RCA RS177H just dosen't sound right! Caps?

oldtexasdog · 5th May 2012, 04:56 PM

I just finished replacing all the power and coupling caps and all the resistors on this and while it plays good and has bass the treble is just too high and sounds kinda "SCRATCHY" not smooth? I used metal foil coupling caps at .27uf just as the schematics called for? Should I have increased them to say .35uf?
Thanks as always for your time and thoughts folks

HollowState · 5th May 2012, 06:09 PM

If you have replaced all the original paper capacitors with modern plastic dielectric types, the frequence response will be increased on the high end over what it was, And if you replaced the original carbon composition resistors with metal films, that exacerbates the problem. Somewhat less so for carbon films. It is not the numerical value, but the material "upgrade" that does it.

SoNic_real_one · 5th May 2012, 06:15 PM

Maybe now you are really hearing how it should sound. Give your brain some time to adjust, maybe it is still "compensating" for the high-end drop that it experienced before.

oldtexasdog · 5th May 2012, 07:41 PM

Well I'll try giving it a while

It's just the high end sounds a little distorted.

Frank Berry · 5th May 2012, 07:49 PM

I don't have a copy of the schematic. If there is a capacitor in the feedback network, make sure that it's the correct value.

oldtexasdog · 5th May 2012, 08:04 PM

There is but I did leave those two and a power cap resistor orginal.
I cant seem to get the schematic to up load as it sayus the file is too large?

Frank Berry · 5th May 2012, 08:10 PM

Please email the schematic to me. You should be able to find my email address by looking at my profile.

Frank Berry · 5th May 2012, 08:11 PM

The site doesn't show my email address. Email me through this site and I'll respond. That will give you my email address.

oldtexasdog · 5th May 2012, 10:26 PM

Quote:

Originally Posted by Frank Berry

The site doesn't show my email address. Email me through this site and I'll respond. That will give you my email address.

E-mail sent
Thanks

oldtexasdog · 6th May 2012, 12:44 AM

Well I took out the 5AS4A rectifier and rolled in a 5U4G and it sounds a LOT Smoother now

5th May 2012, 04:56 PM	#1
oldtexasdog diyAudio Member Join Date: Oct 2011	RCA RS177H just dosen't sound right! Caps? I just finished replacing all the power and coupling caps and all the resistors on this and while it plays good and has bass the treble is just too high and sounds kinda "SCRATCHY" not smooth? I used metal foil coupling caps at .27uf just as the schematics called for? Should I have increased them to say .35uf? Thanks as always for your time and thoughts folks

5th May 2012, 06:09 PM	#2
HollowState diyAudio Member Join Date: Aug 2006 Location: Taxland, New Jersey	If you have replaced all the original paper capacitors with modern plastic dielectric types, the frequence response will be increased on the high end over what it was, And if you replaced the original carbon composition resistors with metal films, that exacerbates the problem. Somewhat less so for carbon films. It is not the numerical value, but the material "upgrade" that does it. __________________ "The supercomputer is technologically impossible. It would take all of the water that flows over Niagara Falls to cool the heat generated by the number of vacuum tubes required." ~ Professor of Electrical Engineering, New York University

5th May 2012, 07:49 PM	#5
Frank Berry diyAudio Member Join Date: Sep 2003 Location: Midland, Michigan	I don't have a copy of the schematic. If there is a capacitor in the feedback network, make sure that it's the correct value. __________________ Frank

5th May 2012, 08:10 PM	#7
Frank Berry diyAudio Member Join Date: Sep 2003 Location: Midland, Michigan	Please email the schematic to me. You should be able to find my email address by looking at my profile. __________________ Frank

5th May 2012, 08:11 PM	#8
Frank Berry diyAudio Member Join Date: Sep 2003 Location: Midland, Michigan	The site doesn't show my email address. Email me through this site and I'll respond. That will give you my email address. __________________ Frank


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5th May 2012, 06:15 PM	#3
SoNic_real_one diyAudio Member Join Date: Jan 2008 Location: Virginia	Maybe now you are really hearing how it should sound. Give your brain some time to adjust, maybe it is still "compensating" for the high-end drop that it experienced before.

5th May 2012, 07:41 PM	#4
oldtexasdog diyAudio Member Join Date: Oct 2011	Well I'll try giving it a while It's just the high end sounds a little distorted.

5th May 2012, 08:04 PM	#6
oldtexasdog diyAudio Member Join Date: Oct 2011	There is but I did leave those two and a power cap resistor orginal. I cant seem to get the schematic to up load as it sayus the file is too large?

6th May 2012, 12:44 AM	#10
oldtexasdog diyAudio Member Join Date: Oct 2011	Well I took out the 5AS4A rectifier and rolled in a 5U4G and it sounds a LOT Smoother now

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