seventenths said:
I am hoping for someone to give a pictorial instruction on how to improve the sound for a newbie like me. I have one but like to improve the sound.
gychang
Step 1: Remove receiver board.
Step 2: Reroute output as input and label exterior as such.
Step 3: Rotate transformer until humm and buzz are minimum.
Step 4: Route audio input away from transformer and turn the
RCAs into preamp output (to drive another amp)
Step 5: Bypass AC power switch located on preamp board and
move away from lowlevel preamp signals.
Step 6: Replace cheap parts on preamp.
Step 7: Bypass preamp all together and make the unit just an amp.
Step 8: Rebox the unit.
Step 9: Listen Test.
I'm moving into step 6. . .not sure, but I might stop. . .the unit did
cost less than $20. . . the law of deminishing returns.
Post #53 shows my mods. . .since I have routed the input wires
to below the preamp board.
The orange board is my output board of a 330 ohm and 47ohm L-pad
fed from the outputs to drive the preout for another amp.
Step 2: Reroute output as input and label exterior as such.
Step 3: Rotate transformer until humm and buzz are minimum.
Step 4: Route audio input away from transformer and turn the
RCAs into preamp output (to drive another amp)
Step 5: Bypass AC power switch located on preamp board and
move away from lowlevel preamp signals.
Step 6: Replace cheap parts on preamp.
Step 7: Bypass preamp all together and make the unit just an amp.
Step 8: Rebox the unit.
Step 9: Listen Test.
I'm moving into step 6. . .not sure, but I might stop. . .the unit did
cost less than $20. . . the law of deminishing returns.
Post #53 shows my mods. . .since I have routed the input wires
to below the preamp board.
The orange board is my output board of a 330 ohm and 47ohm L-pad
fed from the outputs to drive the preout for another amp.
I don't think the circuit will bridge to mono. . .that would require
some major circuit modifications in the input drivers.
Internally, you could add a sum circuit before the preamp to make
it mono.
some major circuit modifications in the input drivers.
Internally, you could add a sum circuit before the preamp to make
it mono.
I've been driving 1 4ohm bass shaker to industrial music for 45 minutes now. It's not hot, but definitely warm to the touch. I am going to let it cool off again and run 2 bass shakers and see how it handles it. If the amp can handle 45 minutes to a hour of constant use, I'm sure it'll do fine during a movie or two.
I have installed the amp section (minus the preamp) inside my
Yamaha M-45 amplifier. . .pictures to come. . .dc offset is now
below 5mV on either channel. Bench testing right now. . .will
listen test this afternoon.
Yamaha M-45 amplifier. . .pictures to come. . .dc offset is now
below 5mV on either channel. Bench testing right now. . .will
listen test this afternoon.
The Yamaha/Accurian Amplifier
The Accurian amp transformer is mounted under the power switch
board and wired into the old Auto Class A switch; the main power
still powers the meters; the old power supply caps and rectifier
will power the two Aussie amps to be mounted on the heat sinks
in the read of the unit.
The Accurian amp transformer is mounted under the power switch
board and wired into the old Auto Class A switch; the main power
still powers the meters; the old power supply caps and rectifier
will power the two Aussie amps to be mounted on the heat sinks
in the read of the unit.
Attachments
so does someone want to send me one? i had one organised a few weeks back but never heard anything more about it. lol
huh, excuse me...
Damianl,
You need to read more closely: As I said in the thread, post #69, I have had the one I said I'd get you for more than a week now. If you want it, send money via paypal to stuarteasson@yahoo.com and you will get it sometime thereafter.
Stuart
Damianl,
You need to read more closely: As I said in the thread, post #69, I have had the one I said I'd get you for more than a week now. If you want it, send money via paypal to stuarteasson@yahoo.com and you will get it sometime thereafter.
Stuart
cool i am so sorry. yes i should have read more closely. can you get me 2 if possible? and sorry what will be the total cost to 3185 melbourne australia? sorry if this was mentioned earlier too i am just verifying again.
just curious is there 220v taps on the transformer otherwise i actually wont bother because i just tested my step up (down?) transformer and it no longer works..🙁 buying one is definately not worth it for this amplifier.
I know essentially nothing about electronics design, but let me ask a potentially dumb question:
The Accurian has a low freq limit of 50 Hz. I assume this is due to caps on the input to the pre-amp. Can the caps be changed to set the low freq limit down to 20 Hz? If so, then how (what exact parts?)
I have two of these amps, one I intend to use for breaking in new FR drivers. The other I would like to give to my daughter and son-in-law for use w/ a pair of speakers I plan to build for them using FR drivers of 96 dB sensitivity which should have response down to at least 30 Hz. I'd hate to lose the low end to the amp's limited range.🙁
Thanks for your help!
Jim
The Accurian has a low freq limit of 50 Hz. I assume this is due to caps on the input to the pre-amp. Can the caps be changed to set the low freq limit down to 20 Hz? If so, then how (what exact parts?)
I have two of these amps, one I intend to use for breaking in new FR drivers. The other I would like to give to my daughter and son-in-law for use w/ a pair of speakers I plan to build for them using FR drivers of 96 dB sensitivity which should have response down to at least 30 Hz. I'd hate to lose the low end to the amp's limited range.🙁
Thanks for your help!
Jim
sorry...
...No 220v tap, so no trivial way to make *one* of these work at 220v.
On the other hand with two, it would be perfectly valid to simply connect them in series, but then you would have to always use them together. Your call.
The local radio shack still has two or three, let me know if you really want two, though I wont be spending any more of my money on your behalf: once you've made up your mind, send money.
Stuart
...No 220v tap, so no trivial way to make *one* of these work at 220v.
On the other hand with two, it would be perfectly valid to simply connect them in series, but then you would have to always use them together. Your call.
The local radio shack still has two or three, let me know if you really want two, though I wont be spending any more of my money on your behalf: once you've made up your mind, send money.
Stuart
Jim Shearer said:
You can either bypass the input caps or increase their value from the 4.7uF electrolytics that are on the preamp board. There's also a cap on the input to the amp board, but I can't remember the value. I'm not sure you need to do anything. Based on my measurements, the FR is a little lumpy, but solid to 20Hz and has a -3dB of ~10Hz.
Here's all 4 channels of the 2 amps that I got. The tone controls don't have any center detents, so I had to fiddle to get them as flat as possible.
I'm not sure I'm going to keep them. I just don't feel like redesigning the preamp board.
Hope this helps...
--Greg
Attachments
no easy way...
...to resistively load the mains down to 120v with any precision.
These are class AB amps, so the power drain is not constant. Thus any specific resistor you choose will be wrong for one end of the power scale or the other. For example, the maximum draw is perhaps 100w at clipping on both channels, so you'd need about a 100w, 120ohm resistor in series, but as soon as the volume dropped, the voltage would rise on the amp and probably damage it...
Strictly speaking putting the pair of them in series is not valid as a means of splitting the 240v unless they are putting out approx. the same power levels, bridging the channels across the pair of amps would ensure this.
HTH
Stuart
...to resistively load the mains down to 120v with any precision.
These are class AB amps, so the power drain is not constant. Thus any specific resistor you choose will be wrong for one end of the power scale or the other. For example, the maximum draw is perhaps 100w at clipping on both channels, so you'd need about a 100w, 120ohm resistor in series, but as soon as the volume dropped, the voltage would rise on the amp and probably damage it...
Strictly speaking putting the pair of them in series is not valid as a means of splitting the 240v unless they are putting out approx. the same power levels, bridging the channels across the pair of amps would ensure this.
HTH
Stuart
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