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Diving into tube amp world with Marantz 8


bharat

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1 hour ago, thebes said:

There was a company, whose name escapes me, that made a reproduction of the 8b for several years, and they had spare cans that they were selling.  They may be out of stock by now, but I would do a little online research, track them down and see if they have any left. 

 

It was VAC but I’d be surprised if they still sell them.

 

http://www.vac-amps.com/

 

miketn

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Here's the 9

 

https://www.audioclassics.com/detail?detail=9B&nav=cat

 

 

Home > Amplifiers > 9B
ACL 9B   Product Brochure [pdf]
80 WPC 160 Watt Mono Tube Original List Price: 9999.00

Grade: NEW NEW: 4999.00
New in a box
Comments:Champagne Chrome
 

Grade: B1 B1: 4399.00
Physical: Some light scratches - Excellent Condition
Electrical: Meets or exceeds original specs, all functions operate
Comments:Champagne Chrome.
 

ACL 9B
File Photo for Representation of item. May not be the actual item offered for sale.
 
 
 
Shipping weight: 70 lbs.

Related Categories:   Interconnect
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11 hours ago, Jeffrey D. Medwin said:

 

 

The highly revered Malantz Model Nine monoblock !! 

 

Here is an interesting and true tidbit on its design.  In the 1980s, I had befriended an avid audiophile, who was also the DEAN of E.E. at the University of Alabama  His name was Charles A. Halijak, PhD.  During his career, he published 20 papers at the University, and received 27 different Citations ( not for speeding, gents !! ).  His published paper record can be seen on-line here :

 

https://www.researchgate.net/scientific-contributions/2017834553_Charles_A_Halijak

 

Here is what I want to tell you all.  Dr.  Halijak's worst-liked amplifier, from a E.E. design point of view, was the Marantz Number Nine.   He felt it had so many design errors, that yearly he would have the students in his class, critique the design, and offer improvements to submit to Dr. Halijak.  This was his own requirement, before they would be able to pass his E.E. course !!!!!!

 

If any E.E. schooled by Dr. Halijak at the University of Alabama in the 1980s is reading this, I would enjoy your confirmation, of what I am reporting herein, and believe to be true.

 

Dr. Halijak was also a big believer of low as possible / practical DCR  ( Direct Current Resistance ) power supplies.   I wrote about that on page 8 of a KT88 build thread, earlier this year.

 

His favorite value power supply choke, for his own personal tube amp builds, had to be custom made back then.  He had Stancor build for him to his spec :  1 HY at 8 Ohm DCR power supply chokes.   Isn't that interesting, because it does not meet critical inductance, as is always taught the last maybe 100 years in all the conventional EE courses.  Dr. Halijak was brilliant, look at his papers.   

 

Today, Hammond has a off-the-shelf 159ZA choke, six ohms, and it requires 75 hours of music - playing to break in.  One would always use at least two of these, in each tube amp's supply, as a L1/C1/L2/C2 B+ filter to feed the Finals.  Two 159ZAs, connected in series, is only 12 Ohms total DCR feeding the Finals tube,  from inductors .

 

Jeffrey Medwin

 

I agree with the belief of better sound through Direct Current power supplies. Especially with tube amps.

 

Unusual in today's world though. See: http://www.emissionlabs.com/Articles/TECH-BULLETIN/TB-09-Why-DC-Heated-Tubes-can-still-hum/TB-09-WHY-DC-heated-tubes-can-still-hum.html

 

Wb

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Hi Jeffrey,

 

Thanks for the reply.

 

It is an Amp that can use either a pair of 45's or a pair 2A3 tubes that I use in rotation: Yamamoto A08. It sounds great with my Belles. All 2 WPC. etc... notwithstanding what an old curmugen that makes Crossovers had to say about low out put wattage. ;)

 

I also have amps that can output 300 WPC and more too but they are solid state, multi-channel (5 and 7) and are used for Home Theatre. Some times to my neighbor's expressed discomfort. She particularly didn't like the pictures shaking on her walls from the opening scene of the movie Predator (Helicopter). Wife was away and my buddies and I got too far into the wine, Beer, Scotch and Rye Whiskey.:emotion-22::emotion-46:🍺

 

Not a mixture I recommend.

 

Regards,

 

Wb 

(Greg)

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  • 1 month later...
On 10/20/2019 at 1:14 PM, Jeffrey D. Medwin said:

Out of all the replies to this thread, what Tom1066 said rings truest to "me",  about Crooner's ( seemingly experienced ) 8B updating approach.  

 

I feel, one should not try to change " all the caps" or " all the resistors",  as SOP - standard operating procedure,  because it changes the SOUND of the stock amplifier.

 

However :  

 

One can MEASURE, individually, methodically, all the caps, as to their uF value, and measure each cap as to their ESR , and determine if ANY are way out of spec, and needing attention. 

 

Likewise, one can easily MEASURE, individually, methodically, all the resistors, to see if they drifted, and vary greatly from their intended ( schematic ) values.

 

- - - - - - - - - - -

 

There MAY possibly be no parts that are GROSSLY out-of-spec.  This might take up to 3 hours of time / labor to do and carefully document these measurements in 2019, VS this piece being around and unchanged, virgin,  since about 1959 ... six decades !!

 

- - - - - - - - - - -

 

I am sure I personally could  easily improve upon the sound of this amp, by using well-thought-out new film caps, and highest-quality resistors. 

 

But then, it is no longer a Marantz 8B one is listening to.  That's the RUB !!!!

 

Have fun, but think twice, before acting.  Its up to the Original Poster.   This is just little-ole-me's " two cents " worth of thoughts. 

 

Jeffrey  Medwin

 

 

Well, you are not wrong with any of it!

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