Pre-amp/DAC for JOB 225

[maty]

"DACT Type SMD 21 Stepped Attenuator"

DACT - Danish Audio ConnecT

-> http://www.dact.com/html/attenuators.html

-> http://www.dact.com/html/attenuator_data_sheet.html

SPECIFICATIONS

Number of steps 24
Bandwidth (10kOhm): 50 MHz
Channel matching: +/-0.05 dB
Attenuation accuracy: +/-0.05 dB
THD: 0.0001 %
Mechanical life, min. 25,000 cycles

 

[maty]

DACT Audio input selector switches

-> Data sheet for DACT audio input selector switches

Features

2/4/8-pole switches 2/4/8 channels simultaneously
Gold plated contacts for long lifetime even in hot and humid environments
High reliability
Matches perfectly with DACT CT2 audio attenuators
Mechanically “programmable” for 1 to 3 or 5 or 6 postions

 

[Glareskin]

Of course with a Job power amp what you need a Job pre-amp.

 

[wisnon]

One of these should work fine too… Hehehehe

 

[joeinid]

I received my passive from Aum Acoustics, made by Richard Becker. My Teddy Pardo power supply arrived on the same day. I hooked everything together and I am a happy camper. Very easy volume control with the Job 225. Richard makes the passive with upgraded tweaks and a better complement of metals to connect the sockets and components. He obviously has done his homework because it sounds fabulous.

One of these should work fine too… Hehehehe

View attachment 5519

 

[Glareskin]

I received my passive from Aum Acoustics, made by Richard Becker. My Teddy Pardo power supply arrived on the same day. I hooked everything together and I am a happy camper. Very easy volume control with the Job 225. Richard makes the passive with upgraded tweaks and a better complement of metals to connect the sockets and components. He obviously has done his homework because it sounds fabulous.

Very nice Joe! The display shows the gain? And do you have remote control?

My favorite passive amp is the Khozmo from Poland. It comes with optional wooden remote control!

 

[joeinid]

Very nice Joe! The display shows the gain? And do you have remote control?

My favorite passive amp is the Khozmo from Poland. It comes with optional wooden remote control!

I think the number is just the relative output. I'll have to ask Richard. The unit comes with an Apple remote.

 

[Glareskin]

I think the number is just the relative output. I'll have to ask Richard. The unit comes with an Apple remote.

Even though I think the Khozmo one is a wee bit more stylish I'll have to admit that the Apple is pretty cool too. And hands down the best RC in my house!

 

[joeinid]

I think it's perfect for my needs but yours looks great too.

 

[maty]

tnt-audio.com DACT switches. Are switches audible?

Comparing the DACT to the generic switch is more interesting. The DACT does sound superior. I really mean that the DACT adds to or removes from the signal less obviously than the generic switch. The difference is one of very slight (and I mean VERY SLIGHT) veiling of some of the subtler nuances at the highest frequencies, like the character of gentle stick-work at the centre of a ride cymbal, or a slight catch in the throat during a vocal performance. The difference is akin to replacing a commercial grade coupling cap in a pre-amplifier circuit with a well chosen audiophile cap. Not re-capping the whole pre-amp, just changing one.

More noticeable is a reduction in 'grain'. Again this is analagous to a capacitor upgrade, but this time more akin to replacing the power supply smoothing capacitors with higher quality items. The DACT CT3 selector switch clearly offers advantages both ways: less of what we don't want and more of what we do want...

Conclusion

Conclusion 1 is that if we have vintage gear (anything over 10 years old) we must establish that the switches are in good order, if not, replace them now.

Conclusion 2 is that input selectors must break 'earth' (or 'negative' or 'ground') as well as 'plus' (or positive' or 'live' or 'hot') to avoid breakthrough, hum-loops (ground-loops) or distortion. This reduces or eliminates the need for shorting plugs.

Conclusion 3 is that even switches in as new spec may sound different!

Conclusion 4 is that a further test is needed to establish whether an audiophile switch is actually audibly different from another brand of audiophile switch.

I am not saying that DACT switches are the best in the world (and if they misquote this sentence I'll marmalise them) but I am saying that DACT selector switches are significantly and audibly better than generic switches advertised as being of high quality.

If you have high quality vintage gear they will be worth the cash and hassle. If you have high-end modern gear with unidentified flimsy switches, they will benefit too. If you are building your own project with any pretension to greatness there is no question that you should be using switches of the quality of DACT CT3.

 

[maty]

emotiva.com Control Freak. Passive Volume Control. $59.99 / $49.99

SPECS

10k 4-gang audio-taper potentiometer (2-gang on single-ended model, 4-gang on balanced model)

XLR stereo inputs and outputs on balanced model



RCA stereo inputs and outputs on single-ended model

-> http://emotiva.com/resources/manuals/control_freak_10.pdf

Specifications

The balanced version of the Control Freak uses four precision matched audio taper 10 kOhm potentiometers to control output level - while adding virtually no noise or distortion.

The unbalanced version of the Control Freak uses two precision matched audio taper 10 kOhm potentiometers...

 

[watchdog]

I got a preloved Amtrans APCG-01S passive preamp last week. It's a little bit unusal as it offers 6 db gain by using a Lundahl step-up transformer, followed by a 10k discrete resistor potentiometer.

Sounds really good with the Job. In fact, it's been the best pairing I've heard so far among the various options I've tried. I am guessing that if you don't need the gain, any 10k pot passive preamp should sound good so long as you have quality parts. I suppose it makes sense, the maximum output impedance of a 10k pot is still manageably low for the Job's input impedance.

 

[maty]

remusic.it Shootout Test | Eleven Passive and Transformer Preamps by Roberto Rocchi, 24.10.2012

But now back to our transformer passive preamps. I would like to introduce the eleven preamps following a rigorous alphabetical order:

Audio Tekne 9701 | Japan

Cello Etude | USA

DaVinciAudio Labs | CH

Fidelity Research AS1 | Japan

Luxman AT3000 | Japan

Music First Audio | UK

Promitheus Audio TVC | USA

Promitheus Audio TVC Reference | USA

Stereo Knight Magnetic Silverstone Balance | USA

Stereo Knight Silverstone SE | USA

The Mod Squad Line Drive | USA

 

[maty]

2013 Recommended Components Preamplifiers

-> 2013 Recommended Components Preamplifiers | Stereophile.com

Class B

Amtrans Passive Controller APCG-01S: $2960

Housed in a small (6.6" W by 3.5" H by 5.9" D) sheet-metal chassis, the Amtrans APCG-01S passive controller uses a Lundahl transformer to provide 6dB of voltage gain. It has an input selector, volume control, Stereo/Mono switch, and four sets of line-level RCA inputs. Though it lacked the tonal color of Conrad-Johnson's ET3 SE line stage and couldn’t match the transparency of George Hi-Fi's Lightspeed Attenuator, the Amtrans produced a big, dynamic sound with a wide soundstage and "deep, tight, beautifully articulated bass," said ST. "There's nothing "passive" about the Amtrans sound," he quipped. (Vol.34 No.11)

-> Amtrans Passive Controler APCG-01S

 

[ICTWoody]

Of course with a Job power amp what you need a Job pre-amp.

Is this what they are working on at Job? Or is this something from the past? Details?

- Woody

 

[wisnon]

yes, preamp by June and monoblocs by December. That is still the timeline.

 

[Anatta]

At this point, I have greater interest in the Mytek than the Benchmark for two reasons. First, while the Benchmark's volume control is digital-only with digital sources (that is, there's no option for analog control of volume for digital sources), the Mytek allows switching between a digital volume control and an analog stepped attenuator. Second, the Mytek reportedly has internal jumpers for reducing the overall level of gain, which would facilitate pairing with the JOB.

Regarding the Benchmark DAC2 VC it isn't entirely correct what you say.

The Benchmark (HGC and L versions) has both analog and digital inputs. On the digital inputs the VC is digital, while on the analog inputs the VC is analog.

Concerning the gain, since you'd use the unbalanced outputs of the Benchmark into the Job, it is only 0.5dB from RCA in to RCA out. So if you use the analog outs of your digital source to the analog ins of the Benchmark, the DAC2 will act almost like a buffered attenuator with only 0.5dB of gain, offering a low output impedance of 30 Ohms.

 

[Naim101]

Got a confirmation from JOB last week the Job Preamp will be available from Mid-June this year. Cant wait!

 

[Etunes]

Got a confirmation from JOB last week the Job Preamp will be available from Mid-June this year. Cant wait!

Great news any update on the mono blocks?

 

[joeinid]

Great news Naim101. Thanks