Leaderboard

Look what arrived: Works like a charm. Big thanks to DOTU and Dr. Wood!

Had a routine check up with new Dr. A1C = 6.3, blood pressure and cholesterol both in target range. Looks like you people may have to put up with me for a bit longer.

Spirit of Eden Talk Talk 1988 https://album.link/i/701395363 Example: Why was I not listening to this in the 80s? I was into jazz and classical, along with Nobody in my high school. This would have been something that I would have listened to. I guess it just comes down to exposure. It was not getting radio play, And I didn't have friends to expose me to it. But like I have said many times in this thread, I am happy to discover these albums now. I really liked this, it is more brooding and a journey than The Colour of Spring.

I haven't found any wasp products at my local store but I did find this... 😁

& his last words be chiseled into his tombstone: I KNOW YOU ARE, BUT WHAT AM I? cancer be fucked...

^ You posted that just to F with all the OCD'ers

This might be too subtle for some.

For what it's worth, my CFA3 bords fell 2,5V short in terms of offset when I built them. In my case, swapping all the red LEDs to a version with much less forward current than the ones I installed first (I'm now using LTL-4221, which has 2mA I believe) put all numbers back in the right places.

Four Roses bourbon tasting dinner. Very nice having the master distiller in town to walk us through all the pours. HS

Somethin’ Else is possibly one of those records that would take me to a deserted island... About Birth of the Cool, I could be wrong but I think not, Rudy only remastered the second or third generation recordings tapes. My "The Complete Birth of the Cool", which was remastered by Mark Levinson using Cello equipment (I have only been able to listen to a preamp and a phono stage of this brand and I remember that the sound was spectacular)

But if all that fails...

So I've been looking at a bunch of tube/solid state hybrid dynamic amp schematics, and every one of them is some form of bad, or really bad. (one person/ex company in particular) Low voltage plate, capacitve coupling of a high impedance source into a low impedance, poor balance etc. There had to be a better way. true balanced input. dc coupling. low impedance output. no feedback. proper use of a tube (pure transconducance) etc so I came up with this, work in progress. 4 x 3 inches ubaltobaltubeschem.PDF

well all the el34s survived, right hand channel input 6922 is bad. Time to go to bed and cry.

RIP MY T2 ever had a day when everything goes wrong and you wished you had not got out of bed.... well I just wrecked my T2. Don't have the energy or will power to even troubleshoot it... what happened. I was slowly over time getting a DC offset on both channels, I would correct with the trim pot until I ran out of travel. My first thought was the valves were getting old. Yesterday I decided to open up on the amp case and check the virtual batteries and voltages.... Well the -560V rail was -600V... I spent most of yesterday looking for shorts, diode checking the transistors and doing the usual troube shooting. Since the psu was basically working but not regulating the -560V I also looked a live voltages... To cut a long story short I discovered partly by logic and partly by accident that even maxing out the trim pot only gave me -9.6V on the 20K resistor on the voltage set string. The voltage reference was correctly outputting 10V. I checked the trimmer and it would change in resistance over its travel. So my conclusion was with the two 540K resistors had drifted up in value and therefore reducing the voltage across the 20K resistor or else something was stealing voltage from the 20K resistor... today I did more testing and desoldered one end of each of the 540K resistors and measured them... 580K and 700K... I remembered that I had replaced all the voltage set resistors with TE 0.1% 1/4W a while ago... I checked the spec sheet and they are rated at 250V.. too little for the job and I think this is what caused them to drift high. My guess is the 700K resistor started to drift high, got more voltage drop across it which naturally increased the drift. I replaced them with Xicon 1/2W 1% 350V and for the -560V rail immediately started regulating again. job done back to listening right.... RIGHT....???? After some testing I connected the psu back to the T2 and the led on both channels close to the -260V terminal did no light. But with no load the -260V rail was rock solid. Connected to a T2 the rail only provided +75V on top of the -560V rail rather than the +300V it was designed to give. I guessed the 2N3904 in the -260V rail had spontaneously decided to fail in the current limiter and so decided to replace it. The 2N3904 I desoldered measured on a peak dca75 as shorted so I was sure I had found the fixed the problem.... again testing without a load everything seemed fine. So back to listening now... right... well... Then I did something really stupid. I thought the psu was off and connected the high voltage cable from the psu to the amp (the low voltage cable with the heater supplies was not connected) there was immediately sparking noises and I quickly turned off the psu. I tested the psu without load - all rails seemed good. I connected the psu to the T2 and powered it up. All the voltage rails where at the correct levels on the T2 But I had massive ballance issues between the + and - halves effecting both channels. All 4 virtual batteries now only read about 550V, (all the leds light so that's something)... SH*T SH*T SH*T DAMN DAMN I guess next step is to test all the valves, take the amp apart and hope the 2SK216 and 2sj79 are ok. I have one complete set of spare 2SK216 and 2sj79 and do have a spare set of amp pcbs so I am debating if it might be simpler just to build a new set of amp boards rather than try to troubleshoot and salvage what I have. today I simply should not have got out of bed.

Wool - Hugh Howey. Fun book. They adapted the first half of this one in to the TV show "Silo". I do enjoy the story archetypes where they drop you in a world with lots of strange stuff where things start happening and you have to keep reading to figure out what the heck is going on.

measure the DC voltage to ground at every node in the circuit, and write it down on the schematic, will be very helpful also do you have pF caps across the feedback resistor in SS Mode?

OK, a bit more testing. The previous tests I did were all with the SS jumpers in place. I have taken them off and jumped all the ZF jumpers and get some different results. In ZF mode, on the board that was reading -2.5v the DC offset comes down considerably - 145mv and -81mv @ ~150mA bias. On the other board that was measuring -500mv it still measures the same in ZF mode, however I need to adjust the 5k trim-pots a fair amount to get back to ~150mA bias - I think I saw a post a few pages back with a similar situation so will go back and read the thread again!

According to these documentaries, I think you need that. Original:

New title- "Jose, destroyer of wasp empires".

I have not used diesel but have heard the same thing. I also have not used brake or carburator cleaner, but have read many times that they kill wasp nests effectively. What I have used many times effectively is the foaming wasp spray, especially with the long range sprayer. Always do it after dark when they are in the nest and less likely to attack you. If they are all in the open like you pic above, then it should be straightforward. Buena suerte!

If the internet has taught me anything it’s that honey badgers are a natural predator of bees and wasps. Maybe get three or four honey badgers as pets?

Have a great one Todd! Cheers!

I put a Muses board by Academy Audio into an AMB M-cubed headphone amp I built. Wrote that up at Innerfidelity when it was still in existence. I set up a switch between a passive TKD 1 dB/step attenuator and the Muses attenuator. After hours and hours and hours of listening, I'm still not sure if I can tell the difference, the Muses chip is that good. These both go into the input opamp through a double pole front panel switch. The Input opamp is either an OPA 604 or 627, I forget what I put in there.

I kinda like Morrissey slightly more today. https://variety.com/2023/music/news/morrissey-criticism-sinead-oconnor-tributes-1235681468/

Need to start matching these but liking the results from the basic tester so far

Have used the 300B tubes with DIY T2 for three months now. First two months with an amplifier with all original transistors and the last month with an all-modern transistors’ amplifier. Only issue so far is a failed small solid-state relay in filament supply. Otherwise, I find the DIY T2/300B pleasant.

confirmed: tubes are inside

Finally got around to casing this (also posted in the What are you building thread. Needs a bit of wiring cleanup, and the transformer needs to get bolted down, but sounds great.

Somebody turns 80 today. There's certainly no other earthly reason I'd post this particular album cover. No siree....

...is Mikhail under the table too... ?

nice surprise! Picked up at the Harvard Book store while visiting

Got the east coast ping pong table reassembled.

here are both of them, not sure which one was in the group buy 3) Its a current mirror. So output voltage depends on impedance, currently 1100 ohms. Needs an output buffer if you are going to use it for a preamp.