Passive Pre-Amp causes huge power loss?

Dominick22 · 28th September 2006, 01:09 AM

I built a passive preamp for my old tube amp using only the proper connectors and a pot. The problem is that I lose over half of the volume even when fully torqued?

I did connect all of the grounds together at the pot ground...Is this wrong? The grounding was my only confusion...but it plays?

Thanks,
Dominick

Enzo · 28th September 2006, 01:27 AM

What value is the pot? Is it wired right to a grid?

I doubt the grounding is an issue, you are loading the signal down.

Dominick22 · 28th September 2006, 01:29 AM

Grid?

It isnt wired to anything. I tried both a 100k pot and a 10k pot.
Same results.

Also, as I turn the pot, the volume goes up and then back down as I continue turning.

Dominick

Original Burnedfingers · 28th September 2006, 01:58 AM

Please include your schematic.

Dominick22 · 28th September 2006, 02:30 AM

Here is a rough sketch!

Dominick

aerius · 28th September 2006, 02:38 AM

Quote:

Originally posted by Dominick22
Also, as I turn the pot, the volume goes up and then back down as I continue turning.

Dominick

That's odd...is it possible you got a balance pot by accident instead of an audio taper pot? If the volume starts going back down once you hit the halfway point on the pot's rotation, chances are you got a balance pot.

Peter Daniel · 28th September 2006, 02:40 AM

Your connection is not correct, the center pin should be out, not ground.

Tuukka · 28th September 2006, 02:52 AM

try this

Dominick22 · 28th September 2006, 03:02 AM

Peter and Tuukka,

LOL,
Sometimes I overlook the smallest things and stump myself. Problem fixed. Thanks so much...Now I can tone it down for the neighbors!

Dominick

Original Burnedfingers · 28th September 2006, 11:34 AM

As stated above.. when looking at the back of any pot the ground is on the left, out the center, and input on the right.

That is when you face the tabs up.

28th September 2006, 01:09 AM	#1
Dominick22 diyAudio Member Join Date: Aug 2005	Passive Pre-Amp causes huge power loss? I built a passive preamp for my old tube amp using only the proper connectors and a pot. The problem is that I lose over half of the volume even when fully torqued? I did connect all of the grounds together at the pot ground...Is this wrong? The grounding was my only confusion...but it plays? Thanks, Dominick __________________ A real amateur enthusiast!

28th September 2006, 01:29 AM	#3
Dominick22 diyAudio Member Join Date: Aug 2005	Grid? It isnt wired to anything. I tried both a 100k pot and a 10k pot. Same results. Also, as I turn the pot, the volume goes up and then back down as I continue turning. Dominick __________________ A real amateur enthusiast!

28th September 2006, 02:30 AM	#5
Dominick22 diyAudio Member Join Date: Aug 2005	Here is a rough sketch! Dominick __________________ A real amateur enthusiast!

28th September 2006, 02:40 AM	#7
Peter Daniel diyAudio Member Join Date: Jul 2002 Location: Toronto, Canada	Your connection is not correct, the center pin should be out, not ground. __________________ www.audiosector.com “Do something really well. See how much time it takes. It might be a product, a work of art, who knows? Then give it away cheaply, just because you feel that it should not cost so much, even if it took a lot of time and expensive materials to make it.” - JC

28th September 2006, 03:02 AM	#9
Dominick22 diyAudio Member Join Date: Aug 2005	Peter and Tuukka, LOL, Sometimes I overlook the smallest things and stump myself. Problem fixed. Thanks so much...Now I can tone it down for the neighbors! Dominick __________________ A real amateur enthusiast!

28th September 2006, 01:27 AM	#2
Enzo diyAudio Member Join Date: Sep 2004 Location: Lansing, Michigan	What value is the pot? Is it wired right to a grid? I doubt the grounding is an issue, you are loading the signal down.

28th September 2006, 01:58 AM	#4
Original Burnedfingers diyAudio Member Join Date: Nov 2002	Please include your schematic.

28th September 2006, 11:34 AM	#10
Original Burnedfingers diyAudio Member Join Date: Nov 2002	As stated above.. when looking at the back of any pot the ground is on the left, out the center, and input on the right. That is when you face the tabs up.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
HELP! my amps loss power	rrlax24	Subwoofers	1	8th November 2006 09:02 AM
Extremely low power and low loss transformers	percy	Tubes / Valves	12	23rd February 2005 11:30 AM
dB loss by using passive crossovers? Active vs Passive and 1st vs 4th order	Hybrid fourdoor	Multi-Way	3	11th July 2004 10:16 PM
SPL loss with passive XOs	Rocky	Multi-Way	2	15th June 2004 02:53 PM
Good price on huge power transformer for power amp.	G	Solid State	3	15th September 2002 02:23 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read