Do I need a DAC?

The OP is reporting the opposite. He is more concerned about the volume pot position being up too far: "Seems I have to turn the volume up to about three quarters before it starts bringing the 601's to life." "It is normal with the AU-9900 to have to turn volume way up to have powerfull sound"

Also, CD players have had a standard output of 2.0V since 1983. Sansui amplifiers have often had strange volume 'laws'- they are less conventional and arguably, more usable. He's used to the Yamaha where it all happens by 11o'clock on the dial.

130mV sensitivity rating on the AU-990 is for full power with volume pot fully rotated.
That sounds like what I'm asking about.
 
With the AU9900 putting out 80W @ 8 ohms maximum, and the 601's rated at 200W @ 8 ohms maximum; it may be that the Sansui is a bit low on power to adequately drive the speakers.
Kind of what I was starting to wonder. Going to try them with a pair of late 70's Kenwoods.
 
I think you'd be better off upgrading from the 601s than worrying about DACs. I lived with a roommate who had those, and my opinion is you're just not going to get dynamic sound out of them. They're at least 24 years old, too, and if you stick with them, it's probably time to think about replacing the crossover capacitors.
The 601's have been fully restored by certified shop this last winter. Will have to try different speakers, I agree.
 
If you need help spending your $$'s, you will find it on this site.

Do you want to play more than CD's?
If your FM dial doesn't do much for you there in Iowa. Mine doesn't play what I like where I live. You could try:
I'm very new to streaming, but I've enjoyed this:
For instance you could get a Chromecast "Audio" dongle, a $35 wifi music streamer w/builtin dac. Input analog to your amp. Control it remotely from a smartphone, for streaming internet radio stations (no subscription cost) and subscription music services.
Step up its sound quality further with an added inline dac and optical cable, between Chromecast and amplifier. I use a SMSL Sanskrit 6th. dac about $110. Just an example, a application to use a dac.

Welcome to AK!

You could try some different speakers too. Match them to your amps power and room accoustics. Good luck.
No streaming for me. I'm happy with my cd collection. I have a computer and small desk top system that is more than adequate for that use. But yeah, try some different speakers is what I need to do. Thanks.
 
And how relevant is that to the OP's issue, the sensitivity of the Sansui, or the price of fish?

Answer: it's not.

He probably needs to consider some much better speakers IMO.

The output level of CD players was an industry standard (for the 30 Japanese manufacturers in the consortium) of a nominal 2V RMS at 0dBfs. That translates to 5.66V PP. The front end impedance of the AU-9900 is rated at 50K.

Here is a typical CD player loaded with 10K ohms at full output:

View attachment 1295736



You are off on a tangent. Study the schematic.

The front end buffer stage is after the 250k volume pot. Overload is a non-issue in this particular case- he doesn't have the volume wide open or the amplifier anywhere near being driven to overload, either at the front end, the back end, or in the middle. Also, you have no idea what it will take to overload the AU-9900 front end. Even at the wide-open position- I can assure you it will be a whole lot more than 130mV.

Just for fun, try to overload the front end of a typical 150mV sensitivity preamplifier line stage and report back here with your findings. I'm happy to do the same with any number of preamplifiers and integrated amplifiers I have here if you cannot.

Where you have a high sensitivity line level buffer/gain stage before the attenuator/volume pot, overload from CD level sources could conceivably be a problem, but this is not the case here and is extremely rare except in some really ancient stuff.

Again, he is not talking about overload, in fact quite the opposite, he has to turn the volume pot further than he is used to. That is common with some models of Sansui. Again, it not the sensitivity*, it is the psuedo log/linear taper they used.

I have several AU-xxx series amps and they are the same- it was a Sansui thing.

* most amplifiers of that era had a 100-150mV into 50K for full power into a line (aux) source.

The Sansui concerned also has a three position 'level set' in addition to the -20dB muting cascaded one after the other. Hopefully that is set to the normal position too.
Yes, the 'level set' is in the normal position. So, in layman's terms your saying that the unit is in no danger of being run at 3/4 volume or higher? Please, I'm just a 50 something year old blue collar dude, no tech schooling. Give it to me straight doctor, maybe I'll absorb it.
 
Yes, the 'level set' is in the normal position. So, in layman's terms your saying that the unit is in no danger of being run at 3/4 volume or higher? Please, I'm just a 50 something year old blue collar dude, no tech schooling. Give it to me straight doctor, maybe I'll absorb it.

3/4 is pretty high, but as long as the amplifier is not being driven into clipping (that's pretty audible distortion that adds a metallic edge-like sound) and your speakers and ears can handle it, there's no problem.

Generally, speakers and ears give out before Sansui amplifiers.

Clearly, you like it loud, maybe look at some bigger, more efficient speakers? :)
 
3/4 is pretty high, but as long as the amplifier is not being driven into clipping (that's pretty audible distortion that adds a metallic edge-like sound) and your speakers and ears can handle it, there's no problem.

Generally, speakers and ears give out before Sansui amplifiers.

Clearly, you like it loud, maybe look at some bigger, more efficient speakers? :)
Yeah, 3/4 is high to me too. I'll be looking at more efficient speakers. Any ideas?
 
I'll be looking at more efficient speakers. Any ideas?

I would create a thread in the speakers forum and ask the guys. I'm not the bloke to ask as the last high efficiency loudspeakers I sold were big Cerwin Vegas back in the day (not exactly 'refined' to say the least).

There's heaps of big, powerful and large, good sounding and efficient American made speakers and I'm sure the boys will have plenty of suggestions. Tell them what you want.

Cheers.

PS, whenever I see 'Iowa' I think of Iowa class battleships; Iowa, Missouri, Wisconsin and New Jersey. :)
 
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Agreed with Restorer John. I installed _lots_ of 601s back when they were new and in larger rooms than you have. You must give the speakers space around them for the reflected sound to do its job. If that's not possible, you'll have the experience you getting now.

This has nothing to do with the relative position of the volume control. The 3 main variables for perceived sound pressure level are:

1) Size of the room

2) Relative efficiency of the speakers

3) How loud you tend to run the system.

Output power is determined by these same variables in most consumer installations, too. You've got plenty of power in either of the amps. That's not the problem.

I would strongly recommend that the crossover caps be swapped out. It is easy and cheap since the woofers are run full-range by design. Also, be sure that all the tweeters are operating, too.

Hope that helps.

Cheers,

David
 
Do you use a source other than CD? Turntable? FM? Laptop?

Or do you have another CD player you can try?

The question is whether or not you must turn the volume knob to such a high position with a different source. That's what I'm wondering.

Also, you wrote that the speakers were restored. Were any drivers replaced? And if so, were they replaced with originals?

If the speakers simply don't provide the volume you desire because they aren't efficient enough, a pair of Klipsch Fortes (or similar highly sensitive speaker model) would be an eye-opener for you.

Oh, also, what input do you have the CD player jacked into on your amp? Have you tried a different input? Does that change anything? Probably won't, but this is an easy check.

As for volume position, well, that isn't the only factor related to loudness or an amp's power output. For instance, some sources produce a lower output than others. If the source output is low, then you have to turn the volume control further to play the same loudness as a higher output source. The thing is, when you have a low output playing the same track on a CD with an amp and speakers, and match the volume with a CD player having a greater output through the same speaker/amp combo, then the amps are putting out the same power even though the positions of the volume knob are quite different.

The thing is, CD players usually don't vary that much (if one did, it would more likely be one with a variable output that was turned down, but even that would be rare, I think). Back in the vinyl days, such discrepancies were much more common because phono cartridge outputs could vary wildly in level. Some lower-output cartridges required rotation of the volume knob further. Of course, some MC carts output a level so low that they require stepping up before the amp, adding another component to the chain.

Also, source output impedance and amp input impedance can be mismatched and cause similar issues, but that shouldn't be a factor in this case.

Many tend to think that the setting of a volume control always results in the same power output at a given mark, but that's not the case. Still, three-quarters rotation does seem quite high, especially for a CD player as source. It would be helpful to know the SPL levels at which the speakers awake for you.
 
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