Pass Labs Design 10 watt Class A amp for $329

Emil · « **on:** 3 Jun 2018, 03:28 pm »

The case alone should cost $329 I would think.

I don't believe there is any theft of intellectual property here since Nelson Pass has been known to publish his designs freely but then again I don't believe he would approve someone making money off his clones

https://www.ebay.com/itm/PASS-AM-10W-10W-Class-A-Audio-Power-Amplifier-Hifi-AMP-Balanced-input/222153666558?hash=item33b963effe:g:mU8AAOSwNuxXYOiN

What do you guys think of the build design and parts quality

paul79 · « **Reply #1 on:** 3 Jun 2018, 03:47 pm »

Case, connectors, and transformer alone would cost us Americans more than that. Pretty iffy feedback though, but I don't think you are taking too much of a gamble for the price!

paul79 · « **Reply #2 on:** 3 Jun 2018, 03:54 pm »

Here's the case!

https://www.ebay.com/itm/BZ3612A-Aluminum-enclosure-Class-A-Power-amplifier-chassis-box-360-120-275mm/132480163889?hash=item1ed86ee031:g:b2kAAOSwn9VaZu4T

mr_bill · « **Reply #3 on:** 3 Jun 2018, 04:01 pm »

Wow!
Somebody should buy one and find out.

fredgarvin · « **Reply #4 on:** 3 Jun 2018, 04:32 pm »

On another forum, 3 or 4 guys have purchased a Hood copy, also 10w a side, with good reports on it's sound.-

https://www.ebay.com/itm/Nobsound-NS-02G-Perfect-Hood-1969-Gold-Pure-Class-A-finished-Power-AMP-Amplifier/251547955482?hash=item3a916d311a:g:ipwAAOSwPhdVNxkf

Folsom · « **Reply #5 on:** 3 Jun 2018, 09:38 pm »

What pass amp is it based on ?

RDavidson · « **Reply #6 on:** 3 Jun 2018, 10:34 pm »

Quote from: Emil on 3 Jun 2018, 03:28 pm

I don't believe there is any theft of intellectual property here since Nelson Pass has been known to publish his designs freely but then again I don't believe he would approve someone making money off his clones

Assuming these are unauthorized, this is the exact reason Nelson no longer makes his work free to the public. He used to do it entirely out of generosity to the DIY crowd, but people are a-holes and will eventually take advantage, as seen here. If you support immoral a-holes then go for it.

2bigears · « **Reply #7 on:** 3 Jun 2018, 11:14 pm »

other countries do this all the time. Free market. Reverse engineering .

Stercom · « **Reply #8 on:** 3 Jun 2018, 11:32 pm »

The Hood circuit design has been around for 30 or 40 years. There is nothing illegal or unethical about using it.

RDavidson · « **Reply #9 on:** 3 Jun 2018, 11:53 pm »

Quote from: 2bigears on 3 Jun 2018, 11:14 pm

other countries do this all the time. Free market. Reverse engineering .

Yeah, I know. Still lame.

RDavidson · « **Reply #10 on:** 3 Jun 2018, 11:56 pm »

Quote from: Stercom on 3 Jun 2018, 11:32 pm

The Hood circuit design has been around for 30 or 40 years. There is nothing illegal or unethical about using it.

Yeah. Designs that old are certainly open for public use. That's understood.

Norman Tracy · « **Reply #11 on:** 4 Jun 2018, 05:01 am »

Notice in the photo above the case actually has the Krell logo.

Such respect for intellectual property.

Norman Tracy · « **Reply #12 on:** 4 Jun 2018, 05:19 am »

If you're going to go with DoukAudio this is the one to get https://www.ebay.com/itm/Douk-Audio-FU32-Vacuum-Tube-Amplifier-Stereo-Single-Ended-Assembled-Board-3W-2/272866698942?hash=item3f881f66be:g:SKwAAOSwynRZzayz. Leave it as the open stack of PCBs with the exposed high voltage, hot tubes and anode cap wires, place it on an accessible shelf and you also have a solution for getting rid of that pesky cat your girlfriend moved in with.

The smell of burnt fur will only last a few days...

wushuliu · « **Reply #13 on:** 4 Jun 2018, 05:41 am »

Nelson has a patent on this design and probably still offers support/advice on it, so IMO this should be avoided. Anyway, odds are the original parts specified have been replaced with cheaper and/or fake substitutes and a quick google search reveals the schematic used may have wrong values for some of the parts.

When you buy these amps they are only a good deal if you are prepared to open them up and modify them. Otherwise, you get what you pay for. No free lunch.

@Norman - yes, that amp looks like it was designed for the singular purpose of feline population reduction.

FullRangeMan · « **Reply #14 on:** 4 Jun 2018, 06:22 am »

Great amp, great value, very good looks, unfortunately 10W not suffice to my 94dB FR.

roscoe65 · « **Reply #15 on:** 4 Jun 2018, 02:19 pm »

Quote from: RDavidson on 3 Jun 2018, 11:56 pm

Yeah. Designs that old are certainly open for public use. That's understood.

Hell, designs more than two years old are available for public use. Nelson seems to make his designs almost immediately available for non-commercial use. Of course, this is commercial use, but I doubt anyone is cutting into Nelson's current sales.

Of course, rather than buy this you could spend the same amount of money and buy the 8wpc ACA from DIYAudio.com. You would have to sling a little solder, but you'll have something that has about the same power, probably sounds better, is currently supported, and which has a ready market for resale if you want to move it along.

Nelson is one of the most prolific and generous designers our hobby has known. I would prefer to respect his generosity by patronizing him if possible.

fredgarvin · « **Reply #16 on:** 4 Jun 2018, 02:21 pm »

There several other 'tribute' amps from the Chi sellers, DartZeel, Goldmund, Quad and some other Pass types. The DartZeel models are interesting, 4 versions I know of 200 wtt amps that increase in price from around $500 to 3 X that.

sts9fan · « **Reply #17 on:** 4 Jun 2018, 03:39 pm »

Quote from: Stercom on 3 Jun 2018, 11:32 pm

The Hood circuit design has been around for 30 or 40 years. There is nothing illegal or unethical about using it.

Using his name is unethical and illegal I think.

Stercom · « **Reply #18 on:** 4 Jun 2018, 03:58 pm »

I think there is some confusion here. One amp referred to is claiming to have a design by Nelson Pass. The other amp claims to have a Hood circuit design. The Hood circuit has been around since 1969 when John Linsley Hood wrote a paper called a "Simple Class A Amplifier". (I remembered a little of this and Googled the rest)

Stercom · « **Reply #19 on:** 4 Jun 2018, 03:59 pm »

I agree commercially selling an amp with a Nelson Pass DIY design (when he specifically asked people not to) is unethical.