View Full Version : G-4700 into 4 Ohms


yosl
08-13-2011, 05:16 PM
I picked up a nice set of 2-way 4 Ohm speakers and I'm wondering whether I can drive them with my G-4700 without over stressing the unit. On the back it says specifically 8 Ohm or higher yet most of my other units from the era (not necessarily Sansui) can accomodate 4 - 16 Ohm on A and 8 - 16 Ohm on both A & B. Was Sansui just being conservative or is it an indicator that this was a "cheaper" receiver line than the G-X000 series and their integrated amps from the same time frame, i.e.: will the components handle the higher loads?

Sorry, I know this question has been asked but I can't find a ready answer.

kevzep
08-13-2011, 06:44 PM
I picked up a nice set of 2-way 4 Ohm speakers and I'm wondering whether I can drive them with my G-4700 without over stressing the unit. On the back it says specifically 8 Ohm or higher yet most of my other units from the era (not necessarily Sansui) can accomodate 4 - 16 Ohm on A and 8 - 16 Ohm on both A & B. Was Sansui just being conservative or is it an indicator that this was a "cheaper" receiver line than the G-X000 series and their integrated amps from the same time frame, i.e.: will the components handle the higher loads?

Sorry, I know this question has been asked but I can't find a ready answer.

I just looked up the specs and it does not give any performance figures at 4ohms, given this and my experience with these amps, I would stick with an 8ohm load, however other receivers in this series like the G-7700 can do a 4ohm load.....problem partly due to the economy of design these amps dont handle a great deal of current......
It may well drive them but it will probably run quite hot, and if you turn it up it might just tip it over the edge.....

yosl
08-13-2011, 07:57 PM
I just looked up the specs and it does not give any performance figures at 4ohms, given this and my experience with these amps, I would stick with an 8ohm load, however other receivers in this series like the G-7700 can do a 4ohm load.....problem partly due to the economy of design these amps dont handle a great deal of current......
It may well drive them but it will probably run quite hot, and if you turn it up it might just tip it over the edge.....

Probably good advice but I just checked the 221 in my daughter's room and it's rated for 4 Ohms. Rather ironic that a baby receiver putting out a measly 12 wpc (if I'm not mistaken) can out do the G-4700!

kevzep
08-13-2011, 09:00 PM
Good excuse to buy a monster Sansui then....G-9000DB perhaps??....:D

yosl
08-14-2011, 12:14 AM
The presumption is that I don't have a few more arrows in my quiver, as it stands I have a G-8000 and a G-7700. That's not the point, I'd like to drive these speakers with a G-4700. So far what I've heard is a reference to the specs. Although it reinforces what I suspect, who I'd really like to hear from is someone can tell me technically what the G-4700 can handle.

kevzep
08-14-2011, 03:12 AM
The presumption is that I don't have a few more arrows in my quiver, as it stands I have a G-8000 and a G-7700. That's not the point, I'd like to drive these speakers with a G-4700. So far what I've heard is a reference to the specs. Although it reinforces what I suspect, who I'd really like to hear from is someone can tell me technically what the G-4700 can handle.

Given Sansui dont give any performance figures for 4 ohms, thats a good technical indication the amplifier is not suited to drive 4 ohm loads....

In my technical view as a technician, and the experience I have with these amps, I would also say, as they are just pushing one single pair of TO-3P's per channel, this would be another indication they are not really suited to drive 4ohm loads..........

However you will get away with it at low levels, but its not something I would recommend.

Sorry about the presumption, as you dont have your arrows plastered across the bottom of the page, its hard to know what you have.....:D

Hyperion
08-14-2011, 09:32 AM
The presumption is that I don't have a few more arrows in my quiver, as it stands I have a G-8000 and a G-7700. That's not the point, I'd like to drive these speakers with a G-4700. So far what I've heard is a reference to the specs. Although it reinforces what I suspect, who I'd really like to hear from is someone can tell me technically what the G-4700 can handle.

By this I presume you mean someone who has or is running 4 ohm speakers with a G-4700 ? - if this is the case then you are most likely to find people who have 4 ohm speakers (likely not the same as yours) with flat impedance curves, and thus may have not experienced amplifier component failure doing it. You don't say what these speakers are - so how can all we know how well behaved they are, impedance wise?

Remember your first post says "On the back it says specifically 8 Ohm or higher" - you cannot assume that just because other Sansui models can drive 4 ohm loads that by implication the G4700 can too !

What Kev says is the bottom line - effectively, it's not recommended and if you do drive those 4 ohm speakers, do so with the greatest of caution, the G4700 does not drive 4 ohm natively and with ease.

yosl
08-14-2011, 01:06 PM
Thank you gentlemen, your advice will be heeded.

PS: Rather sad that the 4700 is limited relative to its elder brethren.

ericson38
08-15-2011, 06:50 PM
I have a G4700 that has been driving a pair of Yamaha NS 670s for years.

The 4700 main drivers are flat pak 2SA1102s (TO-218 package), which are not as hefty as T0-3 style cans. This transistor can take 6 amps (Ic max).

A similar, but earlier Sansui I own is a 771, which is rated for both 4 ohm loads and 8 ohm loads. It is a 40-55 watt per channel unit, depending on load and frequency being amplified. The drivers here are 2SC1402 (TO-3 case) types, and Ic is 8 amps.

I definetly like the sound of the 771 and 881 series amps more than the G4700 and G5700, but the later's FM lock feature is very convenient for casual listening.

kevzep
08-15-2011, 08:03 PM
I have a G4700 that has been driving a pair of Yamaha NS 670s for years.

The 4700 main drivers are flat pak 2SA1102s (TO-218 package), which are not as hefty as T0-3 style cans. This transistor can take 6 amps (Ic max).

A similar, but earlier Sansui I own is a 771, which is rated for both 4 ohm loads and 8 ohm loads. It is a 40-55 watt per channel unit, depending on load and frequency being amplified. The drivers here are 2SC1402 (TO-3 case) types, and Ic is 8 amps.

I definetly like the sound of the 771 and 881 series amps more than the G4700 and G5700, but the later's FM lock feature is very convenient for casual listening.

2SA-1102 are TO-3P....

ericson38
08-16-2011, 04:47 PM
Here's a link to the datasheet and some pictures I just took-

http://alltransistors.com/transistor.php?transistor=6914