Need help with 5881 tubes

Zzpomzz

Member
Messages
40
So I’m trying to find a good 5881 pair and it seems like the best thing to do is to get the reissue Tung Sols. I’ve considered the NOS ones but at 150 a pair it’s pricy for an amp I tour with.

I recently came across a seller who has some Sylvania and Phillips tubes that are labeled 5881/6L6GB. I’ve been finding lots of conflicting information if these are the same tubes or if they are more similar to 6L6GC tubes. I’m looking for a 23 watt tube as I’m a harp player so them being less efficient works to my advantage. These would only be about 70 a pair but if they’re just 30 watt tubes that wouldn’t be worth it to me and I’ll buy reissues.

anyone tried these?
 
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5,671
Number of Watts would be a moot point as long as it conpresses and clips like a 23 - 25W bottle - compare to the modern day TS 6L6GC STR and the TAD 6L6WGC.
 

StratStringSlinger

Supporting Member
Messages
3,236
When I A/B-ed many years ago the Reissued Tung-Sol 5881’s were very close to the original U.S. NOS ones. At on my Milkman Creamer combo. Just raised the bass a bit with the reissued tubes to match and the NOS maybe had a bit punchier treble. But I keep the Russian made ones in there for everyday playing/rehearsals and gigs.
 

Stormin

Tele's and Plexis
Staff member
Gold Supporting Member
Messages
4,123
So I’m trying to find a good 5881 pair and it seems like the best thing to do is to get the reissue Tung Sols. I’ve considered the NOS ones but at 150 a pair it’s pricy for an amp I tour with.

I recently came across a seller who has some Sylvania and Phillips tubes that are labeled 5881/6L6GB. I’ve been finding lots of conflicting information if these are the same tubes or if they are more similar to 6L6GC tubes. I’m looking for a 23 watt tube as I’m a harp player so them being less efficient works to my advantage. These would only be about 70 a pair but if they’re just 30 watt tubes that wouldn’t be worth it to me and I’ll buy reissues.

anyone tried these?
Talk to Mike at KCA - he’s a member here. The JAN Phillips 6L6WGB is what you’re looking for and they’re $105 a pair.
 

HotBluePlates

Member
Messages
9,731
... I’m trying to find a good 5881 pair and it seems like ...
If you're trying to lower the volume of your amp (perhaps at the onset of distortion), you'll need to go about it a different way.

Unless you've tried & know you want the sound of a specific brand/era of old-US 5881 (or 6L6WGB), then consider your search is for a tube "of the 6L6 class, 23 watts or more." Many decades on from the release of the 5881/6L6WGB (originally a special-version 6L6) all manner of things get the type number screened on them, rightly or wrongly.

... I’m looking for a 23 watt tube as I’m a harp player so them being less efficient works to my advantage. ...
It doesn't work like that.

- The amp's circuit dictates how much power output tube tube will make.

- The rating of the "23 watt version" 5881/6L6WGB means only the manufacturer said the tube's plate can withstand dissipating 23w before tube life/performance is impaired.

- How hot the tube's plate will get (its "dissipation") depends on the amp's circuit design, how hot you bias the tubes at idle, and how hard you're pushing the output tubes.

- Audio power output to the speaker can exceed the dissipation rating of the tubes, if the amp's design allows it.

- While you can reduce the power output of your amp by using a lower-dissipation tube (mainly something like 6V6 instead of 6L6), it's a kludge and the small tube may not endure the abuse of the amp's circuit (gotta investigate specific situations).​

It's kinda like thinking your car will go faster if you put different tires on it. Other factors make the car able to go fast (engine, and also transmission, suspension). While the car is going fast, it needs tires that will grip the road & not fly apart. And that's basically where you are with power output & tubes. The tubes only control the power output the amp's circuit allows, but on the other hand the tubes need to be stout enough to stand up to use in the circuit. The tubes themselves don't make the power and can't be the only thing changed to raise/lower the power output.

If you want your amp quieter, it might be worth investigating lowering the power supply voltage within the amp. However, the cost of doing that the right way usually leads one to buying a different amp designed to have that lower voltage & specific performance.

... a seller who has some Sylvania and Phillips tubes that are labeled 5881/6L6GB. I’ve been finding lots of conflicting information if these are the same tubes or if they are more similar to 6L6GC tubes. ... anyone tried these?
I've used those tubes in a Super Reverb before. Depending on the specific year made, they were either labeled "JAN Sylvania 6L6WGB" (in green print) or "PhilipsECG 6L6WGB" (in green or blue print). IF we did a power output test with a dummy load maybe there was a few watts less output, but the sounded as-loud as when I had RCA 6L6GCs in the same amp.



Some people debate whether American 5881s are the same as 6L6WGB, and sometimes point to slight differences in data sheets. Tung Sol created the 5881 in the 50s, and check out one of the ones I have below, marked both "5881" and "6L6WGB":


 
Last edited:

slider313

Silver Supporting Member
Messages
8,128
The Russian Tung Sol 5881 is a 23 watt tube and, in my experience, sounds very close to it's original 1950's namesake. The difference is the Russian tube is more mid forward an less defined.
 

Zzpomzz

Member
Messages
40
hey man,

I’m not looking for less volume really. More less headroom if that makes sense. I don’t need the amp to be quieter or anything but if anything all harp buddies (and even guitar buddies) have expressed putting 5881 or more so 6L6GB tubes in place of the GCs the previous owner put in will lower the head room to achieve more compression. This amp definitely can handle it as it’s made to the exact spec of a 57 Bandmaster. I have an amp for quieter gigs but I don’t want the amp to be cleaner than it needs to be.
If you're trying to lower the volume of your amp (perhaps at the onset of distortion), you'll need to go about it a different way.

Unless you've tried & know you want the sound of a specific brand/era of old-US 5881 (or 6L6WGB), then consider your search is for a tube "of the 6L6 class, 23 watts or more." Many decades on from the release of the 5881/6L6WGB (originally a special-version 6L6) all manner of things get the type number screened on them, rightly or wrongly.



It doesn't work like that.

- The amp's circuit dictates how much power output tube tube will make.

- The rating of the "23 watt version" 5881/6L6WGB means only the manufacturer said the tube's plate can withstand dissipating 23w before tube life/performance is impaired.

- How hot the tube's plate will get (its "dissipation") depends on the amp's circuit design, how hot you bias the tubes at idle, and how hard you're pushing the output tubes.

- Audio power output to the speaker can exceed the dissipation rating of the tubes, if the amp's design allows it.

- While you can reduce the power output of your amp by using a lower-dissipation tube (mainly something like 6V6 instead of 6L6), it's a kludge and the small tube may not endure the abuse of the amp's circuit (gotta investigate specific situations).​

It's kinda like thinking your car will go faster if you put different tires on it. Other factors make the car able to go fast (engine, and also transmission, suspension). While the car is going fast, it needs tires that will grip the road & not fly apart. And that's basically where you are with power output & tubes. The tubes only control the power output the amp's circuit allows, but on the other hand the tubes need to be stout enough to stand up to use in the circuit. The tubes themselves don't make the power and can't be the only thing changed to raise/lower the power output.

If you want your amp quieter, it might be worth investigating lowering the power supply voltage within the amp. However, the cost of doing that the right way usually leads one to buying a different amp designed to have that lower voltage & specific performance.



I've used those tubes in a Super Reverb before. Depending on the specific year made, they were either labeled "JAN Sylvania 6L6WGB" (in green print) or "PhilipsECG 6L6WGB" (in green or blue print). IF we did a power output test with a dummy load maybe there was a few watts less output, but the sounded as-loud as when I had RCA 6L6GCs in the same amp.



Some people debate whether American 5881s are the same as 6L6WGB, and sometimes point to slight differences in data sheets. Tung Sol created the 5881 in the 50s, and check out one of the ones I have below, marked both "5881" and "6L6WGB":


 

HotBluePlates

Member
Messages
9,731
... I’m not looking for less volume really. More less headroom if that makes sense. I don’t need the amp to be quieter or anything but if anything all harp buddies (and even guitar buddies) have expressed putting 5881 or more so 6L6GB tubes in place of the GCs the previous owner put in will lower the head room to achieve more compression. ...
"Headroom" in this context sounds somewhat like "less power." But there could be ways to move forward towards your goal. The downside is the ways to dial-in the exact response you want require a sharp tech who is willing to devote some real time to your request.

1. Rectifier: If you're using a GZ34/5AR4 or 5U4 rectifier in your amp, try out the 5R4 rectifier first. It will lower voltage somewhat and increase the power supply impedance, and your amp will tend to have more sag.

- If your tube sockets grip the tubes loosely, be careful with the 5R4WGB (aka "Potato Masher"). It is a big tube with very thick glass and a heavy base. While certainly more bomb-proof than other 5R4 types, it is more likely to fall out of a socket that's too loose and holding the tube upside down.​

2. Tubes: The easier route might be to to get some output tubes that have Low Plate Current and somewhat Low Transconductance among the 6L6-class. This requires the tech or vendor to test tubes and pick a set that's lower than average for these parameters.

- The Low Plate Current will result in a smaller bias voltage being applied to these tubes to get them to the proper idle current. That will mean a smaller preamp drive-signal (Volume knob set lower) will push them to distortion, which will seem to reach one of your goals.

- The Low Transconductance will result in the tube swinging less output power when driven (doubly-so given that smaller drive signal above). This will knock down the actual volume-in-the-room some, and also seem to reach your low headroom goal.

- Most tube vendors appear to grade tubes by plate current & transconductance as part of their matching process. Calling or otherwise specifying in your tube order that you want tubes measuring lower in each category will probably get you what you want.

- It's hard to know without experimenting how far this will satisfy your needs, and ideally there would be a lot of different candidate tube-sets to try before buying to see if they do what you want.
3. Screen/Power Supply Resistors: This is more likely to get exactly what you want, but will probably give perfect response at one loudness level, and requires auditioning different resistors values with the tech while playing at gig-volume to listen for the amount of sag/compression you want.

- Using screen resistors much-larger-than-stock will cause the compress & deliver less output power, but only when you're playing the amp very loud. The resistor values to use have to be found experimentally, as it all depends on what the output tubes do in that amp when played at the gig-volume you want the compression to occur.

- A sharp tech might put 2 or more values on a switch for you (to be manipulated when the amp is Off or in Standby) so that you have options about the amp-loudness when the compression kicks in. This can be important, because the non-master volume amp having key parts of its sonic response dependent on the power section also typically has a narrow range of loudness where that effect is just-right.

- This same effect could be achieved adding a series resistor in the power supply to knock down the whole amp's voltage. However, the same need for experimentation to find the right value for the desired gig-volume exists.
 

HotBluePlates

Member
Messages
9,731
... putting 5881 or more so 6L6GB tubes in place of the GCs ... This amp definitely can handle it as it’s made to the exact spec of a 57 Bandmaster. ...
Yeah, I'm not worried about the amp being able to handle it (or even whether the tubes can handle it). It's more about whether what you expect to happen will actually happen.

Your amp's power output is dictated by the power supply (voltage output & current capability) and the output transformer (OT) primary impedance.

- To hit a certain power output goal Baier/Fender assumed the output tubes would pull a certain amount of current through the OT primary. That creates a varying voltage (which cannot exceed a certain % of the power supply voltage), and the Voltage x Current is your power output.

- The specific tube used doesn't enter the equation, except that the designer needs to know that the tube won't overheat or exceed its ratings given the chosen supply voltage & power output target.

- If the tube can handle the peak current desired but tends to overheat (rated for 19w rather than 23w, or rated 23w rather than 30w), the most likely change would be to idle the tube cooler (perhaps well below the ubiquitous 70% of rated dissipation), so that the tube has more time to cool during the signal cycle.

- The tweed Bandmaster was originally designed back in the ear when 5881 or 6L6GB was the biggest 6L6-type around, so there's no doubt it can work in this circuit.
So where does that leave us? I'm sure you're not gonna be changing power or output transformers to hit your goal of less headroom (though that is option, albeit an extreme one). So we're looking at nibbling at the margins of how the power supply (changed rectifier, series power supply resistance) or how the tubes (Low-current/Low-Gm, screen resistance) contribute to the power section's function.

Some of my suggestions above will tend to work against each other. It pays to have a sharp tech who knows how each of the elements interact, because you'll be working with that tech to figure out the ideal balance that achieves your goal.
 
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bluesky636

Member
Messages
2,335
hey man,

I’m not looking for less volume really. More less headroom if that makes sense. I don’t need the amp to be quieter or anything but if anything all harp buddies (and even guitar buddies) have expressed putting 5881 or more so 6L6GB tubes in place of the GCs the previous owner put in will lower the head room to achieve more compression. This amp definitely can handle it as it’s made to the exact spec of a 57 Bandmaster. I have an amp for quieter gigs but I don’t want the amp to be cleaner than it needs to be.
I use JJ 5881s in my 5F6A clone. They sound great and are reasonably priced.
 

Red House

Silver Supporting Member
Messages
1,960
I’m not looking for less volume really. More less headroom if that makes sense. I don’t need the amp to be quieter or anything but if anything all harp buddies (and even guitar buddies) have expressed putting 5881 or more so 6L6GB tubes in place of the GCs the previous owner put in will lower the head room to achieve more compression. This amp definitely can handle it as it’s made to the exact spec of a 57 Bandmaster. I have an amp for quieter gigs but I don’t want the amp to be cleaner than it needs to be.
This is easy, just install/bias JJ 6v6's in it - they will work and do what you require.
 

bluesky636

Member
Messages
2,335
So I’m trying to find a good 5881 pair and it seems like the best thing to do is to get the reissue Tung Sols. I’ve considered the NOS ones but at 150 a pair it’s pricy for an amp I tour with.

I recently came across a seller who has some Sylvania and Phillips tubes that are labeled 5881/6L6GB. I’ve been finding lots of conflicting information if these are the same tubes or if they are more similar to 6L6GC tubes. I’m looking for a 23 watt tube as I’m a harp player so them being less efficient works to my advantage. These would only be about 70 a pair but if they’re just 30 watt tubes that wouldn’t be worth it to me and I’ll buy reissues.

anyone tried these?
What are you using in V1, 2, and 3?

I thought most harp players use tubes like a 12AU7 in V1 and for the phase inverter to reduce the amp gain.
 

HotBluePlates

Member
Messages
9,731
With twice the expected load connected I see no problem there.
Leaving the speaker load as-is actually contributes to why the tubes will make less output power (though only one of the reasons).

Either way, the only real concern for this scenario is voltage stress on the 6V6s. JJs ratings & long experience have shown they will tolerate it, rightly or wrongly. The OP isn't looking for maximum clean power output, so it's not really important to match the load to the tubes.
 

Steviecaster

Member
Messages
601
to my ear, power tubes make such a small difference that I would not pay for the NOS. A speaker makes a much much larger difference than power tubes. Even changing from 5881 to EL34 makes such a small difference.
 




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