Recent Posts

31

Eros Phono / Re: Shunt regulator voltage test anomaly

« Last post by maarten on November 21, 2024, 08:45:25 AM »

Some voltages:

kregA 2V              kregB 4V
1A 265V              1B 264V
+regA 220V.        +regB 260V
bregA 220V.        bregB 260V
OA 220V              OB 260V
xA 1V                   xB 2V
bA 0V                  bB 0V 

32

Eros Phono / Shunt regulator voltage test anomaly

« Last post by maarten on November 21, 2024, 08:12:44 AM »

Hi,

I have shunt regulator A side voltage (top of metal tab MJE5731A) at 220V, very stable
I have shunt regulator B side voltage (top of metal tab MJE5731A) at 261V, also stable
All LEDs light up fine

I may have damaged the MJE5731A a little due to a mistake before when I had to pull it out. However, I checked resistance between all legs (no short circuiting of the legs), and between the legs and the metal tab (only the middle leg is connected to the metal tab) and all seems in order.

I left all tubes in when doing this test.
Any idea what could be the cause here?

33

Kaiju Stereo 300B amp / Re: Painting Suggestions Concerns for PC-5's

« Last post by Doc B. on November 21, 2024, 06:57:25 AM »

Don't strip the varnish off, just sand it smooth and wipe down with something like acetone before painting. And yes, definitely stay away from the oven. That's just for metal-only pieces like chassis panels and power transformer end bells.

34

Kaiju Stereo 300B amp / Re: Painting Suggestions Concerns for PC-5's

« Last post by Emoreigns on November 21, 2024, 05:57:10 AM »

After taking a closer took at my PC-5's they are pretty beat up, and will need a coat of paint. I'm just planning on matching it silver. Do I need to strip the factory coating off before I paint? And there are some uneven spots on the coating as well-.... Could I sand those down to get a cleaner finish?

Hahah and of course this piece isn't going in the over

Thanks as always for the advice

35

General Discussion / Re: sound cutting out when using dac

« Last post by pawantanwar on November 20, 2024, 11:22:30 PM »

disable USB power management, change audio settings, update/reinstall USB drivers, use a different USB port/cable, check for driver conflicts, and install Windows updates. Let me know if it works!

36

Kaiju Stereo 300B amp / Re: Painting Suggestions Concerns for PC-5's

« Last post by Doc B. on November 20, 2024, 06:19:12 PM »

As long as the oven temp is down where you suggest this is fine. We learned the hard way several years ago that higher temps can cause pretty bad embrittlement of the hammered paint and it can crack and chip off the part.

37

Technical topics / Re: Fixed attenuator for balance control?

« Last post by 2wo on November 20, 2024, 05:43:38 PM »

How about adding a pot in place of L-pad to the desired channel and dial it in.

38

Technical topics / Re: Fixed attenuator for balance control?

« Last post by phatfish on November 20, 2024, 03:52:20 PM »

I'm good with rolling my own.  It sounds like an LPad would be more appropriate than a single resistor?

I did find a calculator, but it seems geared towards speakers:
https://sengpielaudio.com/calculator-Lpad.htm

Using 50,000 Ohm and 1.5 db came up with pretty different numbers than hmbscott.
R1 = 7930.24
R2 = 265248.86

How would I go about calculating this for the EROS2 > Mainline?  Sounds like the mainline impedance is variable due to the attenuators I assume "25Kohms minimum" from the product page.  Is 50K more typical or was that just an example?

39

Kaiju Stereo 300B amp / Re: Painting Suggestions Concerns for PC-5's

« Last post by hmbscott on November 20, 2024, 01:21:55 PM »

I've been painting chassis plates and end bells with Rust-oleum Hammered, which takes forever to harden so I use a little trick that should work well with any similar gloss enamel. Note that I specifically recommend against doing this with a choke or transformer or anything else with circuitry in it. This is strictly for metal parts.

After spraying I give the part 24-48 hours to dry then I place it in our kitchen oven set at 180F and leave it there to bake for 30-45 minutes. After which I give it another 24 hours before using. This does two things. It greatly speeds up the curing and making it hard enough for assembly without fear of marking it up soft paint, a huge benefit because without this step I have had to wait 2-3 weeks for a thick Hammered paint coat to harden sufficiently. Secondly, it really enhances the gloss. It gives it much higher gloss than as-sprayed.

After using (abusing?) the oven this way I run a self-clean cycle on it to blast out the fumes that had off-gassed from the paint. Oh, by the way, I haven't shared with my better half that I have abused our oven in this manner, and I have made sure she would not be home until several hours after completing the paint bake/oven clean cycle to ensure the kitchen no longer smelled of paint fumes.

40

Kaiju Stereo 300B amp / Re: Painting Suggestions Concerns for PC-5's

« Last post by Emoreigns on November 20, 2024, 08:45:10 AM »

Thanks Doc-

Painting the bell of the transformer is always the first thing I do on these builds, so the paint can dry- All good there!

I liked the look of the PC5's the way they are, so I am glad I don't have to paint them and can use them as is!

As always thanks for the help!