|
Tubes Asylum Questions about tubes and gear that glows. FAQ |
|
|
|
Tubes Asylum Questions about tubes and gear that glows. FAQ |
|
In Reply to: REVIEW: Ming Da MC3-R Preamplifier (Tube) posted by sgb on August 19, 2005 at 08:32:31:
My experience with the rectifier tube was the exact opposite of yours.I have the MC-7R, it has 1 rectifier, 2x12AU7 and 2x12AX7 tubes.
I purchased this unit used and it arrived with a JAN 5Y3 WGTA (A9/85)rectifier tube. This being my first venture into tubeland I emailed Mei-xing to ensure that a 5Y3 was the correct replacement tube.
They replied that "You can replace a 4 pin 5Z3 , a 5 pin 5Z3P and 5UR4, these tubes are right". Thank you Xiao.I ended up ordering a pair NOS 5Z3 tubes from DIY HiFi Supply in Hong Kong, for the outrages sum of US$ 16.00 for the pair. ;-O (Couldn't seem to find any 5Z3 tubes listed for sale on web sites on this side of the pond). What arrived, within a few days, were a pair of 5Z3PA-T (73 iv) tubes. If I recall, this is the rectifier tube which a H.K. audio club raved about when they did a rectifier bake off one time. In any case, I swapped the 5Y3 WGTA out for the NOS 5Z3PA-T and noticed an immediate and dramatic improvement in dynamics.
After listening for a few hours I then swapped out the Chinese 12AU7 tubes with Mullard CV4003 tubes and noticed and improvement in the noise floor.
... So far, so good, better dynamics and improved noise floor.
Then I tried to swap out the Chinese 12AX7 tubes with some Groove Tube 12AX7M tubes...well that wasn't pretty! The system would play for a few minutes and then the volume would start to fade and finally my amps (Simaudio W-3)protection circuit would kick in and shut down.
After a search on this and other web sites for possible causes; bad tube, bad tube connector, cold solder joint, or bad capacitor. I then tried the very technical solution of just wiggling the tubes in their sockets but that didn't accomplish much. So next I tried swapping the 12AX7M tubes side to side but it seemed at best I could only get them to play, noisily, for about 2 hours before everything would finally crap out again.
In the end I finally put the Chinese 12AX7 tubes back in and they have being playing very nicely with both the Mullard CV4003's and the 5Z3PA-T rectifier tube.
I agree, the tonal balance is good with clear, extended highs, a supple, transparent midrange, and bass depth and tautness that belies the component's affordable price.
...but now of course, I'll have to give the RCA Command 5751's a try. ;-O
One day I might also get around to swapping out the rectifier tube for one of those Webber copper cap rectifier replacements...just to see how that sounds.
This post is made possible by the generous support of people like you and our sponsors:
Follow Ups
- Re: I replaced the rectifier with a vintage Raytheon 5Y3GT - Heli_Dog 14:43:38 08/23/05 (3)
- 5Z3 & 5Z3PAT - pins - Les H 04:35:23 08/30/05 (1)
- Re: 5Z3 & 5Z3PAT - pins - sgb 07:58:47 08/31/05 (0)
- Thanks for the input - sgb 05:44:42 08/24/05 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
