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I found a Hitachi SR-2004!

J

johndoe3

Well-Known Member
Banned
As I mentioned in another thread, I found a Hitachi SR-2004 at the city wide garage sale day yesterday. I was going to pass this particular sale by when I saw the seller grunting and groaning while hefting a giant silver receiver down his driveway. I quickly turned around and bought the sucker just while he was putting it down.
Curious, as this unit does not say Class G like my smaller SR-804. Rather, it says Dynaharmony on the right side of the faceplate. Above the tuning meter is says SAW Filter.
Check out the pics
 
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Awesome score!!! Dynaharmony and Class G are pretty much different names for the same circuit. Perhaps there were several versions of this receiver.

Don't forget to let us know how she sounds!!! :thmbsp:
 
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100 smacker-oons!

savv said:
ReEdger,

Just curious, how much did she cost you?
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Only a C note. I didn't bargain. I just plunked down the cash.
I am very happy. :banana:
So far, the big Hitachi sounds great. It really presses the point that it is a very powerful receiver. Hard to explain... This thing really feels like it has POWER. Well, as opposed to my SX-1980 which has a rather thin sound to it, especially for such a powerhouse. I hope that I am making sense. I will have to listen to it for a while to articulate it's sonic qualities a little better. All in all, I am very please with the way this big unit sounds. :D
 
The only concern the class G designs have is the presence of two crossover notches per channel instead of 1. This is because the design is basically two amplifiers in one. Two sinewaves superimposed. According to Hitachi the notches are very small and not detrimental to the sound. However, after 30 years it's worth checking the bias current. I wonder if there's two adjustments per channel... :scratch2:
 
ReEdger said:
Well, as opposed to my SX-1980 which has a rather thin sound to it, especially for such a powerhouse.
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Do both of your SX-1980's sound thin? That's a pretty high batting average, 1000!!!! :D

In my experience the SX-1980 is quite transparent. It will produce bass if the recording has it in the first place....
 
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crooner said:
The only concern the class G designs have is the presence of two crossover notches per channel instead of 1. This is because the design is basically two amplifiers in one. Two sinewaves superimposed. According to Hitachi the notches are very small and not detrimental to the sound. However, after 30 years it's worth checking the bias current. I wonder if there's two adjustments per channel... :scratch2:
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I have the service manual, so tell me.
 
There's only one adjustment per channel and a positive and negative terminal to measure voltage. I was looking at my SX-1980 manual and it has the same arrangement. Equivalent voltage on the Pioneer is 30 mV, meaning the output transistors are biased slightly higher at idle.
 
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crooner said:
Do both of your SX-1980's sound thin? That's a pretty high batting average, methinks....

In my experience the SX-1980 is quite transparent. It will produce bass if the recording has it in the first place....
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Only one of my SX-1980's works! The first one has given me nothing but fits since I bought it. It was constantly in the shop for one problem or another. I grew frustrated with the money pit, so I just parked it. If I remember correctly, it had similar characteristics as this running one. I don't know if it's a high batting average, but rather how 1980's just happen to sound to me.
Hear me out here. I'd still love the 1980 regardless if it were reknown for being the greatest sounding receiver of all time, or the worse. It's just so dang cool!
 
I know that the final product and sound doesn't depend on the method of acquisition, but secretly I believe that a cunningly hunted piece of gear responds to the hunter and produces lower distortion.

Don't get your saws near that SAW filter in your tuner-- it'll filter out all the pointy bits and dull 'em right down.

Seriously, the SAW device is one of the more fascinating of the wide variety of solid state widgets. I didn't know you could make motors out of 'em.

http://www.sensorsmag.com/articles/1000/68/main.shtml

http://www.intellect.pe.u-tokyo.ac.jp/research/sawmotor/sawmotor_e.html
 
Foos said:
Could you possibly scan the manual and post it?
Thanks
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The service manual is like 50 pages. Not including the fold out schematic. Scanning the whole manual and posting it wouldnt make the moderators happy.

If you like a copy of it, I could try to get copies of it made. The only fee for doing this would be a small donation to this site.
 
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