I thought this was an interesting piece on Don Garber and Fi, and the NY valve scene back in the day. It really made me wish I could find my Sound Practices CD.
simon wrote: ↑Mon Aug 26, 2024 12:02 pm
I thought this was an interesting piece on Don Garber and Fi, and the NY valve scene back in the day. It really made me wish I could find my Sound Practices CD.
simon wrote: ↑Mon Aug 26, 2024 12:02 pm
I thought this was an interesting piece on Don Garber and Fi, and the NY valve scene back in the day. It really made me wish I could find my Sound Practices CD.
After many many years of faithful service, my Peak DCA 55 and LCR 40 are being replaced with the newer versions... I need the higher test current of the DCA 75 Pro, particularly for thyristors, so took advantage of an offer and upgraded both.
The existing ones, which are in perfect condition, will be offered here first before eBay.
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Don't be in too much of a hurry to get rid of the DCA55. My DCA75 Pro irritated me (beep) and has been relegated to the back of the drawer, with the DCA55 and ESR60 at the front. Peak testers fit nicely in small baby bud boxes, protecting them from being switched on and flattening their batteries.
Morgan Jones wrote: ↑Thu Aug 29, 2024 8:06 am
Don't be in too much of a hurry to get rid of the DCA55. My DCA75 Pro irritated me (beep) and has been relegated to the back of the drawer, with the DCA55 and ESR60 at the front. Peak testers fit nicely in small baby bud boxes, protecting them from being switched on and flattening their batteries.
Here's an example of a power thyristor that the '75 can handle but the '55 can't (just gives "unknown component"). I grant you this is an edge condition that won't affect 99% of users and certainly not those doing audio work, but I'm currently doing a project with thyristors that need an Ig up to 10mA or so, and only the '75 can do that.
Interestingly, if testing a thyristor and then you retest it immediately without disconnecting it first or allowing the unit to power off, the DCA thinks it's a diode as it's already turned on and conducting... Probably should turn off all leads for a few mS first.
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I perennially found Peak instruments with flat batteries both at work and at home, hence the boxes. A moment ago, I was going to look in the menu to gag the beeper, but when I switched my DCA75 on, it chirped at me then said "low battery".
Turning to your thyristor gate current requirements, I found triacs (effectively an AC thyristor) were quite poorly specified on their data sheets and measurement was essential.
Morgan Jones wrote: ↑Thu Aug 29, 2024 1:36 pm
I perennially found Peak instruments with flat batteries both at work and at home, hence the boxes. A moment ago, I was going to look in the menu to gag the beeper, but when I switched my DCA75 on, it chirped at me then said "low battery".
In 10 years or more of having Peak DCAs and LCRs, I've never had a flat battery issue or stuff magically turning on etc. They've always behaved in an exemplary manner.. maybe they just don't like being kept in your drawers! When it's on, press and hold the left button and the settings menu comes up.
Morgan Jones wrote: ↑Thu Aug 29, 2024 1:36 pm
Turning to your thyristor gate current requirements, I found triacs (effectively an AC thyristor) were quite poorly specified on their data sheets and measurement was essential.
That's exactly what I'm doing with the thyristors... characterising them...
New battery fitted and irritating sounds switched off. I'm trying to think when I bought my DCA55. The ESR60 is more recent and was bought about twenty years ago. Both are very nice little instruments, but you can't lob them in a tool box - that's how they switch on and flatten their expensive battery. In their baby bud boxes in drawer, they're fine.
I'm at GE Transformers in Stafford for factory acceptance tests on two 33/275kV transformers they are building for us for a 400MW BESS site. On the left in the above photo is their impulse tester, will be chucking 640kV at the transformers tomorrow, should be fun!
Love the control room, 60 odd year old gear, real old school!
good find!
