Author Topic: passive pre's  (Read 5329 times)

shep

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passive pre's
« on: February 13, 2007, 11:23:20 AM »
As a long time user/believer in these, I want some experience/feedback from other users. My homemade pair got too many bad repair jobs from yours-truly and they're shot. I'm facinated by the hair-shirt approach (though my knees are not), the ultimate expression being the Endlers and the "ultimates" from tweak.com. The reason being that they do away with the interconnect story altogether. They bring another problem, namely that they will not fit on the back of many amps due to spacing issues. That said, my new amp could have holes drilled out and new rca's put in that would accept these passives. I am fairly conversant with the issues, the pros and cons and am in the pro camp obviously. If anyof you have hands-onexperience of these two mentioned or similar ones that I don't know of, I would be gratefull to hear about same.

mgalusha

  • Guest
passive pre's
« Reply #1 on: February 13, 2007, 04:39:43 PM »
I've built several, one just using simple pots and a second using a GoldPoint stepped attenuator.

I liked the results quite a bit at the time but for some reason I went back to a vacuum tube line stage. Sadly I can't remember exactly why as it's been a few years. I *think* it was because of reduced dynamics when I changed amps as the newer amps had a much lower Zin that the old ones and were not a good match for the passive pre.

Interestingly enough I was offered a TVC in trade today for a pair of Greg Ball's GB-300D amp modules. I've agreed and hopefully will be receiving that in the near future. It will in interesting to see how it works in the system once I repair it.

mike

WEEZ

  • Guest
passive pre's
« Reply #2 on: February 13, 2007, 05:21:35 PM »
shep,

what is it you like about passives? do you have a high current source..and a high gain amplifier? curious..

shep

  • Guest
passive pre's
« Reply #3 on: February 14, 2007, 12:21:46 AM »
Nothing so thought-out! The answer is: Simplicity, Reliability, Transparency, Economy. The last should be first. I don't mind the trade off
of dynamics against a see-thru, straight-wire approach. Maybe I've been lucky or just ignorant but I've never heard a down-side and I'm an old school, one source, keep it rudimentary approach... I get addled if there are two many buttons and switches. Seriously though, anything that removes the cable variable has got to be better. If I would decently solder everything together in one chain I would, but it makes up-grading a royal pain in the ass.

WEEZ

  • Guest
passive pre's
« Reply #4 on: February 14, 2007, 08:43:31 AM »

gonefishin

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passive pre's
« Reply #5 on: February 20, 2007, 12:42:32 PM »
Hi mgalusha,

   Did you get the TVC yet?

   Which one are you getting?  I had the S&B and was pleased with it's performance...but have since sold it some time ago to buy my deqx-p.  I've also got a sowter but haven't had th time to throw it together.  

   Were you happy with the GB-300D or 150 amplifiers?  

  take care,
  dan

mgalusha

  • Guest
passive pre's
« Reply #6 on: February 21, 2007, 08:03:47 PM »
Hi Dan,

No I didn't get it. I was going to trade a fellow my pair of GB-300 modules for it but he's decided to wait a while until he has some additional funds for chassis. I don't know which one it was, we didn't get that far. :)

I was never completely happy with the GB-300 modules. I don't think the power supplies were good enough. Part of their appeal was that they were not very sensitive to the power supply. I was going to build new supplies for them but one of the modules failed when I clipped the amp on the test bench and I didn't like them well enough to fix it.

Mike

gonefishin

  • Guest
passive pre's
« Reply #7 on: February 22, 2007, 02:52:24 PM »
Do you still have the modules?  Are they repaired and working?


   hmmmm :idea:


  thanks,
  dan

mgalusha

  • Guest
passive pre's
« Reply #8 on: February 23, 2007, 04:38:48 PM »
Hi Dan,

I have them and I didn't bother to repair the dead one. I told the person who was interested that I'd hold onto to them for a while as I wasn't looking to sell them. If he changes his mind I let you know.

mike

Offline Mike B.

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passive pre's
« Reply #9 on: March 27, 2007, 05:44:17 PM »
I recently built a passive I really like. It is a bit more complicated than just a attenuator, but a very good pre IMO. It is called a Lightspeed and uses LDR opti couplers. A 100K volume control is used but it just varies the current from a 5 volt DC power source to the LED section of the LDR. If you want more info, there is a multi page thread at DIY Audio.com at the solid state forum.
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