Hello everyone,
Well, after much measuring and thinking and fiddling my 1st modifications to the SI are complete.
What a difference a mod makes! It's not the same amp. I was about to declare that all the hype over the SI was pure B.S., but no longer. This little devil has some magic up its sleeve.
Now there is plenty of bass, and a much more dynamic sound. Gone is the thin brassy sound, hello roundness. Soundstage and details are vastly improved. The sound stage seemed to get much deeper and higher. Percussive sounds are now much better, the slap of the skin on a conga is amazing.
Musical phrasing is much better now too, more expressive. Detail is improved, with room sounds and reverb more pronounced.
I replaced all the in and out connectors, put everything in a tin box, PSU included. Replaced the input caps and resistors, including the pot. Replaced the output filter coils. Replace the power electrolytic with a Panasonic FM series.
The connectors and input caps made the biggest difference.
You can read more about these modification and the results on my site:
Sonic Impact News
I may offer these modified amps to those who are interested, see my site for details.
Well, after much measuring and thinking and fiddling my 1st modifications to the SI are complete.
What a difference a mod makes! It's not the same amp. I was about to declare that all the hype over the SI was pure B.S., but no longer. This little devil has some magic up its sleeve.
Now there is plenty of bass, and a much more dynamic sound. Gone is the thin brassy sound, hello roundness. Soundstage and details are vastly improved. The sound stage seemed to get much deeper and higher. Percussive sounds are now much better, the slap of the skin on a conga is amazing.
Musical phrasing is much better now too, more expressive. Detail is improved, with room sounds and reverb more pronounced.
I replaced all the in and out connectors, put everything in a tin box, PSU included. Replaced the input caps and resistors, including the pot. Replaced the output filter coils. Replace the power electrolytic with a Panasonic FM series.
The connectors and input caps made the biggest difference.
You can read more about these modification and the results on my site:
Sonic Impact News
I may offer these modified amps to those who are interested, see my site for details.
Aloha ohenry,
Thanks for the kind words. I'm an ex tarheel myself. (from O'Henry's home town).
Everyone has a right to be scepitcal, I know I was. In fact it was just about time to cry "The Emporor has no Clothes!" The S.I. just didn't cut it for me. Even with a big beefy PSU unit connected thru the power jack, the improvement was nothing to rave about.
So I went into replacing the input circuit ond output coils thinking it was just "the right thing to do." Well, surprise, surprise, surprise! The changes were dramatic and all for the better.
All I can say is, try it. Working on this tiny PCB is a royal pain in the butt, it can be done though. Buy a pair of magnifying glasses.
Happy modding!
Thanks for the kind words. I'm an ex tarheel myself. (from O'Henry's home town).
Everyone has a right to be scepitcal, I know I was. In fact it was just about time to cry "The Emporor has no Clothes!" The S.I. just didn't cut it for me. Even with a big beefy PSU unit connected thru the power jack, the improvement was nothing to rave about.
So I went into replacing the input circuit ond output coils thinking it was just "the right thing to do." Well, surprise, surprise, surprise! The changes were dramatic and all for the better.
All I can say is, try it. Working on this tiny PCB is a royal pain in the butt, it can be done though. Buy a pair of magnifying glasses.
Happy modding!
I had an SI and freaked when I saw how tiny it was. And I'm a bit surprised that there is enough heat sinking available for times the amp has prolonged party periods, but evidently it does.
I'm playing with an evaluation board, it has a little more room for the clumbsy guys like me. I'm still debating as to trying to mod it; I WILL need magnification as my older and tiring eyes still have trouble with fine work (even through bifocals
). I'll most likely order some parts and have a little electronic masochistic picnic. Then I'll change the subject when my wife inquires about the project.
BTW and surprisingly, Profusion PLC gave me a decent deal on that eval board (a little cheaper than buying it in the states). They probably think that I'll fry this one and be back for more. And they're probably right!
I'll be monitoring your progress.
I'm playing with an evaluation board, it has a little more room for the clumbsy guys like me. I'm still debating as to trying to mod it; I WILL need magnification as my older and tiring eyes still have trouble with fine work (even through bifocals
). I'll most likely order some parts and have a little electronic masochistic picnic. Then I'll change the subject when my wife inquires about the project.BTW and surprisingly, Profusion PLC gave me a decent deal on that eval board (a little cheaper than buying it in the states). They probably think that I'll fry this one and be back for more. And they're probably right!
I'll be monitoring your progress.
BTW and surprisingly, Profusion PLC gave me a decent deal on that eval board (a little cheaper than buying it in the states). They probably think that I'll fry this one and be back for more. And they're probably right!
I'll be monitoring your progress. [/B][/QUOTE]
The Evaluation Board is a much better circuit than the stock SI. I may have to break down and try ordering a couple from Profusion PLC. No luck with getting a response from the US distributors on purchasing two.
Looking over the detailed circuit of the EB-2024, the only thing I would change is maybe the inductors. Do not know what the output decoupling caps are stock, but the tech notes recommend 0.47 ufd for 4 ohm loads, and 0.22 ufd for 8 ohm. Getting these in the ballpark range should take care of topend rolloff and ringing also.
George
I'll be monitoring your progress. [/B][/QUOTE]
The Evaluation Board is a much better circuit than the stock SI. I may have to break down and try ordering a couple from Profusion PLC. No luck with getting a response from the US distributors on purchasing two.
Looking over the detailed circuit of the EB-2024, the only thing I would change is maybe the inductors. Do not know what the output decoupling caps are stock, but the tech notes recommend 0.47 ufd for 4 ohm loads, and 0.22 ufd for 8 ohm. Getting these in the ballpark range should take care of topend rolloff and ringing also.
George
I think the board it looks pretty good as well. I think Wayne at Bolder typically leaves the inductors and adds Auricaps to the output circuit, bybees, etc.
Intuitively, it seems that someone with proper skills could use the eval board platform to eclipse the SI's performance. That platform does triple the starting price, but hey, it's still <$100 US.
Dealing with Premier (the US distributor) has been a hassle. I ordered a board last year and had to fax a copy of my credit card for the transaction. The sales contact there isn't very friendly. Profusion was friendly and their express shipping is quick.
Intuitively, it seems that someone with proper skills could use the eval board platform to eclipse the SI's performance. That platform does triple the starting price, but hey, it's still <$100 US.
Dealing with Premier (the US distributor) has been a hassle. I ordered a board last year and had to fax a copy of my credit card for the transaction. The sales contact there isn't very friendly. Profusion was friendly and their express shipping is quick.
Panelhead said:
George, you mean the caps that are placed across the output connectors, yeah? Not the caps that are part of the low pass filter? If so, I replaced those when I did my 1st round of mods. My replacements were 0.01uF polypropylene. Maybe too small, but they seem to work well. I want to try larger values to see if they will reduce the RF coming out.
Of course I did the very unscientific thing of making a lot of modifications all at once, so now it is hard to know how much each contributed to the overall improvements.
I have yet to replace the .47uF caps in the output filters, that will be next, after I get a new SI board - I killed this one...
That little chip gets HOT!
You can't even keep a finger on it if it's been running a while. It seems to me that the sound quality degrades as the chip gets hot. A heat sink is in order, to be sure.I've posted about these before, but here they are again.
I use them on all my SI's and they fit like they were made for them. They come with thermal tape attached so all you have to do is peel and stick. They can be found here . Lucky for me, he lives in my home town and all I have to do is meet him at the post office if I need more.
Heres a pic of one attached.
I use them on all my SI's and they fit like they were made for them. They come with thermal tape attached so all you have to do is peel and stick. They can be found here . Lucky for me, he lives in my home town and all I have to do is meet him at the post office if I need more
.Heres a pic of one attached.
An externally hosted image should be here but it was not working when we last tested it.
Oh, that pic was from awhile back before I did any real mods. I've replaced it with a blackgate standard 16v 2200uf cap. I got rid of the whole input section too and use externaly mounted dayton poly caps for coupling. I didn't change the output inductors do to lack of space in the new case.
BTW, Profusion also sells a "reference board" for the TA2024. Tripath refers to it as RB TA2024. It's a mini version of the evaluation board without the provisions for hook up (no jacks, just solder connections). It's even smaller than the SI board and has circuitry more similar to the SI than the evaluation board. They do recommend heat sinking be added as the board area is so tiny.
panomaniac said:
I have not traced out the circuit on the outputs, but I think that SI is using the 0.15 cap across the outputs as the ringing and the lowpass filter cap.
The Tripath sheet shows these 0.47 caps to ground, and the 0.01 cap strapped on the outputs +/-. The notes say to use 0.22 ufd for 8 ohm speakers. The 0.15 cap used is equivilent to using a pair of 0.30 ufd caps hooked from output to ground instead of across the outputs. Since the Soundpax speakers are 6 ohm, this is just about the correct value. We need to keep in mind that this amp was designed to be part of the Soundpax system, not drive real speakers.
My speakers are rated 15 ohm, but are 30 - 40 ohms at high frequencies. I am now using a 0.22 ufd multilayer leaded ceramic hooked up output to ground like Tripath recommends, and then a 0.033 ufd soldered to the binding posts. It is just breaking in, but the highs are not rolled, and thee are no headaches from high frequency ringing.
I need some of those heatsinks also. I need to look around locally, but are those custom jobs or sourced from a normal supplier?
George
Hello boys, have you read this evaluation
The guys that paid 15K dollares will never accept that....they cannot without feeling very bad!
regards,
http://www.tnt-audio.com/ampli/t-amp_e.html
Carlos
The guys that paid 15K dollares will never accept that....they cannot without feeling very bad!
regards,
http://www.tnt-audio.com/ampli/t-amp_e.html
Carlos
Re: Hello boys, have you read this evaluation
I think he is overating the stock SI-5066. It is nice, but I have several amps that are better overall. But 500.00 for a Clari-T, or 400.00 for the Boulder unit will completely close the gap comparing to his amps with the same speakers.
I am still trying to get the most out of them myself, new box, regualr connectors, better power, improved caps, it just goes on and on.
But I now have maybe a 100.00 amp that is unreal good. It betters my Hiraga Le Monstre in many areas, maybe overall. The LeMonstre has about 700.00 in parts alone.
George
destroyer X said:
I think he is overating the stock SI-5066. It is nice, but I have several amps that are better overall. But 500.00 for a Clari-T, or 400.00 for the Boulder unit will completely close the gap comparing to his amps with the same speakers.
I am still trying to get the most out of them myself, new box, regualr connectors, better power, improved caps, it just goes on and on.
But I now have maybe a 100.00 amp that is unreal good. It betters my Hiraga Le Monstre in many areas, maybe overall. The LeMonstre has about 700.00 in parts alone.
George
Hiriga Amps
Hey George, You have a Le Monstre? I knew you were a cool guy!
I've always wanted to build one of those, but never did. I have built this amp several times:Hiraga Class A
A sweet sounding amp, better than many triode amps I've heard.
Uses a "massive passive" PSU like the Le Monstre.
Interesting to hear that your Tripath equals the sound of the Hiraga amp. Your talking about pretty rare company, there. Encouraging!
Panelhead said:
Hey George, You have a Le Monstre? I knew you were a cool guy!
I've always wanted to build one of those, but never did. I have built this amp several times:Hiraga Class A
A sweet sounding amp, better than many triode amps I've heard.
Uses a "massive passive" PSU like the Le Monstre.
Interesting to hear that your Tripath equals the sound of the Hiraga amp. Your talking about pretty rare company, there. Encouraging!
At the risk of repeating scores of other posters, I have to brag a bit on my stock TA2024 evaluation board. Well, maybe it's not too repetitive since it's not the SI board. Once in a good chassis with "real" connectors and a battery, it sounds really fine. The bass is definitely not lacking and very controlled, and the highs have smoothed remarkably over the past 40 hours.
I squeezed it all in a nice black anodized Hammond box and used midline WBT posts, so now the aesthetics are somewhat commensurate with the sonics.
The sound is much more involving, detailed and clean than the modest tube amps I have been using. And power isn't lacking as my speakers are back-loaded single driver horns at approximately 94 db.
I have more goodies coming for mods and can't wait for the weekend where I can find more time to play. I hope the caps and inductors do pay off as others have stated...we'll see. I'm grateful to the more knowledgeable DIY-er's for posting their opinions regarding parts and experiences as I don't possess the expertise to effectively experiment.
This amp sounds better than it should and has postponed my tube project for a while (my wife is ).
I squeezed it all in a nice black anodized Hammond box and used midline WBT posts, so now the aesthetics are somewhat commensurate with the sonics.
The sound is much more involving, detailed and clean than the modest tube amps I have been using. And power isn't lacking as my speakers are back-loaded single driver horns at approximately 94 db.
I have more goodies coming for mods and can't wait for the weekend where I can find more time to play. I hope the caps and inductors do pay off as others have stated...we'll see. I'm grateful to the more knowledgeable DIY-er's for posting their opinions regarding parts and experiences as I don't possess the expertise to effectively experiment.
This amp sounds better than it should and has postponed my tube project for a while (my wife is
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