• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

HH Scott 222C receiver & 350B Tuner

Todd in fact was a vendor for Fisher. The size of the OPT in the K-14 is impressive, but it's doubtful that the transformer used in that receiver employed the same high quality grain oriented steel that their later transformers employed -- which makes the comparisons rather skewed.

Dave
 
Ok, got the AU70 out and measured the output transformer. The laminations are a stack that is 2 x 2.875 x 3.5 inches or a volume of 20.125 cubic inches.
 
So the Sansui transformers are physically bigger yet than the Fisher's by 6.0%. With this information then, the size is so close and there are enough other factors besides core size that can come into play that trying to determine which transformer might be a superior device by size alone would be folly. The frequency and power response performance of the Fisher SA-100 is a known quality -- it would be nice to know if any real world performance measurements have been performed on the AU70 as well. For me anyway, this puts the AU70's OPTs on the radar, where before I was generally not aware of them. I don't know how popular the AU70 was compared to the SA-100, so the Fisher has typically always gotten unchallenged top billing in the 7189 OPT department not only because of its established performance, but because of its popularity as well. Because the transformers are electrically identical in the SA-100 and X-202 integrated amplifier, I'm guess that the AU70 was a knock off of the 202? It doesn't look to have near the sophisticated small signal section with 5 tubes versus 8, but certainly fires a shot over the Fisher's bow with its transformers.

Thanks Primo for making the info available, and Batt for the off topic discussion. I have measured the performance of a Scott LK-48 (same transformers as the 222C) and they are certainly no slouch. As with most things in life, size isn't the only factor.......

Dave

Edit: Oops, I see the AU70 appears to have a SS phono preamp section so tube count alone is deceiving. Of course, Fisher made a standalone SS phono preamp back in the 50s at some point (one of Avery's claimed firsts), but never as a stereo piece, or as part of an otherwise vacuum tube offering.
 
Last edited:
dcgillespie said:
So the Sansui transformers are physically bigger yet than the Fisher's by 6.0%.

Dave

Edit: Oops, I see the AU70 appears to have a SS phono preamp section so tube count alone is deceiving. Of course, Fisher made a standalone SS phono preamp back in the 50s at some point (one of Avery's claimed firsts), but never as a stereo piece, or as part of an otherwise vacuum tube offering.
Click to expand...
I don't know if having the biggest opt on the block was a factor in the design but more like this and the AU111 were the "flag ship" products or statement products for the soon to be ended tube equipment line from Sansui. The 111 also had for 7581 output tubes, huge trannys. Here are the manufacturer specs for the AU70.
Power Output: 25watts into 8ohms(stereo)
Frequency Response: 10Hz-80KHz
Total Harmonic Distortion: 0.95%
Input Sensitivity: 0.9mV(mic), 1.1mV(MM), 50mV(line)
Signal to Noise Ratio: 52db(line)
Speaker Load Impedance: 8 ohms - 16 ohms

Valve Complement(Tubes): four - 7189, two - 6AN8 and three - 12AX7

This is "online information" for quick reference, and i need to check the AU70 owners manual to double check if there are errors.
 
Yeah, I saw the factory specs on one of the on-line sites as well. I believe the .95% THD claim was relating to 30 Hz at 20 watts RMS power output -- something that both the Fisher and the Scott can do as well.
 
Tom Bavis said:
Sams didn't cover the 222C (though the 222B has a folder) or any version of the the 350
Click to expand...

And unfortunately Tom, the 222B is not anything like the 222C with its 6BQ5 outputs. It took the place of the 299 series when HH Scott used the 7591 outputs. But still a very, very nice amplifier. Very straight forward, plenty of room under the hood and quite a performer.

Nice...
 
dcgillespie said:
Yeah, I saw the factory specs on one of the on-line sites as well. I believe the .95% THD claim was relating to 30 Hz at 20 watts RMS power output -- something that both the Fisher and the Scott can do as well.
Click to expand...
I checked my "Operating instructions and service manual", which shows the same info. The frequency response is 10 - 80khz + or - 1db. Which is very good is it not?
 
You must log in or register to reply here.
Back
Top Bottom