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RE: [dallasaudioclub] Finished : Heath W3M

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  • Dennis Boyle
    Jim, The Williamson Mods took place a long time ago. They turned Altec 1569 Amplifiers with the 4 EL-34s connected as triodes into wonderful amps that blew
    Message 1 of 5 , Apr 14, 2006
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      Jim,

       

      The Williamson Mods took place a long time ago. They turned Altec 1569 Amplifiers with the 4 EL-34s connected as triodes into wonderful amps that blew away all the expensive Audio Research and CJ tube amps.

       

      I might not have mentioned it in the ‘mod”. But, if you beefed up the capacitance in the power supplies, replace the feedback resistor with pot hooked up as a variable resistor with at least 4 times, or more, the value of the resistor.  Stick the amps (after break in) in your system and reduce the feedback by increasing the resistor value. Once you hit that magic spot, replace the pot with a high quality resistor. The original feedback resistor value was selected to provide stability and low distortion with the original  limp power supply.

       

      If you replace all the dropping resistors in your power supplies with chokes that have the same DCR (you can’t have too high an inductance). This isolates the stages so well you might be able to get away with no negative feedback at all. A local Transformer manufacturer will usually wind them for under $50.00. All he needs to know is the current (measure it at idle and increase by 2) and the DCR. You can buy off the shelf or surplus and install it in series with a resistor to get the right voltage, But you will quickly hear that resistors in a power supply don’t sound anywhere near as good as chokes.

       

      There’s a designer I know that is about to release a Modified Williamson circuit with four 6550 tubes per amp, all chokes in the power supply and hand wound air chokes instead of grid stopper resistors (another device that traps the Music). He is getting very wide bandwidth and low distortion with only 2.5dB of negative feedback. Of course he plans to market them as a revolutionary design and sell these monoblocks for over $10,000……Welcome to the World of High End Audio.

       

      Take Care,            

       

      Dennis Boyle

      Chimera Laboratories

      Website: http://www.chimeralabs.com/

      Website: http://home.att.net/~chimeraone/index.html

       

       

      -----Original Message-----
      From: dallasaudioclub@yahoogroups.com [mailto:dallasaudioclub@yahoogroups.com] On Behalf Of Jim
      Sent: Friday, April 14, 2006 4:49 PM
      To: dallasaudioclub@yahoogroups.com
      Subject: [dallasaudioclub] Finished : Heath W3M

       

      Well, I'm on a roll. This is the second pair of amps finished the last six weeks. But not that impressive if you consider I started on both pair over a year ago or maybe more. These have all new and or matched resistors, caps, RCA, etc. Sockets and bias resistors are old stock. I bought new power transformers for long life. The circuit is a modified Williamson pulled pulled from the Chimera Labs website. It addresses the flaws in the original Williamson circuit. All resistors and signal caps were matched to the limits of my DVM. All B+ caps are Nichicon. Sounds pretty good on the work bench.

       

      Ò¿Ò   jim...

       

    • Jim
      Hi Dennis, Thanks for the input. Yep, I ve been reading a lot about chokes on the web. So many projects, so little money and time. Except for maybe one set of
      Message 2 of 5 , Apr 14, 2006
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        Hi Dennis, Thanks for the input. Yep, I've been reading a lot about chokes on the web. So many projects, so little money and time. Except for maybe one set of amps, I don't plan on investing a lot of money rebuilding and selling what's left in the garage. I've re-organized the garage/work bench area and am ready to 'do some damage' this summer! jim...
        --- In dallasaudioclub@yahoogroups.com, "Dennis Boyle" <chimeraone@...> wrote:
        >
        > Jim,
        >
        >
        >
        > The Williamson Mods took place a long time ago. They turned Altec 1569
        > Amplifiers with the 4 EL-34s connected as triodes into wonderful amps that
        > blew away all the expensive Audio Research and CJ tube amps.
        >
        >
        >
        > I might not have mentioned it in the `mod". But, if you beefed up the
        > capacitance in the power supplies, replace the feedback resistor with pot
        > hooked up as a variable resistor with at least 4 times, or more, the value
        > of the resistor. Stick the amps (after break in) in your system and reduce
        > the feedback by increasing the resistor value. Once you hit that magic spot,
        > replace the pot with a high quality resistor. The original feedback resistor
        > value was selected to provide stability and low distortion with the original
        > limp power supply.
        >
        >
        >
        > If you replace all the dropping resistors in your power supplies with chokes
        > that have the same DCR (you can't have too high an inductance). This
        > isolates the stages so well you might be able to get away with no negative
        > feedback at all. A local Transformer manufacturer will usually wind them for
        > under $50.00. All he needs to know is the current (measure it at idle and
        > increase by 2) and the DCR. You can buy off the shelf or surplus and install
        > it in series with a resistor to get the right voltage, But you will quickly
        > hear that resistors in a power supply don't sound anywhere near as good as
        > chokes.
        >
        >
        >
        > There's a designer I know that is about to release a Modified Williamson
        > circuit with four 6550 tubes per amp, all chokes in the power supply and
        > hand wound air chokes instead of grid stopper resistors (another device that
        > traps the Music). He is getting very wide bandwidth and low distortion with
        > only 2.5dB of negative feedback. Of course he plans to market them as a
        > revolutionary design and sell these monoblocks for over $10,000……Welcome to
        > the World of High End Audio.
        >
        >
        >
        > Take Care,
        >
        >
        >
        > Dennis Boyle
        >
        > Chimera Laboratories
        >
        > Website: <http://www.chimeralabs.com/> http://www.chimeralabs.com/
        >
        > Website: <http://home.att.net/~chimeraone/index.html>
        > http://home.att.net/~chimeraone/index.html
        >
        >
        >
        >
        >
        > -----Original Message-----
        > From: dallasaudioclub@yahoogroups.com
        > [mailto:dallasaudioclub@yahoogroups.com] On Behalf Of Jim
        > Sent: Friday, April 14, 2006 4:49 PM
        > To: dallasaudioclub@yahoogroups.com
        > Subject: [dallasaudioclub] Finished : Heath W3M
        >
        >
        >
        > Well, I'm on a roll. This is the second pair of amps finished the last six
        > weeks. But not that impressive if you consider I started on both pair over a
        > year ago or maybe more. These have all new and or matched resistors, caps,
        > RCA, etc. Sockets and bias resistors are old stock. I bought new power
        > transformers for long life. The circuit is a modified Williamson pulled
        > pulled from the Chimera Labs website. It addresses the flaws in the original
        > Williamson circuit. All resistors and signal caps were matched to the limits
        > of my DVM. All B+ caps are Nichicon. Sounds pretty good on the work bench.
        >
        >
        >
        > Ò¿Ò jim...
        >
        >
        >
        > _____
        >
        > YAHOO! GROUPS LINKS
        >
        >
        >
        > * Visit your group "dallasaudioclub
        > <http://groups.yahoo.com/group/dallasaudioclub> " on the web.
        >
        >
        > * To unsubscribe from this group, send an email to:
        > dallasaudioclub-unsubscribe@yahoogroups.com
        > <mailto:dallasaudioclub-unsubscribe@yahoogroups.com?subject=Unsubscribe>
        >
        >
        > * Your use of Yahoo! Groups is subject to the Yahoo!
        > <http://docs.yahoo.com/info/terms/> Terms of Service.
        >
        >
        >
        > _____
        >
      • jlsem@aol.com
        Dennis, Do you still carry these items? SET-300-5.0 - 5000 Ohm Primary - 4/16 Ohm or 2/8 Ohm Output....$385.00/OEM....$481.00/Retail 3.13 /80mm wide X
        Message 3 of 5 , Apr 15, 2006
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          Dennis,
           
          Do you still carry these items? 
           
          SET-300-5.0 - 5000 Ohm Primary - 4/16 Ohm or 2/8 Ohm Output....$385.00/OEM....$481.00/Retail
          3.13"/80mm wide X 3.69"/94mm long X 3.81"/97mm high w/wire leads - 10.28 lbs/ 4.66Kg
          Mounting Hole Dimensions = 2.50"/64mm wide X 2.44"/62mm long (use 10/32 screw)


          INT-1:0.5/0.5 -1:0.5 X 0.5 Ratio,15-30ma, Split output phase splitter..$190.00/OEM...$238.00/Retail
          2.50"/64mm wide X 3.19"/81mm long X 3.06"/78mm high w/wire leads - 6.65 lbs/ 3.02Kg
          Mounting Hole Dimensions = 2.00"/51mm wide X 2.19"/56mm long (use 10/32 screw)"
          Can the IT be used SE:SE?  I need four of each for VT-52 bi-amp project.
           
          Thanks,
          John Semrad
        • Dennis Boyle
          Hi John, Due to high audio cable order levels and Team Axiom Members pushing me to get off my butt and finish the Axiom Amplifier, I have put all my parts
          Message 4 of 5 , Apr 15, 2006
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            Hi John,

             

            Due to high audio cable order levels and Team Axiom Members pushing me to get off my butt and finish the Axiom Amplifier, I have put all my parts sales on hold. Since I am a one person business and plan to stay that way, as much as I would like to support the DIY community, I am not sure when or if I will start offering part again.

             

            The exception will be the iron and parts used in the Axiom Amplifier. You can go to http://www.chimeralabs.com/axiom_full.html click on the schematic.

             

            I also have some power and output transformers for the Ace Amplifier, that I would consider selling. That schematic can be found at http://home.att.net/~chimeraone/allianceaudioproducts.html just click on the Ace link to get to the schematic. I have put the sale of the ACE on hold, since I plan to update it to a “straight wire” direct coupled circuit similar to the Axiom.

             

            The VT-52, in my opinion one of the best sounding DHT tubes, has a plate resistance of 1600 to 1650 Ohms at the commonly used operating points. It has been my experience that you will achieve the best damping factor and lowest distortion if the tube is loaded by a transformers with an impedance 4+ times more than the tube’s Pr. In this case 6400 and higher. Testing the 300B, we found 5K to sound the best, that’s close to 6 times the Pr. I feel loading the output tube with the loads recommended by the tube manufacturer is a compromise since they felt 5% distortion was acceptable. Western Electric, on the other hand, published 2nd and 3rd order THD numbers at the various operating points and loads for their tubes.

             

            Sorry I couldn’t be more helpful,         

               

            Dennis Boyle

            Chimera Laboratories

            Website: http://www.chimeralabs.com/

            Website: http://home.att.net/~chimeraone/index.html

             

             

            -----Original Message-----
            From: dallasaudioclub@yahoogroups.com [mailto:dallasaudioclub@yahoogroups.com] On Behalf Of jlsem@...
            Sent: Saturday, April 15, 2006 9:43 AM
            To: dallasaudioclub@yahoogroups.com
            Subject: Re: [dallasaudioclub] Finished : Heath W3M

             

            Dennis,

             

            Do you still carry these items? 

             

            SET-300-5.0 - 5000 Ohm Primary - 4/16 Ohm or 2/8 Ohm Output....$385.00/OEM....$481.00/Retail
            3.13"/80mm wide X 3.69"/94mm long X 3.81"/97mm high w/wire leads - 10.28 lbs/ 4.66Kg
            Mounting Hole Dimensions = 2.50"/64mm wide X 2.44"/62mm long (use 10/32 screw)


            INT-1:0.5/0.5 -1:0.5 X 0.5 Ratio,15-30ma, Split output phase splitter..$190.00/OEM...$238.00/Retail
            2.50"/64mm wide X 3.19"/81mm long X 3.06"/78mm high w/wire leads - 6.65 lbs/ 3.02Kg
            Mounting Hole Dimensions = 2.00"/51mm wide X 2.19"/56mm long (use 10/32 screw)"

            Can the IT be used SE:SE?  I need four of each for VT-52 bi-amp project.

             

            Thanks,

            John Semrad

             

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