Passive decission

[Feanor]

A month or so ago I reported a little experiment that compared my current preamp, (Sonic Frontiers Line 1), with simple passive preamp. The latter consisted of nothing but an ALPS potentiometer and connectors. From that experiment, and your comments, I concluded that passive preamps have great potential to sound better than active preamps.

There are considerations however, and not all source and power amp combos are amenable to having nothing between them but an attenuator. However you should be good if your source has low output impedance, your target (power amp) has high input impedance, and you can keep your cables short. I felt these conditions were met in my case, and my experiment proved this me.

Being butt lazy I decided I need a passive preamp with remote volume control at leas; multiple inputs would be handy too. I consider several options based on price and availability. What I ended up with is Jolida JD50A "control unit". Jolida designed this unit to complement their non-remote amps of the time. From what I understand it's basically a 100k ALPS 'Blue' attenuator plus a manual input selector and component power switching facilities.

This unit is now hooked up, driving both my Class D Audio amp and my PSB subwoofer. It's doing a great job. Here's a pic: atop the unit is its remote controller and my new, $50 Wolfson-based DAC which is also doing a great job. BTW, the Jolida is wearing an improvised "collar" aroung the volume control so I can see the setting from across the room, (my eyes being what they are). Under the Jolida is my Belkin power surge protector & filter device.

[Ajani]

Congrats on the new toy!

Finding an inexpensive passive pre with a remote, has always been a bit of a challenge... The cheapest one I knew of was the Creek OBH22 ($500) and that one only has 2 inputs...

[Feanor]

Congrats on the new toy!

Finding an inexpensive passive pre with a remote, has always been a bit of a challenge... The cheapest one I knew of was the Creek OBH22 ($500) and that one only has 2 inputs...

The OBH-22 or its predecessor, the OBH-12, both have a good rep, and if I had found a decent one second hand, as I did the Jolida, I'd have gone for it.

But for $500 I have probably have gone for the LDR (light dependant resistor) -based Eva 2 from Diyparadise, see here.



What I very nearly when for was this PGA2311 digitally controlled attenuator on eBay, see here. There a number of pretty high-end preamps that use this device for volume control.

[Ajani]

The OBH-22 or its predecessor, the OBH-12, both have a good rep, and if I had found a decent one second hand, as I did the Jolida, I'd have gone for it.

But for $500 I have probably have gone for the LDR (light dependant resistor) -based Eva 2 from Diyparadise, see here.



What I very nearly when for was this PGA2311 digitally controlled attenuator on eBay, see here. There a number of pretty high-end preamps that use this device for volume control.

I love the EVA 2 remote - brilliant choice compared to some of the really ugly universals used by some passives...

[Mr Peabody]

Feanor, you prefer the passive pre or are you just beginning to evaluate? And, just curious why is it important for you to see the volume control? Personally, I just adjust the volume to the loudness I want not paying attention to the particular setting.

[Feanor]

Feanor, you prefer the passive pre or are you just beginning to evaluate? And, just curious why is it important for you to see the volume control? Personally, I just adjust the volume to the loudness I want not paying attention to the particular setting.

I'm a little ways in to evaluating but not yet finished. The sound is different but no hugely different from my SF preamp that is know for being neutral. I'm not totally convinced yet that I prefer the passive.

As for seeing the volume setting, the reason is that I know that various recordings are at different levers from each other; if I can see the volume setting, I can anticipate and preset the level before starting play. A major example is moving from Classical to Jazz where I'd get a real blast of sound if I didn't lower the volume in anticipation. Or when I go from a Reference Recording or SACD to standard CD; the former are usually recorded at lower level.

[frenchmon]

Feanor...you make like these little puppies! I think they are passive DYI preamps.



http://www.homebuilthifi.com/amps

And check this out seeing you liker DIY

http://www.homebuilthifi.com/project/221

[Feanor]

Feanor...you make like these little puppies! I think they are passive DYI preamps.



http://www.homebuilthifi.com/amps

And check this out seeing you liker DIY

http://www.homebuilthifi.com/project/221

Yes, they are, 'Mon.

Actually I made myself a functionally -- though far less pretty -- equivalent before I got the Jolida JD50A. It's just an ALPS Blue Velvet pot in box with with one input and one output pair. This was what persuaded me to look for something like the Jolida, i.e. a passive with remote control. Getting up and walking over to the system to adjust the volume is just too much trouble for a slug like me.

[blackraven]

Feanor, what DAC is that?

[Feanor]

Feanor, what DAC is that?

It's the one described in my early posting ...

Cheap DAC working well

[the hand of boredom]

or at least the idea of one.

Hey Bill! I added a passive pre to the mix about three months ago. This is a transformer volume control unit by Stevens & Billington out of the UK. It adds absolutely nothing to the signal, other than gain, which is what a proper pre-amplification device should do.

There's definitely a level of transparency, ambience, detail and openness that I was after. It's allowed me to easily distinguish audible diffences between pre and power tubes.

Enjoy the new toy and keep us posted on your progress.

THOB

[Vinylly]

My experience with a passive pre-amp: I bought a Reference Line Mod 2000 passive pre-amp. The inside consists of a Penny+Giles attenuator and inputs connected with solid silver Kember cable. I use the same solid silver Kember cable for interconnects which are no longer then 18". I found that this passive pre-amp works extreamly well with my VTL tube amps. Also, my Win Labs Strain Gauge phono cart. works extreamly well with it.
At this time, however, I'm using it with a mini-system I have in my shop. It consists of NHT PRO active speakers, Perreaux TU-1 tuner, and Arcam fmj 36 CD player. Before I bought the Pathos Classic One for my living room system, I was using it with my Quad ESL 57's and VTL tiny triods.
I can only say they are incredibly detailed with exquisit demensionality and presence, but they are not as dynamic as active preamps. Oh, yes, this passive preamp works very well with my active NHT speakers, making it about the best mini-system I've ever heard. Tremendous for small jazz combos and vocalists but not so good for monster cathedral organs and large orchestras.

[Feanor]

or at least the idea of one.

Hey Bill! I added a passive pre to the mix about three months ago. This is a transformer volume control unit by Stevens & Billington out of the UK. It adds absolutely nothing to the signal, other than gain, which is what a proper pre-amplification device should do.

There's definitely a level of transparency, ambience, detail and openness that I was after. It's allowed me to easily distinguish audible diffences between pre and power tubes.

Enjoy the new toy and keep us posted on your progress.

THOB

Good to hear from you, Steve.

I think passives are worthwhile experiment for everyone. Like you say, it informs about the played by preamps, i.e. in general whether s/s or tube.

[Feanor]

My experience with a passive pre-amp: I bought a Reference Line Mod 2000 passive pre-amp. The inside consists of a Penny+Giles attenuator and inputs connected with solid silver Kember cable. I use the same solid silver Kember cable for interconnects which are no longer then 18". I found that this passive pre-amp works extreamly well with my VTL tube amps. Also, my Win Labs Strain Gauge phono cart. works extreamly well with it.
At this time, however, I'm using it with a mini-system I have in my shop. It consists of NHT PRO active speakers, Perreaux TU-1 tuner, and Arcam fmj 36 CD player. Before I bought the Pathos Classic One for my living room system, I was using it with my Quad ESL 57's and VTL tiny triods.
I can only say they are incredibly detailed with exquisit demensionality and presence, but they are not as dynamic as active preamps. Oh, yes, this passive preamp works very well with my active NHT speakers, making it about the best mini-system I've ever heard. Tremendous for small jazz combos and vocalists but not so good for monster cathedral organs and large orchestras.

Good to hear your perspective, Vinylly.

Lots of people report loss of dynamics with passives. In my own case I don't, however I suppose this has a lot to do with the up and downstream impedances. I guess the gods favor me.

Unity gain buffers, usually downstream of the passive, are used by some people to remedy the problem. I looked seriously at building a Nelson Pass B1 zero-feedback buffer, (see HERE), but then I figured if it ain't broke don't fix it.

[jrhymeammo]

Good to hear your perspective, Vinylly.
I looked seriously at building a Nelson Pass B1 zero-feedback buffer, (see HERE), but then I figured if it ain't broke don't fix it.

Some people swear by it, Bill. You might want to consider building one with an economical Solen caps. If you can always get a bit greedy by getting more expensive Clarity Caps or some others. There is a local guy who has one, but I haven't had time to go for an audition. I'll let you know when I get to hear it.

[Feanor]

Some people swear by it [Nelson Pass B1 buffer], Bill. You might want to consider building one with an economical Solen caps. If you can always get a bit greedy by getting more expensive Clarity Caps or some others. There is a local guy who has one, but I haven't had time to go for an audition. I'll let you know when I get to hear it.

Pass sells the circuit board and matched transistors for a very reasonable price. The build is quite simple too. It would be quite feasible to put a B1 downstream of my Jolida passive. So it just might happen.

[phileserver39]

Howdy Bill,

For what it's worth I am absolutely LOVING my Luminous Audio Passive Preamp. Yeah, I have come to loath most of my mp3 collection but that is a small price to pay for transparency.

A+++ Also, pay the extra $20 for the upgrade.

I just realized how much of a tool I sound like. I swear to Buddha that I am not trying to promote anything out of my own experience!!

Best,

Jason

[the hand of boredom]

Bill, how would you compare the sound of the passive to that of the SF? One thing you miss from have the tube pre in there is the ability to tweak the tone by tube rolling. I know you had the Amperex (6922?) in. Have you ever had other tubes in there? Can't remember.

[Feanor]

Bill, how would you compare the sound of the passive to that of the SF? One thing you miss from have the tube pre in there is the ability to tweak the tone by tube rolling. I know you had the Amperex (6922?) in. Have you ever had other tubes in there? Can't remember.

Yes, I've had a fair number of other tubes in the Sonic Frontiers. In fact very recently a pair of Siemens 6922 in the gain stage; as for previous trials, these tube are a bit bright and harsh compared to the Amperex PQ 6922.

The Sonic Frontiers is a quite neutral sounding for a tube preamp; (in fact it's been criticized on that account). However I did hear one attribute attributed to tubes, at least when using the Amperex. And that is a sense of depth or ambience not there with the ALPS potentiometers in the passives. Is the ALPS taking something away or are the tubes adding something?

Other solid state preamps, like the passives, have not had this abience effect. So my unproven surmise is that the tubes are adding something, and bear in mind that the only thing you can add is distortion.

BTW, the Sonic Frontiers, like a number of high-end preamps, uses a CS3110 chip for volume control. This chip uses resistor arrays to control volume which presumably good, sort of like a DACT attenuator; however also includes opamps. So at least in principle the CS3110 could be the culprit rather than the tubes -- I doubt that however.

[Feanor]

Howdy Bill,

For what it's worth I am absolutely LOVING my Luminous Audio Passive Preamp. Yeah, I have come to loath most of my mp3 collection but that is a small price to pay for transparency.

A+++ Also, pay the extra $20 for the upgrade.

I just realized how much of a tool I sound like. I swear to Buddha that I am not trying to promote anything out of my own experience!!

Best,

Jason

Great, Jason, another endorsement for passive.