MG Head tube rolling...

[Jbucla2005]

I am getting great results using my MG Head DT paired with AKG K701's and wanted to share my latest tube-rolling experiences. I have tried 3 current production EL84's, the Shuguang 6P14, the Sovtek EL84-M, and the Ei gold pin EL84's (before the production went bad.) I have also previously used 50's Amperex D Getter BB's, and have tried Blackburn Mullard EL84's too.

I just got the Chinese 6P14's today direct from China and they are great! Warm, smooth, and pleasing. The Sovtek EL84-M's are quite impressive as well, with lots of details and a thick meaty bass response. The gold pin Ei EL84's which were the most expensive because they are now NOS (at a certain point they started having production problems) sound very close to the Amperex BB's I used to use. This is the sweetest sounding of the bunch with a little more focus in the highs like the Amperex. Slightly less detailed than the Sovtek. But what is really surprising me is how well these Chinese 61P4's are faring compared to the others. They are the least expensive (I ordered direct from China) and they are my current favorites. While not so punchy they are very smooth and silky sounding, and it's nice and relaxing to listen to. These are sometimes used as stock tubes in the amp and I can see why.

As for 12AX7's I generally stick with my old favorite the Sylvania grey plate GB-5751 but have been experimenting with brand new Shuguang 12AX7's lately with very good results. They are not quite as nice as the NOS Sylvania 5751's but they are very clean and balanced with very tight bass and just the right amount of roll-off in the highs. Warm and meaty. These are about $5 a piece on e-bay. Only drawback is a hint of artificiality or 'plastic' quality to the sound, it is very slight but that is mainly why I prefer the NOS Sylvania 5751 a little more because it sounds very natural, although it is a bit fuzzy and less extended.

I want to try a RCA Command 5751, but besides that I am done tube-rolling for a while. I now have three great choices of EL84's to use, and usually use the Sylvania 5751 but occasionally switch to the Shuguang for a little clean punch and aggressiveness. I have also tried the Mullard CV4004 and Amperex BB 12AX7 but these were not my favorites overall.

I like these combos:

Sovtek EL84-M + Shuguang 12AX7 - for the most detail, gain, and bass

(now NOS) Ei EL84 gold pin + Sylvania GB-5751 tri mica - for a sweet and euphonic sound with slight emphasis in the highs

and right now I'm using the Shuguang 6P14's (sometimes used as stock tubes in the MG Head) with the Sylvania 5751 and it is perhaps the most pleasing overall. I am getting a lovely sweet silky sound, balanced, fluid and gentle on the ears. It's only drawback is that it sounds just a tad weak or flaccid in response (the opposite of the Sovtek EL84-M.)

I use my MG Head as a pre-amp for a T-amp setup with small speakers, and find that I sometimes can benefit from using a Sylvania gold-brand 5814A instead of the usual 12AX7 or 5751. Because I need to turn the volume up much less when using it in this way, I find the lower gain 5814A/12AU7 offers less noise and changes the sound stage effect. If a recording sounds particularly bright and upfront this will spread the sound out and give it more hallow dimensions, but I never found 12AU7's to be that great with headphones where the higher gain is needed.

One more thing, in my experience stay away from JJ tubes. The JJ EL84's and JJ ECC803S were very lacking in detail. An Electro-Harmonix 12AX7 I tried was rather 'blah' as well - just bright and not much else.

[Mazuki]

Are you still getting distortion issues with the DT880?

[Jbucla2005]

I sold my DT-880's a while ago. They didn't seem to match with the MG Head very well at the time that I had them, but I was probably biased towards the HD650/OTL combination. After a long time of really liking that I accidently broke my 650's and switched to the K701's...

Senns + OTL gets much louder than both K701's and DT880's (tranny mode) with this amp so maybe I was looking for a high volume at the time and getting distortion from turning it up too high.

At first the K701's didn't seem to provide enough volume but now I am fine with it after getting used to it, and generally do not use the amp at max volume.

[roastpuff]

Which verson is the MG Head - 1, 2 or 3? I just recently received my MkIII MG Head, and tested it out.

I had horrible scratching noises with the stock EH 12AX7 when I turned the volume knob, and it just sounded rather bright and over-emphasized with that tube. The soundstage was also rather compressed. Not a pleasant experience.

I dropped in a GE 2-mica grey plate NOS 5751 that I had acquired, and it was an immediate improvement. Noise floor dropped immensely, and everything just smoothed out. There was now depth to the amp - everything was detailed, but with a darker bent, and the soundstage extended greatly to the sides. Lovely tube - it's not even the "recommended" 3-mica black plate GE model. I don't mind the lower gain, and the amp still has plenty of power in either mode with a 600-Ohm Darth Beyer.

This just shows how tube amps get greatly affected by the tubes you put in them...

Now I'm on the hunt for a pair of NOS GE 6BQ5's - or even 7189's if I get lucky.

[Mazuki]

how did the HD650s break?

[Jbucla2005]

It is the Mk 3 version.

I 'killed' my 650's when I accidently overamplified them (using a much more powerful amp than MG Head...) and caused the drivers to become deformed (imploded bubbles) and had to sell them, although they were later fixed by the buyer. I do also experience a noise sometimes when adjusting the volume on my MG Head, but it is not a big concern for me.

I have tried GE and RCA 5751's and they are both good. I have tried the 5 star 3-mica blackplate version and the grey plate 2-mica version of the GE and I enjoyed them both. I think the RCA black plate 5751 came out on top by a small margin of these. That is why I want to try an RCA 'Command' 5751.

I have also heard people speak about the NOS GE oval-plate EL84's, but I have not tried them.

[ironbut]

You should give the Raytheon 5751. The one with the windmill/fan getter. A real smoothy. Sylvania 5751's are the top rated but$$$ nowdays. As far as the el84, I like the Ei the best but JJ's are pretty good too. Ei has been closed since the beginning of the year but I'm sure you can find plenty for cheap still. Try Upscale Audio. Kevin should have some left. Mine is a Mkll I think. Just before the separate power supply.

[roastpuff]

Originally Posted by ironbut

You should give the Raytheon 5751. The one with the windmill/fan getter. A real smoothy. Sylvania 5751's are the top rated but$$$ nowdays. As far as the el84, I like the Ei the best but JJ's are pretty good too. Ei has been closed since the beginning of the year but I'm sure you can find plenty for cheap still. Try Upscale Audio. Kevin should have some left. Mine is a Mkll I think. Just before the separate power supply.

The Raytheon 5751's are considered tops, but my goodness the $$! Expensive, on eBay reaching ~100USD! That's nearly 1/3rd of what I paid for my amplifier!

For the EL84's, I think I want to go NOS - keeping an eye out for Sylvania, RCA and GE tubes, but they get more expensive than I want to spend. The Sovteks currently inside are ok, but I'm interested in how the NOS tubes perform. The early Russian military EL84's that Upscale Audio stocks is also quite interesting. Tejas Tubes also has a nice price for a pair of JAN Sylvania's - $55/pair + shipping.

EDIT: Fixed grammar.
EDIT2: Damnit, I think that my power tubes are dying on me. I'm getting this staticky noise during playback - intermittently, and I don't know what's causing it - just like what the EH tube did when I first turned the amp on after I received it. The GE tube, like I said before, is much quieter. I wish I had an extra pair of EL84's to switch so that I can check it out.

[Jbucla2005]

I still think these Shuguang 6P14's (EL84) are soooo smooth. The Ei's and Sovtek's are good but these just sound so smooth, like rushing water against the ears. They take all the edge off. They are under $15 a pair on e-bay too.

I really am just ignoring the fact that these might be the same stock tubes that I thought were worthless years ago. Maybe they improved since then, I don't know.

I actually stocked up on the "top-rated" Sylvania grey-plate GB-5751's a while ago, they are impossible to get now it seems, but I have a few extras. If anyone wants to trade one for a Raytheon 5751 or something comparably good, let me know.

roastpuff: I understand the desire to want to go NOS, but I have trieda few pairs of the "top-rated" 50's Amperex D Getter EL84 and the Ei's are almost exactly the same thing to my ears (I have read they were made using original Philips tooling,) even though I currently prefer the Chinese.

[cotdt]

Raytheon 5751 and GE 6BQ5 is THE combo for any 12ax7/el84 amp.