Custom Hafler DH-500 - $1,200 (New Braunfels)

Custom Hafler DH-500 1 thumbnailCustom Hafler DH-500 2 thumbnailCustom Hafler DH-500 3 thumbnailCustom Hafler DH-500 4 thumbnail
condition: like new
make / manufacturer: Hafler
model name / number: DH-500
This is an amazing vintage amplifier that has been upgraded with components that essentially make this, for all practical purposes, new.

This is a BEEFY amplifier, that weighs nearly 50 pounds, and puts out up to 335 watts into 8 ohms, and over 600 into 4 ohms, making it a BEAST when it comes to raw power. This amp will drive ANY speaker with finesse and clarity!

The custom hardwood faceplate was designed and cnc built gives it a more aesthetic appeal. I have a couple of additional covers in different colors I would consider including if you're interested in something a bit different.

The upgrade kit I purchased and installed was designed by former Hafler engineer Ed Fantasia and is regarded as one of the best upgrades for this amplifier on the market.


The upgrades included: 22000mfd Nippon main filter capacitors, .5 ohm 30 amp inrush limiter , 35 amp diode block , and new power switch, gold plated copper rca inputs, large gold plated output binding posts capable of accepting .154 inch diameter wire with special insulating bushings to fit 1/4 inch chassis holes, and two pc-1 driver boards.

Details about the PC-1 Driver boards:

A. Precise PC board layout with no track crossover.

B. First stage single ended Jfet/bipolar cascode differential amplifier with CCS regulation. Jfets incorporated are genuine Toshiba 2SK170 or 2SK117 devices with IDSS closely matched. If you know anything about these Jfets, I need not say anything else. High input impedance, high gain, tube like presence, and eerie low noise in listening tests makes it a no brainer. Cascode configuration reduces Miller effect, drastically increasing bandwidth and lowering distortion. This all important first stage configuration eliminates the need for massive gain and feedback used in many amps to cover up distortions and design flaws.

C. Second stage also uses SE bipolar cascode amplifier with CCS regulation. Again, Miller effect is reduced and bandwidth is not compromised.

D. Simple bias control and emitter follower circuit to drive output stage is added and all that is needed to complete the design goal. Clipping now occurs at 335 watts into 8 ohms instead of the 270 watts from original PC-10 or PC-19.

E. Polypropylene capacitors throughout with all HE electrolytic caps bypassed with polypropylenes.

F. Vital star grounding realized with pictorial showing proper wiring arrangement.

Signal to Noise Ratio, unweighted:
Exceeds 100 db referred to 250 watts into 8 ohms 103 dB Typical
Typical THD at 200 watts into 8 ohms:
20 Hz: 0.0025%
1 kz: 0.0025%
20 kHz: 0.008%
Input Impedance:
33,000 ohms.
Input Sensitivity:
2.03 volts rms for 250 watts into 8 ohms.
Frequency Response into 8 ohms:
- 3 db, 4.8 Hz to 225 kHz at 1 watt.

See this for more info and reviews: https://www.ebay.com/itm/373653758678

post id: 7755271223



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