[Ichinichi]

damn it! then are there no date codes for miltary tubes?

 

[Rob N]

The code should be etched on the glass near the base of the tube

See here for Philips codes

 

[Agent Kang]

Quote:

Originally Posted by Rob N /img/forum/go_quote.gif The code should be etched on the glass near the base of the tube See here for Philips codes

Thank you for the link.

 

[rad212]

I just got a Sovtek 5U4G and while the tube looks sweet, it sounds polite, thin, uninvolving and has weak bass compared to the stock 5AR4 when listening through my HD-600 with the Cardas cable. I read some other reviews about the Sovtek 5U4G that described them as "punchy" but compared to what? The 5AR4 sounds much punchier with better bass and a more exciting sound.
Does the tube sound change after burn-in? If not, I will go back to the stock tube. After all, it's the sound that is most important to me.

 

[blessingx]

Well, I think the 5U4G is actually too punchy, but either it (it's the only rectifier I have) or the amp seems to require a bit more source output to perform well. I'm turning the Lavry variable output up higher than I have with any other amp to get a good sound and others have told me the same (if you have a similar option you may want to try it too). I'm still in burn-in (probably at 25-30 hours), but it certainly has changed a decent amount since I first turned it on (but again the change may be the amp and/or tubes). I'd give it a little more time.

Anyone know which rectifier would be best to get a more balanced/less tubey sound and more detail? I like the Woo6 in many respects, but these are my two issues... at least at this burn-in time. Rad212, do you think the 5AR4 or 5U4G (maybe after more time) has greater detail, resolution, etc.?

 

[rad212]

blessingx,

Those are interesting points. I use a Shanling CDT-100 as my source and the output level is at max but I did notice the volume was lower with the 5U4G than the 5AR4 with the volume control at about 11 o'clock. Maybe the gain is higher on the 5AR4? I will let the 5U4G burn in a bit before making a final judgement. I will try to compare detail and resolution once the tube burns it.
Thanks for the comments.

 

[jamato8]

It is how much the rectifier sags and the actual voltage you end up getting from it. A rectifier doesn't really have gain. I like the GZ32 in Mullard.

 

[Agent Kang]

I also found the woo6 to sound quite tubey with a bloated mid-range at first. It was a bit too warm for my tastes. But after burn-in this seemed to go away.

I also agree that the Sovtek 5u4g is punchy and a little shap in the upper mids/lower treble, but changing to a vintage 5u4g made the overall sound more grainless and less forceful. Slightly softer imaging but larger soundstage also.

 

[jamato8]

I am finding that the metal base is far superior to any of my Mullards or Amperex in other bases of the GZ34 types. There is just no comparison. To me without the GZ34 metal base the amp is just not the same.

 

[sacd lover]

Quote:

Originally Posted by blessingx /img/forum/go_quote.gif Well, I think the 5U4G is actually too punchy, but either it (it's the only rectifier I have) or the amp seems to require a bit more source output to perform well. I'm turning the Lavry variable output up higher than I have with any other amp to get a good sound and others have told me the same (if you have a similar option you may want to try it too). I'm still in burn-in (probably at 25-30 hours), but it certainly has changed a decent amount since I first turned it on (but again the change may be the amp and/or tubes). I'd give it a little more time. Anyone know which rectifier would be best to get a more balanced/less tubey sound and more detail? I like the Woo6 in many respects, but these are my two issues... at least at this burn-in time. Rad212, do you think the 5AR4 or 5U4G (maybe after more time) has greater detail, resolution, etc.?

The reason you have to turn the volume higher is the 6de7 input/ power tube. The input stage of the 6de7 only has a gain/ amplification factor of 17 .... which is at the low end for a tube amp.

For rectifiers I like the 5u4g myself. The sound quality is very good to excellent and these tubes are reasonably priced for the most part. The older coke bottle shaped 5u4g's are better sounding than the later straight bottle 5u4gb's in my experience. The cleanest, leanest sounding 5u4g I have tried is the Sylvania. The TS, Ken Rad and Raytheon 5u4g's are clean sounding too but have more tone and avoid the leaness of the Sylvania 5u4g. I like the balance of the TS 5u4g best but Ken Rad and Raytheon rectifiers are also quite good.

The only richer and fatter sounding 5u4g I have come across is the RCA 5u4g. For your stated preferances I would avoid the RCA.

A good straight bottle rectifier is the Sylvania brown base 5931 military rectifier. This one has excellent bass and no thiness, actually bordering on a rich sound, but avoids sounding to fat .... atleast in my tube rectified amp.

 

[jamato8]

I have a nice Sylvania 5U4G and RCA coming and a 5V. Should be interesting comparing to the metal base 34's.

Great info SACDLover, as usual.

 

[blessingx]

Thanks much sacd lover. As jamato8 said, great info as usual. I noticed the Sylvania brown base 5931 appears to have a wide base. Could you give us a quick measurement of the diameter? I looks like it may be an issue with the WA6 plate opening depending.

 

[rlanger]

Quote:

Originally Posted by sacd lover /img/forum/go_quote.gif For rectifiers I like the 5u4g myself. The sound quality is very good to excellent and these tubes are reasonably priced for the most part. The older coke bottle shaped 5u4g's are better sounding than the later straight bottle 5u4gb's in my experience.

Great info SACD, thanks. Do you think that a NOS Mullard would be a significant upgrade to the Sovtek 5u4g that I received with my amp?

 

[sacd lover]

Quote:

Originally Posted by blessingx /img/forum/go_quote.gif Thanks much sacd lover. As jamato8 said, great info as usual. I noticed the Sylvania brown base 5931 appears to have a wide base. Could you give us a quick measurement of the diameter? I looks like it may be an issue with the WA6 plate opening depending.

If the Woo 6 has a setup where you have to go through a sized opening, the 5931 is probably not going to fit. The 5931 has a much larger diameter base that measures roughly (with a cloth tape measure) a little more than 5.25" in diameter.

 

[Agent Kang]

Quote:

Originally Posted by rlanger /img/forum/go_quote.gif Great info SACD, thanks. Do you think that a NOS Mullard would be a significant upgrade to the Sovtek 5u4g that I received with my amp?

Definitely. But a cheaper alternative to Mullard would be a Sylvania or RCA 5U4G. These are also a significant improvement over the Sovteks.