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Denon HA-500 Phono Head Amplifier

J

jagdesign

pfm Member
I have a lovely example of this which will be looking for a new home soon as I just don't have space. I recapped it a couple of years back with uprated Nichicons and Panasonic electrolytics, as per instructions created by Phonomac on another forum, possibly AOS.

It sounds sublime, however, even before recapping, it has an occasional niggle whereby, on switching the unit on (to one of the gain settings), one channel doesn't come on until the gain selector is wiggled ever so slightly, left and right. I think I did try cleaning the contacts on the rotary switch a while back, but it seemed to persist. I'm wondering if it might be the relay?

I have the full service manual, but here's the circuit diagram
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and a couple of pics of the unit in question
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Any thoughts or help much appreciated. It's such a lovely thing and would be great to have it working 100% again.
 
Examine all the solder points on the rotary switch with a magnifier just in case there is a tiny crack/dry joint. If all ok it must be the rotary switch. All you can do is put a good qty of contact cleaner in through the holes and work the switch a few times. (Same symptoms as my v. old 'scope)
 
I ended up going with this so I could get it quick, think the can will last me a while - it's huge!

Pleased to report after a light spray on the switch, it's playing beautifully again, so much so in fact, that I questioning selling it again ☺️. Thanks @a.palfreyman
 
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Quite a few will not know what a head amplifier is......

It is the active equivalent to an SUT, it amplifies an MC output to the level of a MM cart'.

I use one here into a Croft Micro - far better than any phono-stage that I have tried to something like £800-1000 new.

I bought mine in Japan - what is the voltage (an Airlink transformer will cost £40).
 
Vinny said:
Quite a few will not know what a head amplifier is......

It is the active equivalent to an SUT, it amplifies an MC output to the level of a MM cart'.
Click to expand...
I used a Lentek battery jobbie for a while with AT and Ortofon MC's but found it a little noisy - hence built the HFW MC phono amp which served me well for a long time.
 
@Vinny I'm currently using an RJM Emerald DIY phono stage, which is doing a very nice job, but must admit, I haven't even tried the HA-500 into it in MM mode, mainly as I went through a bit of a box count cull a couple of years back (spurred on by a growing family), and I fear it may eat the Emerald's MC section alive!

Prior to the Emerald, the HA-500 was replacing the SUT's in my EAR 834P, and again, revealed a lot of the shortcomings with the stock SUT's. It's a very nice piece of kit from the heyday of analogue.
 
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