Hello, I'm new here. An I have some gain issue of my Sansui AU117 amplifier.
I think the gain are slightly under. I Just need a few db of gain to satisfied my listening level. Currently the volume have to go up to 1 oclock position. MM cartridge I use was 3.5mV. My question is, is there any way to increase the gain by changing some resistor on the board? Hope some expert & guru will help of my phono gain problem.
The attached schematics are the Sansui Phono section. Thank you.
I think the gain are slightly under. I Just need a few db of gain to satisfied my listening level. Currently the volume have to go up to 1 oclock position. MM cartridge I use was 3.5mV. My question is, is there any way to increase the gain by changing some resistor on the board? Hope some expert & guru will help of my phono gain problem.
The attached schematics are the Sansui Phono section. Thank you.
Attachments
Those old BJT,s aren't high gain but 2SA726 can be replaced with BC560C or if less gain is required the "A" or "B" versions --all three are low noise.
Similarly, BC550C can replace the second one or the "A" or "B" versions for less gain .
Similarly, BC550C can replace the second one or the "A" or "B" versions for less gain .
Hi Duncan2,
You means to increase the overall gain by changing the TR01 to BC560C & TR03 to BC550C.
Do I correct?
Regards Lone
You means to increase the overall gain by changing the TR01 to BC560C & TR03 to BC550C.
Do I correct?
Regards Lone
Why can't you simple increase the volume?
You cannot increase one of the resistors in the feedback path without recalculating the RIAA network, but you can reduce R13.
______________________________________________
KHN Audio
Last edited:
By turning the volume to 1 o'clock, I can feel that the amp does not like it, working very hard the sound is very weird a lot of noise. The music is become less dynamic. Can you suggest what value to go for R13 to increase the gain by few dB?
Yes, turn the knob past 1:00. That is what it is for. See attached.
Reducing R13 raises gain for treble and middle but this is a "low cost" preamp and does not have any reserve gain in bass. The design gain of 50 @ 1kHz is controlled by the gain available to cover the RIAA 20dB rise at 20hz.
Reducing R13 raises gain for treble and middle but this is a "low cost" preamp and does not have any reserve gain in bass. The design gain of 50 @ 1kHz is controlled by the gain available to cover the RIAA 20dB rise at 20hz.
Attachments
Last edited:
Sounds like your little 15 watt/ch amp is clipping. Changing the gain in the phono section isn't going to change that. You need an amp with more power.
jeff
Strange problem ... The knob at one o'clock is too much for normal volumes, you get too close to the clipping zone ...
In the first instance I concluded that the output of the capsule would be too low for the sensitivity of the phono input, but I see that it is not like that ...
Is it really a 3.5 Mv spec cartridge?
Normally that specification is at 1000 Hz / 5 CM / second ......
I think you would have to try another cartridge before intervening the device, could you inform which one you use?
Also, won't they be low sensitivity acoustic cabinets given the low power of the amplifier?
Sansui AU-117 Stereo Integrated Amplifier Manual | HiFi Engine
In the first instance I concluded that the output of the capsule would be too low for the sensitivity of the phono input, but I see that it is not like that ...
Is it really a 3.5 Mv spec cartridge?
Normally that specification is at 1000 Hz / 5 CM / second ......
I think you would have to try another cartridge before intervening the device, could you inform which one you use?
Also, won't they be low sensitivity acoustic cabinets given the low power of the amplifier?
Sansui AU-117 Stereo Integrated Amplifier Manual | HiFi Engine
OP is tlking *voltage* gain, you are talking individual transistor *current* gain.
ABSOLUTELY unrelated.
Your amp is clipping, priod.
Increasing gain will make it WORSE.
Get/make a more powerful amp and improve speakers.
Hi,
Cartridge I use was a Audio Technical AT3600L. Turntable Custom Technics SL-D2. Speaker Quad 11L2.
I don't think the amp is clipping pass 1 o'clock. It just not sounded dynamic compare to CD. Below are a sample video playing with LP. It sound nice just sometime need more "kick" for playing some jazz song. 🙂
Video link : VID_20201115_162452 | Lone Long | Flickr
Sample video playing on CD : Quad 11L2 sound test No.5 - YouTube
Fully agree on the article, These amp can produce high resolution sound. Normal listening level for CD will be around 10-11 0'clock. But LP need higher level volume to achieve the same sound pressure to CD.
Cartridge I use was a Audio Technical AT3600L. Turntable Custom Technics SL-D2. Speaker Quad 11L2.
I don't think the amp is clipping pass 1 o'clock. It just not sounded dynamic compare to CD. Below are a sample video playing with LP. It sound nice just sometime need more "kick" for playing some jazz song. 🙂
Video link : VID_20201115_162452 | Lone Long | Flickr
Hi, I have others more powerful amp. These Sansui amp are part of my collections, She sounded just nice for me. 🙂
Sample video playing on CD : Quad 11L2 sound test No.5 - YouTube
Fully agree on the article, These amp can produce high resolution sound. Normal listening level for CD will be around 10-11 0'clock. But LP need higher level volume to achieve the same sound pressure to CD.
Do those electrolytic capacitors measure well?
I find 6.3v and 10v caps degrade a lot.
Have you not thought of buying an external phono stage. You'll get a good improvement
I find 6.3v and 10v caps degrade a lot.
Have you not thought of buying an external phono stage. You'll get a good improvement
CD have much louder output than expected line level in AU 117.
Line input sensitivity is 150mV and CD player usually have 2V.
That means CD is 22dB louder than normal line source.
Phono preamp in AU117 have gain to match this 150mV, and sounds 22dB lower than CD.
So your AU117 is good.
Quad 11L2 is good sounding speakers, but with sensitivity 87dB 1W/1m they are not perfect match for your amplifier.
17W means 12dBW amplification, so at 99dB sound pressure level, your amplifier will clipping.
If you use tone controls, amplifier will clip much earlier.
Line input sensitivity is 150mV and CD player usually have 2V.
That means CD is 22dB louder than normal line source.
Phono preamp in AU117 have gain to match this 150mV, and sounds 22dB lower than CD.
So your AU117 is good.
Quad 11L2 is good sounding speakers, but with sensitivity 87dB 1W/1m they are not perfect match for your amplifier.
17W means 12dBW amplification, so at 99dB sound pressure level, your amplifier will clipping.
If you use tone controls, amplifier will clip much earlier.
Hi Stewart,
I have a very good external Phono stage for my main system, Burmester 838 driving a ZYX Airy 1000. The sound is superb.
The AU117 are my 2nd system, I was thinking to do something to improve the gain a bit.
For the capacitor, I changed them already.
Last edited:
"Absolutely unrelated " BJT,s are current gain devices they achieve the same objective in the end --voltage gain so you are saying the input circuit doesn't amplify ?
Amazing ! I upgraded plenty of amplifier BJT,s by installing higher grade/higher GAIN devices the output in every case including mosfets increased the output.
Amazing ! I upgraded plenty of amplifier BJT,s by installing higher grade/higher GAIN devices the output in every case including mosfets increased the output.