batteries and chargers
Can I ask a word of advice about ways to run this amp with a battery?
1. Will any inexpensive SLA battery of 9AH or more do, or are there reasons to favor certain brands?
2. Would it be possible to set up a DPDT switch so that the battery was switched between the amp and some sort of top-up (trickle?) charger -- so that turning the amp "off" meant switching the battery over to its charger? (I'm looking for a low-maintentance solution where I don't have to swap batteries or recharge manually.)
thanks
Can I ask a word of advice about ways to run this amp with a battery?
1. Will any inexpensive SLA battery of 9AH or more do, or are there reasons to favor certain brands?
2. Would it be possible to set up a DPDT switch so that the battery was switched between the amp and some sort of top-up (trickle?) charger -- so that turning the amp "off" meant switching the battery over to its charger? (I'm looking for a low-maintentance solution where I don't have to swap batteries or recharge manually.)
thanks
Re: batteries and chargers
Check out www.batterymart.com and look for 12V SLA batteries and their 500ma $8.95 charger. This will work well.
Use a SPDT switch. One position is ON, and the other is OFF/CHARGE. Simple and sweet!
CD said:
Check out www.batterymart.com and look for 12V SLA batteries and their 500ma $8.95 charger. This will work well.
Use a SPDT switch. One position is ON, and the other is OFF/CHARGE. Simple and sweet!
Noise on SI Output?
Hi AMT,
Very nice mod indeed. I have a new SI which I am using to run some headphones. I am noticing hissing even when there is no input or even an input connection. It is constant ie. it does not increase when I increase the volume oddly enough. I am wondering if anyone else has heard hiss from their amp. I am currently running off batteries.
I really like the sound of this amp. Vocals and cymbals are wonderful. I may exchange it if this is not a common experience... actually I probably will anyway... so I can take it apart and see what it can really do.
Thanks for the post of your amp.
Best,
Paul
Hi AMT,
Very nice mod indeed. I have a new SI which I am using to run some headphones. I am noticing hissing even when there is no input or even an input connection. It is constant ie. it does not increase when I increase the volume oddly enough. I am wondering if anyone else has heard hiss from their amp. I am currently running off batteries.
I really like the sound of this amp. Vocals and cymbals are wonderful. I may exchange it if this is not a common experience... actually I probably will anyway... so I can take it apart and see what it can really do.
Thanks for the post of your amp.
Best,
Paul
Taking the amp apart
Hi amt and all,
When you took your SI apart, were you able to separate the case without breaking it?
I took the 4 screw out - the ones that are right under the rubber feet - and my amp is still in one piece. I noticed two smaller screws in the battery compartment. Are these the final two screws that hold the case together?
I'm amazed at how small the circuit board is.
Thanks,
KT
Hi amt and all,
When you took your SI apart, were you able to separate the case without breaking it?
I took the 4 screw out - the ones that are right under the rubber feet - and my amp is still in one piece. I noticed two smaller screws in the battery compartment. Are these the final two screws that hold the case together?
I'm amazed at how small the circuit board is.
Thanks,
KT
Yeah,
I'm taking the SI apart to change the pot out to a 50k Taiwan Alpha pot. I'll lose the power switch in the process, I'm sure, but that's not such a big deal to me.
Anyone know if those two little screws in the battery compartment are the final ones that hold the chassis together? I took off the four that sit under the feet, but the amp is still in one piece. Doesn't come apart, yet.
I'm doing this for my brother and I was originally thinking about putting the innards into a cheap little plastic Radio Shack case with the cheapie binding posts and the cheapie RS RCAs. I figure this would be a little better than the stock connectors. But if I can just change out the pot in the original case, I'll most likely go ahead and do that.
If I took out the pot entirely and replaced the pot with 50k resistors, do you think the gain would be too much to run with a set of 96db sensitive speakers? My brother would be using a preamp with this.
Thanks,
KT
I'm taking the SI apart to change the pot out to a 50k Taiwan Alpha pot. I'll lose the power switch in the process, I'm sure, but that's not such a big deal to me.
Anyone know if those two little screws in the battery compartment are the final ones that hold the chassis together? I took off the four that sit under the feet, but the amp is still in one piece. Doesn't come apart, yet.
I'm doing this for my brother and I was originally thinking about putting the innards into a cheap little plastic Radio Shack case with the cheapie binding posts and the cheapie RS RCAs. I figure this would be a little better than the stock connectors. But if I can just change out the pot in the original case, I'll most likely go ahead and do that.
If I took out the pot entirely and replaced the pot with 50k resistors, do you think the gain would be too much to run with a set of 96db sensitive speakers? My brother would be using a preamp with this.
Thanks,
KT
Yes, you want to remove those final two little screws.
I'm moving the thing to a cheap 2"x3"x5" radio shack aluminum case, which lets you mount the board so it just fits front-to-back, allowing holes for the led in front and connectors in back.
I'd think that bypassing the pot and using the preamp to attenuate would be fine, but I've never had a 96db speaker.
I'm moving the thing to a cheap 2"x3"x5" radio shack aluminum case, which lets you mount the board so it just fits front-to-back, allowing holes for the led in front and connectors in back.
I'd think that bypassing the pot and using the preamp to attenuate would be fine, but I've never had a 96db speaker.
You think it's hard getting one in Canada? Try Australia...been searching but no luck so far.
Was excited to see that AMRMart place ships os, but discovered shipping to oz is $40 - twice the price of the amp!
Anyone either seen them in Oz or willing to post? Surely they don't weigh much....
TIA,
Adam F
Was excited to see that AMRMart place ships os, but discovered shipping to oz is $40 - twice the price of the amp!
Anyone either seen them in Oz or willing to post? Surely they don't weigh much....
TIA,
Adam F
Been quite busy and havent visited lately...
The case on my first SI didnt have the screws in the battery compartment. It just separated after removing the bottom screws and prying a bit. I will have to check out this new version and see what the differences are.
The hiss is non-exsistant on my modded version and not very noticable on the stocker. I do use only SLAs though and short power cord length. Since the lowest efficiency speaker I use with them is 93db and usually a 104, at the milliwatt levels, I dont hear it. I will check the hiss thing out further
The binding posts are inexpensive HT stock I purchase from a local electronics supplier. I think they are Calrad or similar. They work great, are very beefy and fairly well built.
Now, for some disassembly.
amt
The case on my first SI didnt have the screws in the battery compartment. It just separated after removing the bottom screws and prying a bit. I will have to check out this new version and see what the differences are.
The hiss is non-exsistant on my modded version and not very noticable on the stocker. I do use only SLAs though and short power cord length. Since the lowest efficiency speaker I use with them is 93db and usually a 104, at the milliwatt levels, I dont hear it. I will check the hiss thing out further
The binding posts are inexpensive HT stock I purchase from a local electronics supplier. I think they are Calrad or similar. They work great, are very beefy and fairly well built.
Now, for some disassembly.
amt
For those that havent done it yet, the two screws in the battery compartment do need to be removed.
And they have cleaned up the board substantially. The first gen was probably an embarresment once it was learned that everyone is dismantling them. The led is nicely mounted on the board rather that poorly soldered on with a lead that looks like an afterthough. Way less hot glue on everything. And a better PCB.
amt
And they have cleaned up the board substantially. The first gen was probably an embarresment once it was learned that everyone is dismantling them. The led is nicely mounted on the board rather that poorly soldered on with a lead that looks like an afterthough. Way less hot glue on everything. And a better PCB.
amt
I just received a pair of SI amps.. I'll be testing them and disassembling them shortly. If I can get the digital camera going, I'll try to document taking them apart. I plan on using JRsun's RCA (wbt-ish) and Binding posts.. with the small aluminum enclosures I have, I figure that all the mods are going to cost far more than the amp itself! (I Paid $20 each from some place I found on froogle, plus $8 for shipping!).
I'm going to try them out in my bedroom system (AR-17 bookshelves with a nakamichi cd-player) and see how it sounds. 5-10 watts should be plenty in such a small room with fairly (~90-91db) efficient speakers.
I'm going to try them out in my bedroom system (AR-17 bookshelves with a nakamichi cd-player) and see how it sounds. 5-10 watts should be plenty in such a small room with fairly (~90-91db) efficient speakers.
Vinnie R. said:
Don't forget to try a 12V SLA battery with it!
Enjoy!
Vinnie
Oh, most definitely. I just have to figure out which one I want to get! I was thinking more along the lines of a 12ah or 20ah just so I don't have to recharge it as often.
I'm also going to look at adding Low-ESR caps on the PS rail (based on the pics I've seen, they don't appear to have any), and possibly replacing the booster cap with something a little bigger/better. I have a big ol' honkin' pile of Cerafines laying around, so it may be worth experimenting with.
I'll also be rewiring it with some silver plated OFC, or possibly the solid silver cable I have laying around as well.
Damn this DIY stuff.. So many fun things to do, so little time!
KT,
Ive been using my stock SI while I finished my new mod chassis, so the only look I got of it was the bottom of the board. I will now be removing the board to build another amp and will check the wiring on the new PCB. But from what I can tell, the circuitry is the same, and all the wires appear to be identical and attached at the same points (except the LED). The changes are really in the board quality and the better assembly.
amt
Ive been using my stock SI while I finished my new mod chassis, so the only look I got of it was the bottom of the board. I will now be removing the board to build another amp and will check the wiring on the new PCB. But from what I can tell, the circuitry is the same, and all the wires appear to be identical and attached at the same points (except the LED). The changes are really in the board quality and the better assembly.
amt
Did I kill my board?
Just finished moving the SI board to a new chassis. 12V DC is definitely arriving at the board, and I also get a voltage reading from where the power switch leads used to be, but the LED doesn't come on and I get no sound, not even a hiss, from speakers.
My only on-board soldering was to bridge the power switch leads (I'm instead running the power leads that went to the battery case directly to a switch), so I don't think I cooked anything. I did pull off both jack housings at the back of the board, though, and I'm wondering if doing that left a switch open.
Just finished moving the SI board to a new chassis. 12V DC is definitely arriving at the board, and I also get a voltage reading from where the power switch leads used to be, but the LED doesn't come on and I get no sound, not even a hiss, from speakers.
My only on-board soldering was to bridge the power switch leads (I'm instead running the power leads that went to the battery case directly to a switch), so I don't think I cooked anything. I did pull off both jack housings at the back of the board, though, and I'm wondering if doing that left a switch open.
As you can see from my board picture, I left the power jack on the board and feed in through the battery leads. You may be right in that you created an open circuit by removing the jack. It might be switched so that both the battery and wallwart current dont flow into the chip at the same time. Check the jack and see if a pair of the leads appear to be part of the circuit.
amt
amt
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