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Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?

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Posted on December 24, 2020 at 14:02:01
AA6U
Audiophile

Posts: 34
Location: Riverside CA
Joined: September 21, 2009
I bought a Marantz 8b several months ago and it works fine, except that it is somewhat lacking on the lower end compared to numerous other amps I own and have worked on. It has the original Goodall caps in the 6BH6 section, but the coupling caps to the output tubes are Sprague 160P black beauties. Are the Sprague caps original as installed by Marantz when it was manufactured or were they changed? I think all of photos I've seen of stock units have Goodall caps coupling to the output tubes.

If the Sprague caps are not originals, then I would not devalue the unit if I replaced them with new, better capacitors and hopefully improve the bass.

Note: I'm aware of the high pass filter hooked to the standard input jacks, so I'm using the "test" jacks which helps the bass response a little. However, it's still lacking bass compared to other amps.
Scott

 

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RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 26, 2020 at 05:35:32
Story
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Posts: 10302
Location: NJ
Joined: December 11, 2000



it sounds like you are concerned with possible resale value. The early sprague's are probably compromised and I doubt you'll find any 8b's with the original coupling caps.

A later substitute that is better would be the Sprague or SBE 716p series of the same value.



 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 26, 2020 at 09:05:43
AA6U
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Posts: 34
Location: Riverside CA
Joined: September 21, 2009
Yes, resale value is my reason for asking the question. The 8b works now with the 160P black beauties but with low bass.

If the black beauties are not original, then I won't have any qualms about replacing them. That's why I'm trying to find out if they are original and hence my post.
Scott

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 27, 2020 at 12:12:26
Alpha Al
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You should be able to look at the solder joints to tell if they came in it.

I recommend not using that amp with those Black Beauties, original or not.

They're notorious for getting leaky or shorting. When that happens, it eats power tubes, and maybe an output transformer.

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 27, 2020 at 12:27:24
AA6U
Audiophile

Posts: 34
Location: Riverside CA
Joined: September 21, 2009
Someone suggested that, but it looks like someone in the recent past unsoldered them to test them, probably for leakage, so that is not going to be revealing on their originality. However, that may be a sign that they were replaced.

I'm hoping there is some Marantz 8b historian expert out there who would know if Marantz ever used the Black Beauties as stock in the 8b.

However, I agree that those Black Beauties are probably ticking time bombs and can't sound as good as new polypropylene caps. I'm not interested in hearing what is purported to be "original" sound because old capacitors will never sound the same as when they were new.
Scott

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 27, 2020 at 17:34:59
crooner
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Posts: 2516
Location: San Diego, CA
Joined: April 13, 2003
They only used them in the very late versions (10000 serial number range), and they are of the DIFILM variety which are mylar. Those are less prone to leakage than the earlier bumblebees.

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 27, 2020 at 19:50:00
AA6U
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Posts: 34
Location: Riverside CA
Joined: September 21, 2009
Thanks! That's what I wanted to know.
Scott

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 27, 2020 at 22:21:43
AA6U
Audiophile

Posts: 34
Location: Riverside CA
Joined: September 21, 2009
Although the Black Beauties may be stock, I think I'm going to replace them to be protect the output tubes and transformers. I will save them in case I sell it, and the next owner can reinstall them if they want "original" sound.
Scott

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 27, 2020 at 22:41:16
crooner
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Location: San Diego, CA
Joined: April 13, 2003



The DIFILM caps are pretty good. You can always test them and if the ESR is high or their value have drifted, replace them.

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 28, 2020 at 08:35:19
AA6U
Audiophile

Posts: 34
Location: Riverside CA
Joined: September 21, 2009
I tested the ESR in the Black Beauties and it was about 14 ohms vs. 0.5 ohms for polypropylene caps that I use in audio equipment refurbishing. Leakage was within limits and they hadn't drifted in value much.

I think I will try replacing them in one channel and see how it sounds. I can always put them back if there is no significant improvement.
Scott

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 28, 2020 at 22:04:21
AA6U
Audiophile

Posts: 34
Location: Riverside CA
Joined: September 21, 2009
I tested the ESR in the Black Beauties and it was about 14 ohms vs. 0.5 ohms for polypropylene caps that I use in audio equipment refurbishing. Leakage was within limits and they hadn't drifted in value much.

I think I will try replacing them in one channel and see how it sounds. I can always put them back if there is no significant improvement.
Scott

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 29, 2020 at 16:04:30
Alpha Al
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Usually, if they have been unsoldered to test for leakage, it's done at one end only. The other solder joint should be original. No need to take then out completely for that.

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on December 29, 2020 at 17:43:39
AA6U
Audiophile

Posts: 34
Location: Riverside CA
Joined: September 21, 2009
That is how it appears.
Scott

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on January 20, 2021 at 13:18:48
Posts: 9
Location: Atlanta
Joined: January 17, 2021
Hello, I think it is normally, if the leak test is not soldered, it can only be done on one end. The other solder joint should be original. There is no need to remove them completely for this.

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on January 20, 2021 at 13:38:30
AA6U
Audiophile

Posts: 34
Location: Riverside CA
Joined: September 21, 2009
Yes, that is correct.

As a follow up to this thread, I replaced the black beauty caps with new polypropylene caps and it sounds a lot better (ESR if black beauty caps was 13 ohms and the new ones measure 0.5 ohms). I replaced one channel and then compared it to the unmodified stock one. There was a marked difference in clarity and bass. I left the old caps in (disconnecting one end of each). Now it still has the old caps that can be easily hooked back up if some person in future feels so inclined.
Scott

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on August 14, 2021 at 02:15:28
dubai2000
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Posts: 218
Joined: November 19, 2002
Just in case somebody else is looking around for information on caps in this amp: many years ago Russian PIOs K40-Y9 caps had become quite fashionable and wanting to "improve" the sound of my 8b I had them installed in palace of the Good All caps the the Sprague Bumblebees. Well, move forward to the present: had the power amp section of the amp rebuilt and gave it a spin - mmmmmh - nice tone but no soundstage to speak of. I don't know why but all those years I had kept the Good All coupling caps - and behold, outside the circuit they measured alright so I put them back again - and the sound improved remarkably - same gorgeous tone but now it is open and up there with its legendary status - wanted to sell but that is certainly off the table now.

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on August 14, 2021 at 12:31:33
sony6060
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Location: USA
Joined: August 8, 2014
This is the first time in 25 years I ever read an old capacitor outperform the K40Y-9 except the Sprague Vitamin Q highest series (think 196P) that seems equal or perhaps slightly better. You are stating a night & day difference. Your post may be the most important post I ever read if it is true. Very little is posted about old Good All capacitors. You are sure about this? What Good All series are these capacitors? Your statement is revolutionary if true.

On my best upgraded tube amp voices are not heard from the speakers, they are projected in mid air. I can barely tell the difference in-between a person talking in front of me or thru the stereo. I can easily hear the differences in coupling capacitors.

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on August 15, 2021 at 05:54:46
dubai2000
Audiophile

Posts: 218
Joined: November 19, 2002
I am absolutely sure that my ears are not deceiving me. Let me add: the person who rebuilt the power supply section also had my MC-30s on loan and he stated that he greatly prefered the Macs for greater clarity. To be honest, I did not believe him at the time (shame on me). But yes, with those Russian caps installed the 8b did not sound bad but there was very little soundtage/depth - everything seemed to be kind of congested in the plane between the speakers - with the Good All installed I get the presentation that you have decribed. The Good Alls have a reddish/brown body (the ones usually seen in pics taken of an original 8b) - and no, I did not expect that at all either.
As for the truth: obviously this what my two hears hear but let me repeat - I was about to sell the amp, now-----no way!

 

RE: Did Marantz Ever Install Sprague 160P Caps in the 8B as Stock?, posted on August 15, 2021 at 06:01:15
sony6060
Audiophile

Posts: 1465
Location: USA
Joined: August 8, 2014
I found the model number on an image of the bottom of the amp. These capacitors are maroon, not red. They are Model 600UE. I will pursue these. Thanks.

 

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