audio-talk

I have posted a reply on the diyaudio thread where he originally shared the Symmetric Reichert circuit, in the hope he may spot it.

Cracking build Dave Thanks Ray. I think I succeeded more or less in optimising the signal path lengths and layout, being able to plan it all out beforehand in CAD helped, although I did end up making a few tweaks at build time. It helped that Lynn laid out the ground paths in his schematic, and I f...

Here's a full interior build pic, actually in focus this time. There is one item outstanding and that is to wire in the power relay at top right, so that it can be remotely powered up / down from the preamp.

More listening into the early hours tonight, so I'm going to be like a dead duck in the morning - again. I really need to get this thing back onto a space near the bench with the base off so that I can use it as a visual reference to quickly get the second one finished, but I can't stop listening to...

Cressy Snr wrote: ↑Tue Jan 05, 2021 10:51 am

....Thanks Steve - M and I were talking last night and when lockdown is over we'd love to hear them with your latest sealed unit speaker creations.

Yes, that’d be good.

I think I'm going to have to buy them their own sack trolley though - my God they're weighty!

Thanks Ali - very pleased with it. After running OTLs for the best part of 8 years, it has me re-evaluating output transformer coupling for sure.

Thanks Steve - M and I were talking last night and when lockdown is over we'd love to hear them with your latest sealed unit speaker creations. I had hoped to have them both done by now, but as always these things take longer than one expects, and now I have work getting in the way again. So the nex...

In action - bit tricky getting it all in focus as it's so big. And yes, I know I need to get the labels off the 300B's - I was that impatient to get it going. https://user.fm/files/v2-4a3864154bcebcbee8015a17bab7219a/P1030104.jpg We were listening to it last night well into the early hours - it's re...

Finished - and it works perfectly! Voltages pretty much on the button with my Spice model predictions. It sounded a little edgy and congested at first, but bedded in nicely after an hour or two. Does it improve on the Beasts? Actually, we think it does, but final judgement will be reserved for when ...

Ohmite Audio Gold are nice sounding resistors. :) Not too costly either. That's good, it's the first time I've used them. Usually I opt for Mills but it starts getting horribly expensive if you use them everywhere, and I already had a lot of parts budget in the eight Jensen PIO coupling caps I need...

Some more progress. The signal path wiring is basically all done, and yesterday I also tested and set the CCS's to the 29mA value required for the 6V6's. Next thing is the heater wiring on the 300B's and the power supplies. Sadly it looks like my target of getting both amps built by the end of this ...

Progress in the last couple of days - the signal circuitry and heater wiring for the input and driver stage is now done.

Today, I focussed on this bit of the circuit - specifically the input transformer and its load resistors as recommended in the Lundahl documentation: https://user.fm/files/v2-e6a762b764812c3d6e1ad59afb4a200d/Screenshot%202020-12-22%20at%2013.50.31.png Here's the transformer in place and configured 2...

Further progress today - standoffs and hum bucker pot fitted, along with some of the rear panel-mounted elements including two of the motor run caps. These are what I can put on without blocking access to the transformer mounting holes and covers etc. I've done this on both chassis but from now on I...

See here: https://www.ebay.com/itm/DIY-PCB-Solid-state-LR-phono-preamp/162045745934?hash=item25baaddb0e:g:vgYAAOSw~gRVpThF I'm thinking of trying this out once my 300B project is done. However the shipping is more than the cost of the PCB!! Is anyone else here (in the UK obviously) interested in one...