12ax7 and 5751 tube hunters... caveat emptor!

[Nick Dangerous]

The time has come to revise my MG Head OTL & tuberolling webpage. Not because the amp has fallen out of favor with me, no no. Far from it. Rather, I've recently had some weird experiences with tubes and the results are baffling. In short... my current production tubes sound VERY GOOD.

I recently picked up a used MG Head amp from Audiogon (courtesy of a tipoff from a Head-Fi member, thanks!) for a mere $165. Included were two JJ EL84's and one JJ ECC83 (12ax7). They give me good bass, good midrange, and satisfying highs. This is not what I expected. Back in 2001-2002, my experiences with the JJ ECC83 were underwhelming to say the least. It was one crappy hombre. Now it sounds darn good!

As a reality check, I ordered a pair of the treasured Sylvania blackplate triple-micas with the gold JHS-5751 designation. I couldn't believe how disappointed I was with them. They sounded thin, had weak bass, and were distant in the vocals. The JJ blew them away. Blew. Them. Away.

The Sylvanias were probably fakes. Or, they were on the verge of giving out despite testing as "near NOS". Whatever the case, they sucked.

That's vaccuum tube humor, get it? Yuk yuk.

My #2 favorite, the Raytheon 5751 blackplate w/"windmill" getter, fared far better. This has to be a difficult tube to fake. It is the only one I know of that has both the unusual getter & blackplate construction. It's the one I can depend upon. Old Faithful. If you're gonna go NOS these days, I recommend snagging a Raytheon.

Modern tube manufacturing quality has improved over the last couple of years. When I launched the Team Head Six Pack a few years ago, we were in almost unanimous agreement on the tube rankings. Elite NOS was amazing, decent NOS was great, and current production sucked. With today's JJ in the mix, I suspect the rankings might be different if I re-launched the THSP.

Website update is pending longer-term trials in case I find myself eating my words down the road. Also planning to do some EL84 rolling.

Bottom line: When it comes to tube rolling, your mileage may vary. Best strategy is the same as it ever was: Buy a bunch, keep the ones you like, and sell the rest. Don't be scared of current production tubes!

 

[Dusty Chalk]

You should also try the Ei Elites (gold pin, if it's a choice). With lots of burn-in time, they do sound pretty good.

Some tubes just need a lot of warm-up/burn-in time. (Micro-air leaks? Just guessing...) Like on the order of a day of constant 'on' time.

 

[drarthurwells]

Can you and did you bias adjust for each tube?

 

[replytoken]

Now if your post could only gain cult status like the one Joe posted back in 1999 that still keeps driving up the price of NOS 5751's! Then I might be able to find a decent one or two at a reasonable price.

Seriously, Dr. Lloyd has similar feelings about the new Sovtek 5751 tube that he uses as standard issue on many of his amps. And Jon at The Tube Store likes their 12AX7LPS. Its refreshing to hear that an affordable tube can deliver. I see some of the prices people are asking for certain NOS and I have to wonder how many of those tubes are worth their price. Many I am sure, but probably not all. (Damn, I am starting to write like Yoda! Time for bed it is!!

) Of course YMMV with equipment, but at least those of us trying to keep our wallets intact have some hope.

 

[Afrikane]

Lol! After reading your MG Head guide about two weeks ago I sourced and bought the Raytheon, it's on its way to me now. At least it won't sound worse so no worries.

 

[pageman99]

Quote:

Originally Posted by Nick Dangerous Bottom line: When it comes to tube rolling, your mileage may vary. Best strategy is the same as it ever was: Buy a bunch, keep the ones you like, and sell the rest.

I would have to agree. I've spent a lot of time and money on tube rolling with my MAD Ear+ HD Purist. From Telefunkens to RCA Commands.

I won't go into details. I'll save that for a long post on each tube later. But I will say in my exhaustively researched opinion, most of Joe's Tube Lore is simply wrong for most folks.

While sound within each brand and type of tube is generally similar in character, the variations are so wide that one must listen to each tube individually.

Are the more expensive tubes worth the money? Yes and no. If you get a good example they can be very, very good. A bad example, can be very, very bad as well.

My favorite tubes cost me $2.50 from the local TV store. They were pulls from old organs and scientific instruments. I tried dozens, and kept 5 or 6.

Easy to do for $2.50 a shot. Not so easy when buying on Ebay or elsewhere for $40 each.

On another note, I received the Sovtek from Dr. Lloyd as the stock tube in the HD. I didn't like it at all. On the other hand, my buddy who collects old radios and helped me test all my acqired tubes, liked it a lot.

Bottom line, everyone's ears are different. Try what you can afford WITH AN OPEN MIND!

And like Nick says caveat emptor and resell the ones you don't like, they may be some one elses holy grail.

I gave my buddy most of the tubes that tested electrically poor to use as replacements in his old table radio collection. I kept the ones that tested as NOS or close. Have around 30 or so left out of 200. Long story!

Will put them in the For Sale thread later I guess.

 

[ken36]

Good advice on tube rolling.

 

[Hirsch]

I've been finding that several of the Chinese amps sound better with new production tubes than with NOS. These are the tubes they were designed with. I did some MG Head tuberolling with a friend today. We swapped out Siemens EL34's for Ei EL34's. Then stuck an Ei 12AU7 in as the driver. Not bad. However, moving to a Raytheon windmill getter was a bigger improvement still. Possible best though, was a Sovtek 12AX7LPS. That tube kept getting stronger the longer it played. Bass and detail were all there, along with a transparency I'd never heard using the Siemens output tubes. I wish I'd had this tube set working for the NJ meet, and will have it working at the MD meet coming up. My friend is going to be burning the tubes in, so that they're all settled in by the meet. It's downright amazing what you can do with a $200 amp and new production tubes, sometimes. NOS is not always the way to go. There are some very nice new production tubes if you use them in the right circuit.

 

[Nick Dangerous]

Aw shoot. Curiosity wins again. I bought a brand new Sovtek 12ax7LPS to compare with the others.

It might not beat the Raytheon, but if it's close enough...

 

[tuatara]

Seriously, Dr. Lloyd has similar feelings about the new Sovtek 5751 tube that he uses as standard issue on many of his amps. /QUOTE]

When I purchased my Ear+ Lloyd stated that in his opinion the supplied Sovtek tube gave a very good result and that I might not gain alot using NOS valves. I'd have to agree with that, a couple of current production tubes have been quite acceptable and justifying the cost of expensive replacements becomes increasingly difficult.

 

[Blasyrkh]

hello nick, i'm in the MG HEAD OTL MK3 tube rolling world too, with the hd650.

these are the tubes i own/owned:

sovtek EL84
JJ EL84

Electro Harmonix 12ax7
JJ ECC83S
JJ ECC803S
Sylvania 5751 triple mica ecc
RCA 5751 Command
Mullard 12ax7 (don't remember exactly)

these are the tubes that are coming:

Ei Elite gold EL84
Electro Harmonix EL84

Ei elite gold 12ax7
Tung-sol 12ax7
Ei 12ax7 grey plate
Sovtek 12ax7 LPS
Grove tubes 12ax7 M


I'm now using the JJ el84 with JJ ECC803S most of the time, because is the best balanced, dynamic, punchy sound.
I use the Electro Harmonix 12ax7(amazing) or Sylvania 5751 for a "groover" sound, much thick low end (sometimes too much) than the JJ
it's really strange that your sylvania sounds thin, i'm sure there's a problem with that. however i suggest you to try the Electro harmonx 12ax7 (better if gold pin), its sound is harmonically complex like the the sylvania, but maybe has better dynamics in the low end.

i'm now waiting for the new tubes to arrive, if you need help/impressions about tubes for your page, just ask

 

[Nick Dangerous]

Hey Blasyrkh, sorry to hear about your diagnosis with TR (Tube Rolleritosis). It's an insatiable curse.

Do post your impressions of those EL84's. I've never done a comprehensive sampling of them, but it may happen.

In what ways do you find that the JJ ECC803S exceeds the JJ ECC83?

 

[Blasyrkh]

Quote:

Originally Posted by Nick Dangerous Hey Blasyrkh, sorry to hear about your diagnosis with TR (Tube Rolleritosis). It's an insatiable curse. Do post your impressions of those EL84's. I've never done a comprehensive sampling of them, but it may happen. In what ways do you find that the JJ ECC803S exceeds the JJ ECC83?

yes it's a curse, but it's too much fun

of wich EL84 do you want the impressions? JJ vs Sovtek, or the new ones i bought?

the new ECC803S are very similar to the ECC83S, the difference is really subtle, but i hear a tighter bottom end, thicker midrange, crisper highs...maybe a little bit brighter too

 

[ken36]

I've spent a small fortune on tubes and thus far my favorites have been very inexpensive. It really is a crap shoot. So to speak.

 

[Blasyrkh]

Quote:

Originally Posted by ken36 I've spent a small fortune on tubes and thus far my favorites have been very inexpensive. It really is a crap shoot. So to speak.

and that's why after i bought sylvania, rca and mullard, i'm now interested only in new tubes