What can I do?

[Alex Kramer]

I bought an Aiwa ad-6550 off ebay. I got everything mechanically working nicely, cleaned and aligned the heads and it makes sound. The sound it makes isn't as good as I expected. The high end on any tape I play is quiet and very dirty. Dolby NR off and the correct tape is selected. This deck is from the late 70's so should I expect this? Is there anything I can do or check? I can troubleshoot basic circuits so maybe I can swap out some caps.

 

[Mark_71]

I have an AIWA M700 and an AD-6900. I refurbished the M700 myself and bought the 6900 already done. The 6900 is the better deck (crazy double needles), but I've noticed it sounded a bit muddy at times compared to my other decks. I was surprised. I found I needed to turn up the treble a bit on the amplifier to get the sound I wanted. Other than that, they're both solid decks. I also gave mine a good DeoxIT bath too, including Q-tips in the RCA connections. I didn't swap out any caps.