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August 05, 2020, 09:27:40 PM

Recent Posts

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11
S.E.X. Kit / Re: Progress Update
« Last post by Darkblade48 on Today at 03:16:37 PM »
Thank you everyone for their kind words so far!

https://forum.bottlehead.com/index.php?topic=11676.0
You could try this mod, it may keep some of that grunge out.
Excellent, thank you for the quick reply! I just want to confirm that I want to replace the drain wire (i.e. remove the drain wire completely) between ground of the IEC outlet and the chassis ground tab (circled in red in the attached photo) with two diodes as specified in the linked thread (one diode going one way, and another the other way). For the picture, you can ignore the (lack of) wires, as it was taken before the S.E.X was completed

I saw from the other thread that you recommended a STTH2R06; however, checking my box of jellybean components, I have the following:

1N4148
1N4007
1N5819
1N5399
1N5408
1N5822
FR107
FR207

I am supposing that the average forward rectified current rating of the diode should be at least 2A, and non-Schottky, which eliminates the 1N4148 (150 mA), 1N4007 (1 A), 1N5819 (1 A, Schottky), 1N5399 (1.5 A), 1N5822 (3A, but Schottky), and FR107 (1 A)

Of the two remaining choices, I have the 1N5408 (general purpose, rated for 3 A average forward rectified current, 1000 V) and a FR207 (fast recovery, 2A, 1000 V).

Would either of these be a suitable replacement for the STTH2R06?

Edit: It appears that the 1N5408 should work, as mentioned in the other thread! My apologies for not looking more carefully

Edit 2: It appears that I should be looking at peak forward surge current instead, and not the average forward current. If this is the case, would the above non-Schottky diodes work? The 1N5408 has thick leads, so if possible, I'd love to replace them with something smaller like a pair of 1N4007.

Yes.  The SEX amp does not need a load on the speaker terminals and it won't do any harm to your headphones if they are plugged in during powerup.  Your confusion is well founded, there's a lot of misinformation out there!
This is good to know! I was a bit concerned because upon powering on, I can hear a bit of hum as soon as the switch is flipped. I was wondering if this might cause damage.
12
Stereomour II / Re: Should upgrades be done in any particular order?
« Last post by Twodawgzz on Today at 11:42:52 AM »
Thanks Paul.
13
Kaiju Stereo 300B amp / Ideal plate-to-0V voltage for Kaiju 300B?
« Last post by Deke609 on Today at 09:59:50 AM »
The schematic shows B+ of 450 VDC. The manual tests call for 490 VDC +/- 20%.  Both figures are for B+ before the plate choke and do not take into account the voltage dropped across the DCR of the choke.

Since I am rebuilding my Kaiju, I can dial in the plate-to-ground voltage. What voltage at the plate (relative to 0V) should I aim for to hit PJ's intended operating point?

MTIA, Derek
14
The absolute most important thing is that you build the amp stock first and getting it 100% working.  It's far harder to debug an amp with upgrades when you don't know whether it's the upgrades or the stock build that caused the issue.

I would put the DC filament in first, because it's far easier than the other two upgrades.  I would do the SR driver next, then the attenuator last, mostly because you'll be well warmed up by then and you want to do your best work on that attenuator.
15
Stereomour II / Should upgrades be done in any particular order?
« Last post by Twodawgzz on Today at 08:01:19 AM »
I have the DC Filament Supply, Shunt Regulator, and MourQuiet Attenuator upgrades to install.

Does it matter which one I work on first?
16
S.E.X. Kit / Re: Progress Update
« Last post by Doc B. on Today at 07:18:54 AM »
Looks great, congrats!
17
Technical topics / Re: Noise shunt for 431 bias regulators?
« Last post by Deke609 on Today at 07:07:56 AM »
On the off chance that you need to drop the 12V to 5V to get a directed 5V gracefully for your A/D converter power flexibly...

Nope.  But thanks.
18
General Discussion / Re: NEW Electrostatic headphone amp
« Last post by adydula on Today at 05:39:55 AM »
Wow....YOU GOT IT RIGHT!!!

 ;)
19
MonAmour / Re: Monamour 45???
« Last post by Paul Birkeland on Today at 05:19:23 AM »
It could, but the output transformer impedance isn't ideal for the normal range of #45 operating points.  If you want to run the #45, the Stereomour II has some documented modifications to allow this and uses different iron that better supports the #45.
20
General Discussion / Re: NEW Electrostatic headphone amp
« Last post by Paul Birkeland on Today at 05:17:58 AM »
"What the difference between a VTVM and a VOM"??

Vacuum Tube Valley Magazine and Voice of Music? ;) 
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