Most likely ordinary, a perfect audiophools amp with that price tag and performance.
😀😀😀
Sakis little amp probably sounds better.
Did you check the pics of the assembly work? OMG....that's no commercial product, whatever it sounds like! 😱
I did a google pictures search for this amp and found one picture showing the M10 or whatever size nuts as spacers for the top cover, so maybe saki's amp is the real massproduced version after all, and the diy looking assembly really is genuine.
Why would that vent space be needed anyways when the heatsink is at the back of the amp ?
Why would that vent space be needed anyways when the heatsink is at the back of the amp ?
thanks tekko ...can you please post a link ?
There is bias considerations and there is also some note in the brochure of the amp that bias can be lowered or pitched in a higher level upon costumers request
probably amplifier gets pretty hotter if biased higher both on heatsinks and inside so may be some extra ventilation becomes handy
Kind regards
sakis
There is bias considerations and there is also some note in the brochure of the amp that bias can be lowered or pitched in a higher level upon costumers request
probably amplifier gets pretty hotter if biased higher both on heatsinks and inside so may be some extra ventilation becomes handy
Kind regards
sakis
I'm not sure if this is the model you have but it shows the nuts used as spacers: Yba passion 1000 stereo image by hifi_shock on Photobucket
Hello sakis,
It always amazes me to read that many useless, even damaging comments from users who know absolutely nothing about the product they are commenting about...
The YBA Passion amplifier has always been made by hand and was never intended for mass production. I do not approve either of the way it is built but this is no indication of how it sounds. I believe many of you would want to own one if you had the chance to listen to it. I even know a recording studio who uses the same amplifier in his reference system.
To correct your ground problem I suggest you solder two short lengths of green wire to the shield at both ends of the power cable and solder the other ends of those short lengths to the ground lug of the AC connectors. To access the shield you have to recess the external insulation of the cable and may need to heat it to be able to do so. I never approved of ground less power cables but YBA has always done it saying it sounded better this way. Make sure you solder another piece of green cable between the ground lug of the chassis IEC connector and screw the other end to the chassis of the amplifier.
The balanced XLR inputs have always been wired this way as YBA has never believed in the necessity of balanced inputs in Hi-Fi equipment but installed one as a courtesy so you could connect an XLR to it. It sure will not be balanced but it will play just the same and the convenience is there.
All YBA amplifiers are biased as low as possible to be just above the crossover distortion. The bias should be set no higher than 15 mV as stated in the service manual and I strongly advise you respect that as the amplifier is prone to thermal runaway at higher bias settings. Here is the link for the service manual:
http://dl.dropbox.com/u/59013041/yba_p1000_sm.pdf
Be aware that adjusting the biases on this amplifier is a lengthy process that may take several hours. It takes time for the massive heat sinks to reach a stable temperature once you have changed the bias setting. Take your time and go very slowly and make sure you do it when mains AC power is at peak.
As for the mica insulators they probably tried to do without them, as in the model 1 and the Signature series amplifiers, but were unable to do so in the Passion and "forgot" to remove the mention from the manual. The metal used is not bronze or plated aluminum but brass. Brass is often "confused" with copper in the French language.
As for the top cover, YBA has been using nuts or nylon spacers and I even saw some units with machined top sides to do away with the spacers. You can install thinner spacers If you think the gap is too wide...
The solder used by YBA has a high content of silver making it much harder to have shiny looking solder joints. Many solder joints may look bad but they usually are all right. I rarely have YBA products with solder joints problems and I have repaired hundreds of them over the last 20 years.
The circuit is balanced by hand with discrete resistors piggy backed on the PCB. It is almost impossible to achieve perfect balance this way explaining why the amplifier may clip a little faster on one side.
YBA has always limited the frequency response as he believes you run into problems with higher bandwidth than necessary amplifiers.
Except for the grounding problem, as far as I can see there is nothing wrong with this amplifier. It is exactly the same as when it left the YBA factory. I see no reason why it could not serve your client for years to come. He only needs reassurance and less hysteria and everything will be fine.
I am at your disposal if you need more help or information.
Best regards,
Michel
It always amazes me to read that many useless, even damaging comments from users who know absolutely nothing about the product they are commenting about...
The YBA Passion amplifier has always been made by hand and was never intended for mass production. I do not approve either of the way it is built but this is no indication of how it sounds. I believe many of you would want to own one if you had the chance to listen to it. I even know a recording studio who uses the same amplifier in his reference system.
To correct your ground problem I suggest you solder two short lengths of green wire to the shield at both ends of the power cable and solder the other ends of those short lengths to the ground lug of the AC connectors. To access the shield you have to recess the external insulation of the cable and may need to heat it to be able to do so. I never approved of ground less power cables but YBA has always done it saying it sounded better this way. Make sure you solder another piece of green cable between the ground lug of the chassis IEC connector and screw the other end to the chassis of the amplifier.
The balanced XLR inputs have always been wired this way as YBA has never believed in the necessity of balanced inputs in Hi-Fi equipment but installed one as a courtesy so you could connect an XLR to it. It sure will not be balanced but it will play just the same and the convenience is there.
All YBA amplifiers are biased as low as possible to be just above the crossover distortion. The bias should be set no higher than 15 mV as stated in the service manual and I strongly advise you respect that as the amplifier is prone to thermal runaway at higher bias settings. Here is the link for the service manual:
http://dl.dropbox.com/u/59013041/yba_p1000_sm.pdf
Be aware that adjusting the biases on this amplifier is a lengthy process that may take several hours. It takes time for the massive heat sinks to reach a stable temperature once you have changed the bias setting. Take your time and go very slowly and make sure you do it when mains AC power is at peak.
As for the mica insulators they probably tried to do without them, as in the model 1 and the Signature series amplifiers, but were unable to do so in the Passion and "forgot" to remove the mention from the manual. The metal used is not bronze or plated aluminum but brass. Brass is often "confused" with copper in the French language.
As for the top cover, YBA has been using nuts or nylon spacers and I even saw some units with machined top sides to do away with the spacers. You can install thinner spacers If you think the gap is too wide...
The solder used by YBA has a high content of silver making it much harder to have shiny looking solder joints. Many solder joints may look bad but they usually are all right. I rarely have YBA products with solder joints problems and I have repaired hundreds of them over the last 20 years.
The circuit is balanced by hand with discrete resistors piggy backed on the PCB. It is almost impossible to achieve perfect balance this way explaining why the amplifier may clip a little faster on one side.
YBA has always limited the frequency response as he believes you run into problems with higher bandwidth than necessary amplifiers.
Except for the grounding problem, as far as I can see there is nothing wrong with this amplifier. It is exactly the same as when it left the YBA factory. I see no reason why it could not serve your client for years to come. He only needs reassurance and less hysteria and everything will be fine.
I am at your disposal if you need more help or information.
Best regards,
Michel
Design flaw number one: Brass heatspreader between transistor and main heatsink, brass is a very poor conductor of heat.
Design flaw number two: the bias circuit is inadequate, not able to compensate at higher currents.
Design flaw number three: Undersized heatsink, incapable of keeping the amp cool at higher bias, worsened severely by using the brass heatspreader.
Design flaw number two: the bias circuit is inadequate, not able to compensate at higher currents.
Design flaw number three: Undersized heatsink, incapable of keeping the amp cool at higher bias, worsened severely by using the brass heatspreader.
I think some poor component and construction choices rather than "design" errors can be forgiven but gross clipping behaviour shows incompetence with electronics and it is inexcusable in a high-end, professional, consumer or any commercial product regardless of whether it sounds fine at lower levels.
Hand wired products are everywhere on this forum. Most images posted (thankfully guys), show better execution than what we see in this commercial product. It is disappointing considering the reasonable expectations of a client for equal attention to all aspects of the product they are paying so much for.
There are many manufacturers of great sounding products built by people who know little about electronics but will at least seek advice when they begin to accept money for their efforts. Then there are standards and conformance indications in most countries that are legally required to be affixed to new electrical appliances offered for sale, whether we make 1 or 1,001 units.
Hand wired products are everywhere on this forum. Most images posted (thankfully guys), show better execution than what we see in this commercial product. It is disappointing considering the reasonable expectations of a client for equal attention to all aspects of the product they are paying so much for.
There are many manufacturers of great sounding products built by people who know little about electronics but will at least seek advice when they begin to accept money for their efforts. Then there are standards and conformance indications in most countries that are legally required to be affixed to new electrical appliances offered for sale, whether we make 1 or 1,001 units.
I wonder why YBA dident use a heatsink like the dual flange one on conrad heatsinks, the brass feels a bit like cost cutting just like with consumer electronics.
Anyone who knows metals know that brass is among the worst conductors of heat.
I wonder how much of the brass heatspreader is actually in contact with the heatsink, i imagine its folded like a U channel with two wings for the transistors with the bottom of the U bolted to the main heatsink.
The heat of several transistors having to converge into one narrow strip of metal and then creep into a small section of the heatsink, no wonder it goes into thermal runaway at just 20-50mA bias.
They coluld atleast have used flat pack transistors bolted directly onto the surface of the main heatsink.
Just my
Anyone who knows metals know that brass is among the worst conductors of heat.
I wonder how much of the brass heatspreader is actually in contact with the heatsink, i imagine its folded like a U channel with two wings for the transistors with the bottom of the U bolted to the main heatsink.
The heat of several transistors having to converge into one narrow strip of metal and then creep into a small section of the heatsink, no wonder it goes into thermal runaway at just 20-50mA bias.
They coluld atleast have used flat pack transistors bolted directly onto the surface of the main heatsink.
Just my
Well, here is another proof point that ultra low distortion and high performance in general mean squat in a subjective review. However, that is no excuse for sub-par engineering.
I took a quick look at the circuit this morning. There are a number of problems:-
-compensation design was clearly not the designers forte - very heavy handed and there are likely serious slew rate problems, especialy given the very high output rails
-front end LTP current sources not ideal
-LTP's could have done with cascoding IMV, but with matching, you could get away without. The problem with high voltage small signal devices is they usually have low Hfe . . .
- The feedback resistor values are far too high
- no protection - given the huge output stage, I think this could have been added with little extra effort - even a crowbar type would at least save expensive speakers (which are probably what a $16k amp would be driving anyway)
My conclusion is this amplifier is is easily modified to significanlty improve on the following:-
- PSRR
- distortion
- Slew rate
For the thermal problem mentioned by the posters above, some attention to the mecahincal coupling will be needed. However, getting stable thermal performance shouls also be fairly easy in my view.
You have a great platform here to turn this frog into a prince - just needs a bit of effort to fix a few things.
I took a quick look at the circuit this morning. There are a number of problems:-
-compensation design was clearly not the designers forte - very heavy handed and there are likely serious slew rate problems, especialy given the very high output rails
-front end LTP current sources not ideal
-LTP's could have done with cascoding IMV, but with matching, you could get away without. The problem with high voltage small signal devices is they usually have low Hfe . . .
- The feedback resistor values are far too high
- no protection - given the huge output stage, I think this could have been added with little extra effort - even a crowbar type would at least save expensive speakers (which are probably what a $16k amp would be driving anyway)
My conclusion is this amplifier is is easily modified to significanlty improve on the following:-
- PSRR
- distortion
- Slew rate
For the thermal problem mentioned by the posters above, some attention to the mecahincal coupling will be needed. However, getting stable thermal performance shouls also be fairly easy in my view.
You have a great platform here to turn this frog into a prince - just needs a bit of effort to fix a few things.
michel ....
thanks for taking the time to explain the above more or less i have nothing against your sayings.
two points though are a bit different
Dont know how it works in Canada but this is Europe there is regulations, classification, and approvals for any electric device .It cant be simply a manufacturer's choice to ground the device or not .Also there is the CE marking that approves the above .
Second there was never a question about he soldering of the actual amplifier all soldering problems are located on the additional soft start pcb ...
kind regards
sakis
thanks for taking the time to explain the above more or less i have nothing against your sayings.
two points though are a bit different
Dont know how it works in Canada but this is Europe there is regulations, classification, and approvals for any electric device .It cant be simply a manufacturer's choice to ground the device or not .Also there is the CE marking that approves the above .
Second there was never a question about he soldering of the actual amplifier all soldering problems are located on the additional soft start pcb ...
kind regards
sakis
Some quick calcs from my side
LTP tail current c. 2.7mA so 1.35mA per side
VAS bias voltage c. 1.6V
VAS current 4mA (very, very low for a big EF2 amp like this)
Driver stage current c. 16mA - so driver is class A up to about 6A peak output current - also low in my view - you want the driver to remain solidly in class A
Output offset, assuming worst case Hfe on front end mismatch of 100 c. 0.6V. In practice, probably 0.1-0.3V of offset. The high feedback resistance does not help here.
VAS loaded with 10k resistors, means the loop gain on this amp (DC and AC) is very low.
I suspect this amp has some loop gain at lower frequencies, but it actually runs open loop at HF - but I could be wrong.
LTP tail current c. 2.7mA so 1.35mA per side
VAS bias voltage c. 1.6V
VAS current 4mA (very, very low for a big EF2 amp like this)
Driver stage current c. 16mA - so driver is class A up to about 6A peak output current - also low in my view - you want the driver to remain solidly in class A
Output offset, assuming worst case Hfe on front end mismatch of 100 c. 0.6V. In practice, probably 0.1-0.3V of offset. The high feedback resistance does not help here.
VAS loaded with 10k resistors, means the loop gain on this amp (DC and AC) is very low.
I suspect this amp has some loop gain at lower frequencies, but it actually runs open loop at HF - but I could be wrong.
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All the changes you are suggesting will improve measured specs, but it will also very much alter the sound. Maybe it wont sound so good anymore. Where does that leave us, taking as an example, this amp??
Mmm, going French for 15K, or South-African on a very much cheaper Ovation 250 Screw-IY ?
Difficult choice.
Well, I think the YBA performance could certainly be improved.
I'd like to think a well engineered $15k amp sounds good when it comes up against an amplifier like this.
Now you know why I think subjective reviews on their own are not enough. Measurements and comparative listening tests are needed as well. So, two out of three to Stereophile.
I'd like to think a well engineered $15k amp sounds good when it comes up against an amplifier like this.
Now you know why I think subjective reviews on their own are not enough. Measurements and comparative listening tests are needed as well. So, two out of three to Stereophile.
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LOL Jacco The wines from SA are also good. And they are cheaper! You have to spend a
to to get a decent French one but I'll concede that may be better at the high end.
to to get a decent French one but I'll concede that may be better at the high end.
In a certain 90s year I cannot recall now, 2 cheap 1.50 euro south african sparkling wines (champagne) won best awards against french versions that cost 500 times the price.
Ill stick to Electrocompaniet.
Ill stick to Electrocompaniet.
Just my
Anyone who knows Mr YBA, knows he's always been into Copper, not bras.
Yves-Bernard André is a lecturer/researcher at the (prestigious) tech-U in Palaiseau, just under Paris, full-time employed since before he started the YBA brand.
(My favorite vintages are quarante-cinq to soixante, percent. The red stuff is the ingredient for the resto business to make a profit, otherwise good to drown a chicken with, not yourself)
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