If you guys think that one is bad, you should have seen the one I had back in 07 or so...the ones in those pictures look like they came from Nelson compared to what mine looked like. The seller wouldn't take them back, so I flipped them 2 days later for a $15 loss (shipping) and moved quickly on.
Ahhh, but I've seen the suggestion to add a resistor in series with speaker outputs in order to get rid of hum many times, regardless of whether it actually works.
For the record, it does not have my boards, which have never been made
available in any form.
Flashback, to the movie "This is Spinal Tap"...... 'I must have a very high power amp.....because the volume control goes to 11.......not just 10, but 11......!!
Now, forward to this thread: "My boards were made by Nelson Pass"......because his name is stamped on it...' Geesshh....... don't we all KNOW how easy it is to silk screen ANYTHING (part number, name, etc) on a PCB????
I'm tempted to type more about this thread, but instead I'll refrain......
OK, I think the point is made, but nobody expects the OP to send the amps back and so on. ........The only important thing here is to confirm that this build is not a shock or
fire hazard.
Mr Pass--you are a bona fide "class act". Although we're discussing an obvious rip off amp (an act that irritates the @#*&$@ out of me), you take the time to point out the safety defects in the construction, in an effort to help the buyer avoid potential disaster.
You are a far better man than I.......
not disputing what you wrote , but OP got safety warning in first reply
Agreed, mighty ZM..... but if I had created the circuit, and subsequently had it "stolen" by a clone maker, I would not have taken the time to warn the buyer. Let them get hoisted on their own Rawson petard, as it were.....
POS??? That is short for "processor of sound"...... is it not??
I think I'm gonna paint them Ferrari Red with flames on the front panel.
They are on a dedicated 30A GFI line so that ought to help things. I have two homeruns into my stereo with heavy duty "hospital" outlets. Phase is correct.
Thanks for the picture review.. yes, that's them. I will look into that. For the time being, they are hooked up but my wife keeps watching TV in the den, so that puts the kibosh on my listening.
(1) I will unbundle the wires coming out of the AC plug, I was curious about that part, how all those wires are so tight and I could not find the thermistor. That could be a fire danger.
(2) I wonder if there's a fuse. I must admit I did not look for it.
(3) Yes, I will earth ground the chassis, I also wondered about that, however, I am not so concerned about ground faults since I would figure the GDI circuits would find that ( but -yes, yes- if the ground is not hooked up... sort of defeats the thing, huh?
(4) I did notice too that speaker black is grounded. Should I take that out and drive it to the AC black? That would lift the electronics ground from the earth ground. It looks like the entire chassis is not ground to earth and instead the electronics are ground via the chassis which is thus floating. I guess this ought to be a simple fix?
Now, I have a question... I have some older amps that have two prong plugs... those amps are not earth grounded either. Marantz, Kenwood, Sansui... admittely these are all vintage amps but I've had them for a very long time and they have never blown up or burnt the house down. One of my Marantzes and the Sansui are "mega" receivers that put out hundreds of audio watts...
Thing is, they make pretty good sounds through my Maggies.
Thanks to those of you who gave constructive comments.
They are on a dedicated 30A GFI line so that ought to help things. I have two homeruns into my stereo with heavy duty "hospital" outlets. Phase is correct.
Thanks for the picture review.. yes, that's them. I will look into that. For the time being, they are hooked up but my wife keeps watching TV in the den, so that puts the kibosh on my listening.
(1) I will unbundle the wires coming out of the AC plug, I was curious about that part, how all those wires are so tight and I could not find the thermistor. That could be a fire danger.
(2) I wonder if there's a fuse. I must admit I did not look for it.
(3) Yes, I will earth ground the chassis, I also wondered about that, however, I am not so concerned about ground faults since I would figure the GDI circuits would find that ( but -yes, yes- if the ground is not hooked up... sort of defeats the thing, huh?
(4) I did notice too that speaker black is grounded. Should I take that out and drive it to the AC black? That would lift the electronics ground from the earth ground. It looks like the entire chassis is not ground to earth and instead the electronics are ground via the chassis which is thus floating. I guess this ought to be a simple fix?
Now, I have a question... I have some older amps that have two prong plugs... those amps are not earth grounded either. Marantz, Kenwood, Sansui... admittely these are all vintage amps but I've had them for a very long time and they have never blown up or burnt the house down. One of my Marantzes and the Sansui are "mega" receivers that put out hundreds of audio watts...
Thing is, they make pretty good sounds through my Maggies.
Thanks to those of you who gave constructive comments.
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I looked at the pictures in more detail.... amps are closed right not and it's late.
...
(4) I did notice too that the three prongs of the AC plug are not used. I wonder if he used the earth ground instead of the AC return? That would ground everything to earth ground. It looks like the entire chassis is thus also ground to earth. I guess this ought to be a simple fix? I just lift the "green" and "orange" from the chassis, hook them up to the AC return and then ground the chassis to the earth ground. That should lift the PS while grounding the chassis proper. Will that do it?
...
...
(4) I did notice too that the three prongs of the AC plug are not used. I wonder if he used the earth ground instead of the AC return? That would ground everything to earth ground. It looks like the entire chassis is thus also ground to earth. I guess this ought to be a simple fix? I just lift the "green" and "orange" from the chassis, hook them up to the AC return and then ground the chassis to the earth ground. That should lift the PS while grounding the chassis proper. Will that do it?
...
Hi Tony, hard to see from those pics. Please read this Power Supply Wiring Guidelines. Also read 6L6's build guides. You know there's a problem there, please fix it before a kid or a cat gets electrocuted.
Have fun!
(Hey, Jim!!! Your power supply build guide isn't listed in your sig)
Have fun!
(Hey, Jim!!! Your power supply build guide isn't listed in your sig)
It doesn't look too complicated -from an engineer's perspective. I guess I'll start by taking some "mechanical" considerations and then figure out where the AC return is going.
I still want to paint them Ferrari Red with flames on the bottom of the front panels.
Oh, in regards to the 3 ohm resistor on the return to the speaker... I was told these amps were built to drive Maggies.. which are a 4 ohm load. Perhaps this is why it was done? I dunno, I will open them and measure them next week.
I still want to paint them Ferrari Red with flames on the bottom of the front panels.
Oh, in regards to the 3 ohm resistor on the return to the speaker... I was told these amps were built to drive Maggies.. which are a 4 ohm load. Perhaps this is why it was done? I dunno, I will open them and measure them next week.
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Tony(EE),
I finally had time to look at the pics in this thread. If these are truly the amps you bought, the comments from Mr. Pass, 6L6 and the others are "right on the mark"...... you have an electrical disaster waiting to happen--not in the original design, but in the construction skills and knowledge.
Don't take this personally, but in one of your comments, you noted the power supply drained off quickly after removal of AC power--and you asked if this was due to the capacitors. I sense audio and power supply design are not "long suits" in your EE background. Please be careful. You may not have to "paint red flames" on your chassis face--they may become reality unless you rebuild these amps. Personally, I'd feel safer if you "canned" them for useable parts, purchased a new chassis, and rewired everything--properly.
Please read (and study) the pics of Pass Amps thread, and 6L6's outstanding build guides, and attempt to benefit from good amp construction.
I'm particularly proud of this build quality: http://www.diyaudio.com/forums/pass...ifferent-drummer.html?highlight=drummer+music
(Oh....wait.....that's MY F5 construction thread!)
Your pics really point out a lot of glaring errors in building. Another one, that I don't think anyone has highlighted (and one you should have noted, even as a DIY builder rookie) is the grouping of the power MOSFETs on the heatsinks. There is a reason this amp has such MASSIVE heatsinks --i.e,. to help dissipate the heat from the semi's...... and it's VERY poor construction to group all MOSFETs next to one another on the "end" of a heatsink....(!)... This is a very fundamental error.
I finally had time to look at the pics in this thread. If these are truly the amps you bought, the comments from Mr. Pass, 6L6 and the others are "right on the mark"...... you have an electrical disaster waiting to happen--not in the original design, but in the construction skills and knowledge.
Don't take this personally, but in one of your comments, you noted the power supply drained off quickly after removal of AC power--and you asked if this was due to the capacitors. I sense audio and power supply design are not "long suits" in your EE background. Please be careful. You may not have to "paint red flames" on your chassis face--they may become reality unless you rebuild these amps. Personally, I'd feel safer if you "canned" them for useable parts, purchased a new chassis, and rewired everything--properly.
Please read (and study) the pics of Pass Amps thread, and 6L6's outstanding build guides, and attempt to benefit from good amp construction.
I'm particularly proud of this build quality: http://www.diyaudio.com/forums/pass...ifferent-drummer.html?highlight=drummer+music
(Oh....wait.....that's MY F5 construction thread!)
Your pics really point out a lot of glaring errors in building. Another one, that I don't think anyone has highlighted (and one you should have noted, even as a DIY builder rookie) is the grouping of the power MOSFETs on the heatsinks. There is a reason this amp has such MASSIVE heatsinks --i.e,. to help dissipate the heat from the semi's...... and it's VERY poor construction to group all MOSFETs next to one another on the "end" of a heatsink....(!)... This is a very fundamental error.
Look, I did not post in here to get insulted by the likes of you.
I have 35++ years of experience in digital, RF and some analog electronics, plus I can write encyclopedias on embedded software.. and I can follow schematics, JTAG, etc, etc... so if you intend to insult me, you can just keep that and move along.
If you had waited on your post before attempting to flame me, you might have noticed that I DID NOT BUILD THIS AMP. Those were NOT my pictures, those came from Audiogon.
My plan right now is to fix these amps working from the schematics because I like the way they sound. And for SURE I WILL NOT ASK FOR HELP FROM THE LIKES OF YOU, because to tell you the truth you have an EGOs that really sucks wind. In my line of business we check our egos at the door, otherwise we'd never get our products out the door, or into space (yes, as I matter of fact I did work as a rocket scientist for a while...).
Now then, personally, I don't care about how cool your builds are. I just don't care. If I wanted to spend the money, I might buy a used Pass Aleph 5 -there was one in Audiogon yesterday. I figure Pass Labs and Nelson know more about building an amp than ten of you put together. The man at least checks his ego... he knows he's good so he doesn't have to go around insulting people, specially people who he knows nothing about.
So, you know what? ADIOS... I'll might go back to lurking and you can bask in the secure knowledge that your are an absolute bore.
BTW, you might want to brush up on your physics, bud. There is nothing thermodynamically wrong on the heat transfer of those FET to the heat sink even if it offends your sensibility. It's all about how fast heat travels through the heat sinks, the overall sink rate and capacity of the heat sinks and the steady state of the system. I have seen far more complex systems where the heat sources had to be physically grouped together. So, my advice to you is to reflect on the fact that a little knowledge can be dangerous.
And yes, power supplies are the most complex part of an analog design. I have been in many hardware design teams where the power supply and heat dissipation design phase took far more resources than the rest of the boards -including the micro-controllers. The things that you can do when your boards are going to sell for tens of thousands of bucks each (and often far, FAR more) are amazing... of course, the best ones are when you're doing pure IRAD.
I have 35++ years of experience in digital, RF and some analog electronics, plus I can write encyclopedias on embedded software.. and I can follow schematics, JTAG, etc, etc... so if you intend to insult me, you can just keep that and move along.
If you had waited on your post before attempting to flame me, you might have noticed that I DID NOT BUILD THIS AMP. Those were NOT my pictures, those came from Audiogon.
My plan right now is to fix these amps working from the schematics because I like the way they sound. And for SURE I WILL NOT ASK FOR HELP FROM THE LIKES OF YOU, because to tell you the truth you have an EGOs that really sucks wind. In my line of business we check our egos at the door, otherwise we'd never get our products out the door, or into space (yes, as I matter of fact I did work as a rocket scientist for a while...).
Now then, personally, I don't care about how cool your builds are. I just don't care. If I wanted to spend the money, I might buy a used Pass Aleph 5 -there was one in Audiogon yesterday. I figure Pass Labs and Nelson know more about building an amp than ten of you put together. The man at least checks his ego... he knows he's good so he doesn't have to go around insulting people, specially people who he knows nothing about.
So, you know what? ADIOS... I'll might go back to lurking and you can bask in the secure knowledge that your are an absolute bore.
BTW, you might want to brush up on your physics, bud. There is nothing thermodynamically wrong on the heat transfer of those FET to the heat sink even if it offends your sensibility. It's all about how fast heat travels through the heat sinks, the overall sink rate and capacity of the heat sinks and the steady state of the system. I have seen far more complex systems where the heat sources had to be physically grouped together. So, my advice to you is to reflect on the fact that a little knowledge can be dangerous.
And yes, power supplies are the most complex part of an analog design. I have been in many hardware design teams where the power supply and heat dissipation design phase took far more resources than the rest of the boards -including the micro-controllers. The things that you can do when your boards are going to sell for tens of thousands of bucks each (and often far, FAR more) are amazing... of course, the best ones are when you're doing pure IRAD.
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Well, i can tell you what !
IF you know "THAT" much about electronic, why you buy this amp on the first place ?
PSU on PASS amps are simple as can be, and again - still problem for you? And you need a help to fix it?
You come here for help, and people try to help, if you don't like it - fine ...
I can't understand why this "Rawson" guy build amps like that, and even more questionable for me is - why people are buying ...
Like i said in my first post on this topic, i am banned for good on Audio Karma for pointing on one POS amp on sale there ...
How ever, i am sorry you make mistake with this amp, and don't be mad @ people talking shi* about this build ... I am just one of guys here, and i am sure all of us just want to help you ... not just to talk - i offer to send you set of F5 PCB's for free, if you want to build one amp by your self, with help of US here ...
F5 PCB - mirrored + PSU
OR, even to put PCB's together for YOU if you want to provide parts ...
•
Tony, no need for you to accept my advice, although I come with a 45 year background in Physics and 30 years of EE experience. Please read the following extract I found for your info:
-------------------------
14 - Transistor Placement
Since heat rises by convection, one might think that mounting the transistors on the bottom of the heatsink might improve thermal performance. This is incorrect, and will actually cause the devices to run hotter. Aluminium is an excellent conductor of heat, and the idea is to ensure that the transistors are mounted in such a way that each has sufficient clearance from the others, and they are close to the geometric centre of the sink. This method ensures that the heat from each transistor has a similar mass of aluminium to disperse its heat into, ensuring that all devices have a similar and equal chance of dispersing the heat generated.
Refer to: ESP - Heatsink design and transistor mounting (The Australian author is a very respected audiophile engineer)
---------------------
The above advice gives sound thermal management guidelines--ones that I remember when I'm designing and "flying" 15 Ghz thick-film GaAs power radar modules to reliably operate (without overheating) in the vacuum of space (yeah.... I'm a satellite "dink" too).
P.S. I never stated you had BUILT the amp in my earlier comments.....but I did certainly emphasize the need to REBUILD it, for reasons of safety and good engineering practices. Be safe.
Do what you want with this info.
-------------------------
14 - Transistor Placement
Since heat rises by convection, one might think that mounting the transistors on the bottom of the heatsink might improve thermal performance. This is incorrect, and will actually cause the devices to run hotter. Aluminium is an excellent conductor of heat, and the idea is to ensure that the transistors are mounted in such a way that each has sufficient clearance from the others, and they are close to the geometric centre of the sink. This method ensures that the heat from each transistor has a similar mass of aluminium to disperse its heat into, ensuring that all devices have a similar and equal chance of dispersing the heat generated.
Refer to: ESP - Heatsink design and transistor mounting (The Australian author is a very respected audiophile engineer)
---------------------
The above advice gives sound thermal management guidelines--ones that I remember when I'm designing and "flying" 15 Ghz thick-film GaAs power radar modules to reliably operate (without overheating) in the vacuum of space (yeah.... I'm a satellite "dink" too).
P.S. I never stated you had BUILT the amp in my earlier comments.....but I did certainly emphasize the need to REBUILD it, for reasons of safety and good engineering practices. Be safe.
Do what you want with this info.
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So now....
OK, so I'm working on fixing the amps... they really sound good and drive my Maggies better than the ARC D70MkII.... and I put out the Acoustic Reality amps out to pasture in the HT... good riddance.
So... so.... I have been seeing Aleph 3s and 1s on Audiogon.... but those are old amps by now. I'm not quite sure that 30 watts will drive the Maggies and the ARC D70 at 60 watts can barely do it.
I'm also curious about the Pass Aleph 60, but I haven't seen on sale for ages.
I was planning on getting a pair of ARC 100 MkIIs but this class A stuff has suddenly done a job on my head. But as I want to keep the Maggies, I guess I need reasonable power. So the Aleph J is likely not on the cards.
OTOH, I could get some Lowthers, get kicked out of the house, move to a big garage...
What should I look for at old Aleph 1s? By now I suppose they need new caps by now. Does Pass Labs ( the company ) offer repairs? I'm OK with soldering but I really don't have the time and it'll take time. As it now stands the closet is full of stereo gear and now the dining room table is loaded as well. Are the old Alephs hard to fix on your own? I assume all they need by now is new power supply caps...
Yeah, I know... why I'm I posting on a DIY forum? Well, I did build the B1 and I just got a new soldering station.... and since I got nicely flamed, I figured I might as well continue while I move onto painting my Ferrari Red to be home flamethrowers.
Do they make audiophile grade smoke detectors?
OK, so I'm working on fixing the amps... they really sound good and drive my Maggies better than the ARC D70MkII.... and I put out the Acoustic Reality amps out to pasture in the HT... good riddance.
So... so.... I have been seeing Aleph 3s and 1s on Audiogon.... but those are old amps by now. I'm not quite sure that 30 watts will drive the Maggies and the ARC D70 at 60 watts can barely do it.
I'm also curious about the Pass Aleph 60, but I haven't seen on sale for ages.
I was planning on getting a pair of ARC 100 MkIIs but this class A stuff has suddenly done a job on my head. But as I want to keep the Maggies, I guess I need reasonable power. So the Aleph J is likely not on the cards.
OTOH, I could get some Lowthers, get kicked out of the house, move to a big garage...
What should I look for at old Aleph 1s? By now I suppose they need new caps by now. Does Pass Labs ( the company ) offer repairs? I'm OK with soldering but I really don't have the time and it'll take time. As it now stands the closet is full of stereo gear and now the dining room table is loaded as well. Are the old Alephs hard to fix on your own? I assume all they need by now is new power supply caps...
Yeah, I know... why I'm I posting on a DIY forum? Well, I did build the B1 and I just got a new soldering station.... and since I got nicely flamed, I figured I might as well continue while I move onto painting my Ferrari Red to be home flamethrowers.
Do they make audiophile grade smoke detectors?
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