Passive Preamps

Wheel-right

Chief Journeyman
Joined
Jun 24, 2019
Messages
781
Location
SoCal
Tagline
Man, Ya shoulda been here yesterday
#1
Anyone use or have opinions about passive preamps? Trying to learn about them. Thank you.
 

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
11,223
Location
Minnie-Soda
Tagline
Screw it
#2
I'd be worried about getting enough pre out to fully drive the amp (when needed), that is, getting full line level to the amp. Might not be an issue though.
 

Wheel-right

Chief Journeyman
Joined
Jun 24, 2019
Messages
781
Location
SoCal
Tagline
Man, Ya shoulda been here yesterday
#3
I'd be worried about getting enough pre out to fully drive the amp (when needed), that is, getting full line level to the amp. Might not be an issue though.
Thank you, something to look into deeper maybe? This site is the greatest thanks to all the help.
 

Gepetto

Administrator
Staff member
Joined
May 15, 2011
Messages
13,473
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#4
Do you have any examples you are interested in so we can look them up and perhaps provide opinions?
 

Wheel-right

Chief Journeyman
Joined
Jun 24, 2019
Messages
781
Location
SoCal
Tagline
Man, Ya shoulda been here yesterday
#5
Do you have any examples you are interested in so we can look them up and perhaps provide opinions?
This is the one that got me started and wondering about them https://www.ebay.com/itm/Vintage-Purset-Sound-System-PSS-by-David-Hum-Passive-Preamp-Out/312796748958?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649. Also https://www.bellariaudio.com/index.php/products/pp532-passive-preamplifier/. I'm just always trying to learn about other options. Thinking that the clearer and cleaner the signal that's sent to the power amp, the better.Thank you.
 
Last edited:

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
11,223
Location
Minnie-Soda
Tagline
Screw it
#8
from what I have been reading, getting a unit with impedance matching circuitry is important for the sound. Now, finding the right Passive Preamp to set right with your system sounds to be a pain in the ass and maybe expensive too. What sounds good on yours, may not cut it on mine but aint that the way Actives work too??? We'll have to wait for the smart guys to chime in. I'm way happy with the state of sound with my pre so....
 

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
11,223
Location
Minnie-Soda
Tagline
Screw it
#9
Oh, and forget about the dude designing and building their own Passives.... They will think their's sounds 10 times better than an active and with the sound of an audio system being subjective and inversely proportional to your hearing loss...... HUH???
 

Wheel-right

Chief Journeyman
Joined
Jun 24, 2019
Messages
781
Location
SoCal
Tagline
Man, Ya shoulda been here yesterday
#10
from what I have been reading, getting a unit with impedance matching circuitry is important for the sound. Now, finding the right Passive Preamp to set right with your system sounds to be a pain in the ass and maybe expensive too. What sounds good on yours, may not cut it on mine but aint that the way Actives work too??? We'll have to wait for the smart guys to chime in. I'm way happy with the state of sound with my pre so....
Me too, but it might be an interesting thing to play with.
 

Gepetto

Administrator
Staff member
Joined
May 15, 2011
Messages
13,473
Location
Sterling, MA
Tagline
Old 'Arn Enthusiast
#11
If all your sources are very high level, then you can probably get away with a passive pre. The power amp you feed with this typically has ~47K input impedance. Not sure what resistance pot they use in these but unless very low in value will interact with the input impedance of the power amp.

Typical active preamps deliver a very low output impedance to be able to drive just about any power amp.

Yes Fred, Hum is a bad name for anything audio.
 

Wheel-right

Chief Journeyman
Joined
Jun 24, 2019
Messages
781
Location
SoCal
Tagline
Man, Ya shoulda been here yesterday
#12
Oh, and forget about the dude designing and building their own Passives.... They will think their's sounds 10 times better than an active and with the sound of an audio system being subjective and inversely proportional to your hearing loss...... HUH???
Yep, I "hear" that one.
 

mlucitt

Veteran and General Yakker
Joined
Jun 24, 2011
Messages
3,339
Location
Jacksonville, FL
#13
Unless I am missing something, a "passive preamplifier" is an oxymoron. There is no amplification, pre, or otherwise. These units are switch boxes with volume controls. I think it would be better to add a volume control to your amplifier similar to the way Phase Linear did on the 700B model.
For switching, you could pull on the pair of RCA cables and plug them into something else.
They used to have these in stereo stores, they were called "Selector Panels" for auditioning the various stereo units or speakers.
 

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
11,223
Location
Minnie-Soda
Tagline
Screw it
#14
Well, I know this much.... I use my Ipod straight into my WOPLs when doing initial testing on the bench and it sounds like crap without a pre......
 

Lazarus Short

Veteran and General Yakker
Joined
Mar 10, 2012
Messages
14,293
Location
Independence, MO
Tagline
I'm the Red Knight, by grant of the Black
#17
I have a Superphon SP100 - it's a buffered passive preamp, so it does have a power cord. I traded a VERY good Yamaha integrated amp for it, and am currently using it between my Bluray player and my power amp. It is simply because the TV's internal speakers are going bad, and yeah, I want that BASS! My main system uses a tubed, one-input, one-output, no tine controls preamp, powered by eight "C" cells. It's very quiet. I like it better in some way than the passive.
 

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
11,223
Location
Minnie-Soda
Tagline
Screw it
#18
I have a Superphon SP100 - it's a buffered passive preamp, so it does have a power cord. I traded a VERY good Yamaha integrated amp for it, and am currently using it between my Bluray player and my power amp. It is simply because the TV's internal speakers are going bad, and yeah, I want that BASS! My main system uses a tubed, one-input, one-output, no tine controls preamp, powered by eight "C" cells. It's very quiet. I like it better in some way than the passive.
Laz, "Tine Control"???
 

WOPL Sniffer

Veteran and General Yakker
Joined
Aug 10, 2015
Messages
11,223
Location
Minnie-Soda
Tagline
Screw it
#19
after reading that several times, I assume you mean no Tone Control???

I'll skip the battery powered stuff though (except for vibrators).... They should not plug into the wall. You could trip and hurt yourself.

HUH?
 

Lazarus Short

Veteran and General Yakker
Joined
Mar 10, 2012
Messages
14,293
Location
Independence, MO
Tagline
I'm the Red Knight, by grant of the Black
#20
Yes, tone control. As you get older, it's the vowels that get confused first...

I tried the stock wallwart: HUM. I tried every other wallwart that I could use on the preamp: HUM. Then I went to batteries.
 
Top