You'll have far more interaction on MW and EM regarding synths, in their DIY sections. Try it.
I doubt it, it's quite simply that here the focus in on music reproduction. I am fine with it this way.
Other than that, check your Modular thread for some pics of what I've been working on instrument-side.
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Lab 1
Actually, I don't have 'a Lab'. I have various stations at which work for various pursuits (audio is just one of several of them) is done. Some of this work is talked about online by me and not just on forums, some of it isn't.
This morning, I wanted to re-organise the measurement instruments to my right. This leaves some space to the left for the laptop and parts boxes and my notes and designs.
So this is what is on the bench (the one you can see - there are several other ones simultaneously) tonight.
Not shown: a DIY low-noise Dual Rail Lab PSU, still being worked on. While this is being done, I am using another one for some audio experiments.
These little Fostex bi-amped monitors are really good. It's a shame we can't easily repair them as they are hard to open. I have a busted tweeter on one of them I 'd like to replace but can't find a way to open it up. Well, I can always re-use and modify the two amplifiers in it for other experiments or a custom 2-way build.
Apparently, two 3-way Tower speakers should be arriving today so things are looking up.
Actually, I don't have 'a Lab'. I have various stations at which work for various pursuits (audio is just one of several of them) is done. Some of this work is talked about online by me and not just on forums, some of it isn't.
This morning, I wanted to re-organise the measurement instruments to my right. This leaves some space to the left for the laptop and parts boxes and my notes and designs.
So this is what is on the bench (the one you can see - there are several other ones simultaneously) tonight.
Not shown: a DIY low-noise Dual Rail Lab PSU, still being worked on. While this is being done, I am using another one for some audio experiments.
These little Fostex bi-amped monitors are really good. It's a shame we can't easily repair them as they are hard to open. I have a busted tweeter on one of them I 'd like to replace but can't find a way to open it up. Well, I can always re-use and modify the two amplifiers in it for other experiments or a custom 2-way build.
Apparently, two 3-way Tower speakers should be arriving today so things are looking up.
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I didn't know this. Why / what happens when an amp starts clipping? I have a TDA7297 that I sometimes drive too hard.
YashN,
Awesome setup! Thanks for sharing your bench.
On my bench was some foam core surgery to install a TWS Bluetooth amplifier in foam core speakers I made nearly 8 years ago. They still sound great.
Awesome setup! Thanks for sharing your bench.
On my bench was some foam core surgery to install a TWS Bluetooth amplifier in foam core speakers I made nearly 8 years ago. They still sound great.
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When an amp clips, the tops and bottoms of the waveform are chopped off. This creates lots of harmonics. Most of the excess harmonic energy lies in the region of the tweeter in a multi way speaker, and the tweeter is the most fragile driver in the cabinet. Bang a solid state amp into hard clipping for long and the tweeter will overheat. Tube amps tend to be a little easier on the tweeters since the output transformers filter out some of the harmonics.
Square waves contain more energy than a sine wave of similar amplitude. Consumer grade speaker systems are often power rated assuming that the user will be playing typical music at a power level below clipping.
Most music had at least 10 dB peak to average ratio, usually quite a bit more. This means that the average power (heat energy) is 10 db less than the peaks. A 100 watt amp run at a level where the peaks just touch 100 watts will have less than 10 watts of average power, on most music, a lot less. Running that amp harder into clipping will not make the peaks any higher, but it will raise the average taking away all that headroom in the speaker's power handling capability.
Loud compressed music run at the edge of clipping may contain enough energy to overheat the woofer or midrange if the clipped music is at a power level close to, or above the speaker systems maximum power rating.
Thanks Mr Tubelab for a great explanation. I sure don't want to blow up my speakers or stuff like you. But I am also gaining experience in that field - blew up my TDA7293 amp a few months ago and one board of a half built USSA5.
Mm, I get by with a little help from my friends. Thanks to X, I will have an Alpha Nirvana build on my bench next. Mm, gonna try with a little help from my friends, not to blow up this one too. Then clipping will no longer be a concern.
Mm, I get by with a little help from my friends. Thanks to X, I will have an Alpha Nirvana build on my bench next. Mm, gonna try with a little help from my friends, not to blow up this one too. Then clipping will no longer be a concern.
I got a small pair of Cerwin Vega satellite speakers from a thrift store for $5 each. I also made a pair of MTM cabinets with cheap drivers. They have a switch to turn off the tweeters for "extreme" testing or guitar amp duty.
So far both sets have survived everything I have thrown at them, but some severe abuse with a TI TPA3255 class D EVB loosened up the bolts holding the drivers in the DIY pair.
Hi Tubelab,
I like the TPA3255 a lot. A great amp and about as low noise as one can find anywhere. I have no other amp that can boast a 1uV rms noise floor (with a good SMPS from MicroAudio) in the 20Hz to 20khz band.
I just sold my last two units and I guess I will need to order some more in the near future. These seem to be getting popular...
Shaking bolts loose is either vvery loud or your bolts were not tightened well?
I like the TPA3255 a lot. A great amp and about as low noise as one can find anywhere. I have no other amp that can boast a 1uV rms noise floor (with a good SMPS from MicroAudio) in the 20Hz to 20khz band.
I just sold my last two units and I guess I will need to order some more in the near future. These seem to be getting popular...
Shaking bolts loose is either vvery loud or your bolts were not tightened well?
I built a pair of "test speakers" that got used for all sorts of tough duty including being used for a portable PA system for a rock band fed by a 125 WPC tube amp. The bolts WERE tight when I built the boxes, and I had even used double lock nuts on the #8 bolts. That was over 10 years ago and they had not been taken apart until this event. Here is the recipe:
Take two of these Dayton 6 inch drivers and one Pyle bullet tweeter and mount them in a 1.2 cubic foot box made from wood that was too thin (but free), with the port tuned to 70 Hz. I got the drivers back when they were $20 each. Total expense for both speakers was under $150.
https://www.parts-express.com/Dayton-Audio-PA165-8-6-PA-Driver-Speaker-295-015
I fed these 4 ohm cabinets from the TI 3325 EVB which was running off of a 48 volt SMPS that was robbed from a dead MRI RF amp. Loud, yes, but not as loud as one would expect since once Xmax is exceeded it doesn't get any louder, just more distorted, which sounds louder up to a point.
I was playing the "how far can I launch a wad of paper from the port with a kick drum hit" game when things started sounding funny. One driver was quite loose and only three of its 8 nuts were still on the bolts. Liberal use of Loctite has so far prevented recurrence.
I have 4 Faital Pro 6FE200 drivers waiting in their boxes for when I blow these up, but I now think I will just build a new set of cabinets and keep these as is for future "tests". My job site table saw is an outdoor use only kinda thing. The current weather is not compatible with table saw activity and making more speakers are pretty far down the list.
The speakers can be seen here:
75 watt per channel triode mode tube amp prototype - YouTube
Take two of these Dayton 6 inch drivers and one Pyle bullet tweeter and mount them in a 1.2 cubic foot box made from wood that was too thin (but free), with the port tuned to 70 Hz. I got the drivers back when they were $20 each. Total expense for both speakers was under $150.
https://www.parts-express.com/Dayton-Audio-PA165-8-6-PA-Driver-Speaker-295-015
I fed these 4 ohm cabinets from the TI 3325 EVB which was running off of a 48 volt SMPS that was robbed from a dead MRI RF amp. Loud, yes, but not as loud as one would expect since once Xmax is exceeded it doesn't get any louder, just more distorted, which sounds louder up to a point.
I was playing the "how far can I launch a wad of paper from the port with a kick drum hit" game when things started sounding funny. One driver was quite loose and only three of its 8 nuts were still on the bolts. Liberal use of Loctite has so far prevented recurrence.
I have 4 Faital Pro 6FE200 drivers waiting in their boxes for when I blow these up, but I now think I will just build a new set of cabinets and keep these as is for future "tests". My job site table saw is an outdoor use only kinda thing. The current weather is not compatible with table saw activity and making more speakers are pretty far down the list.
The speakers can be seen here:
75 watt per channel triode mode tube amp prototype - YouTube
When I worked at Sun Stereo we sold Pro Lab speakers some one striped all the screws on the woofer on a batch ( crap speaker any way) we called them the super pro labs when you turned the loudness on and cranked them the woofer would jump out of the cabinets. Lots of fun there Mr Pass worked for them at the same time but I never met him then. Out tech got drunk and crashed his car and broke his fingers, I was his hands for 6 weeks, I was shocked how he would substitute transistors and not match them. At least I didn’t follow his example.
Bill
Bill
I’ll have to try the launch a wad of paper with a kick drum trick.
On TL’s the cross sectional area is much larger so velocities are lower and less chance of launching something. The amount of air a TL or horn can move with a flapping piece of paper is impressive though.
Nelson Pass worked at Sun Stereo? Was this in the Bay Area or SoCal?
On TL’s the cross sectional area is much larger so velocities are lower and less chance of launching something. The amount of air a TL or horn can move with a flapping piece of paper is impressive though.
Nelson Pass worked at Sun Stereo? Was this in the Bay Area or SoCal?
Had this on another 'bench' - actually the dinner table doubling as office desk - with a pesky 'overload' condition. That happened right after several blocks in my area lost one phase of AC mains completely.
We heard the relays clicking incessantly and then that fault developed.
Cleaned it up a little. Attempted a reflow this morning, but no go: slight burning smell and an orange spark near one MOSFET module, near instantaneous 'overload' condition, so that's it for this beauty.
Too bad the modules are expensive. I'd rather not continue to work on this and instead recuperate anything worth salvaging. It's quite an old design, a receiver but with no HDMI, but the sound was rather good - MOSFETs, Class H+ modules.
The transformer has +/- 48V and +/- 24V if I'm not mistaken. It's heavy.
We heard the relays clicking incessantly and then that fault developed.
Cleaned it up a little. Attempted a reflow this morning, but no go: slight burning smell and an orange spark near one MOSFET module, near instantaneous 'overload' condition, so that's it for this beauty.
Too bad the modules are expensive. I'd rather not continue to work on this and instead recuperate anything worth salvaging. It's quite an old design, a receiver but with no HDMI, but the sound was rather good - MOSFETs, Class H+ modules.
The transformer has +/- 48V and +/- 24V if I'm not mistaken. It's heavy.
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xrk,
Are you going to make a speaker using ESS Heil AMT? ESS Heil AMT seem to be out of stock except for ESS store. On ESS store ESS Heil AMT large limited edition on sale for $199.00
ESS Speakers USA
Are you going to make a speaker using ESS Heil AMT? ESS Heil AMT seem to be out of stock except for ESS store. On ESS store ESS Heil AMT large limited edition on sale for $199.00
ESS Speakers USA
I have made many speakers with Heil AMT. One of the best speakers I have heard anywhere ever is the Synergy that I made with a Heil AMT and B&C 6MDN44 midrange on top of a large bass horn of my own design.
And a Heil AMT in top of a dipole Karlson aperture - KaZBa with dual RS225-8:
Rockin' the KaZba Dipole (K aperture Z-baffle Dipole)
And a Heil AMT in top of a dipole Karlson aperture - KaZBa with dual RS225-8:
Rockin' the KaZba Dipole (K aperture Z-baffle Dipole)
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It's a Panasonic, as second-hand I bought cheap, without remote and an issue with the main volume pot. A lot of those older receivers are built similarly, and not just the Technics ones which belonged to the same manufacturer. Some of them have the transformer in the middle and two rows of large transistors on large heatsinks on the side. It's always interesting to have a look inside of them. The older Yamahas have a very good reputation.
I had found another one left on the sidewalk here, so I salvaged from that but didn't think of keeping the MOSFET modules or else I might have been able to fix it. I did have a look inside the modules. Some people call this an IC, but it's a small PCB with several components in them and encased.
I like the transformer. I have two of them so I could make an isolation transformer out of them, or else just use the two of them individually for two audio builds. The speaker terminals are really nice as well. There are a few large diodes I can re-use for power experiments, probably a few other components to salvage.
Probably, although I am not sure since no other gear has been affected: computers, game console, 4K Blu-ray Player, etc...
I will still get one as the local mains distribution is notoriously unreliable, especially during big winter storms, and a new modern receiver with Atmos is being eyed and that's quite a big investment.
On the bench tonight was my small tube at low voltage experimental platform, to which I added a MOSFET buffer. Many of the configurations just distorted too much at around 70% of the iPhone volume, but after some more tweaking of resistor values here and there, I managed to get something interesting on the earphones. These are cheap and slightly 'shouty' earphones for testing. I tried on the Fostex bi-amp monitor at low volume too and it sounded good. Couldn't do higher volume testing as my gf is sound asleep
Rummaged through parts bucket and set aside transformers for higher voltage tests. Also found some high-power resistors to go with these HV builds, If not, I'll do some parallel or series-parallel or what not to get what I need and as last recourse, some orders could be sent.
Some common tubes are out-of-stock in some places. Supply issues don't affect only Solid-State.
Also salvaged some good RCA connectors from old gear, some caps and more.
Satisfied with the progress tonight.
Rummaged through parts bucket and set aside transformers for higher voltage tests. Also found some high-power resistors to go with these HV builds, If not, I'll do some parallel or series-parallel or what not to get what I need and as last recourse, some orders could be sent.
Some common tubes are out-of-stock in some places. Supply issues don't affect only Solid-State.
Also salvaged some good RCA connectors from old gear, some caps and more.
Satisfied with the progress tonight.