ericson38
Active Member
Wife spent $45 apiece for the Pioneer SX-1000TW and the Sansui 3300. Pioneer is 50 watts rms, <0.5% distortion. Sansui is 45 watts rms at 1 KHz, 0.4% distortion (1970 and 1972). Both have 4 gang FM tuners, and both have sensitive FM front ends.
I went through the bias and symmetry adj. for both of these unit (thanks mark the fixer for posting the Pioneer's procedure), which also works for the Sansui.
Driving a 8 ohm resistive load, the Pioneer clipped at 16.6 volts RMS AC across the load, for a 35 watt RMS output. You could hear the power supply strain (60 Hz buzz) with the 1 KHz tone, so most likely the 1000 uf 80 v power supply caps (there are two) have lost capacity and gained some ESR. Output voltage was clean all the way.
The Sansui results were 19.1 volts for 45 watts RMS. The Sansui power supply was wisper quiet, it uses a single 3000 uf rectifier cap.
They both use 1000 uf coupling caps to pass current to the speakers.
The AC RMS was read from the fluke 8012A, no conversion performed on the scope trace, which was over 50 volts peak to peak anyway, beyond the Tech 465 scope's range without a 10x probe.
Both units had a input/output phase shift, but between 100 Hz and 10 KHz, it was constant, within a couple of degrees (eye balling the scope).
Both units are what I would call true Woodies-the cabinets wrap around them completely.
They can both drive 4 ohm speakers. The Pioneer can drive two pairs, the Sansui 3 pairs.
Both of these units are strong in the base department, making the EPI 100's sound 10x what they are worth, compared to the Kenwood KA7100 sitting under the Pioneer (The KT815 Tuner though is in a league of its own).
This was back in the day when these companies made equipment to just sound good, they weren't into the THD arms race yet, and it was OK not to have a flat passband (since speakers were bass shy anyway), and they knew where not to make it flat. Later on, the arm chair techocrats weighed in on everything, and amps got flat, lower distortion, and speakers got more elaborate to create the bass for the listeners that the old woodies used to make with ease.
Don't pass up the chance at these early designs. Lights are easy to change, the MPX decoders are created on whole boards (not chip sets), and they do look cool. They are articulate, and warm doesn't mean muddy.
I went through the bias and symmetry adj. for both of these unit (thanks mark the fixer for posting the Pioneer's procedure), which also works for the Sansui.
Driving a 8 ohm resistive load, the Pioneer clipped at 16.6 volts RMS AC across the load, for a 35 watt RMS output. You could hear the power supply strain (60 Hz buzz) with the 1 KHz tone, so most likely the 1000 uf 80 v power supply caps (there are two) have lost capacity and gained some ESR. Output voltage was clean all the way.
The Sansui results were 19.1 volts for 45 watts RMS. The Sansui power supply was wisper quiet, it uses a single 3000 uf rectifier cap.
They both use 1000 uf coupling caps to pass current to the speakers.
The AC RMS was read from the fluke 8012A, no conversion performed on the scope trace, which was over 50 volts peak to peak anyway, beyond the Tech 465 scope's range without a 10x probe.
Both units had a input/output phase shift, but between 100 Hz and 10 KHz, it was constant, within a couple of degrees (eye balling the scope).
Both units are what I would call true Woodies-the cabinets wrap around them completely.
They can both drive 4 ohm speakers. The Pioneer can drive two pairs, the Sansui 3 pairs.
Both of these units are strong in the base department, making the EPI 100's sound 10x what they are worth, compared to the Kenwood KA7100 sitting under the Pioneer (The KT815 Tuner though is in a league of its own).
This was back in the day when these companies made equipment to just sound good, they weren't into the THD arms race yet, and it was OK not to have a flat passband (since speakers were bass shy anyway), and they knew where not to make it flat. Later on, the arm chair techocrats weighed in on everything, and amps got flat, lower distortion, and speakers got more elaborate to create the bass for the listeners that the old woodies used to make with ease.
Don't pass up the chance at these early designs. Lights are easy to change, the MPX decoders are created on whole boards (not chip sets), and they do look cool. They are articulate, and warm doesn't mean muddy.
