This is really nice! I may have to make up something similar. I have a few random smaller chassis that would be perfect with some quick paint. I'm tired of having to undo binding posts all the time 🙂
Thought of an amp switcher recently myself: need a way to test new amps or the SET Tube Amp with the new Sony Towers that are usually hooked up to the Sony Receiver.
A customers model railway shuttle controller which had failed.
No output so looked like motor driver failure.
PIC was outputting DCC signals and voltages around motor driver were fine.
So a motor driver failure.
A pig to unsolder. Cut off pins high up and heated them up one by one and grabbed end with long nose pliers.
Solder suck the holes to clear them.
Luckily I already had a motor driver IC spare.
Soldered new IC in and all was well.
Had a look at the circuit and motor driver power supply wasnt decoupled so added 47uF to kill motor flyback spikes.
No output so looked like motor driver failure.
PIC was outputting DCC signals and voltages around motor driver were fine.
So a motor driver failure.
A pig to unsolder. Cut off pins high up and heated them up one by one and grabbed end with long nose pliers.
Solder suck the holes to clear them.
Luckily I already had a motor driver IC spare.
Soldered new IC in and all was well.
Had a look at the circuit and motor driver power supply wasnt decoupled so added 47uF to kill motor flyback spikes.
I use this. You need to remove the wirewound load resistors inside and replace with metal thin film ones to reduce distortion. Class D amps don’t like no load.
2-Way Amp Amplifier Receiver to 1 One Pair of Speakers Selector Switch Switcher Splitter Combiner https://a.co/d/iiwOj4t
I connected the SE Class A preamp to drive a Topping Class AB headphone amp. Super nice and sweet sounding headphone amp with a JFET/MOSFET source follower. This plays very well with the TPA6120A2 output stage.
Good to know, thanks. Set Tube Amps don't like no loads either.
I was wondering if it's worth it to build such a switcher, but the no-load thing starts to complicate the implementation, which is why I suppose @kodabmx is using a relay? For Amp A to switch to Amp B, with a no-load condition, you'd want A to also connect to the dummy load first, then disconnect A from the Speaker Outs, then B to connect to the Speaker Outs if I understand correctly.
Else, maybe I'll just build a far simpler rig which would allow me to swap manually, provided I turn off the first Amp first. It's less good for A/B which relies on short-term memory but it can still work fine for me.
The product on Amazon is affordable enough too. Does it allow hot-swapping?
Not sure I'll dabble in Class D soon. I suppose people are buying ready-made modules and integrating those? No sense in competing with Purify / Hypex / Putzeys or what not.
My main Lab Desk is full again today: re-started some tests with R.E.W. Haven't touched it for a while now, so I might have forgotten how to perform some of the calibration steps. Of course, now I can't find the bloody Behringer audio interface I hacked now that I put things in cardboard boxes and moved those around several times over...
This said, the power we have nowadays to engineer and build quality audio gear is immense. Unprecedented, really. So I'm looking forward to that.
Other things that need attending to: Music Studio and related gear, thermal isolation: thermal cam comes in very handy here.
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“The product on Amazon is affordable enough too. Does it allow hot-swapping?”
Yes, you can “hot swap” A/B tests.
I have built a relay based switcher at headphone signal levels using small relays and a 9v battery driving a DCDC boost to activate 12v relay and toggle switch. I did this to A/B test headphone amps.
The DPDT relays can be used to do this. You need two.
Yes, you can “hot swap” A/B tests.
I have built a relay based switcher at headphone signal levels using small relays and a 9v battery driving a DCDC boost to activate 12v relay and toggle switch. I did this to A/B test headphone amps.
The DPDT relays can be used to do this. You need two.
Cool, thanks.
Thanks again. I think the product itself uses an always in-line 100 Ohm load if I am understanding this properly. Small enough not to make a big influence on the output path.
Small things I did today after the REW tests:
In the first pic, the upper red one is the normal probe used with a Fluke DVM. Lower red one is an adapter, showing the difference in size.
Second pic shows how the normal probe fits into the new one, as well as some simple supplies used.
I can now do micro-probing.
In the first pic, the upper red one is the normal probe used with a Fluke DVM. Lower red one is an adapter, showing the difference in size.
Second pic shows how the normal probe fits into the new one, as well as some simple supplies used.
I can now do micro-probing.
Attachments
Up early and the Main Lab Desk was enticing. What to do apart from a big mug of black tea and doing an unconventional test with REW, separating DAC and ADC?
It seems the only way to set this up with two pieces of gear is via the Java driver (Java, ouch!), and the latter seems to limit the output bandwidth possible for the Behringer, which, by the way, was found hiding in a small cardboard box near the front door.
It does work, but it's not very practical with the above-mentioned limits. There was some pickup of mains freq. Didn't bother doing the SPL/VRMS cal for that test.
Maybe on macOS it's easier to do with the setting up of a virtual 'combined' interface, not sure, but it would have to wither do away with the Java. Only tested on Win, not Linux. That would help characterise various ADCs separately from the DAC itself, like my Apogee for the studio as well as the Sampling input of the Kurzweil, which also does real-time capture using a special and extremely useful mode called Live Mode.
The other question that arose is whether we should do some harmonic compensation before actual soundcard calibration. I checked out the REW Help file to brush up on the calibration procedure and it's quite well written so that was cool but this was not mentioned. Picked up the motions quite fast after that.
I might sleep through the New Year transition so best of the New Year's Eve and of 2023 to all.
It seems the only way to set this up with two pieces of gear is via the Java driver (Java, ouch!), and the latter seems to limit the output bandwidth possible for the Behringer, which, by the way, was found hiding in a small cardboard box near the front door.
It does work, but it's not very practical with the above-mentioned limits. There was some pickup of mains freq. Didn't bother doing the SPL/VRMS cal for that test.
Maybe on macOS it's easier to do with the setting up of a virtual 'combined' interface, not sure, but it would have to wither do away with the Java. Only tested on Win, not Linux. That would help characterise various ADCs separately from the DAC itself, like my Apogee for the studio as well as the Sampling input of the Kurzweil, which also does real-time capture using a special and extremely useful mode called Live Mode.
The other question that arose is whether we should do some harmonic compensation before actual soundcard calibration. I checked out the REW Help file to brush up on the calibration procedure and it's quite well written so that was cool but this was not mentioned. Picked up the motions quite fast after that.
I might sleep through the New Year transition so best of the New Year's Eve and of 2023 to all.
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I am planning on doing some tests on CD/DVD and Blu-Ray players so I was thinking of generating a CD with test signals, but the last thing I want is to miss adding the proper files to it and later find out I missed a few test audio tracks that would be needed for better characterisations, e.g. things like Jitter tests, intermod, etc...
One thing I have in the projects list is to take the Linear-Regulated Akai DHT300 CD player/receiver and hook it up to the Sony receiver. But since the Akai is a receiver itself, I'd have to find a way to tap a preamp output from it.
Hard to find info on it, let alone schematics. Might be worth it, might not be...
One thing I have in the projects list is to take the Linear-Regulated Akai DHT300 CD player/receiver and hook it up to the Sony receiver. But since the Akai is a receiver itself, I'd have to find a way to tap a preamp output from it.
Hard to find info on it, let alone schematics. Might be worth it, might not be...
I finally finished building this headphone amp.
6N1P -> 6N6P designed for high Z headphones but it'll put 12mW into 32R which is usually quite loud.
Now to find a buyer! 150$CAD plus post if anyone is interested... Comes with the PSU (12V 10A inline brick). Pick-up available in the GTA.
6N1P -> 6N6P designed for high Z headphones but it'll put 12mW into 32R which is usually quite loud.
Now to find a buyer! 150$CAD plus post if anyone is interested... Comes with the PSU (12V 10A inline brick). Pick-up available in the GTA.
Nice work kodabmx. I am also working on a headphone amp using the 6N6P - a beast of a small tube! The LSA HyperDrive-2 headphone amp has 6N1P and the sound better than E88CC’s.
If you want to sell your stuff maybe post it on the swapmeet forum and keep this thread for showing your bench projects. What’s the schematic / topology if your amp? Namely, I am curious what B+ voltage you are using and are you using DCDC step up converters. We are finding it hard to get a nice signal without at least 90v.
Here is proof of concept headphone amp JPS64 designed around 6N6P with solid state MOSFET follower outputs. Lots of DCDC converters to get all the voltages we need using just a single 24v brick.
Still needs to be built and tested.
If you want to sell your stuff maybe post it on the swapmeet forum and keep this thread for showing your bench projects. What’s the schematic / topology if your amp? Namely, I am curious what B+ voltage you are using and are you using DCDC step up converters. We are finding it hard to get a nice signal without at least 90v.
Here is proof of concept headphone amp JPS64 designed around 6N6P with solid state MOSFET follower outputs. Lots of DCDC converters to get all the voltages we need using just a single 24v brick.
Still needs to be built and tested.
Thanks...
Now on the bench is a Modular Amp 1 which used to bet set up for 6P43P, but 30 minutes later, it's set up for 6P44S (or 6P36S). Modular designs kick it! Blue LED showing there is still a little B+ left after bench testing it (1M dropper - it uses µA and this is probably about 10V left).
Now on the bench is a Modular Amp 1 which used to bet set up for 6P43P, but 30 minutes later, it's set up for 6P44S (or 6P36S). Modular designs kick it! Blue LED showing there is still a little B+ left after bench testing it (1M dropper - it uses µA and this is probably about 10V left).