mere overkill ??
Unchartered territory for me.. as yet.
Fooled about some more .. and gotten One PCB to work on my assumed to be dead SMPS. A lashup mess but...
Stan Rogers provided the inaugural tunes. Hey! it was handy And I Am a Canadian!
On a waljkman type CD gizmo, thru the headphone plug (volume wheel) Into a Sole Mark Audio 4" full range driver.
Damn If it doesn't sound good.. Clear and V detailed, surprisingly so.
Not harsh either...Even thru all the junk gear.
You guys were absolutely right. Was worried there as the Praise was Very Canadian: ie Faint and Modest
No ideas re bass as One channel / a 4" driver isn't conducive to bass.
SMPs Will Not power the "other board'.
Clearly then, it's a Board (me 😱 issue.
More sleuthing for the hidden bungle.
Then there's the 'flame the resistors' SMPS.. which still meters identically to the 'working' one... Electrotrickery ?
Interestingly the SMPS is outputting 23.1 V, both rails, under use/load with One PCB energized. Possible problem when it has Two boards..?.. Dunno yet
Interestingly Volume is More than enough.
Burst the pore 86db driver enough.
Likely Could do same with my 94db Tannoys.
No joke that, they use Far Less amp power than the wee full rangers for a Lot more sound.
This amp will get a Volume pot.
Makes me wonder What? are people using for speakers that the power of 45+ V is appropriate? Concert Stage Gear ?
As I'm embarking on the CM PS adventure.. I'm wondering if ~30V at/to the modules is More than enough
or if a 300va Tx is actually required, necessary or mere overkill ??
Unchartered territory for me.. as yet.
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We always want more VA capacity in the transformer than we expect to draw. I suggested 300VA as tat gives a comfortable capacity buffer for the pair of VSSA without being overkill. The VSSA is capable of operating on as much as +/-45V rails which just affords some extra headroom, but they can operate from as little as +/-20V without issue, so there is some flexibility.
Hi Bare,
Like I said, if the SMPS feels an overload it will cycle off. If it is the one I have it is 200W which is more than enough to power two channels. You have a problem with the board and it is causing the SMPS to cycle. If you get that fixed it should work fine. The problem with using the SMPS is it is either on or off. Makes it difficult to do troubleshooting. A transformer/PSU is easier because you can control the current using a light bulb tester.
Like I said, if the SMPS feels an overload it will cycle off. If it is the one I have it is 200W which is more than enough to power two channels. You have a problem with the board and it is causing the SMPS to cycle. If you get that fixed it should work fine. The problem with using the SMPS is it is either on or off. Makes it difficult to do troubleshooting. A transformer/PSU is easier because you can control the current using a light bulb tester.
G'day:
I have One SMPS powering /connected to One PCB, showing 23.1 v in use.
A bit far from it's claimed 28 v and a fair drop from it's no load 26.1v.
Not stellar performances IMO, although it Was cheap 😉
However the vssa sounds V good despite it.
You guys were Right.
Now I needs uncover what atrocity I inflicted on the not responding PCB.
And whether the other smps stands as falsely accused?
Power babble above was about choosing a decent/affordable Transformer, preferably Once.
My speakers Don't need much power. Other owners use ~5watt '45s happily, I disagree with them, but only in degree. Had 'em for 40 years, planning on another 30.
Learned (tripped over) of the 1.414 increase from AC to DC conversion.
Also suggestions that VA should be 2x the Amp wattage expectation for best sounds.
Sooo; would 200VA & sub 30 v secondaries supply me a Lowish power amp, w reasonable headroom reserves and significant Instantaneous Current capability?
Dunno if this is clever or Daft.. yet.
I haven't played this game before
I have One SMPS powering /connected to One PCB, showing 23.1 v in use.
A bit far from it's claimed 28 v and a fair drop from it's no load 26.1v.
Not stellar performances IMO, although it Was cheap 😉
However the vssa sounds V good despite it.
You guys were Right.
Now I needs uncover what atrocity I inflicted on the not responding PCB.
And whether the other smps stands as falsely accused?
Power babble above was about choosing a decent/affordable Transformer, preferably Once.
My speakers Don't need much power. Other owners use ~5watt '45s happily, I disagree with them, but only in degree. Had 'em for 40 years, planning on another 30.
Learned (tripped over) of the 1.414 increase from AC to DC conversion.
Also suggestions that VA should be 2x the Amp wattage expectation for best sounds.
Sooo; would 200VA & sub 30 v secondaries supply me a Lowish power amp, w reasonable headroom reserves and significant Instantaneous Current capability?
Dunno if this is clever or Daft.. yet.
I haven't played this game before
Hi Bare,
In DIY we often go to some excess largely because we can, but also to extract the most potential we can for our builds. In many OEM implementations, the transformer is only capable of about 70% of the amplifiers' maximum power rating. This is adequate in the real world since we don't listen to full power sine waves, but rather music with it's much lower average levels with intermittent peaks.
If you are seeking strict economy I can say I have used a 160VA 22V dual secondary Piltron for a pair of these and that worked perfectly well. That gave me ~30V rails and no issues with sagging or heat.
As far as the problem board goes, are you able to verify the input pair is oriented properly? These are the ones we glue or shrink-wrap together. I always suggested marking one with paint (like red for right) so the orientation is assured correct on assembly since we can't see the device markings after putting them together. Aside from the output MOSFETs the transistors are very cheap, maybe just go straight to installing new ones just to be sure none are damaged / misoriented / incorrect...
In DIY we often go to some excess largely because we can, but also to extract the most potential we can for our builds. In many OEM implementations, the transformer is only capable of about 70% of the amplifiers' maximum power rating. This is adequate in the real world since we don't listen to full power sine waves, but rather music with it's much lower average levels with intermittent peaks.
If you are seeking strict economy I can say I have used a 160VA 22V dual secondary Piltron for a pair of these and that worked perfectly well. That gave me ~30V rails and no issues with sagging or heat.
As far as the problem board goes, are you able to verify the input pair is oriented properly? These are the ones we glue or shrink-wrap together. I always suggested marking one with paint (like red for right) so the orientation is assured correct on assembly since we can't see the device markings after putting them together. Aside from the output MOSFETs the transistors are very cheap, maybe just go straight to installing new ones just to be sure none are damaged / misoriented / incorrect...
Time for brute force, if you can't find the issue quickly. Take your good board next to the bad and measure ohms across every resistor. Measure across every transistor. Diode test across all ss device terminals. Something will be different. With that info we can nail it.
Sheldon
from my point of view is not good idea use switching PSU for amplifier... from my experience doesn't sound so good as with classics PSU..
Ok 😱
Small update; my Smoke the 10r resistors SMPS is Genuinely Garbage.
Fitted to my working PCB..
It again immediately started to smoke the test resistors.
It's for the Trash bin.. end of.
Been having a Very careful look at my sketchy channel pcb.
Once again verified that ALL the "Q" s and "M"s are correctly fitted. Whew!
They Diode checked OK as per Utube 'how to's'
Will revisit that 'procedure' though.
Checking every other bit is ..Next. Good suggestion.
Clearly the board is sucking/draining Power when fitted to the 'working' SMPS.. Maybe the load is beyond it's meager capabilities.
Likely it's instantly shutting down the PS.. (ambiguous as there are no PS noises), Definitely No power output though.
Wondering If it's the world renowned Quality control on these Chinee SMPS gizmos?
Seemingly they are poorly adjusted for Current draws?? One is hair trigger and the other doesn't know when to stop?
Was wondering If I bungled the initial VR2 setup (opposite of the Max it out to 5k requirement) ?? That could suck up juice?
Where do I meter it under the board (or?) accurately ? And which direction to turn the wee screw, until it ends (as the beginner method) with the board oriented with the 10uF Cap facing my belly?
Thought I did it correctly.. must have.. on the working board.. But?
Small digression; No believer in Cap burn in.. But? Bass is markedly improved today. In the one working channel 🙄
I'm motivated 😀
PS: IF I had an alternate PS on hand.. Both... these SMPS things would be out in the trash bin
Small update; my Smoke the 10r resistors SMPS is Genuinely Garbage.
Fitted to my working PCB..
It again immediately started to smoke the test resistors.
It's for the Trash bin.. end of.
Been having a Very careful look at my sketchy channel pcb.
Once again verified that ALL the "Q" s and "M"s are correctly fitted. Whew!
They Diode checked OK as per Utube 'how to's'
Will revisit that 'procedure' though.
Checking every other bit is ..Next. Good suggestion.
Clearly the board is sucking/draining Power when fitted to the 'working' SMPS.. Maybe the load is beyond it's meager capabilities.
Likely it's instantly shutting down the PS.. (ambiguous as there are no PS noises), Definitely No power output though.
Wondering If it's the world renowned Quality control on these Chinee SMPS gizmos?
Seemingly they are poorly adjusted for Current draws?? One is hair trigger and the other doesn't know when to stop?
Was wondering If I bungled the initial VR2 setup (opposite of the Max it out to 5k requirement) ?? That could suck up juice?
Where do I meter it under the board (or?) accurately ? And which direction to turn the wee screw, until it ends (as the beginner method) with the board oriented with the 10uF Cap facing my belly?
Thought I did it correctly.. must have.. on the working board.. But?
Small digression; No believer in Cap burn in.. But? Bass is markedly improved today. In the one working channel 🙄
I'm motivated 😀
PS: IF I had an alternate PS on hand.. Both... these SMPS things would be out in the trash bin
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Entirely possible that VR2 was set to the wrong extreme to start with. If so, then the output MOSFETs would be fully saturated (on, low resistance in the channel) making the board behave like a shorted part in present. Minimum bias would be when VR2 is adjusted fully CW and bias increases as you turn it CCW.
Thanks.. Yeah I grasped the concept /drill re the adjustment.
But Presumably bungled the Setup Seems that (possibly 🙂 I had the thing turned the Wrong direction.
As I did it with the boards mounted and opposite to each other. My Small defense as to orientation screw-ups.
( Was now too excited/unthinking to meter it's setting though.. Grrr)
It took a lot of turns to get it to faintly' click' and read ~5k at the end of it's travel.
Will check it out.
But Presumably bungled the Setup Seems that (possibly 🙂 I had the thing turned the Wrong direction.
As I did it with the boards mounted and opposite to each other. My Small defense as to orientation screw-ups.
( Was now too excited/unthinking to meter it's setting though.. Grrr)
It took a lot of turns to get it to faintly' click' and read ~5k at the end of it's travel.
Will check it out.
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Checked ALL bits to the best of my eyesight and pore meters.
Nothing untoward spotted.
Non working board's bits measure/look the same as on the functioning one.
Adding Insult to Injury.. the 'working' SMPS smokes the 10R test resistors on This board.
Sigh.. I give up on this thing as this is my Saturation point.
Unknown ( unknowable?) faults aided/abetted by Garbage power supplies .
It's future seems to be long term storage.
Thanks for the patience... people.
Nothing untoward spotted.
Non working board's bits measure/look the same as on the functioning one.
Adding Insult to Injury.. the 'working' SMPS smokes the 10R test resistors on This board.
Sigh.. I give up on this thing as this is my Saturation point.
Unknown ( unknowable?) faults aided/abetted by Garbage power supplies .
It's future seems to be long term storage.
Thanks for the patience... people.
Hi,
Had similaire issue with my TO-3 version I bought from Jason, I used my own output devices and one of them was defective.
If you can, desolder the output mosfet and see if your 10R are still smoking.
Don't give up, it's a well worthed power amp.
BR,
Eric
Had similaire issue with my TO-3 version I bought from Jason, I used my own output devices and one of them was defective.
If you can, desolder the output mosfet and see if your 10R are still smoking.
Don't give up, it's a well worthed power amp.
BR,
Eric
Thank You.
Jason you have Mail.
Yess... My one working board is imo sounding very good.
NO disappointments there.
Jason you have Mail.
Yess... My one working board is imo sounding very good.
NO disappointments there.
Usually the trim pot is set up to connect the wiper (inner lead) to one end of the pot or the other. Then the position of the wiper determines the resistance across the outer leads of the pot. I'm assuming that is the case here.
If you install the pot backwards it will still work, but it will also reverse the adjustment direction. The easiest way to be sure is to measure across the outer leads of the pot. Lesson is always measure. Don't just rely on turning the trim screw one way or the other.
Sheldon
If you install the pot backwards it will still work, but it will also reverse the adjustment direction. The easiest way to be sure is to measure across the outer leads of the pot. Lesson is always measure. Don't just rely on turning the trim screw one way or the other.
Sheldon
Sheldon; Sadly there are No obvious Bungles.
Shame actually, as it would be a simple repair.
Thanks for the Input though.
Jason is gonna 'fix' it 😀
For which I'm Seriously Grateful.
Shame actually, as it would be a simple repair.
Thanks for the Input though.
Jason is gonna 'fix' it 😀
For which I'm Seriously Grateful.
Good for you Bare.
Jason does provide excellent customer service. I had some issue with my VSSA, Jason and Fab also from this forum were both a great help. You can tell these guys have a passion !
Your ears will thank you..LOL
Eric
Jason does provide excellent customer service. I had some issue with my VSSA, Jason and Fab also from this forum were both a great help. You can tell these guys have a passion !
Your ears will thank you..LOL
Eric
Hi Paulo,
If boards are available, the Group Buy is here :
http://www.diyaudio.com/forums/group-buys/251782-vssa-through-hole-version-jason.html
BR,
Eric
If boards are available, the Group Buy is here :
http://www.diyaudio.com/forums/group-buys/251782-vssa-through-hole-version-jason.html
BR,
Eric
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