Why SI?

AZNracerx1989 · 19th August 2006, 11:14 PM

Why do you guys think the SI is good? I hooked them up to my 50watt RMS omega 400 speakers and they sound worst than my Yamaha 100watt/ch amp. The bass is gone, only loud and harsh mids and highs.. I broke it in for 100 hours already. With the yamaha back on, the speakers sound richer in bass and sound much better. Why SI if it has no Bass?

RX5 · 19th August 2006, 11:22 PM

uhmmmmm what is "SI" ???

lucpes · 20th August 2006, 12:36 AM

Quote:

Originally posted by RX5
uhmmmmm what is "SI" ???

Sonic Impact T-amp.

sx881663 · 20th August 2006, 04:58 AM

You have not done your homework! The stock SI has very limited bass. The input caps must be changed for larger/better ones and an adequate power supply must be used. This is for starters, the next thing is that the SI does not like speakers that have complex crossovers and are inefficient. They are just too power limited to handle this situation. Now take the situation like my friend, he uses the little SI to drive his really big old Altec speakers and it fills a large room with very good sound. He has dozens of amps all the way up to an industrial pro sound unit of 600W/ch. Most all are modified and good sounding but he prefers the SI.
These little things are capable of astounding sonics but only modified and with the right speakers!
Roger

AZNracerx1989 · 20th August 2006, 07:46 AM

I did the input cap mod today... I used 4.7UF caps for input.... It did not make any difference! I couldnt tell a single difference. The only difference is that now it makes a little noise when you barely turn the amp on. A little click noise when I turn the amp on.

Bgt · 20th August 2006, 09:57 AM

what's your psu made off? what caps, transf? What is your pre capable off? Is it cap. coupled? and does it have low imp. out?
The Tripath amp1B I have works like a charm. Hardly any diff. with the big boys.

Davet · 20th August 2006, 02:46 PM

What kind of caps did you employ?

Did you do the cap mod suggested on the Michael Mardis site; which includes removal of SMD caps and resistors?

In my experience, increasing the capacitance of C10 to 3,000 MFDs helped considerably with the bass. I use a 12 volt 5 amp power supply. Use of a under powered PS will not allow the SI to play all that it can play.

I suggest playing a piano solo as a source. With the SI the instrument sounds as if it is my listening room, and the silence between notes is apparent. On quiet passages and between tracks the unit sounds as if it is off. I don't find this to be the case with most SS amps. Even with nothing playing you are aware the SS unit is on. YMMV

There seems to be an artificiality to the sound when played through SS amps. The quietness just is not there. This alone separates the SI amps from most other SS amps.

If after hearing a solo piano, you still hear brittle highs - the amp, most likely, is not for you in your current environment.

AZNracerx1989 · 20th August 2006, 07:17 PM

I removed 2 caps and bridged 2 like on the site. I used some caps I found in a computer speaker amp. It is blue.. I know nothing about it except that it is rated at 50V

mike.m216 · 20th August 2006, 07:22 PM

Wrong type of caps.

Davet · 21st August 2006, 02:15 AM

Which of the capacitor mods did you implement, version 1, 2, or 3?

Are the caps you used film or electrolytics? Are they flat chicklet looking devices or round cylindrical?

19th August 2006, 11:14 PM	#1
AZNracerx1989 diyAudio Member Join Date: Aug 2006	Why SI? Why do you guys think the SI is good? I hooked them up to my 50watt RMS omega 400 speakers and they sound worst than my Yamaha 100watt/ch amp. The bass is gone, only loud and harsh mids and highs.. I broke it in for 100 hours already. With the yamaha back on, the speakers sound richer in bass and sound much better. Why SI if it has no Bass?

19th August 2006, 11:22 PM	#2
RX5 diyAudio Member Join Date: Apr 2004 Location: TaC	uhmmmmm what is "SI" ??? __________________ RoCk On!!! I love my diy UcD!!

20th August 2006, 04:58 AM	#4
sx881663 diyAudio Member Join Date: Nov 2003 Location: so. ca.	No lows? You have not done your homework! The stock SI has very limited bass. The input caps must be changed for larger/better ones and an adequate power supply must be used. This is for starters, the next thing is that the SI does not like speakers that have complex crossovers and are inefficient. They are just too power limited to handle this situation. Now take the situation like my friend, he uses the little SI to drive his really big old Altec speakers and it fills a large room with very good sound. He has dozens of amps all the way up to an industrial pro sound unit of 600W/ch. Most all are modified and good sounding but he prefers the SI. These little things are capable of astounding sonics but only modified and with the right speakers! Roger __________________ Happiness is being owned by a cat

20th August 2006, 09:57 AM	#6
Bgt diyAudio Member Join Date: Jan 2005 Location: NL, Voorschoten	what's your psu made off? what caps, transf? What is your pre capable off? Is it cap. coupled? and does it have low imp. out? The Tripath amp1B I have works like a charm. Hardly any diff. with the big boys. __________________ Kind regards, Bert

20th August 2006, 02:46 PM	#7
Davet diyAudio Member Join Date: Mar 2004 Location: Reston, Virginia (surburb of Wash, DC)	Caps?? What kind of caps did you employ? Did you do the cap mod suggested on the Michael Mardis site; which includes removal of SMD caps and resistors? In my experience, increasing the capacitance of C10 to 3,000 MFDs helped considerably with the bass. I use a 12 volt 5 amp power supply. Use of a under powered PS will not allow the SI to play all that it can play. I suggest playing a piano solo as a source. With the SI the instrument sounds as if it is my listening room, and the silence between notes is apparent. On quiet passages and between tracks the unit sounds as if it is off. I don't find this to be the case with most SS amps. Even with nothing playing you are aware the SS unit is on. YMMV There seems to be an artificiality to the sound when played through SS amps. The quietness just is not there. This alone separates the SI amps from most other SS amps. If after hearing a solo piano, you still hear brittle highs - the amp, most likely, is not for you in your current environment. __________________ Davet


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20th August 2006, 07:46 AM	#5
AZNracerx1989 diyAudio Member Join Date: Aug 2006	I did the input cap mod today... I used 4.7UF caps for input.... It did not make any difference! I couldnt tell a single difference. The only difference is that now it makes a little noise when you barely turn the amp on. A little click noise when I turn the amp on.

20th August 2006, 07:17 PM	#8
AZNracerx1989 diyAudio Member Join Date: Aug 2006	I removed 2 caps and bridged 2 like on the site. I used some caps I found in a computer speaker amp. It is blue.. I know nothing about it except that it is rated at 50V

20th August 2006, 07:22 PM	#9
mike.m216 diyAudio Member Join Date: Jun 2006	Wrong type of caps.

21st August 2006, 02:15 AM	#10
Davet diyAudio Member Join Date: Mar 2004 Location: Reston, Virginia (surburb of Wash, DC)	Cap Mod?? Which of the capacitor mods did you implement, version 1, 2, or 3? Are the caps you used film or electrolytics? Are they flat chicklet looking devices or round cylindrical? __________________ Davet

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