Page 2 of 2

Re: Phase inverter

Posted: Sat Oct 14, 2017 1:11 pm
by fiveightandten
Agreed. I bought an old tube tester off eBay for $50. I use that to test for shorts and other issues. But it tests at like 30V, so although it gives an indication of tube life, I don’t really trust the data as being representative of functionality in an amp.

The VT1000 is enticing, just too expensive to justify.

Re: Phase inverter

Posted: Fri Dec 22, 2017 11:03 pm
by Farrerdale Records
I've got a VT1000, while not the best value for money, it has helped with trouble shooting, matching tubes to determine what is best for V1 or other important slots.

I'm sure over a decade or so it might pay for itself :D

Re: Phase inverter

Posted: Fri Jan 12, 2018 10:56 pm
by robbvant
So on the subject of phase inverters which tubes are best? And for what purpose.
Someone said some are better for harmonics.
I’m interested in higher gain and more output and good harmonics

Re: Phase inverter

Posted: Sat Jan 13, 2018 12:35 am
by Orphin
jontheid wrote:
Wed Jun 21, 2017 8:01 am
(The Retro 50 is the sole definite exception to this that I know of. I don't know what the AD50 uses).
http://www.valvewizard.co.uk/acltp.html
Just saw this post. Haven't read any of the other. :oops:

The Marshall 2061X has that same PI.
I've been having issues on and off for years about something in the feel of that amp that I've never liked. Finally I took a chance on rebuilding it into a regular LTP since nothing else seemed out of the ordinary circuit-wise.
"That" feel was now gone. In result, a much more 'relaxed' sound, much more effective tone stack, more treble in general, but less gain. Actually slightly less output as well.
In conclusion I can say that I'm not by any means a fan of this rare type of PI. (I can see why it's never used by amp designers :lol: )
However, quoted from the book of Orange:

"We developed the Custom Shop Retro 50. This sounded very much like the original Pics only. It had a concertina phase splitter, but it still had the EQ after the volume, which made it stable and very reliable, switching it from 30 watts Class A, to 50 watts Class AB." - Ade Emsley

I hope Ade would have better knowledge to amp classes than that (Maybe just a speech for the gallery?). I sure hope he didn't confuse that PI with a Concertina. :shock:

BTW. The AD50 has a regular LTP-PI. :)

Re: Phase inverter

Posted: Mon Jan 15, 2018 11:06 am
by bestazy
fiveightandten wrote:
Sat Oct 14, 2017 1:11 pm
Agreed. I bought an old tube tester off eBay for $50. I use that to test for shorts and other issues. But it tests at like 30V, so although it gives an indication of tube life, I don’t really trust the data as being representative of functionality in an amp.

The VT1000 is enticing, just too expensive to justify.
No joks?50$?Can you share ebay link please :shock: :roll:

Re: Phase inverter

Posted: Mon Jan 15, 2018 3:09 pm
by fiveightandten
bestazy wrote:
Mon Jan 15, 2018 11:06 am
No joks?50$?Can you share ebay link please :shock: :roll:
I bought it in 2013, so a link to the auction will not be active any more. But it's one of these: https://www.ebay.com/itm/PRECISION-Mode ... SweLBaU65W

It was a lucky find. This woman was cleaning out her deceased father's house. It belonged to him and she listed it on eBay, local pickup only. I happened to be traveling to the very town she lived in for work, so I was able to meet up with her and grab it (I'm in CT, she was in NY). She came right to my hotel!

Anyways, they're out there. But it can be tough to find one that's complete and verified to be functioning for a decent price. As I mentioned, this one tests at very low voltage, so I'm not sure I would pay a lot for one. But for $50, it was definitely worth the money.