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    "120Watts of Hi-Fi Power" by David Hafler

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    denny9167

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    Age : 49
    Location : Texas

    "120Watts of Hi-Fi Power" by David Hafler

    Post by denny9167 on Mon Dec 19, 2011 4:28 pm

    I just acquired an issue of "Radio and TV News" dated February 1959,and inside is an article written by David Hafler himself describing a Mark III modification,allowing a power output of 120 watts,and a second set of output tubes and using only one 6AN8 driver tube!! He goes into detail of the use of other various driver curcuits,and concludes that with just one modification to the original "Mark III" driver curcuit, which would yield the best results,being a single 600pf/ 1000v capacitor to the original curcuit design,and maintaining a close tolerance in resistor values for the triode phase splitter would give the best results. If anyone is intrested, I can scan the entire article and post it.

    The magazine was a great find, an in excellent shape.

    [img][/img]

    Blitzen

    Posts : 47
    Join date : 2009-07-10

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by Blitzen on Mon Dec 19, 2011 7:06 pm

    Scan and post!!

    stewdan

    Posts : 161
    Join date : 2010-03-07
    Age : 78
    Location : Houston Texas

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by stewdan on Mon Dec 19, 2011 8:06 pm

    Please scan the article and post it!!

    Thanks in advance.

    PeterCapo

    Posts : 386
    Join date : 2008-12-05

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by PeterCapo on Mon Dec 19, 2011 8:27 pm

    Yes! Please scan and post!

    Thanks...

    GP49

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    Location : East of the sun and west of the moon

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by GP49 on Tue Dec 20, 2011 1:37 am

    Of COURSE, we'd like you to scan and post!!! Very Happy

    tubes4hifi
    Admin

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    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by tubes4hifi on Fri Dec 23, 2011 3:09 pm

    two extra KT88 tubes plus an extra GZ34 rectifier tube

    denny9167

    Posts : 152
    Join date : 2011-05-09
    Age : 49
    Location : Texas

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by denny9167 on Fri Dec 23, 2011 4:46 pm

    tubes4hifi wrote:two extra KT88 tubes plus an extra GZ34 rectifier tube

    My apologies,thanks for the correction.

    baddog1946

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    Join date : 2010-02-03
    Location : Costa Rica

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by baddog1946 on Sun Dec 25, 2011 12:38 pm

    Hi Denny:
    Great posting. Please post the article ASAP. dying of curiosity.
    Merry Christmas
    Baddog

    denny9167

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    Age : 49
    Location : Texas

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by denny9167 on Fri Dec 30, 2011 11:00 pm

    Here's the article. I have provided the link to the PDF file. Thanks for your intrest.

    120W of Hi-Fi Power_by_David_Hafler.pdf

    snav

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    Join date : 2011-05-18

    Re: 120w MK3

    Post by snav on Sun Mar 04, 2012 11:17 pm

    Looks like new iron as well

    baddog1946

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    Join date : 2010-02-03
    Location : Costa Rica

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by baddog1946 on Mon Mar 05, 2012 9:21 am

    I have a PDF of the article that is not a scan. Very good quality. Where can I post it for downloading on the forum?

    Falcon4646

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    Join date : 2010-02-21

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by Falcon4646 on Tue Mar 27, 2012 12:33 am

    Did the pdf of the Hafler article ever get posted?

    denny9167

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    Join date : 2011-05-09
    Age : 49
    Location : Texas

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by denny9167 on Tue Mar 27, 2012 9:53 pm

    baddog1946 wrote:I have a PDF of the article that is not a scan. Very good quality. Where can I post it for downloading on the forum?

    I would think that there would be some sites similar to photo bucket or others that would allow you to upload various different file formats,if you didn't have a web server available.

    tubes4hifi
    Admin

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    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by tubes4hifi on Wed Mar 28, 2012 10:36 pm

    the high quality PDF provided by BadDog is now hosted and posted on my website here:
    120w UL amp by David Hafler
    first page is blank, then 3 full pages


    Last edited by tubes4hifi on Wed Apr 04, 2012 8:20 pm; edited 1 time in total

    denny9167

    Posts : 152
    Join date : 2011-05-09
    Age : 49
    Location : Texas

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by denny9167 on Fri Mar 30, 2012 7:15 am

    I haven't had a chance to actually implement this design because
    Of other projects, but I would be interested to hear if someone else has
    Tried, I do plan on this in the near future.

    Luddite

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    Location : Texas

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by Luddite on Fri Mar 30, 2012 10:56 am

    denny9167 wrote:I haven't had a chance to actually implement this design because Of other projects, but I would be interested to hear if someone else has Tried, I do plan on this in the near future.

    Denny, I say go for it. On a slightly different note, back in the 90's I found an article from a 1957 issue of "Audio Engineering" magazine with a design for a rear loaded, folded horn speaker cabinet. I decided to build a pair (testing the limits of my woodworking skills!). I am still using these today in my "home theatre" system. My hi-fi system, of course, is all Dynaco...all the time!

    Best Regards,
    Charlie

    tubes4hifi
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    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by tubes4hifi on Fri Mar 30, 2012 11:22 am

    wbain and probably many others . . .
    I rarely "log-off" of this forum but I did yesterday and then noticed this morning that the LINK doesn't show up at all
    unless you are logged-into the forum!!

    denny9167

    Posts : 152
    Join date : 2011-05-09
    Age : 49
    Location : Texas

    Re: "120Watts of Hi-Fi Power" by David Hafler

    Post by denny9167 on Fri Mar 30, 2012 10:22 pm

    tubes4hifi wrote:wbain and probably many others . . .
    I rarely "log-off" of this forum but I did yesterday and then noticed this morning that the LINK doesn't show up at all
    unless you are logged-into the forum!!

    I finally came to that realization myself.

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