Job 225

mep · Jun 10, 2013

The power transformer in my KSA-250 weighs 83 lbs.

wizard · Jun 10, 2013

225 power output with lowest distortion in 2 ohms is 125 watt.
It can go down to 1 ohm but deliver only around 70 watt.

soundArgument · Jun 10, 2013

I received my Job 225 today. It sounds incredible: remarkably extended high frequencies and vastly increased transparency and imaging over other amps I've heard with my speakers (which range from mid-fi NAD gear to Jeff Rowland).

My enjoyment, however, has been marred by problems with 60 Hz hum, which is audible from my loudspeakers whenever the Job 225 is on, whether or not the preamp or any sources are turned on. I've tried plugging the amp both into a couple of different wall outlets and into different outlets on my Furman M10-HT-PRO (with all my other gear), and the hum is still there. I also switched out interconnects and speaker cables with no luck. I even tried running the speaker cables over the middle of the floor, where they're far away from wall outlets and power cables. The quality of the hum seems to change only when I remove all interconnects from the amp, but all interconnects that I've tried yield the same hum.

It could be that my mains are terrible, but I'm perplexed as to why these issues surfaced only with the Job 225.

mep · Jun 10, 2013

Did you try a cheater plug to lift the ground? You may also want to try running a ground wire from somewhere on the JOB chassis back to your preamp.

soundArgument · Jun 10, 2013

mep said:
Did you try a cheater plug to lift the ground? You may also want to try running a ground wire from somewhere on the JOB chassis back to your preamp.

Thanks for the tips, Mep--I tried both to no avail.

joeinid · Jun 10, 2013

soundArgument said:
Thanks for the tips, Mep--I tried both to no avail.

I'm so sorry. Mine is dead quiet.

mep · Jun 10, 2013

soundArgument said:
Thanks for the tips, Mep--I tried both to no avail.

Since no one else has raised this issue, maybe you have a defective amp. Did you contact the company yet to ask them for advice?

Elberoth · Jun 10, 2013

joeinid said:
By selling it of course.

Love your sense of humor

Let me know when you decide to sell it. I may just order custom made power transformer to replace the 115V one.

PS. If your lil Pioneers didn't blow up, you will be fine with TADs too. Most SS preamps are DC-coupled anyway, and have virtualy no DC at the output.

soundArgument · Jun 10, 2013

mep said:
Since no one else has raised this issue, maybe you have a defective amp. Did you contact the company yet to ask them for advice?

Yep, just emailed Goldmund. The problem improves somewhat, but not completely, if I unplug the interconnects running to the amp (whether or not the preamp is connected or powered up).

The manual is replete with warnings about interference from wiring and other devices, and I live in an apartment in an urban area, which might explain the problems.

Despite the hum, it sounds great.

Elberoth · Jun 10, 2013

wizard said:
View attachment 10084

Pictured is the recently released Telos 390.5 integrated amp.
The circuit board underneath to the right looks like the same used in Job 225, and the circuit board underneath to the left is the same used in the Metis 2 preamp.

Just checked - the Telos 390.2, which was the Telos 390.5 predescessor, used to cost $17,620. The Telos 390.5 is probably even more ...

Job 225 uses the same power amp section - seems like an amazing value.

mep · Jun 10, 2013

Because this amp has so much bandwidth, having really good shielded ICs from your preamp to power amp is essential so you don't pick up RF.

Elberoth · Jun 10, 2013

soundArgument said:
Yep, just emailed Goldmund. The problem improves somewhat, but not completely, if I unplug the interconnects running to the amp (whether or not the preamp is connected or powered up).

The manual is replete with warnings about interference from wiring and other devices, and I live in an apartment in an urban area, which might explain the problems.

Despite the hum, it sounds great.

Sounds like a ground loop problem to me.

mep · Jun 10, 2013

Elberoth said:
Sounds like a ground loop problem to me.

He tried a cheater plug and that didn't work. Even with no ICs plugged into the amp from the preamp he still has hum so I'm not convinced on the ground loop theory.

soundArgument · Jun 10, 2013

mep said:
He tried a cheater plug and that didn't work. Even with no ICs plugged into the amp from the preamp he still has hum so I'm not convinced on the ground loop theory.

Just to clarify, the hum is much reduced with no ICs plugged in at all, but it doesn't matter whether the ICs are plugged into anything on the other end. I've tried three pairs of ICs, too, just to make sure I didn't have a bad ground on one of them.

Mysterious--I'll wait to hear from Goldmund before I make any moves.

joeinid · Jun 10, 2013

Hi Adam,

Thanks! I really love this amp. It sounds great. I will eventually try it on the TADs because I have no problems with the Pioneers. If you want me to send you one, I'll help in any way. If you want this one because I know it's perfect. Let me know.

Elberoth said:
Love your sense of humor Let me know when you decide to sell it. I may just order custom made power transformer to replace the 115V one.

PS. If your lil Pioneers didn't blow up, you will be fine with TADs too. Most SS preamps are DC-coupled anyway, and have virtualy no DC at the output.

Elberoth · Jun 11, 2013

Thanks Joe, you are great. I think I would try to get one from Goldmund directly. But first need to read some more ppl comments.

soundArgument · Jun 11, 2013

soundArgument said:
Just to clarify, the hum is much reduced with no ICs plugged in at all, but it doesn't matter whether the ICs are plugged into anything on the other end. I've tried three pairs of ICs, too, just to make sure I didn't have a bad ground on one of them.

Mysterious--I'll wait to hear from Goldmund before I make any moves.

Goldmund responded quickly to my email, and recommended using their "star grounding" technique, in which all ground current is routed through the preamp. The instructions are complex and, if I'm understanding them correctly, will require that I use a 3-to-2 "cheater plug" with the amp. I'll give it a try and report back. Thanks to all who have posted suggestions.

Because the amplifier makes no noise when the shorting plugs are inserted, I suspect it's not defective and that the problems I'm having owe to my listening environment and accompanying equipment.

If anyone else is thinking of buying a JOB 225, I can report that despite the problems I've had with it, the amp sounds unbelievable for the money. I don't remember hearing an amp with high-frequency response like the JOB's. To my ear, the JOB sounds more transparent than similarly powerful Accuphase, Rowland, McIntosh, Quad, and Simaudio equipment that I've heard. I wish I could compare it to Spectral gear, but I've never had the opportunity to hear a Spectral amp.

joeinid · Jun 11, 2013

I can honestly say that I love this Job 225 amp. There is something right about how it sounds. I am sure that as long as your speakers are not too complex a load it will drive them well. This has killed many amps costing several times the asking price. It has a huge sound stage with clarity and smoothness.

I'd love a monoblock version for more fun.

soundArgument · Jun 11, 2013

I can confirm that my Job 225 is defective. Experimenting with different RCA configurations, I pinpointed the source of the problem. When a cable is plugged into the left RCA jack, the speakers are connected, and the amplifier is turned on, there's a lot of 60 Hz hum with harmonics from both speakers. Unplug a cable from the left RCA jack, and the problem goes away. That's it. :-(

I'll report how the manufacturer responds to the defect.

joeinid · Jun 11, 2013

Let's hope nothing short of replacement.

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