OT: Anyone remember this vintage audio amp?

Started by Chris in sci.electronics.design2 years ago 21 replies

Hi all, Without venturing into 'stupid money territory' the best quality audio by far I've ever heard came from one particular solid state...

Hi all, Without venturing into 'stupid money territory' the best quality audio by far I've ever heard came from one particular solid state stereo amplifier I'd be interested in re-acquainting myself with. Unfortunately I can't recall the make or model number which is obviously a big barrier to the desired reunion. However, if I mention some scant details I *do* remember about it, mayb...


Spot the Design Error

Started by Phil Allison in sci.electronics.design3 years ago 72 replies

Hi to all my pals, a certain "design genius" here called John thinks any clever engineer can quickly decide if a design is good or otherwise...

Hi to all my pals, a certain "design genius" here called John thinks any clever engineer can quickly decide if a design is good or otherwise by assessing only a schematic. I say that is bollocks, maybe a simple test will make my point. -------------------------------------------------------------- This schem is for the famous Yamaha P2200 power amplifier sold in large numbers thro...


Using CMOS logic for amplifying small signals

Started by Mr. B in sci.electronics.design15 years ago 16 replies

Something has occurred to me, and I was wondering if anyone knew more about this. Could a CMOS logic inverter, like a 4049, be used as a very...

Something has occurred to me, and I was wondering if anyone knew more about this. Could a CMOS logic inverter, like a 4049, be used as a very high gain amplifier if it were properly biased? I figured that the DC offset should be set at just about half the supply voltage, so that the gate was always between a '1' and a '0'. I am not sure if the gate would behave linearly in that region, or...


Stabilizing pHEMTs

Started by Phil Hobbs in sci.electronics.design11 years ago 65 replies

So, JL's thread about level shifting a pHEMT switch brings up another issue: stabilizing the silly things. I have this little SKY65050 preamp...

So, JL's thread about level shifting a pHEMT switch brings up another issue: stabilizing the silly things. I have this little SKY65050 preamp that works very well--about a nanoamp of input current, 0.5 nV/sqrt(Hz) noise in the flatband, 0.8 pF Cin, flat from DC to about 120 MHz where the THS3091 second stage craps out. A very nice amplifier, but for the intended use, it could stand a bit ...


Guesstimate A Transformer

Started by Anonymous in sci.electronics.design4 years ago 14 replies

One of my useless things I think I'll throw together. An audio amp. I have transformers, audio output transformers from a tube amp that have a...

One of my useless things I think I'll throw together. An audio amp. I have transformers, audio output transformers from a tube amp that have a certain feature I need for this. This is a mobile audio amplifier. The basic configuration is shown at the end of this post in Spice. The coils, L1 and L2 are actually a center tapped winding. What I want to know is how much power dare


Maxim Instrumentation Amplifiers

Started by DemonicTubes in sci.electronics.design6 years ago 51 replies

Does anybody here have experience with MAX4208/MAX4209? Current project is going to need an instrumentation amplifier, looking at my inventory...

Does anybody here have experience with MAX4208/MAX4209? Current project is going to need an instrumentation amplifier, looking at my inventory all I have is some through hole INA111 that still have Burr-Brown stamped on them (probably bought them in the mid 90s)...time to upgrade my stock! As I go see what's new I find the Maxim MAX4208 and MAX4209. Normally there seems to be a


Gate resistor for lateral power MOSFET?

Started by Frank Miles in sci.electronics.design6 years ago 26 replies

I'm designing a power amplifier using some Exicon lateral MOSFETs as the final common-source stage. These will be used in various experimental...

I'm designing a power amplifier using some Exicon lateral MOSFETs as the final common-source stage. These will be used in various experimental systems. Each only needs to run around +/-50V out, up to 4A, and driving sinusoidally between 50 and 400kHz. The load can be approximated as a lossy series LC circuit, driven near resonance with R generally 10-20 ohms. There's an additional > 200


Isolated high voltage opamp

Started by bitrex in sci.electronics.design8 years ago 21 replies

So I have a need for an analog isolation amplifier thing into a HV section at low audio frequencies. I remembered the "HV opamp" thing that...

So I have a need for an analog isolation amplifier thing into a HV section at low audio frequencies. I remembered the "HV opamp" thing that John Larkin posted a while back and that seems to work well, but I'd like to isolate the feedback via pwming it and sending it back across the barrier via an optocoupler and integrating. I dont really want to chop it first and have more LV elec...


RF power question

Started by John Larkin in sci.electronics.design3 years ago 78 replies

We have an acquaintance who wants to put a roughly 1 KV (2K p-p) sine wave into a roughly 12 pF load near 500 MHz. He wanted us to...

We have an acquaintance who wants to put a roughly 1 KV (2K p-p) sine wave into a roughly 12 pF load near 500 MHz. He wanted us to modify our Pockels Cell driver, but that makes kilovolt or so unipolar gaussian pulses at 0-5 MHz. Seems like what he wants is an RF power amplifier and some sort of high-Q matching network. We are not RF people. Any suggestions for him? What to buy, how ...


Toob Amplified PC Speakers

Started by Tim Wescott in sci.electronics.design8 years ago 56 replies

It's winter, and the amplifier in my PC speakers just died. I think it'd be kinda cool to have a toob speaker amp, but I'm too lazy (and...

It's winter, and the amplifier in my PC speakers just died. I think it'd be kinda cool to have a toob speaker amp, but I'm too lazy (and time-challenged) to build one up from scratch. Are there, by any chance, kits out there? I'm not looking for nickel- cored transformers with solid silver windings, genuine paper caps rolled on the thighs of virgins, toobs dipped in LN2, and all that c...


RF transistor Acrian TT5021

Started by Jeroen Belleman in sci.electronics.design7 years ago 2 replies

I got my hands on a small lot of Acrian TT5021 RF power transistors. They are bipolar RF transistors in 7mm diameter white ceramic pucks...

I got my hands on a small lot of Acrian TT5021 RF power transistors. They are bipolar RF transistors in 7mm diameter white ceramic pucks (probably BeO) with four wings and a stud. They are probably roughly 30W VHF amplifier transistors. Does anyone have a datasheet for these things? Google came up dry. Thanks, Jeroen Belleman


2 GHz buffer with 2N390x

Started by Anonymous in sci.electronics.design3 years ago 22 replies

...

https://www.allaboutcircuits.com/technical-articles/voltage-buffer-simulation-composite-amplifie r-simulation-boost-output-current-drive/ -- John Larkin Highland Technology, Inc The cork popped merrily, and Lord Peter rose to his feet. "Bunter", he said, "I give you a toast. The triumph of Instinct over Reason"


Running out of ideas: stability, bootstrap

Started by Gerhard Hoffmann in sci.electronics.design6 years ago 24 replies

Hi, all, we had a bank holiday here, nicely positioned close to the weekend and I took the free time to play with my multi-IF3601 low noise...

Hi, all, we had a bank holiday here, nicely positioned close to the weekend and I took the free time to play with my multi-IF3601 low noise amplifier. That was not so funny because it features a negative input impedance over most frequencies, so with a suitable inductance on the input it makes a stable oscillator. Some observations: - Zin is negative also with the feedback loop cu...


Spot the Design Error 2

Started by Phil Allison in sci.electronics.design3 years ago 34 replies

Hi to my many admirers, see schem for tube instrument amplifier, the famous Fender "Bassman 50"....

Hi to my many admirers, see schem for tube instrument amplifier, the famous Fender "Bassman 50". https://schematicheaven.net/fenderamps/fender_bassman50.pdf Thousands made and sold, yet it has a fatal design flaw. Owners can, in a single step that they would never imagine was hazardous, instantly damage or destroy output tubes and/or the output transformer. This during ...


OT: Should this receiver get hot?

Started by John Doe in sci.electronics.design2 years ago 25 replies

Generally speaking, a receiver (with no output amplifier) requires extremely little power? That's because they are listening for tiny signals,...

Generally speaking, a receiver (with no output amplifier) requires extremely little power? That's because they are listening for tiny signals, therefore only tiny current is required? So why is my device getting hot? I realize it might be using the case as a heatsink, I'll open it up sooner or later. But what causes the heat, the video signal output circuit? Thanks. 40 Channel 5.8GH...


interim layout

Started by Anonymous in sci.electronics.design1 year ago

I like to do the tricky parts of a pcb layout myself, rather than trying to explain it to a pcb designer. Actually, I don't know how parts...

I like to do the tricky parts of a pcb layout myself, rather than trying to explain it to a pcb designer. Actually, I don't know how parts should be arranged until I push things around for a while. It's chaos until something clicks. https://www.dropbox.com/s/rgjkb17itlkpud3/Z508A3_pcb1.jpg?raw=1 That has two 20 GHz $20 MMICS summing into a 20 GHz $350 distributed amplifier. That's sc...


Looking for fast-ish sot-89 NPN

Started by Gerhard Hoffmann in sci.electronics.design7 months ago 7 replies

Hi, I'm trying to build a 2-200 MHz isolation amplifier. For 13 dBm I need abt. 120 mA peak current, 70 mA quiescent. The circuit is a...

Hi, I'm trying to build a 2-200 MHz isolation amplifier. For 13 dBm I need abt. 120 mA peak current, 70 mA quiescent. The circuit is a voltage to current converter, followed by a double cascode. 2N3904 is too slow, BFQ19S is too hot, it would do 1 GHz, but brings me negative input impedance, gain peaks and so on. I'm playing with the usual ferrite beads, but that does not bring com...


Photodiode bootstrap phase rolloff

Started by David Nadlinger in sci.electronics.design5 years ago 16 replies

Hi all, I am currently working on a range-switched photodiode design for use in our laboratory [1]. It took me a while, but I've arrived at a...

Hi all, I am currently working on a range-switched photodiode design for use in our laboratory [1]. It took me a while, but I've arrived at a design I'm fairly happy with (in no small part thanks to Phil Hobbs' helpful writings on the topic): My current draft uses a simple BF862 source follower at the summing node of a ADA4817-based 2 M?/2 k? transimpedance amplifier to bootstrap t


Watch finder

Started by Liz Tuddenham in sci.electronics.design1 year ago 22 replies

A long time ago I made a cable tracer from a coil of 2,000 turns of wire on an old solder spool, connected to a high gain amplifier that...

A long time ago I made a cable tracer from a coil of 2,000 turns of wire on an old solder spool, connected to a high gain amplifier that fed headphones. After using it for the job that needed it at the time, I put it away in a box "just in case". Today I realised that my watch was no longer on my wrist although I remembered putting it on this morning; a thorough visual inspection of the h...


HP5316 1GHz counter front end

Started by Anonymous in sci.electronics.design7 years ago 2 replies

I got a 5316 counter off ebay with OCXO and 1GHz channel. There's a differential amplifier/receiver in there, HP pn 1826-0589. Of course, the...

I got a 5316 counter off ebay with OCXO and 1GHz channel. There's a differential amplifier/receiver in there, HP pn 1826-0589. Of course, the x-ref lists I've found so far jump from 1826-0588 to 1826-0590. Either of those parts have nothing to do with amplifying. Anybody have a clue what this part could be? The BOM claims it's a TO-8, but the schematic shows 12 pin numbers... I'll take t...