Does the Hafler P-7000 shares the same topology as the 9XXX series ?
The reason I am asking is becasue you can find a P7000 for ok money, around $200, the Hafler 9XXX series are getting expensive with time
http://tolisdiy.com/2020/10/08/hafler-9505-9300-power-amplifiers-repair-and-measurements/
The reason I am asking is becasue you can find a P7000 for ok money, around $200, the Hafler 9XXX series are getting expensive with time
http://tolisdiy.com/2020/10/08/hafler-9505-9300-power-amplifiers-repair-and-measurements/
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I am not a tech or have no idea how to read a schematic, I rely on reviews and opinions from others
Here is a review of the 9505.
Here is a review of the 9505.
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Here is a 9505 schematic.
General topology is the same, one difference being input LTP is JFET in 9505 and BJT in 7000.
VAS and output are the same.
9300/9500 are different (input and VAS). To me, 7000 and 9505 schematics 'look' better.
General topology is the same, one difference being input LTP is JFET in 9505 and BJT in 7000.
VAS and output are the same.
9300/9500 are different (input and VAS). To me, 7000 and 9505 schematics 'look' better.
If you pick up a p7000, you could make it better by replacing the power supply capacitors with better, higher capacitance caps. Those caps in these old amps are old and getting worn anyways.
The second thing you could do is replace the rectifier bridge with high speed, soft recovery ones which would improve the high frequencies.
You could see if there is a way to install decoupling caps right at the output transistors if there are none.
Retsel
The second thing you could do is replace the rectifier bridge with high speed, soft recovery ones which would improve the high frequencies.
You could see if there is a way to install decoupling caps right at the output transistors if there are none.
Retsel
Why the distortion numbers are that high for that amp ?
I also found a few Hafler Pro5000 for the same price, very cheap
Is the Pro5000 better than the P7000 ?
Was the fan too loud for the P7000 ?
I also found a few Hafler Pro5000 for the same price, very cheap
Is the Pro5000 better than the P7000 ?
Was the fan too loud for the P7000 ?
If you are referring to this <0.2% THD, I wouldn't worry too much.
This was probably done at full power into load at 20kHz.
At 1kHz, the THD is much lower.
The Pro5000 shares similar circuitry as the DH220.
What separates them is the Balanced Input.
The P7000, on the other hand, is a totally different circuit.
Another point to note is the Pro5000 uses the old metal can TO-3 power mosfets (2SK176/2SJ56)
The later P7000 uses plastic TO-3P (2SK2221/2SJ352).
Maybe the pro5000 has the same topology as the DH-500
I was looking at the part list
12 4700uf 100V power capacitors
I see also a few mylar caps, are those in the audio path ?
I was looking at the part list
12 4700uf 100V power capacitors
I see also a few mylar caps, are those in the audio path ?
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For 1 channel. it's 6pcs of 4,700uF 100V.
That's 3 for the positive rail and another 3 for the negative.
So, you're looking at 14,100uF per rail.
You need to do a screen shot and circle the Mylar caps otherwise nobody knows what you are referring to.
That's 3 for the positive rail and another 3 for the negative.
So, you're looking at 14,100uF per rail.
You need to do a screen shot and circle the Mylar caps otherwise nobody knows what you are referring to.