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Home Theater => Audio => Tubes => Topic started by: TOP 20 on Aug 10, 2012 at 05:36 AM

Title: DIY Passive Preamplifier
Post by: TOP 20 on Aug 10, 2012 at 05:36 AM
Thinking of assembling a passive preamp but has zero DIY skills. Do you know a specialty shop or somebody doing this? Any idea how much it would cost?

Here's a pic of what I have in mind:

(http://www.diyhifisupply.com/files/pictures/DoItBoxInside.jpg)

Thanks!
Title: Re: DIY Passive Preamplifier
Post by: ATJr. on Aug 10, 2012 at 05:44 AM
you can purchase the kit here: http://www.diyhifisupply.com/node/196
Title: Re: DIY Passive Preamplifier
Post by: TOP 20 on Aug 10, 2012 at 05:46 AM
you can purchase the kit here: http://www.diyhifisupply.com/node/196

How about locally sir Tony?
Title: Re: DIY Passive Preamplifier
Post by: ATJr. on Aug 10, 2012 at 06:13 AM
no chance, if ever parts will be imported anyway...
Title: Re: DIY Passive Preamplifier
Post by: TOP 20 on Aug 10, 2012 at 06:16 AM
no chance, if ever parts will be imported anyway...

Thanks sir Tony.
Title: Re: DIY Passive Preamplifier
Post by: odyopayl on Aug 10, 2012 at 07:30 PM
From the picture itself, this seems passive attenuator with input selector? I'm not sure if this is Passive Pre-amplifier. But it uses DACT product

Maybe this is the real passive amp:
(http://i6.photobucket.com/albums/y224/Odyopayl/TransSTA522-1.jpg)
Title: Re: DIY Passive Preamplifier
Post by: ATJr. on Aug 10, 2012 at 08:13 PM
that's a TVC also a passive preamp....
Title: Re: DIY Passive Preamplifier
Post by: markcrenz on Aug 10, 2012 at 08:29 PM
just thinking out loud... isn't it wrong to call it a passive preamp? technically there's no preamplification, just attenuation. sabagay masyadong mahaba yung passive attenuator with input selector.  ;D
Title: Re: DIY Passive Preamplifier
Post by: markcrenz on Aug 10, 2012 at 08:31 PM
no chance, if ever parts will be imported anyway...
talaga bang there are no good pots and selector switches available locally?
Title: Re: DIY Passive Preamplifier
Post by: ATJr. on Aug 10, 2012 at 08:37 PM
walang locally available na quality parts........ you have to order them on-line like greyhill rotary switches and peny and guiles conductive plastic pots........
Title: Re: DIY Passive Preamplifier
Post by: ATJr. on Aug 10, 2012 at 08:38 PM
just thinking out loud... isn't it wrong to call it a passive preamp? technically there's no preamplification, just attenuation. sabagay masyadong mahaba yung passive attenuator with input selector.  ;D

to me these are passive since there are no active devices used in the signal path, meaning no tubes, no ss parts....
Title: Re: DIY Passive Preamplifier
Post by: JojoD818 on Aug 10, 2012 at 08:46 PM
just thinking out loud... isn't it wrong to call it a passive preamp? technically there's no preamplification, just attenuation. sabagay masyadong mahaba yung passive attenuator with input selector.  ;D


parang ganito lang brad...

Partially Reusable Launch System and Orbital Spacecraft = Space Shuttle for short.  :D
Title: Re: DIY Passive Preamplifier
Post by: markcrenz on Aug 10, 2012 at 08:57 PM
sabagay yung hotdog walang dog.  ;D
Title: Re: DIY Passive Preamplifier
Post by: TOP 20 on Aug 10, 2012 at 09:56 PM
talaga bang there are no good pots and selector switches available locally?

Sayang nga eh. Sabi ng kumpare ko he can do something like this but he's not sure if he can get the best parts possible here.
Title: Re: DIY Passive Preamplifier
Post by: ndotcom on Aug 11, 2012 at 06:15 AM
I have one like this but used resistors from alexan, selector/switches from ebay. You can look online for small items may mga free shipping via post office nila padala....
Title: Re: DIY Passive Preamplifier
Post by: odyopayl on Aug 11, 2012 at 06:18 PM
just thinking out loud... isn't it wrong to call it a passive preamp? technically there's no preamplification, just attenuation. sabagay masyadong mahaba yung passive attenuator with input selector.  ;D
TVC seems have gain....
this one is very expensive passive preamp:

(http://i6.photobucket.com/albums/y224/Odyopayl/PassivePre-amp.jpg)
(http://www.audio-zone.ca/assets/Pre-T1.jpg)
Title: Re: DIY Passive Preamplifier
Post by: rascal101 on Sep 15, 2012 at 08:49 PM
Nice TVC.

Thinking of assembling a passive preamp but has zero DIY skills. Do you know a specialty shop or somebody doing this? Any idea how much it would cost?

Here's a pic of what I have in mind:

(http://www.diyhifisupply.com/files/pictures/DoItBoxInside.jpg)

Thanks!

You can contact Mang Rod Teope for your project. I think his number is 5221696. I believe he can source the resistors as well.
Title: Re: DIY Passive Preamplifier
Post by: ATJr. on Sep 16, 2012 at 07:13 AM
TVC seems have gain....
this one is very expensive passive preamp:

(http://i6.photobucket.com/albums/y224/Odyopayl/PassivePre-amp.jpg)
(http://www.audio-zone.ca/assets/Pre-T1.jpg)


if by gain you mean positive gains then yes, it is possible for TVC's to have gains.....isolation types with a 1:1.4 turns ratio for example.....

auto transformer type TVC's otoh have negative gains.....
Title: Re: DIY Passive Preamplifier
Post by: docrob on Oct 18, 2012 at 07:17 AM
ganda nga rin ng passive preamp, pure signal from the source to the power amp then to the driver/s

wanted also to try one kaso wala ata available locally unless custom made

and dami variables dapat match sa system yung specs ng preamp
Title: Re: DIY Passive Preamplifier
Post by: ATJr. on Oct 18, 2012 at 08:13 AM
glorified volume control....;D
Title: Re: DIY Passive Preamplifier
Post by: docrob on Oct 18, 2012 at 05:44 PM
haha onga po sir Tony  :D

ang mahal sa ebay ng mga passive preamps kapresyo na rin ng active ones kaya mapapaisip ka rin kung willing to pay for it kasi napakasimple lang

sana me ma audition dito
Title: Re: DIY Passive Preamplifier
Post by: ATJr. on Oct 18, 2012 at 06:35 PM
naka lineup sa gagawin ko in 2013...tvc...
Title: Re: DIY Passive Preamplifier
Post by: docrob on Oct 18, 2012 at 09:07 PM
uy, something to look forward to next year

nice!
Title: Re: DIY Passive Preamplifier
Post by: JoeyGS on Oct 19, 2012 at 07:53 AM
If this is a TVC passive preamp, why does it have a grounding lug?

From the picture itself, this seems passive attenuator with input selector? I'm not sure if this is Passive Pre-amplifier. But it uses DACT product

Maybe this is the real passive amp:
(http://i6.photobucket.com/albums/y224/Odyopayl/TransSTA522-1.jpg)
Title: Re: DIY Passive Preamplifier
Post by: ATJr. on Oct 19, 2012 at 11:54 AM
If this is a TVC passive preamp, why does it have a grounding lug?


why not?