Sharp GF-508 / 9696 question...

[analogboi]

Hi All,

Do these Sharp boxes (they are the same I think) have a bridged (BTL) amp like the M70 or M90? I'm searching for more boxes with bridged amps. Thanks!

 

[ClaretBadger]

wha?

Really? I'm gonna get me one of these if they do!

Pitch control and trick amps! Love it.

 

[Superduper]

HA1392's.

 

[MasterBlaster84]

Thanks SD, I found some good info on that chip.

The Hitachi audio power Ie HA1392 is specifically designed for cassette-radio, encapsulated in 12-lead single-in-line plastic
package. The HA1392 delivers 4.3 watts per channel under 12 volt power supply and 6.8 watts under 15 volt power supply to 4 ohm load.
• FEATURES
• A low quiescent current (36mA typ) for efficient battery·operation.
• Designed for low crossover distortion under a low idling current.
• Audio muting circuit included, providing 60dB typ of muting attenuation just by 5mA of muting control current.
• No electrical isolation needed for simple chassis-mounting.
• Dual power amplifiers provide 4.3W typ under 12V power supply voltage and 6.8W typ under 15V power supply voltage. (R L =4 ohms, THD = 10%)
• Internal thermal protection.

 

[analogboi]

I found the schematic to the 9696. As SD noted, two HA1392s into a 8 ohm load (so 4 ohms BTL). Each channel makes about 12-13 watts on fresh batteries or AC cord. That's comparable to the M70.

So, my next question... what does this box sound like? Owners...?

 

[Superduper]

I found the schematic to the 9696. As SD noted, two HA1392s into a 8 ohm load (so 4 ohms BTL). Each channel makes about 12-13 watts on fresh batteries or AC cord. That's comparable to the M70.

So, my next question... what does this box sound like? Owners...?

Actually, the M70 is 7wpc RMS into 8 ohm load and the GF-9696 is spec'd at 7.5wpc RMS. Also, these amps are usually rated at 4 ohm load SE but load typically needs to increase to 8 ohms when operated in bridged configuration.

As for sound -- it's really a personal thing. Everyone's ears are different. To me, the M70 sounds better than the GF-9696.

 

[eldorado]

SHARPS RULE

 

[jaetee]

As for sound -- it's really a personal thing. Everyone's ears are different. To me, the M70 sounds better than the GF-9696.

I have good working copies of M70 and the GF-9696. I'd have to agree with SD. Both are great boomers. But, the M70 just seems to have more kick to the low end and the case seems better matched with those woofers. When it comes to the mids & highs, the edge goes to the 9696's 3-way speaker system.

I have noticed that the right side woofer of my 9696 sounds a bit stronger than the other side, and when you open up the box you can see that there's considerably more electronics and such tucked behind that speaker, which I think might reduces the overall amount of bass it can produce.

(Can anyone else check theirs?) Is it just a bit more bassy on the right vs. the left? OR maybe my 9696 has a slight problem with the left channel???

 

[monchito]

blt amped boxes will be alot of them as most boxes have dual chip configuration the m70 uses 2 an7145 chip in a blt config the small panny rx-5090 has the same chip but only 1,,, if you are looking for higher powered boxes i will name just a few but do not be surprized that even smaller boxes used dual chips too,, m70,m90 sanyo has a lot of boxes with the br532 chip 920,720,9998,9994 9975 hitachi has a few also panasonic has some also the 5500,5200,7000, uses 2 br532 just like the sanyos so there a lot of boxes with 2 chips,,, aiwa cs-880 uses2 of the an7146m vesion but the cs-600 only 1 ,, the sharps like the gf series uses the ha1392 chip the 777 the 508 ,9494x 9696 use a different chip but have 2 also

 

[redbenjoe]

hey moncheedoz --
thanks for the big contribution --that was very interesting

 

[Superduper]

Ramon. I think the amp in the Sanyos is the BA532 chip although a few of the earlier ones used the BA521 chip. The Sharp 777 does use 2 of the HA1392 but they are SE and not BTL. The GF-9696 also use 2 of the the HA1392 modules as well but in a BTL arrangement. The 9494 uses the TBA-810S-H module. Not coincidentally, all these boomboxes that use these amps are terrific performers. The easiest way to tell whether a boombox uses a BTL amp arrangement is to look at the speakers. If they are 8 ohm speakers, it's almost a sure sign that it uses a BTL amp arrangement whereas 4 ohm and under speakers likely indicate SE applications. The higher output voltages are needed to drive the higher impedance drivers. On the other hand, amps operated in BTL mode shouldn't be operated with those low 3.2 - 4 ohm speakers as the amps could overheat.

 

[monchito]

thanks norm as always the great info but it was mainly the chip an7145m that i saw mention on the specs the btl config thats exactly why the m70 has the 8 ohm speakers and the high 15v supply i tryed to scource the an7145h which was still a higher rating but its been discontinued for a long time still alot of the boxes do a very good job even with one chip.....

 

[Superduper]

One advantage of using 2 amps instead of 1 is that the output sine wave has twice the output wave deflection therefore, higher voltage, which can drive higher impedance drivers. Also, when 2 amps are used, the inputs are much more immune to inteference and generally don't need to be shielded.

Of course BTL amps also means also that the speaker outputs need to be floating ground and not common ground so greater care needs to be observed when connecting speakers and headphones, etc. That doesn't necessarily mean that single amp configurations are necessarily wimpy. That's because most single ended amp configurations use lower impedance drivers allowing greater current flow, and hence observed power.

As for the AN7145M -- yes, that chip can be used in BTL configuration but it can also be used as a dual SE application as well. The AN7145L is a low voltage version (6volts) while the AN7145M is rated for 9V, 12V and 13.2V whereas the AN7145H seems to be accept 16V.

 

[ghiok]

One advantage of using 2 amps instead of 1 is that the output sine wave has twice the output wave deflection therefore, higher voltage, which can drive higher impedance drivers. Also, when 2 amps are used, the inputs are much more immune to inteference and generally don't need to be shielded.

Of course BTL amps also means also that the speaker outputs need to be floating ground and not common ground so greater care needs to be observed when connecting speakers and headphones, etc. That doesn't necessarily mean that single amp configurations are necessarily wimpy. That's because most single ended amp configurations use lower impedance drivers allowing greater current flow, and hence observed power.

As for the AN7145M -- yes, that chip can be used in BTL configuration but it can also be used as a dual SE application as well. The AN7145L is a low voltage version (6volts) while the AN7145M is rated for 9V, 12V and 13.2V whereas the AN7145H seems to be accept 16V.

Yes, the RX-7200 use two AN7146M same as M70. But if you use AN7145M in BTL with 15v on 4-6ohm, it easy to put a bigger radiator to resolve the extra heating.

 

[shane higgins]

In my opinion my gf9696 kills my m70
The gf is so loud
the m70 is very clear but just don't sound like the gf
So all in all there not a c100 but still very nice

 

[JLF]

Interesting!

My M70 would destroy both my GF-9696 and GF-508ST together! Its the main reason why I sold them! They are so cool to look at, but as I use a box from my collection daily, I was terribly disappointed in their performance.

They were both well used, survivor boxes, and my M70 was a one owner Mint BBX. So perhaps my experience isnt the best to judge by?

 

[shane higgins]

Interesting!

My M70 would destroy both my GF-9696 and GF-508ST together! Its the main reason why I sold them! They are so cool to look at, but as I use a box from my collection daily, I was terribly disappointed in their performance.

They were both well used, survivor boxes, and my M70 was a one owner Mint BBX. So perhaps my experience isnt the best to judge by?

i have had this conversation on here before maybe i got a :superduper: gf 9696 because the m70 works great
just tested them again the gf 9696 has way more range than the m70
and about 5% more volume and 15% more bass so story over