General Asylum

General audio topics that don't fit into specific categories.

Return to General Asylum

Message Sort: Post Order or Asylum Reverse Threaded

Dynaco pas3 with treble and bass

81.132.176.115
Posted on September 23, 2014 at 05:03:56
Netsuke Chip
Audiophile

Posts: 15
Joined: September 20, 2014
 So I have been guided toward a Dynaco pas3 as a good pre-amp which has a public domain schemetic. This machine has a treble and bass, I have been lead to belive the beter pre amps don't need these controls Any advice either a better pre amp to build or not to worry over extra controls.

 

Hide full thread outline!
    ...
How handy are you with a soldering iron?, posted on September 23, 2014 at 05:42:56
olddude55
 There are multiple kits available for the PAS, will let you bypass the tone controls if that's your wish. If you know how to solder, can use a volt-ohm meter, and can build a model car or model airplane, you can bypass the tone controls on your own.
I had a modified PAS back in the 1970's. The tone controls were bypassed and the power supply upgraded. Results were excellent, if I had known that tubes would be easier to find in 2014 than they were in 1980, I'd have kept the pre-amp.

 

RE: How handy are you with a soldering iron?, posted on September 23, 2014 at 06:11:12
Netsuke Chip
Audiophile

Posts: 15
Joined: September 20, 2014
 Fairly new to using a soldering iron but no stranger either! That thought had occurred to me, however, is it a better product for it?

 

Hmmm...., posted on September 23, 2014 at 06:41:22
olddude55
 I had my PAS modified by a local stereo shop--this was in 1976--and more was done to it than just the tone control bypass. It did sound much better after the mods but how much of it was due to better tubes and improved PS, how much was due to the tone control bypass I couldn't say.
If I were doing all that today, I'd do it in stages and also do it myself. Or not at all, since these days I tend to view most tweaks and upgrades with skepticism.
Take a look at the Dynaco Doctor forum, some of the other Dynaco forums. There's a wealth of info out there. You might want to keep your PAS stock, just replace anything defective and put good tubes in it.

 

"keep your PAS stock, just replace anything defective and put good tubes in it.", posted on September 23, 2014 at 07:13:38
Chip647
Audiophile

Posts: 2645
Location: The South
Joined: December 24, 2012
 Absolutely.

If you just want a buffered attenuator, lots of choices without destroying what is now vintage.

 

RE: Dynaco pas3 with treble and bass, posted on September 23, 2014 at 11:50:33
Palustris
Audiophile

Posts: 2408
Location: Cape Cod
Joined: September 12, 2008
 Why not start with the basics? What do you need in a preamp? You have 2 VRMS coming from you CD player or phono stage. What is the input sensitivity of your amp? Start there. If the input sesitivity (the voltage input for full output of the amp) is 1V or less you need to figure out why you need a preamp and not just a volume control on the amp.

 

RE: Dynaco pas3 with treble and bass, posted on September 23, 2014 at 12:06:20
bertdw
Audiophile

Posts: 81
Location: Philadelphia, PA
Joined: January 20, 2011
 Audio Research Corporation has published many of their schematics over the years. Google "Audio Research Schematic" and you'll find some interesting alternatives to the Dynaco, like the ARC SP3A, which I first saw years ago in Audio Amateur magazine.

 

You bet., posted on September 23, 2014 at 16:38:13
olddude55
 All the switches and controls can be replaced if worn out.
Unlike 1976, when I had my PAS, plenty of good tubes available online. I was stuck with a local supplier who had GE only.

 

RE: Dynaco pas3 with treble and bass, posted on September 23, 2014 at 20:32:12
hahax@verizon.net
Audiophile

Posts: 4305
Location: New Jersey
Joined: March 22, 2006
 If it's the later PAS3X, the tone controls are supposed to be out of the circuit in the neutral position.

 

If you get into mods, some simple suggestions, posted on September 25, 2014 at 09:36:34
Ralph
Manufacturer

Posts: 4769
Location: Minnesota
Joined: April 24, 2002
 As one who has done many mods on Dyna equipment over the years, if you get into this, make sure that whatever you do fits into the same box with no need for anything external and without crowding the box.

If you follow this simple rule you will avoid a lot of headaches.

If you think you need more room, get your own chassis and build up your preamp from scratch!

IME you don't even need new circuit boards in order to build a circuit in the PAS-3 that will challenge many high end preamps, some that cost in excess of $10,000 (with the exception of low output moving coil capability). Some tips:

Replace all the filter capacitors, and the selenium rectifier. The power transformer has limited capacity- honor that! Don't physically remove the tone controls even though they may be no longer hooked up. Do not do anything that requires modification of the top cover, chassis or front panel- you can do excellent work without any of that. A possible exception might be a new power cord.

Finally: Do. Neat. Work. Don't make a rat's nest out of it, even if it was a rat's nest to begin with. Have fun!

 

Page processed in 0.024 seconds.

[ Top Top of Page ] [ Contact Us ] [ Support/Wish List ] [ Copyright © 2024, Audio Asylum, all rights reserved ]
[ General ] [ Speakers ] [ Tubes ] [ Vinyl ] [ Digital ] [ Hi-Rez ] [ Video Asylum ] [ Cables ] [ Tweaks/DIY ] [ Music ] [ Films ]