I'm trying to revive an Armstrong 626. Can anyone identify what type of resistor that is? Schematic says its a 0.47ohm resistor but its the first time I've seen one looking like that... Also, can I just replace it with the "normal" ones? Attachment 791419
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Help please... What kind of resistor is this?
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What size power supply for TDA7498E based amp?
Despite thinking i would buy a volt + amp i think i would go for this amp (price power ratio)
AUDIOPHONICS TDA-S50 Amplifier TDA7498E Class D 2x 50W / 8 Ohm
AUDIOPHONICS TDA-S50 Amplifier TDA7498E Class D 2x 50W / 8 Ohm - Audiophonics
I have a 24v 6a power supply but i can get 2 power supplys so the total price would be no more than around 70 euros
ALIENTEK AC/DC Switching Power Adapter 100-240V to 28V 4.3A
FX-AUDIO AC/DC Switching Power Adapter 100-240V AC to 32V 5A DC
What is recommended to buy? Any other suggestions from a european store?
AUDIOPHONICS TDA-S50 Amplifier TDA7498E Class D 2x 50W / 8 Ohm
AUDIOPHONICS TDA-S50 Amplifier TDA7498E Class D 2x 50W / 8 Ohm - Audiophonics
I have a 24v 6a power supply but i can get 2 power supplys so the total price would be no more than around 70 euros
ALIENTEK AC/DC Switching Power Adapter 100-240V to 28V 4.3A
FX-AUDIO AC/DC Switching Power Adapter 100-240V AC to 32V 5A DC
What is recommended to buy? Any other suggestions from a european store?
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Conical Compression Horn Waveguides
What are the drawbacks of the conical horns like Selenium HL14-50N? Obviously the coverage pattern is round instead of squarish. Is there some reason why they arent used in commercial designs?
I am considering a build with similar 60x60 PRV Audio WGP22-50 because the room is hexagonal, and each cabinet presents to a wedge of seating.
I am considering a build with similar 60x60 PRV Audio WGP22-50 because the room is hexagonal, and each cabinet presents to a wedge of seating.
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Preamp for Pass X-250.5
I have purchased a Pass Labs X250.5 and I am looking for a preamp of commensurate ability. I don't need a phono input as I built a Pass Pearl II which handles that effort nicely.
Is there a DIY preamp that would be a favorable match for the X250.5? I am considering an XP-12.
Is there a DIY preamp that would be a favorable match for the X250.5? I am considering an XP-12.
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Fane sale on now.
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ebay TDA7293 board buzz fix
Hi all, just got myself my first amp board to play with. It's the TDA7293 dual channel power amplifier board off ebay for the cheap and it's giving me buzz on both speakers especially on the right channel. I'm already using shielded input cable. I think it's related to ground loop and I'd figure I need a star ground? How do I fix this on this board? TIA!
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FS: PCBs to build an active 2-way crossover, 4th order
I have a few PCBs to build an active 2-way crossover (4th order, Linkwitz transform in both LP and HP sections).
The schematic of the circuit and the PCBs are shown in the photos below.
The cost is 19 Euros for one PCB (shipping is included). For 2 pcbs, the cost is 33 Euros (shipping is included).
I will provide also the PCB assembly guide.
If you are interested send me a Private Message.
The schematic of the circuit and the PCBs are shown in the photos below.
The cost is 19 Euros for one PCB (shipping is included). For 2 pcbs, the cost is 33 Euros (shipping is included).
I will provide also the PCB assembly guide.
If you are interested send me a Private Message.
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Username Change
Dear moderators,
Please update my username if possible to ngen33r. I graduated college a while back and I have surpassed my "crazi" phase. I have been doing a ton of repairs and DIY and want to get back into the community.
Please update my username if possible to ngen33r. I graduated college a while back and I have surpassed my "crazi" phase. I have been doing a ton of repairs and DIY and want to get back into the community.
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Big n Fat
A few years back I started playing with box size/shape/bracing/ material/damping..... I first worked out crude simple ways to make cheap cabinets quickly that although look ugly, were both well damped, AND stiff.
A far more difficult combination than most think BTW ;)
Now please dont get into all the details about the strengths / weaknesses of stiffness and damping etc etc. Trust me I get it. In the end I worked out a way to get both easily. I could get very good results from cheap 1/2 " particle board (yes thats what I said ;) ), so long as the bracing left no more than 3 inches or less cab wall between braces, the braces were no less than 4 inches tall when set on edge, the braces went fully around inside of walls , the braces include cross bracing to opposite walls, AND this is a big one, All bracing was glued to walls and each other with a semi soft setting construction adhesive ( important that glue line was about 1/8 to 1/4 inch thick. The combo results in excellent mid freq resonance suppression AND quite serious stiffness no mater cab size.
Yes, a butt load of bracing etc doesnt sound like a cheap and fast cabinet. But when you dont care about looks at all, and are simply slapping rectangular braces in places using literally GOBS of construction adhesive (urethane sub floor adhesive), using sheet rock screws with no pre drilling to hold the whole mess together while it sets enough to be stable, then remove screws, you can bang together a high perf test bed cab in a short time.
OK so to the point of thred...
I spent years with only open panel planer magnetic bass drivers. Literally a couple hundred prototypes. When I switched to playing with pistons in a box I was disappointed. Love the loudness and precieved dynamics BUT I could never seem to get that ultimate sense of open transparent tuneful bass/ mid perf of open panel.
Now this was always using the typically more acceptable tall thin cab. No matter what I did with shape / size it just never quite impressed enough.
One day I decided to build a fat one. A fat wide box instead of the taller thinner shapes. From the get go, from the first box I finally heard for the first time, a similar sound to the open panel stuff.
I supose some will say for a given volume/ shape, its all in how you damp the box internals BUT seriously, hundreds of different cabs latter and all kinds of different internal damping materials / shapes/ sizes latter, its hard to imagine thats all there is to it.
For the moment I will take the well built Fat girl over the cat walk regulars.
A far more difficult combination than most think BTW ;)
Now please dont get into all the details about the strengths / weaknesses of stiffness and damping etc etc. Trust me I get it. In the end I worked out a way to get both easily. I could get very good results from cheap 1/2 " particle board (yes thats what I said ;) ), so long as the bracing left no more than 3 inches or less cab wall between braces, the braces were no less than 4 inches tall when set on edge, the braces went fully around inside of walls , the braces include cross bracing to opposite walls, AND this is a big one, All bracing was glued to walls and each other with a semi soft setting construction adhesive ( important that glue line was about 1/8 to 1/4 inch thick. The combo results in excellent mid freq resonance suppression AND quite serious stiffness no mater cab size.
Yes, a butt load of bracing etc doesnt sound like a cheap and fast cabinet. But when you dont care about looks at all, and are simply slapping rectangular braces in places using literally GOBS of construction adhesive (urethane sub floor adhesive), using sheet rock screws with no pre drilling to hold the whole mess together while it sets enough to be stable, then remove screws, you can bang together a high perf test bed cab in a short time.
OK so to the point of thred...
I spent years with only open panel planer magnetic bass drivers. Literally a couple hundred prototypes. When I switched to playing with pistons in a box I was disappointed. Love the loudness and precieved dynamics BUT I could never seem to get that ultimate sense of open transparent tuneful bass/ mid perf of open panel.
Now this was always using the typically more acceptable tall thin cab. No matter what I did with shape / size it just never quite impressed enough.
One day I decided to build a fat one. A fat wide box instead of the taller thinner shapes. From the get go, from the first box I finally heard for the first time, a similar sound to the open panel stuff.
I supose some will say for a given volume/ shape, its all in how you damp the box internals BUT seriously, hundreds of different cabs latter and all kinds of different internal damping materials / shapes/ sizes latter, its hard to imagine thats all there is to it.
For the moment I will take the well built Fat girl over the cat walk regulars.
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Battery biased crossovers
I was wonder if anyone here has done this and if so what were the results?
I am thinking of trying with my 1981 Klipsch La Scalas, I am planning to make a type A that crosses midrange to tweeter at 4500hz and thought that would be an easy experiment to try. I know how to do it just wondering about you guys experiences with it.
I went to electronics school in the 70s and was an associate CET and state licensed, I understand circuits pretty well but sometime things that really shouldn't make much of a difference in theory really do in practice.
Thanks
I am thinking of trying with my 1981 Klipsch La Scalas, I am planning to make a type A that crosses midrange to tweeter at 4500hz and thought that would be an easy experiment to try. I know how to do it just wondering about you guys experiences with it.
I went to electronics school in the 70s and was an associate CET and state licensed, I understand circuits pretty well but sometime things that really shouldn't make much of a difference in theory really do in practice.
Thanks
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Germanium audio preamlifier
Hello,
I have a few Germanium transistors. (AC Series) firstly you want to make good audio preamplifier. I have found the attached diagrams. which one should I choose. If you have a better scheme, please write
sorry for my english :)
Best regards.
I have a few Germanium transistors. (AC Series) firstly you want to make good audio preamplifier. I have found the attached diagrams. which one should I choose. If you have a better scheme, please write
sorry for my english :)
Best regards.
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Very, Very cheap compression-drivers and waveguides?
I can get some very, very cheap compression-drivers that on paper looks impressive for the price.
Around 10-15Eu for a 1,5" diaphragm 30-100W rating. Build quality and size looks much better than a similar prized "hifi-tweeter".
I'm looking to match the driver with a "pro" 6" (91dB, 200/400w, above 150Hz), so I don't need 100dB/W sensitivity that a compression´-driver can do with a proper horn. Crossover around 2-2,5Khz, 4th order active filter. Not looking for audio-nirvana, but good-sounding, loud party-music ( assisted by a 12" sub).
Question 1: can a compression-driver be used with a short waveguide instead of a "real" horn or would it be hopeless?.
Question 2: how critical is the mating of horn and compression-driver? - I'm thinking about buying a few cheap one for testing, but if you say its hopeless, I'll go another route.
Kind regards TroelsM
Around 10-15Eu for a 1,5" diaphragm 30-100W rating. Build quality and size looks much better than a similar prized "hifi-tweeter".
I'm looking to match the driver with a "pro" 6" (91dB, 200/400w, above 150Hz), so I don't need 100dB/W sensitivity that a compression´-driver can do with a proper horn. Crossover around 2-2,5Khz, 4th order active filter. Not looking for audio-nirvana, but good-sounding, loud party-music ( assisted by a 12" sub).
Question 1: can a compression-driver be used with a short waveguide instead of a "real" horn or would it be hopeless?.
Question 2: how critical is the mating of horn and compression-driver? - I'm thinking about buying a few cheap one for testing, but if you say its hopeless, I'll go another route.
Kind regards TroelsM
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Braun speakers
I have just acquired a pair of Braun L610 speakers. I would like to ask if any member has any experience of these and if anyone might know of any legacy information etc.
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Finding tweeter for Alesis M1 MKII
Basically I bought a pair of the M1 Mkii of Alesis back in 2014, one of them stopped working.
As the original part (7-02-0028) is discontinued (and as far as I know it should be better to change BOTH the tweeters)
I do not know if
a) I shall sucumb and buy a replacement fom eBay
b) Give up, buy another pair of whatever and try to sell "my monitor and a half" as replacement parts
c)Do what they said in the thread below, and buy a pair of tweeters that fit (sama size, 4 ohm resistance) alesis M1 active Mk2 tweeter
As the original part (7-02-0028) is discontinued (and as far as I know it should be better to change BOTH the tweeters)
I do not know if
a) I shall sucumb and buy a replacement fom eBay
b) Give up, buy another pair of whatever and try to sell "my monitor and a half" as replacement parts
c)Do what they said in the thread below, and buy a pair of tweeters that fit (sama size, 4 ohm resistance) alesis M1 active Mk2 tweeter
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Opamps self-supply with AutoShunt regulators
The idea of using an opamp to regulate its own supplies is not completely new, and a few examples can be found in the application literature of some special amplifiers, like the LM3900 Norton amp or the open collector series TAA86x, but here the concept is more general, and also more radical: the opamp directly regulates its own supply in a shunt fashion, without any interface.
This can be used for standalone circuits, but the main interest is to use one amplifier of a multiple package to regulate the common supply.
Why not just use a zener or a classic voltage regulator?
Sometimes, the supply is used as a reference, and needs to be of a better standard than what these simple solutions can offer.
How does it work?
The principle is to tie the output to one of the supply rails, and operate the output stage in single-ended, Class A mode.
This can be done in a number of ways, as this sheet demonstrates:
![Click the image to open in full size.]()
The input circuitry is basically a bridge, having one (or more) non-linear element.
The examples use a voltage reference, but any element having a concave V/I characteristic like a junction could also be used.
If the non-linear element has a convex characteristic, one of the resistors has to be swapped for the non-linear element, but the mode of operation remains the same.
These circuits are incestuous to a high degree: not only does the opamp regulate its own supply, but this supply also biases the reference.
This could cause self-starting issues, but it also means that the whole circuit operates in a complete stasis, yielding an extreme degree of accuracy and performance.
Of course, these simplified examples are too brutal to work in reality: one of the problem is the direct connection of the output to a supply rail: for example, even when its output is supposed to be in a saturated low state, an opamp does not like having it directly and externally shorted to the - rail: it might misbehave, consume lots of current, etc.
Then, there is the issue of bypassing: a supply should be bypassed, but connecting a decoupling cap between the rails will result in capacitive loading, something opamps do not like.
Therefore, a practical circuit needs some adaptations:
![Click the image to open in full size.]()
A diode is added in the output to allow it some breathing space, and a low-impedance RC network is used as a bypass.
I will discuss these choices later.
This picture shows the performance of the example circuit (impedance):
![Click the image to open in full size.]()
The -94dB at LF/DC is equivalent to a ~20µΩ impedance, which is unusual for such a simple circuit biased at only 3mA.
The rest of the curve follows the GBW characteristic of the opamp, up to the resonance frequency at ~10kHz, determined by the opamp and the 47µF bypass cap.
Beyond 10kHz, the impedance assumes the value of the 1.5Ω damping resistor
This can be used for standalone circuits, but the main interest is to use one amplifier of a multiple package to regulate the common supply.
Why not just use a zener or a classic voltage regulator?
Sometimes, the supply is used as a reference, and needs to be of a better standard than what these simple solutions can offer.
How does it work?
The principle is to tie the output to one of the supply rails, and operate the output stage in single-ended, Class A mode.
This can be done in a number of ways, as this sheet demonstrates:
The input circuitry is basically a bridge, having one (or more) non-linear element.
The examples use a voltage reference, but any element having a concave V/I characteristic like a junction could also be used.
If the non-linear element has a convex characteristic, one of the resistors has to be swapped for the non-linear element, but the mode of operation remains the same.
These circuits are incestuous to a high degree: not only does the opamp regulate its own supply, but this supply also biases the reference.
This could cause self-starting issues, but it also means that the whole circuit operates in a complete stasis, yielding an extreme degree of accuracy and performance.
Of course, these simplified examples are too brutal to work in reality: one of the problem is the direct connection of the output to a supply rail: for example, even when its output is supposed to be in a saturated low state, an opamp does not like having it directly and externally shorted to the - rail: it might misbehave, consume lots of current, etc.
Then, there is the issue of bypassing: a supply should be bypassed, but connecting a decoupling cap between the rails will result in capacitive loading, something opamps do not like.
Therefore, a practical circuit needs some adaptations:
A diode is added in the output to allow it some breathing space, and a low-impedance RC network is used as a bypass.
I will discuss these choices later.
This picture shows the performance of the example circuit (impedance):
The -94dB at LF/DC is equivalent to a ~20µΩ impedance, which is unusual for such a simple circuit biased at only 3mA.
The rest of the curve follows the GBW characteristic of the opamp, up to the resonance frequency at ~10kHz, determined by the opamp and the 47µF bypass cap.
Beyond 10kHz, the impedance assumes the value of the 1.5Ω damping resistor
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Dupont Mylar roll 36-in wide typeS 10-12um
Dupont Mylar FOR SALE 36-inch wide roll type S, which has a high tensile modulus for sale, measures 10-12um thickness label states 20k ft.
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WTB MMBF4860 JFET N-CH SOT23
Hi. Looking to get a source of MMBF4860 JFET N-CH. Let me know if you have a few. Thanks
SB
SB
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Diy designs for high front Atmos speakers
Greetings. I've been lurking for a while and I'm looking for guidance on diy designs which will work well as high front speakers for Dolby Atmos. I can drive 4-8 ohm speakers (marantz 7010). They'll be close to the ceiling and mounted on the wall so I'm looking for a design that's front ported and kind of near field, pointed to the 3 seat couch that's only 8 feet away from the tv and about 10 feet from the wall.
I'm currently using two of the satellites from a Logitech z5500 but they don't sound well with the Sony full tower speakers front speakers, requiring the sub to take over at a high 150 Hz. Something which can reach down to 80 Hz would probably be enough but 60 Hz would be preferable. It's a very small room so they don't need wide dispersion.
I can cut and build cabinets, cut driver openings, I can build a crossover, but I can't really design a speaker from scratch. Are there any design suggestions of full designs that'd work well?
I'm currently using two of the satellites from a Logitech z5500 but they don't sound well with the Sony full tower speakers front speakers, requiring the sub to take over at a high 150 Hz. Something which can reach down to 80 Hz would probably be enough but 60 Hz would be preferable. It's a very small room so they don't need wide dispersion.
I can cut and build cabinets, cut driver openings, I can build a crossover, but I can't really design a speaker from scratch. Are there any design suggestions of full designs that'd work well?
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Dupont Mylar roll 36-in wide typeS 10-12um
Dupont Mylar FOR SALE 36-inch wide roll type S, which has a high tensile modulus for sale, measures 10-12um thickness label states 20k ft.
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LG LHD657 Class D Amp. S-Protect
regards.
please help my brothers all, I have a LG LHD657 Home Theater (Class D Amp. Chip TAS5612LA).
a few days ago accidentally short speaker cable, causing one of the transistors to burn, to the extent that the transistor number could not be read because it caught fire, I tried to look for the LG LHD657 scheme on the internet to find out the transistor number, but until now it was not found, maybe my brother is willing to help, with my heart I will thank you.
regards
please help my brothers all, I have a LG LHD657 Home Theater (Class D Amp. Chip TAS5612LA).
a few days ago accidentally short speaker cable, causing one of the transistors to burn, to the extent that the transistor number could not be read because it caught fire, I tried to look for the LG LHD657 scheme on the internet to find out the transistor number, but until now it was not found, maybe my brother is willing to help, with my heart I will thank you.
regards
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