"Sangean Improves Upon Current HD Radio Tuner"

[R.F. Burns]

Anyone who's ever plugged component a into component b has eventually experienced hum caused by a ground loop. That doesn't signify a defect.

The "problem" Sangean is correcting is that the output of the tuner is "too hot". This 'defect', when mated with a properly designed amplifier (one which won't overload) actually results in a BETTER signal to noise ratio. The "fixed" tuner will have lower output, which means the amplifier will need to be turned up higher, which will result in more noise. Will this noise be audible? Probably not...but still in theory at least, the "defective" HDT-1 will result in superior noise performance compared to the "fixed" one.

I have a HDT-1 and the FM output is fine. The AM is overdriven. I have put a 10DB pad in line with the output to deal with this but I'm not sure the overdrive is at the output stage. If the audio is overdriven prior to the output and the radio is squarewaving, all it will do is lower the clipped audio output. Sangean is making a repair and doing it for free (a word some in here don't understand) The radio doesn't overload my Macintosh however. I'm looking forward to getting the 1X to draw comparisons. By the way, my wife had a 1987 Camray and there was a point where the power window and door lock buttons needed to be replaced. The problem was that Toyota made more than one type of power door lock & window button panel for that car, so you had to buy the right one using the serial number. The point being, even Toyota makes changes and modifications to current vehicles. They are called improvements. HD radio isn't alone in this. Unfortunately those with an agenda won't accept this fact because they won'tr allow reality to stand in the way of a good slander story. By the way, my radios clock is fine.

 

[Tom Wells]

I am stating that, regardless of claims that HD Radio is a defective technology, the Sangean receiver is not defective because it performs up to its published specifications.

Sangean HDT-1 HD Radio Component Tuner

Douglas W. Conmy (Nashua, NH United States):

"I had a couple of problems with the product, one which made it unusable for my use and I returned the unit. The first, fatal problem is that the power supply has a low frequency hum. I purchased the tuner for a home office, and will sometimes work without any music. I contacted the manufacturer hoping that it may have been a manufacturing problem, but they indicated that I should at least not hear the noise from "across the room". Even when the tuner is off, it draws power for its clock and continues to hum..."

http://www.amazon.com/gp/product/cu...ort_by=+OverallRating&s=electronics&x=10&y=12

Due to the thin sheet metal used, insufficient spacing between the power transformer and the case may be causing the large flat top panel to
reasonate at 60 hz from the magnetic field of the transformer. I presume this man is referrring to the device itself humming, not hum in an output.
High tech modern equipment is never really off, the primary winding is always powered, so the "wake up" circuit is ready.
What this often means is that when the load on the secondary is "heavy" with the device on, no hum is generated.
But when the load on the transformer is "next to nothing" with the device off, there is more "reflected" energy from hysteresis back into the primary, which keeps primary current down, but throws a much larger magnetic field from the transformer.
Thus it may hum when off, but not on. I have one tube radio with an "instant on" feature that was really bad about this.
I did not remove the filament-on "house-fire" circuit, but instead I now always unplug this particular radio.
But when I first got it and turned it off I removed the cover so it would not be there to have hum induced into it.

 

[Chuck]

Many of you may remember that I reported on my first impressions on the HDT-1, concluding that it is a pretty good tuner for $200. Today I had an opportunity that convinced me that it is a VERY GOOD tuner, at least in FM Analog.

One of our translators took a lightning hit last night, resulting in a loss of signal. Not knowing what to expect, I loaded my car up with enough spare stuff to cover most any situation. Among those spares was my HDT-1. Upon arriving at the site, I determined that the transmitter and Optimod processor were OK, but just off the air due to a loss of signal from the receiver. The Fanfare FT-1 tuner was on, but no signal was present, nor was any indicated on its signal strength meter.

I substituted the HDT-1 for the Fanfare. Still no signal. It turned out that the problem was a small distribution amplifier upstream from the tuner that is in the antenna line. When I bypassed the defective amplifier, the Sangean came to life and we were back on the air. To my amazement, it was operating cleanly it in stereo and it was a lot quieter than the very good Fanfare.

Because of the close proximity of the send and receive channels, (104.7 receive and 105.3 transmit) I'd never been able to get a quiet stereo signal with any tuner including the Fanfare which up to now, had been by far the quietest and most selective. Even so, I'd been running the translator in mono to get better signal to noise. The Sangean is doing much better. It is even scrolling our RDS display. Keep in mind that it is sitting on top of a 300 watt transmitter and is not being adversely affected by it. Most tuners just flip out under such conditions. I'm impressed.

HD or not, I think this is an exceptional tuner for the money. The Fanfares are a really great piece of equipment. The build quality is a lot better than the Sangean, and Fanfare's have features like muting relays, variable composite outputs and XLR balanced audio outputs. The Sangean has none of these. Still for $200, the Sangean is hard to argue with, even if you have absolutely no use for the HD part.