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hot tubes
Silver Member
Canada
162 Posts |
 Posted - 03/22/2010 : 01:55:23
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Whats the common op amp found in the OD1 , is it the same
as the SD-1 ? |
Edited by - hot tubes on 03/22/2010 01:56:47 |
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ChristoMephisto
Platinum Member
Canada
1288 Posts |
Posted - 03/22/2010 : 12:26:39
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On the later models, its the JRC 4558D
The double DD you find on later ones just have extra sheilding in the op amp, also changed the company name from JRC to NMC, or something like that |
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hot tubes
Silver Member
Canada
162 Posts |
Posted - 03/22/2010 : 23:30:49
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If wanted to increase the bass output of the OD1 what cap
would you change C3 like the SD1 ? |
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ChristoMephisto
Platinum Member
Canada
1288 Posts |
Posted - 03/23/2010 : 14:51:59
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C3 is the one your want to change
Its already at 720Hz, doubling the cap will bring down the high pass to about 338Hz, which is where the input HZ is on the OD1 |
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Dr. Bob
Moderator
Australia
6593 Posts |
Posted - 03/23/2010 : 15:49:15
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Hi Hot Tubes & Guys
The really early OD-1 used the 14-Pin 3403 Quad op-amp.
It's tone is considered very highly over the later 8-Pin 4558 OD-1's.
In the 14 pin model, the extra 2 op-amps were used as the input & output stages.
Where the 4558 versions had discrete transistor, 2SC1815'S or 2SC945's on the input & output stages.
There is some debate that the early 14 pin OD-1's
may have also used other brands & models of Quad op-amps.
Regards Dr Bob 
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hot tubes
Silver Member
Canada
162 Posts |
Posted - 03/23/2010 : 19:58:39
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so if i bumped the cap up to .1 or .15 , will that be too much cap ?
it works in the SD1 , but i'm not as familiar with the insides of the OD1 .
thanks guys  |
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hot tubes
Silver Member
Canada
162 Posts |
Posted - 03/24/2010 : 01:58:29
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where is the C3 cap in question , this board in not marked ??
thanks |
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ChristoMephisto
Platinum Member
Canada
1288 Posts |
Posted - 03/24/2010 : 05:30:14
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quote:
Originally posted by hot tubes
where is the C3 cap in question , this board in not marked ??
thanks
C3 is the second cap down on the right, next to the wire 15
Tho not sure what the out come would be if you increase the cap above .1 and don't lower C2 |
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hot tubes
Silver Member
Canada
162 Posts |
Posted - 03/24/2010 : 19:22:39
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| THANKS !!! |
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Topic |
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OD1 op amp ?
