Preamplifier with LDR volume & remote?

Discussion in 'The Cutting Edge' started by Obankenobi, May 4, 2013.

  1. Obankenobi

    Obankenobi Hypnotoaded

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    Brainstorming here, trying to work out a vision of my next system: I'm all solid state now, but am thinking that a pair of tube monoblock amps could be a very cool thing. One thing holding me back - I'd like a preamp as "pure" as the amps - simple but high quality circuitry. Since I like to fine tune sound from the couch as I rock out, a remote volume control is a necessity. The $64K question - does anybody make a preamp, or kit, with an LDR volume control and remote control? Thanks in advance for any leads
     
  2. tomlinmgt

    tomlinmgt Lunatic Member

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    What's "LDR"?
     
  3. Dingman

    Dingman Do you know where your towel is? Subscriber

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    I didn't know either - googled it - it's Light Dependent Resistor.

    LOL, so then, aren't LDR and "remote volume" synonymous?

    I must be missing something here.

    But I'm also interested in the OP's question. I've also been watching for a nice simple preamp simply for having a couple of inputs and Remote.
     
  4. SuperjazzyJa

    SuperjazzyJa 18 Wheel Member Subscriber

    A very popular combo among high end owners is a tube preamp with ss power amp, MOSFET in particular. There seems to be great synergy and SS friendly speakers are easier find than tube friendly speakers are. One possible route you could explore. :yes:
     
  5. Mr. Lin

    Mr. Lin Lunatic Member

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    It's Light Dependent Resistor like Dingman already said. Apparently popular in the DIY scene right now.

    For the OP, here's a review of a new passive preamp with LDR volume control and remote:

    http://www.6moons.com/audioreviews/tortuga/1.html
     
  6. 240sx4u

    240sx4u Lunatic Member

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    Lightspeed attenuator. and FWIW, it isn't a unanimously thought that they are the best. I wouldn't hesitate to use a high end SS Preamp behind tube amps. Been there done that. My system sounds better with an active preamp.
     
  7. Ed Schilling

    Ed Schilling New Member

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    An LDR is a "light dependent resistor" a 2 legged device and exactly what the name implies. While many call "optocouplers" an "LDR" that is not exactly right. An optocoupler is an LDR in the same package with an LED. It is a 4 legged device. It seems even people building things with optocouplers like to call them "LDRs" as if the terms were interchangeable.

    Ed
     
    Last edited by a moderator: May 6, 2013
  8. Ed Schilling

    Ed Schilling New Member

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    A little more.........
    edit**** Many think that the reason their system sounds better with an active pre amp is because of the gain. This is almost always wrong. The system probably does sound better than most passive preamps but it is the buffering offered by the active preamp, it is almost never because of the gain since 99% of the time every preamp in a good matched system will be used as an attenuator and will seldom if ever be required to make gain. This is fairly easy to demonstrate.....if you think you need gain then just be brave and plug your cd player directly into your power amp and hit "play" and if you require gain it won't be "too loud". You'll probably find that not to be a good idea and may break your speakers! Again, it's not the gain, it's the buffering that makes most active preamps work better for many folks. And in most cases it's the quality of the volume pot. or attenuator that will determine the ultimate quality of the preamp in many cases, it's the weak link.

    Some call passive pre amps passive because they have no gain and no active circuitry. Others refer to any "pre amp" with no gain as "passive" even though they may have active circuitry. The device I build is "active with no gain" and it suffers none of the problems of a passive design.
    Ed
     
  9. Mr. Lin

    Mr. Lin Lunatic Member

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    I have to assume this is what happened about a year and a half ago when I built a DIY preamp and first put it between my CD player and headphone amp. The improvement in the overall sound was dramatic, which seemed counter-intuitive to me at the time.
     
  10. Ed Schilling

    Ed Schilling New Member

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    Thanks Mr. Lin for the edit and not delete! I can get carried away sometimes!
    And yes, it is very likely that is what happened. Happens all the time and the folks never seem to get why, they just say "my active pre amp has better dynamics" and they are probably right but not for the reasons they think and even worse is that there is no "rule" that makes that true in every case.

    A true passive pre amp can work just fine in a well matched system with short cables but a passive (no gain) with active buffers will be as good or better than a true active. If it has a better volume control, it will be better in a well matched system, meaning one that does not require gain!
    Ed
    ps.....I just call a passive volume control (with or without buffers) a "pre amp" but I think in order for that term to be accurate the device should have gain but saying "passive volume control with active buffers" is such a chore!
     
    loonze likes this.
  11. Mr. Lin

    Mr. Lin Lunatic Member

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    No problem and no worries! I appreciate the technical info and I know I'm not the only one.
     
  12. KentTeffeteller

    KentTeffeteller Gimpus Stereophilus!

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    An LDR based volume control would be easily over $200 each in 15 year old prices.
     
  13. Rockyhill

    Rockyhill "I rarely rip CDs but when I do, I rip to FLAC" Subscriber

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  14. stereocoffee

    stereocoffee New Member

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    With LDR's they should be provided DC from a circuit that monitors current, usually called a Vref/r circuit, there are many circuits however that provide a fixed voltage and a high ohm pot which ends up starving the LDR of current. There are very good ways of doing LDR's and not so good.
     
  15. richamor

    richamor Blue Collar Subscriber

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    Tortuga Audio. I love mine and it uses the Apple remote. Not cheap, but the kits aren't too bad.
     
  16. loonze

    loonze AK Subscriber Subscriber

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    I have been using a clone note 2 ldr passive with battery power...it is phenomenal.
     

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