Go Back   Home > Forums > Member Areas > The Lounge

The Lounge A place to talk about almost anything but politics and religion.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 7th March 2013, 09:04 PM   #36441
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by wayne View Post
I do like the way AP does the transformer feedback. Anybody do it on an input circuit?
I've not seen that, although it is an intriguing notion.
  Reply With Quote
Old 7th March 2013, 09:50 PM   #36442
diyAudio Member
 
john curl's Avatar
 
Join Date: Jul 2003
Location: berkeley ca
I must point out something here:
I keep reading that I follow 'market trends' or some-such. This is nonsense. I follow my OWN standards developed for the audio industry over the last 35 years.
I would have used an input transformer for SOME cartridges, IF I could be sure that it sounded best in the mid-range, AND did not have too much low frequency distortion. I put out a sincere effort to find the best transformers possible, and even then I was disappointed. No big deal. Nobody told me to use transformers and nobody told me NOT to use transformers, it just fell out that we could get along without them, when I found that the best transformers that I could find, had tradeoffs.
IF I wanted to conform with market trends, I would design tube equipment.
  Reply With Quote
Old 7th March 2013, 10:00 PM   #36443
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
Quote:
Originally Posted by bcarso View Post
I've not seen that, although it is an intriguing notion.
You wouldn't happen to know where a schematic of their scheme could be found?
__________________
"The way to deal with superstition is not to be polite to it, but to tackle it with all arms, and so rout it, cripple it, and make it forever infamous and ridiculous."- H. L. Mencken
  Reply With Quote
Old 7th March 2013, 10:13 PM   #36444
mlloyd1 is offline mlloyd1  United States
diyAudio Member
 
mlloyd1's Avatar
 
Join Date: Feb 2001
Location: illinois
wayne:

if you don't mind me asking, what characteristics for your preferred choice of hp filter?

mlloyd1

Quote:
Originally Posted by wayne View Post
AP did a nice job with uV signals low distortion and a Jensen transformer. Of course this was on the generator side but we still use it to measure uv sweeps on phono stages. Some of the transformers are pretty good but I still prefer not to use one but that is just my choice.
SY you made a very good point about cartridge output when you think of low level music playing VS rated output. While I DC couple I still prefer to use the RIAA HP filter it keeps out more than record warp.
  Reply With Quote
Old 7th March 2013, 10:26 PM   #36445
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by SY View Post
You wouldn't happen to know where a schematic of their scheme could be found?
If it is the one Wayne is referring to, it's the use of a noninductive copper winding in the transformer to be used to temperature-compensate the positive feedback to reduce the output impedance at the secondary and extend the undistorted lower frequency limit. I think it is Hofer's patent, and I saw a schematic. In fact somewhere I downloaded the service manual for an Ap System One so it probably is there too.
  Reply With Quote
Old 7th March 2013, 10:31 PM   #36446
SY is offline SY  United States
diyAudio Moderator
 
SY's Avatar
 
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 1
OK, then it's the 1986 patent that I'm familiar with. I thought from this discussion that there was a cool input transformer trick.
__________________
"The way to deal with superstition is not to be polite to it, but to tackle it with all arms, and so rout it, cripple it, and make it forever infamous and ridiculous."- H. L. Mencken
  Reply With Quote
Old 7th March 2013, 10:42 PM   #36447
gpapag is offline gpapag  Greece
diyAudio Member
 
gpapag's Avatar
 
Join Date: Nov 2002
Location: Athens-Greece
Quote:
Originally Posted by simon7000 View Post
I'll take that as you didn't read the article.
Ed
What you are pointing at? Vertical or transverse modulation?
http://www.diyaudio.com/forums/attac...1&d=1362699535
http://www.diyaudio.com/forums/attac...1&d=1362699535

Or is it distortion related to modulation amplitude?
See some measurements. Formulas in that link predict distortion products. Measurements show this.
http://www.diyaudio.com/forums/attac...1&d=1362699535
http://www.diyaudio.com/forums/attac...1&d=1362699535
http://www.diyaudio.com/forums/attac...1&d=1362699535
http://www.diyaudio.com/forums/attac...1&d=1362699535

But there are a myriad “small” mechanical details that play a role too. See the following for some of them.
http://www.diyaudio.com/forums/attac...1&d=1362699535
http://www.diyaudio.com/forums/attac...1&d=1362699535
http://www.diyaudio.com/forums/attac...1&d=1362699535
http://www.diyaudio.com/forums/attac...1&d=1362699535
Quote:
Originally Posted by jneutron View Post
Interesting article.
Not much on anti-skate though
Skating force is another problem. If you like see here:
A think a thhow a puthhy cat
Apart from antiskating force doesn’t match the change of skating force across the record radius, skating force varies with the dynamics of the recorded signal. Almost impossible to compensate for this

Quote:
Originally Posted by Kindhornman View Post
Scott,
Thanks for that RCA reference, makes me wish my Radiotron handbook hadn't been destroyed in flood! Still had information that was useful today, but that the way it goes when it rains into a rented warehouse!
A waterproof source
http://ia701507.us.archive.org/25/it...rsHandbook.pdf

George
Attached Images
File Type: png Ult T1.png (34.2 KB, 136 views)
File Type: png Ult s2 t4.png (32.4 KB, 137 views)
File Type: png HFN T6.png (33.1 KB, 135 views)
File Type: png HFN t7.png (35.2 KB, 133 views)
File Type: png HFN t8.png (33.6 KB, 133 views)
File Type: png HFN t9.png (34.7 KB, 13 views)
File Type: png HFN t9 bolts tightened.png (33.2 KB, 13 views)
File Type: png HFN t9 handle dampened.png (33.9 KB, 11 views)
File Type: png HFN t9 balsa insert.png (33.9 KB, 12 views)
File Type: png HFN t9 plastic inser light.png (33.9 KB, 17 views)
__________________
["Second Law is a bitch." - SY] ["The Road To Heaven:Specify the performance & accept the design. The Road To Hell:Specify the design & accept the performance"-Bruno Putzeys]
  Reply With Quote
Old 7th March 2013, 11:01 PM   #36448
gpapag is offline gpapag  Greece
diyAudio Member
 
gpapag's Avatar
 
Join Date: Nov 2002
Location: Athens-Greece
Quote:
Originally Posted by jneutron View Post
Extrapolation of distortion below 1-2hz by curve fitting is inherently unreasonable, as the 1000 percent distortion question raises. Reminds me of the ultraviolet catastrophe.
jn
I concur. Tones of embarrassing stories in the literature with conclusions based on extrapolation/interpolation. I had placed a in front!

George
__________________
["Second Law is a bitch." - SY] ["The Road To Heaven:Specify the performance & accept the design. The Road To Hell:Specify the design & accept the performance"-Bruno Putzeys]
  Reply With Quote
Old 7th March 2013, 11:01 PM   #36449
bcarso is offline bcarso  United States
diyAudio Member
 
Join Date: May 2005
Location: Canoga Park, California
Quote:
Originally Posted by SY View Post
OK, then it's the 1986 patent that I'm familiar with. I thought from this discussion that there was a cool input transformer trick.
I think Wayne is suggesting doing something as an input transformer in some way similar. Perhaps he will clarify.
  Reply With Quote
Old 7th March 2013, 11:25 PM   #36450
1audio is offline 1audio  United States
diyAudio Member
 
Join Date: Mar 2004
Location: SF Bay Area
Blog Entries: 2
Quote:
Originally Posted by bcarso View Post
I think Wayne is suggesting doing something as an input transformer in some way similar. Perhaps he will clarify.
There is a trick. Lundahl has it on their site. it allows the transformer to be much smaller. http://www.lundahl.se/pdf/7101.pdf However it doesn't work for this application (I asked).

The AP output transformer trick works but does require virtually perfect matching of the DCR of the transformer, hence the extra winding. I also asked about this and the Jensen guys did not recommend it, too difficult to execute and expensive. They make the transformer for AP.
__________________
Demian Martin
Product Design Services
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



New To Site? Need Help?

All times are GMT. The time now is 06:25 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright ©1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2