chicks said:
Am i imagining things, or is it plausible that i could cut the EQ section completely off, and shorten the board by about 2 inches?
fwiw - the project in question is a Stax SRD-X. This curious device from the 80's consists of a pair of ta7222ap 5.8w car radio chip amps directly connected to a pair of step-up transformers, high voltage bias supply, and a compartment for 8 C-cell batteries, all to drive electrostatic headphones.
Why? because it's easier than building a high voltage amplifier, I guess. Also more convenient than using a transformer box and an outboard power amp.
It works, but sounds kinda flat and lifeless. I'm looking for a class-D solution to give it a faster, livelier, more detailed sound while retaining the original convenient, luggable formfactor.
oh, and hey there germania.
chicks said:
I actually may be able to sink it directly to the internal metal frame in the SRD-X enclosure. So, it's all good.
Thanks. I've ordered one of these things and will tear into it when it gets here. I'll post pics somewhere - maybe start a thread in the right area instead of just continuing to derail germania's thread here.
I ordered a pair of the Nodus' ... they arrived today. The sound is OK w/ the port blocked off, as theAnonymous1 ... gets rid of some of the boominess, but they're still too muddy for my tastes. I want to get inside to try disabling the MZ01 w/o destroying the case. How are these things held together? Are there screws under the rubber feet on the bottom?
I think I will prb just keep one of them intact, and build separate cabinets for the other one.
Thanks.
I think I will prb just keep one of them intact, and build separate cabinets for the other one.
Thanks.
lincomatic said:
No, you have to carefully pull the grille off - I used a screwdriver to pry, but that will mar the finish on the plastic. A dental tool would be perfect, just slip into one of the perfs, and pull straight out. There are a dozen or so screws behind the grille.
The muddiness is definitely cleared up by bypassing the "enhancement" chip, but the bass suffers considerably.
chicks, would you have the opening diameter of the drivers for the enclosures? i can have workshop time tomorrow, and would love to build the enclosures for my little system, but the psyclones will only be shipped monday or later.
i somewhat guess the answer is 3", but i keep murphy's law in mind.
thanks, g
i somewhat guess the answer is 3", but i keep murphy's law in mind.
thanks, g
geotone said:
I used a 3" hole saw, and had to then increase the diameter slightly with a file.
BTW, the 13-piece hole saw set I used is from Harbor Freight Tools. They have an ad in this morning's paper with the same set for $2.99. They probably won't last very long, but at that price, I don't care
Scored a Klipsch Promedia 2.1, at least the amp and 6.5" sub, at the local Goodwill for $20. The sub's internal volume is ~ 12 liters. Also found a bamboo letter organizer on clearance at TJ Maxx. Its internal volume is ~ 13.8 liters. So, with some 3/8" or 1/2" MDF inside to beef up the sides, and maybe 3/4" MDF for the bottom, I should have a nice looking 12 liter enclosure for the Klipsch unit. Klipsch used 12mm MDF.
I could just add some bamboo sides to the sub enclosure, unfortunately they used the back for the plate amp, one side for the speaker, and the front for the port, making it difficult to skin. I'll try to make the speaker and port both down-firing in the new box.
The Klipsch plate amp uses a PS/2 connector (DIN?). I have figured out the L and R inputs, and can put hum through the satellite speakers no problem. There are also connections for master volume and sub volume controls, which would normally be on one of the satellite speakers. I expect that they just vary a DC voltage using linear pots for these controls, and several of the pins have 14VDC on them, just need to experiment.
Klipsch rates the plate amp @ 55Wpc for the satellites, and 50W for the sub, with internal crossover. I'll have to be careful not to blow the little Psyclone speakers!
I could just add some bamboo sides to the sub enclosure, unfortunately they used the back for the plate amp, one side for the speaker, and the front for the port, making it difficult to skin. I'll try to make the speaker and port both down-firing in the new box.
The Klipsch plate amp uses a PS/2 connector (DIN?). I have figured out the L and R inputs, and can put hum through the satellite speakers no problem. There are also connections for master volume and sub volume controls, which would normally be on one of the satellite speakers. I expect that they just vary a DC voltage using linear pots for these controls, and several of the pins have 14VDC on them, just need to experiment.
Klipsch rates the plate amp @ 55Wpc for the satellites, and 50W for the sub, with internal crossover. I'll have to be careful not to blow the little Psyclone speakers!
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geotone said:
I haven't tested the Fs of my drivers yet, but when I first tested it, I noticed that there was considerably more bass excursion in one of the drivers. Unfortunately, I only tested on one track (and I forgot which one), so I'm not sure if it was just due to the particular track itself. One thing I know for sure, though, is that after bypassing the MZ01, the bass excursion is pretty much equal on the two channels.
I just did some A/B listening tests between my two Nodus' ... there is definitely more distortion @ high SPL w/ the MZ01 enabled. After bypassing, the bass is reduced significantly, but the clarity of the midrange and treble is moderately improved.
I like to listen mostly to acoustic jazz and vocals, and so far, I like the sound w/ the MZ01 disabled and the rear port open the best.
The unit w/ the MZ01 enabled w/ sock in the port has about the same amount of bass, but is a bit flabbier in sound. However, for bass-heavy music and movies, the unmodified, unplugged port is best.
When I get a chance, I'm going to plug the amp sans-MZ01 into my homebrew Dynaudios to see how good it really is.
BTW, my unit w/ the MZ01 disabled sometimes has trouble turning on.. don't know if it's a result of the modification or not.
OK, I was wrong about DC voltage controlling the volume. I added a 1/8" stereo jack to the plate amp, connected to the L and R amp inputs, and summed them through 10K resistors to the sub amp's input. Driven at max line level, it doesn't get really loud, but fills in the bass quite nicely, without getting boomy at all.
The mini DIN connector also has +14V and -14V pins, so I now believe that there are buffer amps in the missing satellite speaker, one with level control for the sub, and one for each of the satellites, with dual level control. The buffer amps clearly must have some voltage gain, because max line level into the unit isn't enough to get really loud.
Looks like I'll need to put together a buffer with a level control for the sub amp. Can put it inside the enclosure, on perf board. Where did I put those LM324's?
The mini DIN connector also has +14V and -14V pins, so I now believe that there are buffer amps in the missing satellite speaker, one with level control for the sub, and one for each of the satellites, with dual level control. The buffer amps clearly must have some voltage gain, because max line level into the unit isn't enough to get really loud.
Looks like I'll need to put together a buffer with a level control for the sub amp. Can put it inside the enclosure, on perf board. Where did I put those LM324's?
Hi, this discussion has definitely drawn my interest. I have a sonic T-amp (first gen) and love it. I just built a pair of sealed box speaker (see my other thread) and my Sonic works very well with them with very good volume. I have been thinking about building another T-Amp from 41hz.com. This thread has definitely changed my mind.
I would guess after the mod on bypassing the MZ01 (4 cuts and two jumper wires), the preamp is still functioning, correct? Also, I would guess the remote control circuit is on the preamp board too so I don't need to put a stereo pot after the mod ?
-AC
I would guess after the mod on bypassing the MZ01 (4 cuts and two jumper wires), the preamp is still functioning, correct? Also, I would guess the remote control circuit is on the preamp board too so I don't need to put a stereo pot after the mod ?
-AC
Well, I'm not sure how this amp compares with the 41Hz products, and I definitely don't have a "golden ear" - this one sounds to me exactly the same as my unmodified Sure Electronics amp, when driving the same speakers. I suppose there are lots of mods that could be done to this amp to improve its sound, but I doubt I'd notice much of a difference. I sure hate to think my playing has resulted in lost revenue for 41Hz.
I'm not using the preamp board at all, but yes, the remote control circuitry is on the preamp, and it should work just fine with the MZ01 chip (which is on the power amp board) bypassed.
A few things irritating about the preamp/control board:
1. It produces hiss in the speakers - a tiny amount, to be sure, but it's there when no music is playing. Bypassing it removes the hiss.
2. It puts the power amp in idle mode after about 10 minutes of no audio input, but it doesn't power the amp back up with the introduction of audio input. The only way to do that is by using the remote control or the power switch, very annoying, since there's no "on" indicator.
3. It doesn't remember the volume setting between power cycles, possibly the most annoying, so you are forced to change it with the remote, or with the volume buttons.
I'm not using the preamp board at all, but yes, the remote control circuitry is on the preamp, and it should work just fine with the MZ01 chip (which is on the power amp board) bypassed.
A few things irritating about the preamp/control board:
1. It produces hiss in the speakers - a tiny amount, to be sure, but it's there when no music is playing. Bypassing it removes the hiss.
2. It puts the power amp in idle mode after about 10 minutes of no audio input, but it doesn't power the amp back up with the introduction of audio input. The only way to do that is by using the remote control or the power switch, very annoying, since there's no "on" indicator.
3. It doesn't remember the volume setting between power cycles, possibly the most annoying, so you are forced to change it with the remote, or with the volume buttons.
Thanks for the info about the preamp. I think I'm going to buy a couple of PSC99 and strip down everything only to keep the final Tripath amps. I don't think your research on the psc99 has caused any lost revenue for 41Hz. They have more variety of kits, some with much higher power. Just different customer base, IMHO.
-AC
-AC
sjetski71 said:
That store has some ridiculously cheap prices & it says free shipping from Tawian.
This must be the best deal.
http://stores.ebay.com/AudioTek-Shop_W0QQcolZ4QQdirZ1QQfsubZQ2d33QQftidZ2QQtZkm
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