Help with Hafler 9505

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Official Court Jester
Joined 2003
Paid Member
partialresponse said:
If the 9305 is to the 9505 what the 9300 is to the 9500, then the only differences between the 9305 and 9505 will be 1 or 2 extra pairs of output devices per channel and larger (higher capacitance and votage) power supply capacitors. The transformer is also different.


- Kofi


somewhere i have manual (with schm pages blank) with exact name :MAN0587D_9303_9505_man.pdf.........
so-you have right regarding that......


A link to the 9x00 schematic appears earlier in this thread.

that was for 915 ,similar but different :devilr:
like I said- I'll check tomorrow for 9303 schm-I know that I somewhere have it printed
 
Zen Mod said:
http://czsr_bac.on.neobee.net/Hafler9505.jpg

889KB

btw-Ar- www button in your posts leads to.....nowhere;
I remember page with your business info.......

Thanks a lot. Manny thanks. Hvala puno.
Thank you for the info. It is already old article and Apple took it of the site since it was their site. Try www.starpointsf.com That is our new web site that we are working on.
Could you send me the email with schematic in higher res so I cold keep it?
Thanks
 
Official Court Jester
Joined 2003
Paid Member
AR2 said:


Thanks a lot. Manny thanks. Hvala puno.
Thank you for the info. It is already old article and Apple took it of the site since it was their site. Try www.starpointsf.com That is our new web site that we are working on.
Could you send me the email with schematic in higher res so I cold keep it?
Thanks


you're welcome ;)
believe me-this is scan from A4 page I was given;I scan it ,if I remember correctly,in 1200dpi to achieve best quality I can from start.
but I didn't bother to clear few dirt spots...
now I don't know where da bloody paper is....

anyway- print it and magnify what you want to see in your pc,(mac,whatever ;) ) ;you can even clear tiny numbers and type them again in bigger format.....you are good enough in graphical redo....? hehe

anyway-to cut story short-this is best I can

regarding Treshold.....sala mala :clown:
 
Bingo,
Done.
Problem solved.
Special thanx to all of you that shared your wisdom. Anatech you guessed correctly - it was transistor that was bad. Special thanks to Partialresponse who remeinded me on this problem after I left it a year ago, and who shared solution to his problem. It turns out to be the same problem.
A special, special thanks to Choky who provided me with schematic.
It was a same problem like Partialresponse had. A transistor MPSA 06 went bad, and that was in the area where circuit board was burnt. I will be happy if someone with a same problem find this tread and gets the solution to his problem.
Thank you
AR2
 
Glad to hear you fixed it. I'm told by some that the 9505 sounds better than the 9500....I've also heard a few comment that it's the other way around. I have been thinking of selling my 9500 but haven't found anything to replace it with at even twice the cost of a used 9500 (~ $600). Any comments?

Regards

Kofi
 
Official Court Jester
Joined 2003
Paid Member
partialresponse said:
Glad to hear you fixed it. I'm told by some that the 9505 sounds better than the 9500....I've also heard a few comment that it's the other way around. I have been thinking of selling my 9500 but haven't found anything to replace it with at even twice the cost of a used 9500 (~ $600). Any comments?

Regards

Kofi


what's exact difference between 9500 and 9505?

and -btw - AR..... I forget to ask :
can you compare,or can you put up differences between your Aleph and 9505?
 
partialresponse said:
Glad to hear you fixed it. I'm told by some that the 9505 sounds better than the 9500....I've also heard a few comment that it's the other way around. I have been thinking of selling my 9500 but haven't found anything to replace it with at even twice the cost of a used 9500 (~ $600). Any comments?

Regards

Kofi

I do not know much about 9500 but 9505 is not bad. I would say it is good AB amp with pretty decent top end and good drive at the bottom.


Zen Mod said:



what's exact difference between 9500 and 9505?

and -btw - AR..... I forget to ask :
can you compare, or can you put up differences between your Aleph and 9505?

The main difference is that 9500 has single ended input, where 9505 is designed as fully balanced. Input area has different components, where rear area of the driver board and output are identical. If compared to Aleph it is hard to do it, as I am using Aleph on the ribbon tweeters and I really didn't listen much in the full range. Other problem is that my Aleph 305 (Aleph 30 configuration with higher voltage that makes it close to be Aleph 5 by power standards) is limited in power compared to Hafler.

I would say that Aleph has much better top end, so far the best I've heard. As I mentioned I have it connected to 5" ribbons - 103dB sensitivity and they have no mercy to the amps, they really reveal everything. I have exchanged many different amps, tube and SS, GC and who knows what and there is nothing as good as this little Aleph. Such a great and clean sound, not too sharp, not to soft just right on, detailed and spacious.

I didn't listen enough Hafler to say much about it, it is for my son so he is enjoying it already. It sounds like typical Mosfet class AB, it has decent amount of power and has very decent top (uses jFets in the front). Overall very good amp. As I mentioned top is good but not as good as Aleph. It's topology uses a few more power stages and that could be recognized. I strongly believe that less is better. In my experience any additional component leaves it's signature and that is why Aleph shines with only two amplification stages. It has beautiful easy wide open top end. Also smaller Aleph with less output devices always sound better that more powerful amp in the high end area. But with that you pay the price in the low end. Unfortunately it is hard to get everything in one, so than active approach is answer. Well that is where simplicity and less is better ends.
I tried to do just that in my active set up, by using small amps and very sensitive speakers.

Mr. Pass did exactly that approach in his Rushmores, high sensitivity speakers driven with low powered class A amps. I am actually using same mids - PHL but driven with small tube amps, as well as Rushmore uses ribbons for the top end. I remember being so proud of myself, as Rushmors came out just after I finished my speakers, when I realized that I made a similar choice of speakers and concept as Mr. Pass. (The only difference is that Mr. Pass knew what he was doing where with me that certainly was not the case. It was just a guess hoping it will work.)

Anyways, not to go too far from the subject I hope I gave you a good description.

Stay well
AR2
 
same problem here... noisy A06,A56 xstrs

Just had a 9505 on the bench tonight with the same symptom... noise in left channel. Fluttering hiss w/ occasional pop/crackle. Somewhat intermittent... after inspecting & probing PCB I could tell is was not cold solder joints, etc.

Once again, it was a couple leaky driver transistors. I changed all four of them... (2) MPS-A06, (2) MPS-A56 for Q8-Q11. Amp is now quiet & running perfectly.

Thanks for the tip... came here for a schematic & ended up saving a couple hours worth of troubleshooting!

Thanks,
Marc - Omaha
 
Great,
I was hoping that someone will be able to use our experience with this amp. This is what makes DIYaudio so great.
It is weird that we all have a problem in the same spot only in one channel. Hafler needs to do some redesignin. It is only one channel even do channels are indentical. Does that mean that second one is on the way? I hope not.
 
Hi guys,
I new here to the forum and I came across this thread about the Hafler. (Sorry for resurrecting a year old thread) I just got the 9505 off ebay and I seem to be having the same "static" issue in both channels, but mainly the right one. Its intermittent. I see that you guys came up with the fix for this issue. (replacing Leaky driver transistors). Is this easy to do? Can you provide some instruction?

I would really hate to have to return the amp, so I would really like to fix this. I did not open it to check for heat damage yet, but I'm at work right now so I'm going to assume that there might be.

Thanks in advance
 
I have a turn off thump not turn on what can it be? I changed most of the capacitors and the inrush limiter so please give me some components to take a look at on the schematic... Hafler 9505. I changed the transistors on another 9505 I had and it fixed the bias rising and falling issue. Pot heat sinks on the trannys because of the heat.
 
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