Vintage Asylum

Update _ bought the Yamaha ax-500.

85.19.92.6

beppe61

A

In Reply to: RE: Nikko na-990 _ what do you think of it ? posted by airtime on December 01, 2015 at 11:32:16

Hi !
i decided to buy also the Yamaha hoping that it is a better amp.
I did not like completely the pcb layout of the Nikko.
When i see high current paths made with thin and narrow traces i get a little puzzled ... what about the Ohm's law ?
I like when i see thick voltage rails and nice output cables to the speaker terminals.
I decided for the Yamaha because it should have a good transformer and the design seems quite basic and suitable for mods.
For instance the wires connecting the speaker terminals look poor.
Thanks again.
Kind regards,
bg

Follow Ups:

RE: Update _ bought the Yamaha ax-500. - airtime 14:24:11 12/02/15 (5)
This is typical of 80's style construction.
Cheap one board layouts with even cheaper parts.

What you're looking for is more in the 70's layout.
- RE: Update _ bought the Yamaha ax-500. - beppe61 23:05:12 12/02/15 (4)
  Hi and thanks a lot again.
  reading around i have the feeling that this ax-500 could be very close to what i need. It should have a robust current delivery (nice EI transformer. More recent models have weaker transformer, at least looking at the power consumption rating on the back).
  For comparison i attach the label of a more recent and similar Yamaha ... it has about 200W less of power consumption !!!!
  No wonder if the bass is weaker.
  And it must be easily serviceable because i would like to try it myself.
  The basic intervention ... replacing caps, bias trimmers and rewire it a little with nice speakers connectors and rca inputs for instance (i use only one channel).
  I could try even to make it a little but strong power amp.
  I love vintage british speakers. Kef, B&W, Celestion and so on.
  They are very common here where i live now (Norway).
  They are extremely well toned ... with a very nice sound.
  But they usually come with plastic woofers that need current to come alive.
  I know that i should go for something like a great old Threshold ...'
  maybe next step.
  Now i am crossing my fingers for this little Yamaha.
  Thanks again.
  Kind regards,
  bg
  
  Edits: 12/02/15
  - RE: Update _ bought the Yamaha ax-500. - Crazy Dave 07:53:16 12/03/15 (3)
    It certainly is a good choice to cut you teeth on leaning to service gear. Make sure you discharge the filter caps before you work on the unplugged receiver.
    
    Dave
    - RE: Update _ bought the Yamaha ax-500. - beppe61 09:29:53 12/03/15 (2)
      Hi and thanks a lot for the precious advice.
      I think i will have to use a resistor maybe ?
      I would like to add that also the Nikko sounds very good to my ear.
      But the pcb design i do not like at all. Small traces even for high current lines ... what were they doing ?
      Potentially they had a very powerful amp indeed. 540W of max power consumption. A pity.
      Thanks again.
      Kind regards,
      bg
      
      Edits: 12/03/15
      - RE: Update _ bought the Yamaha ax-500. - Crazy Dave 09:31:47 12/04/15 (1)
        
        In Reply to: RE: Update _ bought the Yamaha ax-500. posted by beppe61 on December 03, 2015 at 09:29:53
        
        I wouldn't write off the Nikko. Size isn't everything!
        
        Dave
        
        RE: Update _ bought the Yamaha ax-500. - beppe61 02:52:58 12/05/15 (0)
        
        In Reply to: RE: Update _ bought the Yamaha ax-500. posted by Crazy Dave on December 04, 2015 at 09:31:47
        
        Hi and thanks again.
        I did not want to discredit the amp at all. I just see some lack of attention for details that only details are not.
        I believe in designs without bottlenecks.
        And actually i see some efforts to increase the section of the voltage rails. They have soldered on them some wires ... but they are the size of a thick hair !!! i mean ... they are very very thin !!???
        To end my ramblings i see some pcb available for DIY that they appear so much better designed that is unbelievable really.
        Just a little more attention in pcb design could pay big benefits ... i am sure of this.
        Mostly of course for the voltage rails ... i like them very thick and solid and low resistance.
        Maybe this is what separates a good amp from a very good amp.
        Thanks a lot again for all the precious advice.
        Kind regards,
        bg

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