using my Vintage Sansui 331 as integrated amp

[Mason Safari]

Hi all

 

I have never been in Vintage amps ... as Sansui 331 looks very nice, I bought a very good looking one  ( inside and  outside) ... I have 3 issues and can get your help 

1- cant get any radio signal  ... I guess I need antenna ?

2- It has strong smell , not sure it is usual or something going on inside ?

 

3- more importantly, I tried to use it as a integrated amp ( I assume it is a one) so I connected my DAC RCA to the Aux input and can get very very low sound... when I connected to Phono I could get stronger sound but still not loud enough... when I connect my iphone ( through 3.5" jack to RCA) and then I got strong and normal sound and somehow nice... but obviously I want to use it with my DAC ...so not sure what's going on ...I tried all differed DACs and ended up with same issue ...

 

appreciate if you can let me use your experiences here 

 

Regards

Mason

[Domo]

26 minutes ago, Mason Safari said:

Hi all

 

I have never been in Vintage amps ... as Sansui 331 looks very nice, I bought a very good looking one  ( inside and  outside) ... I have 3 issues and can get your help 

1- cant get any radio signal  ... I guess I need antenna ?

2- It has strong smell , not sure it is usual or something going on inside ?

 

3- more importantly, I tried to use it as a integrated amp ( I assume it is a one) so I connected my DAC RCA to the Aux input and can get very very low sound... when I connected to Phono I could get stronger sound but still not loud enough... when I connect my iphone ( through 3.5" jack to RCA) and then I got strong and normal sound and somehow nice... but obviously I want to use it with my DAC ...so not sure what's going on ...I tried all differed DACs and ended up with same issue ...

 

appreciate if you can let me use your experiences here 

 

Regards

Mason

I had one of those a LONG time ago - a Sansui 331 and a pair of AA3900s is about a common combo as you can find in the back of a shed somewhere. You'll definitely need an antenna to pick up FM radio, a length of speaker cable split down the middle and connected to the "FM 300ohm" terminals should get you up and running. There's no good reason why you'd get decent volume with your iPhone but not with your DAC connected to the same AUX input. You'll have to do some investigating. You can try wiggling the RCA connectors when they're hooked up, try seeing if you can get any volume from the headphone jack, try flipping the selector knob around a lot - make sure you've got the input set on "AUX" (and the tape monitor OFF) and the speaker selector on the same set of outputs you've connected your speakers to, try swapping around between the "A" and "B" sets, you can try connecting to the "TAPE PLAY" input and pressing the tape monitor button instead, you can try giving the balance and volume knobs a really good spinning (when the power is off) just in case they're making bad contact, and as for the smell - can you be more specific? Is it a burning electrical smell, or is it more like cigarettes or a damp closet or cat piss? Coz you only really need to be concerned if it's the former  

[Mason Safari]

10 minutes ago, Domo said:

I had one of those a LONG time ago - a Sansui 331 and a pair of AA3900s is about a common combo as you can find in the back of a shed somewhere. You'll definitely need an antenna to pick up FM radio, a length of speaker cable split down the middle and connected to the "FM 300ohm" terminals should get you up and running. There's no good reason why you'd get decent volume with your iPhone but not with your DAC connected to the same AUX input. You'll have to do some investigating. You can try wiggling the RCA connectors when they're hooked up, try seeing if you can get any volume from the headphone jack, try flipping the selector knob around a lot - make sure you've got the input set on "AUX" (and the tape monitor OFF) and the speaker selector on the same set of outputs you've connected your speakers to, try swapping around between the "A" and "B" sets, you can try connecting to the "TAPE PLAY" input and pressing the tape monitor button instead, you can try giving the balance and volume knobs a really good spinning (when the power is off) just in case they're making bad contact, and as for the smell - can you be more specific? Is it a burning electrical smell, or is it more like cigarettes or a damp closet or cat piss? Coz you only really need to be concerned if it's the former  

Thanks Matthew , really appreciate it...

 

good thing is I am given the original instruction manual... it says  that the AUX : almost any instrument have input sensitivity  of 150mv should be able to be connected to AUX... need to check output of my DACs... also the smell is light electrical burning type but not in a bad way... maybe the unit has not been used for long time and the smell goes away...the inside is very clean, I also clean all the switches so maybe smell is like that... it reminds me old days this smell could come from our old TV... maybe it is as part of the vintage experience...  

[wen]

I am currently using a Sansui 331 in my study system with a Marantz CD52MK II SE and custom DIY 8" full range drivers, also used Opera 1A/ Duetto speakers, have a standard wire antenna that came with a NAD Tuner, picks up most stations. Had an issue with left channel dropping out, used electrical contact cleaner on all switches and dials, problem resolved. Absolutly love the sound of this unit, previously had a Sansui 555A, which i moved on, in my humble opinion the 331 sounds miles better, considering sourceing an 881 and redefining my whole stereo setup 

[Mason Safari]

Thanks Wen

I liked it so far ...it has a very smooth sound...even the headphone has decent sound ... not very powerful but nice... it is hooked to my expensive Herbeth speakers , funny combinations  

 

have you ever used  it with any DACs?

 

Mason

[muon*]

Nice Receiver

 

Just a word of caution to never connect a line level device like a DAC to the Phono input, the phono input is for a much lower level signal and applies RIAA equalization to the signal as intended for a turntable.

 

As has been suggested, pots and switches likely need a clean.

 

It's around 45 years old, a recap might be desirable.

[sloper]

Get it cleaned and capped.

 

There is no such thing as owning one Sansui.

 

regards Bruce

[muon*]

We might need to be clearer and say a 'recap' or 'get it capped' means full replacement of all the electrolytic capacitors in the 331, electrolytic capacitors dry out over a long life and end up drifting out of original specification, or at worst they die, maybe swell and leak.

[Mason Safari]

I had a look inside again, it is super clean even might be recapped or at least been serviced recently … I think issue is the AUX sensitivity is not enough to accept current from my DACs… 150ma…when I connect to my phone or the headphone out of my headphone amps then it works perfectly … I’m interested to know anyone could connect DAC directly to 331 ?

[muon*]

Can you post a pic of the internals, we can tell if it has been recapped.

 

Do you have a different DAC or a CD/DVD player to try with it?

[Mason Safari]

I will take pictures later…I tried with all dacs…if I use my Chord Dave as Pre amp with high volume then it works, as only DAC is very weak signal. When I use headphone jack to RCA and then it works perfectly … also could get FM signal very strong … so it should be perhaps those days as there were no DAC, none of the inputs is sensitive enough for weak DACs outputs?

[muon*]

There were no CD Player either and the DAC's and CD & DVD players I had when I had my Sansui AU-555 and AU-505 worked only too well as far as levels go, and those are older than your 331.

 

Edit: unless your DAC is unusual and not like 99% of DACs.

 

Vintage gear like the 331 expected input levels that were lower than what modern DAC's and Players output, as the source gear had lower output levels in those days.

Edited September 9, 2021 by muon*

[wen]

@Mason Safari have not used a stand alone DAC in any of my systems.

I would be very careful using the 331 with your Harbeth's, could damage the speakers with such low power amp . My DIY speakers are 8 ohm and 95dB/w/m efficient, a good match for the 331

[Mason Safari]

3 hours ago, wen said:

@Mason Safari have not used a stand alone DAC in any of my systems.

I would be very careful using the 331 with your Harbeth's, could damage the speakers with such low power amp . My DIY speakers are 8 ohm and 95dB/w/m efficient, a good match for the 331

Thanks Wen,

My Harbeth is small  P3ESR with  Impedance 6 ohms, and Sensitivity 83.5dB/1W/1m also I used my KEF LS50... to me 331 easily could drive them very similar to my Luxman 550AX ?   so what am i missing , should I still be worry ?

[Mason Safari]

4 hours ago, muon* said:

There were no CD Player either and the DAC's and CD & DVD players I had when I had my Sansui AU-555 and AU-505 worked only too well as far as levels go, and those are older than your 331.

 

Edit: unless your DAC is unusual and not like 99% of DACs.

 

Vintage gear like the 331 expected input levels that were lower than what modern DAC's and Players output, as the source gear had lower output levels in those days.

Thanks Muon

it it is the case, something should be wrong here...I have tried different DACs...same result... using the headphone out from iphone or headphone amp and work perfectly... i wish if @wen could try a DAC with his 331 so then be 100% sure 

[muon*]

I see no reason for it not to work.

 

I'd suggest the 331 need a look at.

[wen]

From memory every 3db difference is a doubling value for performance.

A speaker of 83.3 dB/w/m to reach 95dB/w/m will need about 4 times the power to get the same volume output, which i would say makes the 331 work hard to get a decent volume, hence the risk to damage your speakers, if components are not up to spec, the risk would be higher

[muon*]

Yeah, could be driven into clipping and damage the speakers.

[Mason Safari]

Thanks Wen and and Muon... correct me if I am wrong but I cant even pass 3 on volume ( out of 10) as it will be very loud ( i have a small room)  , I thought this shows that amp is very comfortably driving my speakers... so what I m missing here ?

[wen]

if that is the only volume you get to you should be ok, but keep the theory in mind, they are expensive speakers. My room is 4m x 2.8m, the speakers are on the long wall, use of the room makes it impractical to put speakers on the short wall, i rarely get to 1 on the volume dial

[Mason Safari]

25 minutes ago, wen said:

if that is the only volume you get to you should be ok, but keep the theory in mind, they are expensive speakers. My room is 4m x 2.8m, the speakers are on the long wall, use of the room makes it impractical to put speakers on the short wall, i rarely get to 1 on the volume dial

in this case  i might take it to my workshop where I have a pair of KLIPSCH RP-150M so can do more experiences there  and also inspect inside... but is it possible you try the DAC direct to AUX to your 331 , im curious mine has issue or all of them are like this?

[pete_mac]

The AUX input on the 331 is intended for connection to any line-level source, whether a DAC or CD player or the like. You should have no problem achieving more than adequate volume levels.

 

I suspect your amp needs servicing at a minimum - cleaning the controls and switches  with an appropriate lubricating contact cleaner or DeOxIt would be the first port of call.

[matts19]

On 08/09/2021 at 8:01 AM, Mason Safari said:

Hi all

 

I have never been in Vintage amps ... as Sansui 331 looks very nice, I bought a very good looking one  ( inside and  outside) ... I have 3 issues and can get your help 

1- cant get any radio signal  ... I guess I need antenna ?

2- It has strong smell , not sure it is usual or something going on inside ?

 

3- more importantly, I tried to use it as a integrated amp ( I assume it is a one) so I connected my DAC RCA to the Aux input and can get very very low sound... when I connected to Phono I could get stronger sound but still not loud enough... when I connect my iphone ( through 3.5" jack to RCA) and then I got strong and normal sound and somehow nice... but obviously I want to use it with my DAC ...so not sure what's going on ...I tried all differed DACs and ended up with same issue ...

 

appreciate if you can let me use your experiences here 

 

Regards

Mason

 

Regarding 3, I have the same issue with my AU-222 whose AUX input sensitivity is 150mv at 100k ohm. Like you I have no problem feeding signal from my phone or even USB-powered portable DAC whose line out voltage is 1.5V. However from my other DACs with 2V line out the volume is extremely low. I would think it should be opposite, I do not understand why... have you by any chance resolved this issue ?

 

Update: well it turns out any DAC with coaxial input shows this behavior (low volume). Any DAC with USB input works, regardless of output voltage level & impedance. Weird but true. Even on the same DAC, USB works and COAX won't.

 

Edited January 3, 2023 by matts19