Sorry, but I had to show this.
- Thread starter Alan Sledzieski
- Start date
Re: Sorry, but I had to show this.
I made an amp from a kit back when I was in high school. The sheet metal part of the chassis was one of my first projects in the metal shop class if I recall correctly. We ended up calling this the Refrigerator Amp on account of the fridge door handle I put on the front of it. Many years ago I gave it to my brother to drive his subs in his home stereo. When he came around for the holidays this year he brought it back because it recently quit working. I'm not sure whether to be proud or embarrassed but 20+ years of service ain't bad...
I made an amp from a kit back when I was in high school. The sheet metal part of the chassis was one of my first projects in the metal shop class if I recall correctly. We ended up calling this the Refrigerator Amp on account of the fridge door handle I put on the front of it. Many years ago I gave it to my brother to drive his subs in his home stereo. When he came around for the holidays this year he brought it back because it recently quit working. I'm not sure whether to be proud or embarrassed but 20+ years of service ain't bad...
Re: Sorry, but I had to show this.
Also notice the high quality test equipment used. HA-HA. But they worked for what I needed.
Since we are showing old homebrew amps. Here is one that I built back in the very early 80's. It is 4 100 watt amps @ 4 ohms ea. The heat sink is made out of a STOP sign. You can make it out if you look close enough. The front of the amp (rack side) is removed.
Also notice the high quality test equipment used. HA-HA. But they worked for what I needed.
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Re: Sorry, but I had to show this.
2 transformers but one set of caps? Was the stop sign aluminum? Interesting idea.
2 transformers but one set of caps? Was the stop sign aluminum? Interesting idea.
Re: Sorry, but I had to show this.
Since I didn't have any money (I built everything back then-mixers-amps-processing etc), I took the cheap route.
There was a surplus store in the Chicago area that I used to get all sorts of "stuff" that I built with. In order to get what I wanted, I also had to get "extra" stuff-extra output windings etc. This accounted for the extra size and weight of the transformers.
The 2 transformers have the inputs in parallel and the outputs in series-creating a center tap-so to speak. The center was the ground and the "outside legs" went to a single 25A bridge rectifier-then to the caps-one for each the + and- supplies.
So pretty normal stuff there.
Yes the sign was Aluminum. I did get it the legal way. The highway dept would give old signs to the school I went to, so we could make things our of them. On the sides that were "touching" other layers and the outputs, I sanded them down good (to get through the thick crumpeled paint) and used LOTS of heat sink compound and bolts to hold it together tightly.
While not as good as a real heatsink-they did what I needed them to and never had a problem overheating.
You do what you have to when you have no money. This is NO LIE, I actually used to twist my broken guitar strings back together and solder them. You just have to make sure that the "blob" was between frets and you don't play those notes. After a couple would break-I would go to the local Western Auto store and buy Black Diamond strings. They were the only store in the county that had guitar strings. Times were different back then.
Since I didn't have any money (I built everything back then-mixers-amps-processing etc), I took the cheap route.
There was a surplus store in the Chicago area that I used to get all sorts of "stuff" that I built with. In order to get what I wanted, I also had to get "extra" stuff-extra output windings etc. This accounted for the extra size and weight of the transformers.
The 2 transformers have the inputs in parallel and the outputs in series-creating a center tap-so to speak. The center was the ground and the "outside legs" went to a single 25A bridge rectifier-then to the caps-one for each the + and- supplies.
So pretty normal stuff there.
Yes the sign was Aluminum. I did get it the legal way. The highway dept would give old signs to the school I went to, so we could make things our of them. On the sides that were "touching" other layers and the outputs, I sanded them down good (to get through the thick crumpeled paint) and used LOTS of heat sink compound and bolts to hold it together tightly.
While not as good as a real heatsink-they did what I needed them to and never had a problem overheating.
You do what you have to when you have no money. This is NO LIE, I actually used to twist my broken guitar strings back together and solder them. You just have to make sure that the "blob" was between frets and you don't play those notes. After a couple would break-I would go to the local Western Auto store and buy Black Diamond strings. They were the only store in the county that had guitar strings. Times were different back then.
Re: Sorry, but I had to show this.
I see your refrigerator handle and raise you these two bad boys.
You can't see the amp that well in the pictures, on the left side of front facing photo, and in the middle of the other.. You can see one of my Bose knock off DIY speakers, but with 16 drivers each instead of 9 for 7 more, of course.
My amp that I made back in the early '70s was built into an old WE Power supply chassis so 19" wide and about 2 feet high. I only had one transformer in it, but that transformer alone weighed 65#. Amp made 4 channels of 250W into 8 Ohms, decent power for a home hifi back in those days.
Amp is still working (or at least it was the last time I turned it on), I don't enjoy playing CDs as much since having live bands in my living room.
Any thief who can lift this and run away with it, can have it with my compliments and respect.
JR
I see your refrigerator handle and raise you these two bad boys.
You can't see the amp that well in the pictures, on the left side of front facing photo, and in the middle of the other.. You can see one of my Bose knock off DIY speakers, but with 16 drivers each instead of 9 for 7 more, of course.
My amp that I made back in the early '70s was built into an old WE Power supply chassis so 19" wide and about 2 feet high. I only had one transformer in it, but that transformer alone weighed 65#. Amp made 4 channels of 250W into 8 Ohms, decent power for a home hifi back in those days.
Amp is still working (or at least it was the last time I turned it on), I don't enjoy playing CDs as much since having live bands in my living room.
Any thief who can lift this and run away with it, can have it with my compliments and respect.
JR
Re: Sorry, but I had to show this.
Oh the things we used to do. I wish I had photos of the 24 channel mixer I made out of a rack door.
I'll have to dig up a photo of a "different" approach I used for a little while. It was power amps with an outboard power supply. It sat beside the amp rack. Two very large transformers and a bank of caps. I think the power supply weighed around 100lbs or more. I ran 2 6x100 watt amps off of it. So the amps weren't all that large- 3 spaces each.
Oh the things we used to do. I wish I had photos of the 24 channel mixer I made out of a rack door.
Re: Sorry, but I had to show this.
My transformer was one huge lump (ExI core), but for reservoir capacitors I assembled 12 x 3750 uF computer grade surplus caps, screwed to a DIY PCB bus bar to make them act like 2 large caps. I had a relay that disconnected the speakers, so the amp didn't make any turn on/off noise. The old WE power supply had a trick 3 position power switch, so you could warm up the tube heaters before applying full power. I used the old switch, to slow charge my PS through a series resistor, then when I switched it to full on, the resistor was shorted out and the relay connected the speaks... That PS would dim the lights and perhaps eat fuses without that inrush current limiter.
Puny by todays standard, but back in the day with 1kW total I got noise complaints from the next street over.
This was definitely not designed to be portable... even though it did have those two nice big handles. Those handles (cast bronze?) probably weight more than those uber-light modern class D amp.
JR
My transformer was one huge lump (ExI core), but for reservoir capacitors I assembled 12 x 3750 uF computer grade surplus caps, screwed to a DIY PCB bus bar to make them act like 2 large caps. I had a relay that disconnected the speakers, so the amp didn't make any turn on/off noise. The old WE power supply had a trick 3 position power switch, so you could warm up the tube heaters before applying full power. I used the old switch, to slow charge my PS through a series resistor, then when I switched it to full on, the resistor was shorted out and the relay connected the speaks... That PS would dim the lights and perhaps eat fuses without that inrush current limiter.
Puny by todays standard, but back in the day with 1kW total I got noise complaints from the next street over.
This was definitely not designed to be portable... even though it did have those two nice big handles. Those handles (cast bronze?) probably weight more than those uber-light modern class D amp.
JR
Re: Sorry, but I had to show this.
I think both of you have me beat for novelty if only by virtue of your additional years (and perhaps because of the era afforded by those years). If I had been born 5 years earlier I'm almost sure I would have attempted my own mixing console. I made a couple small ones (4 channels or so) but couldn't justify the price for anything larger when Peavey would sell me one for so cheap, with a warranty. One little thing I did do with the amp pictured above is that I added extra windings to the toroid to get the rails up to a whopping +-45v.
~:-D~:grin: That's something that wouldn't have been so possible with a "box" transformer. I just looked on the circuit board for that thing and it says "Tung-Yung Sound Master". I didn't remember it having such a cool name. I think it came from Mark V Electronics if anyone remembers them. A few years ago I realized that I was born at a point where I'm basically between 2 eras. I was just starting to understand how to build stuff when it was becoming ridiculous to consider making your own. The time I spent tinkering with analog audio might have been better spent learning C and becoming an early round digital guy. For some reason I never made the jump from integer basic to the good stuff. Ah, the future's still pretty bright...
I think both of you have me beat for novelty if only by virtue of your additional years (and perhaps because of the era afforded by those years). If I had been born 5 years earlier I'm almost sure I would have attempted my own mixing console. I made a couple small ones (4 channels or so) but couldn't justify the price for anything larger when Peavey would sell me one for so cheap, with a warranty. One little thing I did do with the amp pictured above is that I added extra windings to the toroid to get the rails up to a whopping +-45v.
~:-D~:grin: That's something that wouldn't have been so possible with a "box" transformer. I just looked on the circuit board for that thing and it says "Tung-Yung Sound Master". I didn't remember it having such a cool name. I think it came from Mark V Electronics if anyone remembers them. A few years ago I realized that I was born at a point where I'm basically between 2 eras. I was just starting to understand how to build stuff when it was becoming ridiculous to consider making your own. The time I spent tinkering with analog audio might have been better spent learning C and becoming an early round digital guy. For some reason I never made the jump from integer basic to the good stuff. Ah, the future's still pretty bright...
Re: Sorry, but I had to show this.
I still use the Hafler DH200 I built as a kit in early 80's right after they came out. I did a slight mod to it by adding front panel level controls. In the early days it ran the JBL bullets in my system, for the past many years it has been resting comfortably at home in my stereo system driving a pair of Tannoy DMT10 Series Two studio monitors. The preamp is a Hafler DH110. About a year ago I replaced all the electrolytic caps in the amp short of the main power supply caps and re-tweaked the bias.
I still use the Hafler DH200 I built as a kit in early 80's right after they came out. I did a slight mod to it by adding front panel level controls. In the early days it ran the JBL bullets in my system, for the past many years it has been resting comfortably at home in my stereo system driving a pair of Tannoy DMT10 Series Two studio monitors. The preamp is a Hafler DH110. About a year ago I replaced all the electrolytic caps in the amp short of the main power supply caps and re-tweaked the bias.
Re: Sorry, but I had to show this.
This one used to power a whole stadium full of vitavox horns - 1300 watts and comes with its own loading ramp. The mixer unit on top has a primative priority muting system and a convenient clock. It runs push pull KT66s driving p/p 845s driving p/p 212Es. The bottom two thirds of the amp is filled with ironmongery and mercury vapour rectifiers (3B28s). I just can't bear to throw it out (pretty soon I won't be able to move it anyway).
This one used to power a whole stadium full of vitavox horns - 1300 watts and comes with its own loading ramp. The mixer unit on top has a primative priority muting system and a convenient clock. It runs push pull KT66s driving p/p 845s driving p/p 212Es. The bottom two thirds of the amp is filled with ironmongery and mercury vapour rectifiers (3B28s). I just can't bear to throw it out (pretty soon I won't be able to move it anyway).
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Re: Sorry, but I had to show this.
I think you could sell that to the Dr. Who prop department. Very cool. What kind of output connectors are there?
I think you could sell that to the Dr. Who prop department. Very cool. What kind of output connectors are there?
Re: Sorry, but I had to show this.
Now I know where Funk Logic got their idea from!
I love the mixer!
Now I know where Funk Logic got their idea from!
I love the mixer!
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