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UF1007 vs UG1007

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Posted on October 18, 2016 at 11:27:46
Lee of Omaha
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Posts: 1800
Location: Omaha NE
Joined: September 8, 2006
 We are rebuilding a couple of Marantz 10Bs. We're going to replace all the 'lytics and replace the output coupling caps with with Russian Paper in oil. We're also going to bypass a cathode bypass cap with a Russian Paper in oil.

The original diodes in the demodulating circuit are UG1007. What the heck is the difference between them and the UF1007, and should I replace with UF1007?

Are there any other mods recommended?

 

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RE: UF1007 vs UG1007, posted on October 18, 2016 at 12:17:30
FenderLover
 This is what I found. I guess it depends on the app. Prolly have to stick with UG1007 or equiv, for demodulation app.

 

RE: UF1007 vs UG1007, posted on October 18, 2016 at 12:48:50
Eli Duttman
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Posts: 10455
Location: Monroe Township, NJ
Joined: March 31, 2000
 Lee, unless the demod diodes have failed, leave them be. It's long odds those parts are germanium, not silicon.


Eli D.

 

RE: UF1007 vs UG1007, posted on October 18, 2016 at 13:22:27
Lee of Omaha
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Posts: 1800
Location: Omaha NE
Joined: September 8, 2006
 A quick (not exhaustive) check of the characteristics suggests they are indistinguishable from each other at low currents. If they are germanium then they should have lower voltage drop, but both are rated for 1000 volts and 1 amp, which doesn't sound like germanium to me, especially in a DO-41 package. But I'm not familiar with germanium diodes above the little signal-level ones.

 

Use Russian FT-3 Teflons not PIO, posted on October 18, 2016 at 15:49:46
andy evans
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Posts: 4382
Joined: October 20, 2000
 I've tried a few of the Russian caps, PIO, teflon and silver mica. I clearly prefer the teflons as coupling caps. Try them - they're not expensive. Some like the silver mica - close to teflon.

 

RE: Use Russian FT-3 Teflons not PIO...LOL Ever been under the hood of a 10B? (nt), posted on October 18, 2016 at 16:05:29
Steve O
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Posts: 12383
Location: SE MI
Joined: September 6, 2001

 

"Lee, unless the demod diodes have failed, leave them be.", posted on October 18, 2016 at 18:02:17
FenderLover
 Yes, wise choice. I'm no expert on solid-state devices. If it were me and I needed to swap out the original ones. I'd go with as close to OEM as possible. Just to avoid "post-fix weird, symptom" headaches.

 

Schematic?, posted on October 19, 2016 at 10:45:14
gusser
Audiophile

Posts: 3649
Location: So. California
Joined: September 6, 2006
 What do you mean by "demod diodes"? Are they in a tuner circuit? Are these perhaps the diodes in the stereo demux section?

I agree with the other advice saying leave them alone. If they are functional, nothing good will come from substituting alternate parts in RF circuits.

Basic rule of vintage HiFi work: Rebuild the amp and preamp as much as you want. Stay out of the RF circuits unless you know how they work and have the test gear to perform a FULL FACTORY ALIGNMENT.

Even bending or moving of some parts in the front end can alter performance. If you see what looks like test points, a wire just sticking up on a board, this is probably what is called a gimmik. It's actually a capacitor and moving it will cause trouble. Yes one end is not connected to anything but then RF is weird. And it is actually connected via RF.

 

The 10B uses a plethora of the "UG" diodes..., posted on October 19, 2016 at 11:26:45
Steve O
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Posts: 12383
Location: SE MI
Joined: September 6, 2001
 ...and every single one of them is in a low level RF/IF/discriminator position. Probably germanium and best left alone if not outright defective...as others have already pointed out.

 

I'm convinced..., posted on October 19, 2016 at 15:20:16
Lee of Omaha
Dealer

Posts: 1800
Location: Omaha NE
Joined: September 8, 2006
 ...leave 'em alone.

Thanks for the advice. Still wonder what the heck the difference is, though. Agree with the advice about staying out of functioning RF circuits.

 

The only big difference I see is...., posted on October 20, 2016 at 09:06:29
Russ57
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Posts: 3754
Location: South Florida
Joined: November 16, 2001
 The UG1007 is glass passivated (should stand up better in adverse conditions). There are small differences regarding temperature ratings.

Mostly they are equal to one another.

 

RE:Right! the teflon caps are HUGE, posted on October 20, 2016 at 14:47:42
DAK
Audiophile

Posts: 2712
Location: PACIFIC
Joined: August 8, 2010
 When planning to use them one must make sure during the design phase of things, that the size of those caps are accounted for. I could only find enough space for them in new builds, never a rebuild.

 

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