Is there anything more
fun than listening to E Skip? Or staying up all night logging long haul
tropo, or going to bed at 4am and getting up for work at 8?
MODIFYING THE DENON TU1500RD TUNER
and a side by side comparison with the Onkyo T450 RDS
One of our WTFDA members recently asked me to filter mod his Denon tuner. I found some free time one morning and I did it. I read that Girard Westerberg and David Williams both have 150khz filters in all 4 slots, so that's what I put in the Denon.
I swear that either Onkyo or Denon must have an industrial spy in the other's company because the Okyo T450RDS and the Denon are so alike. Both tuners are smallish and lightweight. I was amazed how little the Denon weighed. The filters on each unit are easy to locate. The Denon has four of them running from left to right. Everything is on one board and on the Denon the underside of the board is full of surface-mounted components that could be easily damaged by high heat. The Onkyo does not have this condition. The Denon's board is larger than the Onkyos. The front panels are alike in some ways. Even the backs are alike except for the plug-in AC line on the Denon.
After I did the mod, I took the Denon upstairs where my Onkyo is, split the 75 ohm coax from my APS-13
through a 2-way splitter to each tuner. Then I ran the audio cables from the Denon to the amp so I could A/B compare each.
I was a little bit surprised by some of the results. Here is what I found:
1. The selectivity of both tuners is the same. In other words, both modified tuners are hot.
2. The Denon decodes RDS faster than the Onkyo. Just a little faster. When I tune to a weaker station (the Bear, Greenfield, MA 95.3)the RDS light on the Onkyo will flash and try to lock while the Denon has already locked and is scrolling radiotext. The Onkyo will display "wait", waiting for radiotext while the Denon is already scrolling it.
3. The Denon mutes between stations while the Onkyo does not. The mute is annoying. No idea if it can be eliminated on that tuner.
4. The only way I could tune this unit was in manual (monaural)mode. If I switched into auto mode, which delivers stereo signals, the Denon will switch itself into scan mode and start scanning as soon as you touch the dial. Many times I forgot to switch back to manual tuning and had to retune to the freq I wanted. This feature alone would probably keep me from buying the tuner.
5. The Onkyo will show stereo on very weak stations while the Denon will not. This really surprised me. Sensitivity on both units is about same. I had CBM 93.5 and CKOI 96.9 Montreal (240mi) fade up from the noise level on both at about the same time. The Onkyo is quicker at delivering a noise-free monaural signal than the Denon. However, we're talking at signal levels way down in the mud here. With weak tropo, this condition might make the difference between hearing or not hearing a station if that signal is hanging around the noise level.
Some stations (WEQX 192.7 VT, WKVR 92.7 VT, WVAY 100.7 VT etc) would not show stereo while the Onkyo would. I don't see anything on the PCB you could adjust to change that condition. Another surprise!
I couldn't really measure overload, but 94.9 on both tuners is trashed this time of year(winter). I'm a little too far from the local transmitters to see much overload.
The Denon tunes from 87.5. The Onkyo tunes from 87.9. The Denon does 10khz steps; the Onkyo does 20khz steps. I don't see any advantage to the Denon's 10khz steps. Everything I heard on the Onkyo I heard on the Denon.
One other thing...could they have made the Denon's tuning dial any smaller? I can just see a bad case of carpel tunnel after working a big FM Es opening. If I owned one of these I'd be out looking to find a larger tuning dial, even if it didn't look good.
And as usual, all opinions stated here are mine and mine only and may not represent those of anyone else, for all I know.
Thanks for reading!
There you have it!Page created March 8, 2005
©2005-2012 M. Bugaj
No reprinting without my permission.