Author Topic: Pioneer SX-410  (Read 213 times)

Offline Bruce M

Pioneer SX-410
« on: June 18, 2018, 09:45:59 PM »
Hello Chaps

I picked this up the other day on the Gummer, mainly because tit has the same ECL82's as my SA-400.

It turns on, the valves glow nicely.... and no flames.

The guy I bought it from says he tested it, but no sound.

It seems to have a few extra small valves, I assume this is for the radio?

It has 4 off Philips ECL82's. My amp has Mallards on one channel, and what are probably the original Japanese units on the other.

Is it worth trying these out, and is there any risk of blowing something up? Or is it just semantics, if they work they work?

Apologies for any stupid questions.... Something quite alluring about these glowing things

Offline Ampdog

Re: Pioneer SX-410
« Reply #1 on: June 19, 2018, 02:42:03 AM »
Hi Bruce,

I take it you mean: Is it worth trying out with the Mullard valves instead of the Philips?

Firstly (and at the risk of upsetting a few souls): Valves of the same type (number) should work the same irrespective of brand. Valves work according to the characteristics given in data sheets - they have no sense of frequency, rythm or whatever else.

What is mostly the cause of honest perceptions of tonal difference is not the make, but spread in characteristics -  even with same brand. In 'modern times' the spread can be as wide as +/- 20%; almost 2:1!
(more's the pity, but that happens to be the situation.)

I would advise against randomly exchanging valves or other components willy-nilly; it is possible to cause irreversable damage. (And the customary warning: There are high voltages inside; don't fiddle unless you know what you are doing.)  Rather find someone capable of servicing valve equipment to check in an orderly fashion.

But perhaps something:  Many of these tuner-amplifiers have a sliding switch at the back for switching off loudspeakers. Check for such; They can be noisy or not-operating. If there be such, you could move then to and fro a few times. (Unfortunately most such switches in Japanese amplifiers become noisy/non-functional; not the best quality.)

Good luck!   
Audio must be the only branch of engineering where lack of basics' knowledge is considered a superior form of wisdom. (Anon)

Offline fredeb

Re: Pioneer SX-410
« Reply #2 on: June 19, 2018, 03:52:51 AM »

Just to the left of the speaker terminals there is an impedance selection switch - you could also try spraying this with an electrical contact cleaner and toggling the switch to and fro , so-as to remove any oxidation that may have built up . You may as well do it to all the same to all the switches and pots in the front of the unit . Be sure that the unit is unplugged , and even then be aware that electrolytic capacitors retain charge if they were not fitted with bleed resistors to discharge them .
...evolution is the gradual development and stratification of progressive series of wholes, stretching from the inorganic beginnings to the highest level of spiritual creation.
Jan Smuts

Offline Bruce M

Re: Pioneer SX-410
« Reply #3 on: June 20, 2018, 01:38:04 PM »
Thanks for the input guys.

I'll be careful.....