Look up flea power Magnavox Dave Gillespie. He shows the oscilloscope waves before and after his modifications

I had the same thought, however I tried it in both configurations, and there was seemingly no difference in stability. But feeding one from the other gives lower ripple since the two filters are in series, so I chose that.

@@messingwithelectronics7462 i learned that practical experience often trumps theory decades ago!

It's worth taking a look at all the grounds and making sure they're good. The RCA shell to chassis ground was problematic in this A-8A. After shooting this video I added a spade lug from the RCA shell to the chassis and it reduced EMI pickup substantially so that the higher-gain inputs weren't swamped by EMI.

How loud are the noises? Do they occur even with signal input but they're just masked by the signal?

I bought new 1N823 Zeners with a similar voltage: www.mouser.com/ProductDetail/494-1N823. I thought they were the same ones because the part number is very similar. However, I think the voltage is slightly off, which is why the whole thing has a slight voltage offset that the adjustment can't fully get rid of. Honestly I think I might have lost the old oven. Thought I saved it but can't find it now.

I was was thinking about simulating the oven circuits with available Zener diodes. I was able to take my oven apart. The bracket that held the thermostat in contact with the internal chamber was broken. I think the chamber got way to hot burning up all the clay coated wire wound resistors. One of my Zener diodes is bad. I will have to un-wind the heater element to weld the bracket back together. But I think I can fix it!

@@barrybreaux5303 That's impressive, I did not have the stomach for all that work! But I hope it comes together. Retaining the original oven is definitely the only way to achieve the original performance.

Retired electrician engineer. I have to be challenged.

@@barrybreaux5303 I found my oven! If you want it, I can ship it to you. I'd list it on Ebay for .99c plus the shipping cost (like $4). I can continuity test the heater if that's the part you need.

Yeah, I did model it in PSU Designer II and it's very overkill. This design is kind of nostalgic for me because it's based on an old Capehart amplifier I restored that also had a huge choke, so I wanted to replicate that 1940s look and feel. Cheers!

Check all wire wraps they can easy break or come loose, also clean the back of the board which is a good time to check for bad solder joints, Bad traces and also re-solder the post which can have cracks in them, Also check for missed new leads that were forgot to solder, double check oration of parts replaced, Good luck

That's a good idea.

That amp is appealing as all get out! Thank you for sharing.

Yes, the receiver on the left is a Pioneer SX-1010! Repaired in one of my previous videos -- it's awaiting a full restoration, but I'm more into tube stuff at the moment. Great idea; I will definitely do a video on my test setup. It is very simple: an SMSL M500 DAC and an E1DA Cosmos ADC with a computer running Room EQ Wizard. The DAC functions as a sig gen and the ADC is the spectrum analyzer. The E1DA cosmos is really a great piece of equipment. For less than $200 you get THD and noise performance that rivals audio analyzers costing $10,000+. It can handle much higher input voltages than a standard soundcard solution thanks to built-in attenuators; the speaker input goes up to 43 volts! Performance is also far better than soundcard/audio interface ADC implementations. The main downside is no built-in calibration (must set cal levels in REW).

@@messingwithelectronics7462 Thanks... That video led me to you as I am trying to repair my SX-1010. Cheers

Hi man, i have the same pcb and i can't volt mod my memory do you know how to do it?

Thanks! Really did not anticipate spending so much time on this thing, but the front panel is too beautiful to sell it as a parts unit.

Yes, using discrete op-amps would be the better solution but I was being lazy and figured I’d try the board instead. It eliminates the need to breadboard or make a PCB. Most of the Ebay differential op-amp boards are designed for audio and I wasn’t sure if their HF cutoff would be too low since there’s no documentation.

it's true

Just past 7 min, it was mentioned: axial replaced radial. Not sure how that would fit(from My viewpoint), but a treasure of a tutorial nonetheless.@@reynir8448

Duly noted retraction! If I had watched further(time is limited in My viewing) I can see @ the 30 min mark the actual dimensions. My deepest apologies. So sorry.