Tube recommendations for 147 amp

[Phil Aiken]

I am replacing the amp in my 145 with a much cleaner amp. I have a pair of NOS Tungsten 6550s, but need a 12au7 and an OC3. My preference would be to have it slightly on the hotter side. Suggestions?

[Outkaster]

Well most guys like old "new" stock tubes if you can get them.

[WesG]

The OC3 is a voltage regulator. Anything will do. The 12AU7 is used in a phase inverter IIRC. Again, anything will do. Provided it's made by a reputable maker.

 

If the 12AU7 and OC3 from your old amp work, I would use those.

 

NOS Tung Sol 6550s should sound great.

 

Wes

[OB Dave]

Correct, the 6550s are the critical tubes. Best ones I've ever had were NOS mil-spec GE 6550As that were manufactured in the early 80s. Wish I could find more of them.

[ITGITC]

 

WesG - thank you!

 

This is really good information.

[dazzjazz]

Where's a good place to buy?

[The Real MC]

The OC3 is a voltage regulator.

 

Rectifier, not voltage regulator. Big difference.

 

The 12AU7 is used in a phase inverter IIRC.

 

Phase SPLITTER.

[Steve Nathan]

As stated above (and imho), the 12 and the OC3 aren't that critical.

I've been very happy with the service and selection from

http://www.valvequeen.com/

 

I bought her last Winged C SED 6550s which are my favorite Leslie tubes of all time.

[WesG]

Voltage regulator, not a rectifier - big difference.

 

http://www.radiomuseum.org/tubes/tube_0c3.html

 

 

 

[WesG]

BTW, can you explain the difference between a phase inverter and a phase splitter? A lot of literature out there uses the terms interchangeably. I haven't got the schematic in front of me right now, but IIRC half the 12au7 acts as a buffer and the other half acts as a phase inverting buffer. Then each half goes to opposing output tubes.

[The Real MC]

BTW, can you explain the difference between a phase inverter and a phase splitter? A lot of literature out there uses the terms interchangeably. I haven't got the schematic in front of me right now, but IIRC half the 12au7 acts as a buffer and the other half acts as a phase inverting buffer. Then each half goes to opposing output tubes.

 

Phase inverter is a single channel buffer that inverts the phase.

 

You are correct that a phase splitter is a dual channel buffer that splits the signal into opposite phases. The important thing is it provides equal gain and equal output impedance of each buffer into the class AB output tube stage.

 

If you see literature using them interchangeably, it is wrong.

[WesG]

Thanks - that makes perfect sense. Half the battle in learning this stuff is getting the vocabulary correct!

[Ross Ward]

As stated above (and imho), the 12 and the OC3 aren't that critical.

I've been very happy with the service and selection from

http://www.valvequeen.com/

 

I bought her last Winged C SED 6550s which are my favorite Leslie tubes of all time.

 

Steve,

 

I bought a matched pair of Winged C 6550s a couple of years ago when you could still get them based on your recommendation (and I love them). Do you have a preferred 12AU7, or do I understand correctly that you don't care that much about it?

 

Just trying to be cool like you.

[Steve Nathan]

Do you have a preferred 12AU7, or do I understand correctly that you don't care that much about it?

 

You understand correctly. I haven't changed them in either of my Leslies since I re-tubed maybe 20 years ago. At the time, I asked my guy at New Sensor for a recommendation and went with his choice. The 6550s I've tried most everything at one time or another until I got to the Winged Cs. I've stayed with them since, and bought up a few pairs to keep around just in case.

[B3Nut]

Pretty much any good 12AU7 is fine. Prefer US/EURO NOS or strong used pulls for reliability.

 

I've heard encouraging things about the JJ KT88 in 6550-based Leslie amplifiers. Wanting to try a set after hearing a good recording of a 122 equipped with them. A tech I know is trialing them as his stock replacement 6550 due to the increasingly-spotty reliability of the TS reissues...the duds don't show up when matching, only until they've been in an actual amp in use for several accumulated running hours. A good idea when buying power tubes online is buy from a vendor who offers 24-hour burn-in. That's enough time to weed out malformed grids and screens etc. in most cases.

 

Oh, the best 6550? 50's Tung-Sol solid black plate. Heaven in a bottle.

 

TP

 

TP

[Aussie_Chicago]

 

 

Oh, the best 6550? 50's Tung-Sol solid black plate. Heaven in a bottle.

 

TP

 

TP

 

Of course, but at $3-400 each, unless you inherit them, out of reach. These black plates are very sought after from audiophiles . Solid grey plate TS also nice, but also $$$ and harder to find.

+1 on the winged svet's

[WesG]

Geez. $300+ each?! I don't suppose GE coke bottles (rebadged TungSol, maybe?) with silver metal bases and grey plates are worth that much, are they? If so, ya wanna buy 'em?

[B3Nut]

 

 

Oh, the best 6550? 50's Tung-Sol solid black plate. Heaven in a bottle.

 

TP

 

TP

 

Of course, but at $3-400 each, unless you inherit them, out of reach. These black plates are very sought after from audiophiles . Solid grey plate TS also nice, but also $$$ and harder to find.

+1 on the winged svet's

 

Oh yes, I know...they are extremely pricey even for pulls. I was having a little fun... I do have a couple sets of pulls...running one in my 45 I run at church (they get run only a few hours a month) though I'll probably stick the JJ KT88's in there when I get those ordered and keep the blackplates here for recording.

 

TP

[B3Nut]

Geez. $300+ each?! I don't suppose GE coke bottles (rebadged TungSol, maybe?) with silver metal bases and grey plates are worth that much, are they? If so, ya wanna buy 'em?

 

Greyplate coke bottles are Tung Sol. Holes in the plates or solid? The 3 hole plates were the latest and final version. GE relabeled TS coke bottles until they came up with their straight-bottle 6550A in 1972. Those are an excellent tube, the Winged-C is closest in tone and power to the GE and was allegedly inspired by it. Harder overdrive than the Tung-Sol, but with a tighter low end.

 

TP

[WesG]

http://i65.tinypic.com/2dalsnk.jpg

 

Solid plates, in my '61 51C. I wonder if these are the original power tubes? V21, P15LL, good sounding Leslie. Seems to accentuate the 2nd harmonic a bit. Nice resonant wood.

[B3Nut]

They may well be original. Not surprised the cab is nice and resonant. There should be an EIA/date code on the metal base somewhere...it'll start with 322 then have 4 digits after it, like 3226123 which would be Tung-Sol, 23rd week of 1961, for example.

 

TP

[Steve Nathan]

To be honest, I've had mixed feelings about the Tungs I've tried. They were certainly big, rich and full, which perhaps makes sense for a Jazz player or church, but I'm completely hooked on the way the Winged Cs break up. They get such glorious crunch, but never smear the notes together. I can get what I like to call "the sound of wood chips flying off the Leslie" and still distinguish every note

 

I am curious about JJs though. I recently put JJ 6L6s in my 60 Fender Concert and they sound damn good!

[SteinwayB]

How are the tubes sold by Goff and B3 Guys?

[WesG]

Goff used to have a Goff-branded version of the Svetlana Winged-Cs...............I wonder if these are still available.

[Ross Ward]

Resurrecting this thread from the dead so as not to get crossways with our friend Sven .

 

My 122 went down this week. Power it up, rotors going full speed with no control, and tubes are cold. Called Murph, who suggested I replace the 1.5A fuse, and if it blew again, it was probably an issue with the power tubes. Replaced the fuse, it blew again. Swapped out my trusty Winged C's for a backup pair of EHXs, and things are normal again, so I'm afraid my poor Winged C's might be goners, although I need to get them tested.

 

I don't particularly love the way the EHXs sound, and I tend to agree with Steve in that I like the way the Winged C's break up. Murph suggested I try the JJ KT88s, which Todd mentioned having heard but not tried yet.

 

Anybody have any updated preferences on Leslie power tubes since this was discussed last? I'm leaning towards biting the bullet and trying to find another set of Winged C's, but that's a more expensive bullet than the last time I purchased, so I thought I'd see if there's anything new that people are digging.

[bill bosco]

i didn't know the TS's were problematic , been using them

for a few years now , since they came out i think ,i like

them alot but haven't replaced any in around 2 years .i'd

like to hear your opinion on the KT88's when you check them

out . i've read they are a little more mid-rangy , this might

work on my c-3 , the bottom end on this thing tends to be a little dark and the stage it's on at my church only makes

it worse

[Jim Alfredson]

The JJ KT88 tubes are really nice. I think they are the best sounding modern tubes for Leslie amps if you cannot afford NOS.

[GRollins]

I went into a shop--nationally recognized vintage guitar broker (lotsa major clients whose names you'd all recognize) with a store front operation here locally. The owner was testing tubes. I leaned on the counter and started chatting. Asked why he was testing a mound of gnarly old tubes. His reply:

 

They're used tubes, but if they test okay, I sell them as NOS (New Old Stock).

 

Guys...face it...true "NEW" Old Stock tubes are loooooong gone. People have been selling NOS tubes since at least the '70s. Do you have any earthly idea how many "New" Old Stock tubes have been sold over the last fifty years?

 

Yes, there are a few old repair shops that go out of business that happen to have, maybe, five or ten NOS 6550s or 12AX7s or something on the shelf, but they're getting more and more rare. Just as a matter of simple math, if a guy started in business at age 20 in, say, 1967, then that's fifty years ago and he's now 70. Yep, retirement beckons. Perhaps he'll close the shop. But what are the odds that he:

 

1) Actually did stay in business for fifty years. (I can assure you that in my area there are few-to-no electronics shops from that time period.)

2) Had tubes from (pick your favorite era) on the shelf that he never used.

3) Was unaware that people were paying premium prices for true NOS tubes and was unaware of eBay, etc. as selling avenues.

4) And hadn't already sold the tubes all the way back in the '80s (at which point there was already a major, thriving NOS market).

5) And...get real, here...what are the chances that you, as opposed to Joe Blow in Montana, are the guy who just happens to be the first to call when three lonely tubes come through the door from a closed shop in Miami? Really? You're gonna believe that? I hear there's a bridge for sale up in Brooklyn...wanna buy that, too?

 

Please, please, please...be careful. NOS means "New" Old Stock, not "Pay an extravagant price for a tube that's already seen 2000 hours in service."

 

Okay?

 

Grey

[mate stubb]

Fair point. However, if the tube is old construction at least, you know it's probably built better than the new ones are.

 

And tubes that came out of leslies and hammonds generally don't matter as to service life because they are little stressed, and can last decades.

[WesG]

I just switched my 145 from 1973 Tung-Sols to brand-new JJ KT88s.

 

The Leslie is a hair louder now (I run it at nine instead of 10), but otherwise sounds the same to me, until it comes time for total distortion. When you put your pedal to the metal, the new tubes are little harder, more aggressive than the ones I pulled out.

 

But I'm not really a Jon-Lord player. These things sound great AFAIC.

 

Oh, I also switched 12AU7s. I suppose I suppose I should have changed one thing at a time.

 

Wes