All,
I just found an interesting and comprehensive web article about building a Pass DIY Class A amp. Granted the amp is a Aleph X model, but the article covers a lot of good info about general construction, transformer selection, power supply building, heatsinking, (FET matching), and amp testing. Again, it covers a lot of info that also exists in many, many of the F5 formum threads--but it is all covered in one article. I'd recommend those new to PASS DIY construction check it out.... It's at:
Aleph-X 100w Amplifier Construction Notes
Ken
Let me know your thoughts..... good article???
I just found an interesting and comprehensive web article about building a Pass DIY Class A amp. Granted the amp is a Aleph X model, but the article covers a lot of good info about general construction, transformer selection, power supply building, heatsinking, (FET matching), and amp testing. Again, it covers a lot of info that also exists in many, many of the F5 formum threads--but it is all covered in one article. I'd recommend those new to PASS DIY construction check it out.... It's at:
Aleph-X 100w Amplifier Construction Notes
Ken
Let me know your thoughts..... good article???
Bksabath......unfortunately, no progress yet on the power supply dummy loads, nor the harmonic distortion testbed.
I've been distracted--just completed another "test rig", but this one automotive. A small block Chevrolet engine, on a Superflow dyno, for this summer's race season--1,153 horsepower, from 383 cubic inch displacement, with 24 lbs intercooled turbo boost, at 7,800 RPM.
My biggest fears have been realized--the start of my "summer hobbies" are starting to impact the finish of my "winter hobbies"....
...... Zen Mod's right.... The E. Santane who authored the website I referenced is also an active member of the Aleph-X thread that is "stickied" in the Pass Lab forum. E. Santane = Eric (his diyaudio screen name).
Still, the Santane site is a good concise compendium of useful info..... check it out....
ZM--you da man!
Hi CanAm Man
Of topic but really IMO interesting question> 383 Cubic in = 4 litters?
On topic and IMO on this tread as best one for F5
It works
I fired up one channel of my F5
No smoke and just over 2 A at 27V = 50% Bias
Followed Zen mod bias setting procedure Apart the closing of the case as mine is pretty open any way.
1 hour run temperature of top of heath spreader 32C
Top of mosfet body 35.6 C
Voltage across R11 0.528 (Probes wrong way around)
2.133 A about 50% of my target
Offset 1.1 mV steady there for 10 15 minutes
I am not going to fuss about the accuracy of the results the ISOTEC is 20 years old the red meter is cheap and nasty and not really accurate but I wont cry if it get blown while measuring current.
The one for the offset is a different story cost much more that my current oscilloscope and that one is spot on.
I did not place on the board the transistors for the current limiting at this stage.
So 10:30 Am now (nice to be on the Greenwich time zone)
I am going to hit the town with my girlfriend and celebrate.
Still to come
Re design the PCB (couple of minor corrections)
While those get ready I will carry on with Zen Mod guide and set bias to 100%
I think the following is right but typing on the fly so I beter go back on this tread and get my figures right so no need for Co. to reply
My target is 4A per rail (2 mosfet at 2 A each total 4 mosfet channel)
Current then 8 A
As I have 4 Homs speakers W=I x I x R
8 x 8 x 4 = 256 W (does not look right)
And W= V x V / R = 8 V
When I started this journey I took a reading of the voltage at the speakers with my current set up and about 8 V was the point at which the output was to loud and annoying.
With 27 volts rails I got plenty of headroom.
I would like to get 2A bias on the mosfet as Papa said that they sound beter
But that mean 54W dissipation, maybe too much but the heath spreaders and the Kerafoll should help.
At present the temperature looks really good but I should check the real temperature of the junction as I think if I remember correctly 70C is about right.
So loads of work in the next weeks.
PS naughty naughty little Alex put a signal on the input
Not much to post there and will spare you the pictures (my sound generator is in serious need of upgrading and its 100 KHz signal looks pretty bad) but the 1 KHz at 1 W trough a PC speaker was enough to give me goose bumps and a big grin.
Of topic but really IMO interesting question> 383 Cubic in = 4 litters?
On topic and IMO on this tread as best one for F5
It works
I fired up one channel of my F5
No smoke and just over 2 A at 27V = 50% Bias
Followed Zen mod bias setting procedure Apart the closing of the case as mine is pretty open any way.
1 hour run temperature of top of heath spreader 32C
Top of mosfet body 35.6 C
Voltage across R11 0.528 (Probes wrong way around)
2.133 A about 50% of my target
Offset 1.1 mV steady there for 10 15 minutes
I am not going to fuss about the accuracy of the results the ISOTEC is 20 years old the red meter is cheap and nasty and not really accurate but I wont cry if it get blown while measuring current.
The one for the offset is a different story cost much more that my current oscilloscope and that one is spot on.
I did not place on the board the transistors for the current limiting at this stage.
So 10:30 Am now (nice to be on the Greenwich time zone)
I am going to hit the town with my girlfriend and celebrate.
Still to come
Re design the PCB (couple of minor corrections)
While those get ready I will carry on with Zen Mod guide and set bias to 100%
I think the following is right but typing on the fly so I beter go back on this tread and get my figures right so no need for Co. to reply
My target is 4A per rail (2 mosfet at 2 A each total 4 mosfet channel)
Current then 8 A
As I have 4 Homs speakers W=I x I x R
8 x 8 x 4 = 256 W (does not look right)
And W= V x V / R = 8 V
When I started this journey I took a reading of the voltage at the speakers with my current set up and about 8 V was the point at which the output was to loud and annoying.
With 27 volts rails I got plenty of headroom.
I would like to get 2A bias on the mosfet as Papa said that they sound beter
But that mean 54W dissipation, maybe too much but the heath spreaders and the Kerafoll should help.
At present the temperature looks really good but I should check the real temperature of the junction as I think if I remember correctly 70C is about right.
So loads of work in the next weeks.
PS naughty naughty little Alex put a signal on the input
Not much to post there and will spare you the pictures (my sound generator is in serious need of upgrading and its 100 KHz signal looks pretty bad) but the 1 KHz at 1 W trough a PC speaker was enough to give me goose bumps and a big grin.
Quite a nice day out yesterday.
Found mint copy of Joy Division in Memory the 4 box set 180 g
and got the vinner on the grand national.
Came home with more dosh than when I came out.
Today the first channel is cooking at 4 A on each rail temperature on the heat spreaders sitting at 42 C 49 C on the same position as yesterday ofset -2 mV
Think I am gona make same noise in a bit.
Found mint copy of Joy Division in Memory the 4 box set 180 g
and got the vinner on the grand national.
Came home with more dosh than when I came out.
Today the first channel is cooking at 4 A on each rail temperature on the heat spreaders sitting at 42 C 49 C on the same position as yesterday ofset -2 mV
Think I am gona make same noise in a bit.
I will as soon as I found the drawing for a DC trap I think I saw yesterday recently posted in one of the Pass Labs forums
Been looking since my previous post but I will never find it Help preaty please
is the one with the Bridge and the 2 6.3 V electrolitic if I remember
Trafo is 1000 VA and is buzing a bit with 4 A
never happened before today
I tried to swap the secondary vires to the one of the bridges but no change
Probably done sometink silly done to to much head bashing.
Just typical Murphy bite on the botom once it does no chance you find the light switch for the light bulb like in the cartoons
You know the one I mean?
Bing (light bulb over your head is all shiny sparckly like) silly me that'it
Been looking since my previous post but I will never find it Help preaty please
is the one with the Bridge and the 2 6.3 V electrolitic if I remember
Trafo is 1000 VA and is buzing a bit with 4 A
never happened before today
I tried to swap the secondary vires to the one of the bridges but no change
Probably done sometink silly done to to much head bashing.
Just typical Murphy bite on the botom once it does no chance you find the light switch for the light bulb like in the cartoons
You know the one I mean?
Bing (light bulb over your head is all shiny sparckly like) silly me that'it
Bksabath. Hope this helps or check out Per Anders website.
http://www.rstaudio.de/AlephP/Wiring230V.pdf
http://www.rstaudio.de/AlephP/Wiring230V.pdf
Not quite that small. 62 cu in = 1 litre, so 383 cu in = 6.2 litre.....
.....so, that's about 177.5 hp/litre, or 3.0 hp/cu in..... and that's about the practical limit of sanity....(!)
Of course your mileage may vary. Some assembly required. Do not attempt this, unless you are a professional.
1,390 ft-lbs
(But there's NO WAY I'll try to convert that to newton-meters, or light-years per second). LOL
Yes. It's got a very hefty forged crank and rods!
Sorry..... that was a typo on the torque.... It's only (!) 1,090 ft-lbs
(Only 1,090 ft-lbs....!)
Sorry..... that was a typo on the torque.... It's only (!) 1,090 ft-lbs
(Only 1,090 ft-lbs....!)
That means that it will take about .025 seconds longer to blow the clutch plate - shred the tranny - snap the drive shaft - and theeeeen eat the rear-end. Ahhhh - all in a days work (or play).
Oh - ya mean the F5 amplifier - I thought we were talking formula racers!!! My Bad - ok - back to on topic and I'll be a good boy and go sit in da corner.
Last edited:
Tanks Mara
Just the one I was looking for
But if I remember caps where 6.3 V 12000u or more
funny (but not realy) I am shure I have seen the drawing on one of the forums day before yesterday but can't find it any more...
Tanks CanAm Man
Al the best for that monster
Way abowe what I would dream off to even start dreaming about
I will have to make do with my totaly standard Galant manual VR4 2.6 L 280 Hp
Had it down south to get a new clutch last year and the owner of the garrage had
a 3000 GT busted up to 995 HP I don't think he would race the thing It was more a show piece for shorth runs on the Dino
Just the one I was looking for
But if I remember caps where 6.3 V 12000u or more
funny (but not realy) I am shure I have seen the drawing on one of the forums day before yesterday but can't find it any more...
Tanks CanAm Man
Al the best for that monster
Way abowe what I would dream off to even start dreaming about I will have to make do with my totaly standard Galant manual VR4 2.6 L 280 Hp
Had it down south to get a new clutch last year and the owner of the garrage had
a 3000 GT busted up to 995 HP I don't think he would race the thing It was more a show piece for shorth runs on the Dino