Retube Time.....Soldano SLO-100

[SpiderWars]

Just the regular stock Sovtek wafer bottom 5881s. All the power tubes are gonna sound the same for the most part in the SLO. Its power section is hi-fi and not meant to really break up at all. Unless you're running it on 8+, in which case you're deaf.

If you have a Depth control (which imo the SLO either doesn't need or only needs a tiny bit) then the power tubes can make a bigger difference. Some tubes seem to have a more extended bass that makes the Depth control more pronounced. I tried one set of GT 6L6GC and the Depth control barely even worked.

I'd be interested to know how the Depth control's effect in the SLO depends on the brand of power tubes used. Whereas in other amps that use the same exact depth control, they do not.

It was the GTs of unknown origin that did that. I think it's just because those tubes didn't have the available bass to boost. Like they didn't even have a sufficient frequency response down there where the Depth control works. I could dime the Depth and it still wasn't too much. Usually I can't turn it up past 9:00 or so and never more than halfway. I recently saw your SLO build thread. Very cool.

 

[godgrinder]

https://images-na.ssl-images-amazon.com/images/I/4190ve83XHL._SX450_.jpg

Ive heard good things about these ...

Max. plate and grid volts: 400V DC.

http://www.tubeampdoctor.com/images/Fil ... ng-Sol.pdf

FWIW, the Sovtek 5881WXT is rated at 360v max plate, 270v max screens, and 23W max plate dissipation (per Duncans Amp pages). The Tung Sol 5881 is made by Sovtek so it's possible that it too is WAY tougher than that but I don't know. Tung Sols are generally bright and ime that's not the best for the SLO.

My friend tried these Tung Sol 5881's in his SLO, they died in a few days.

 

[SLOgriff]

Google search will answer everyone's opinions and questions.

* Different power tubes and bias WILL affect the tone and feel of a real SLO...

* EL34's could damage the amp/transformers (per Mike Soldano). Yes, it has been done....but not worth it.

* Factory Depth is very noticeable no matter what tubes you run.

* Sovtek 5881/wgc "wafer bottoms" biased around 28ma yield the best tone and performance.

* JJ-12AX7's sound pretty darn good in V1, V3, and V4.

* Try an EH-12AX7 in V2, and Sovtek LP in V5....along with the above JJ's.... I've landed on this combination after HOURS of tube rolling. This gets me great tones from Warren Haynes to George Lynch.

Other tubes may work and sound ok, but the above combination and bias setting is what a lot of us long-time SLO owners/players stick with.

 

[Racerxrated]

Google search will answer everyone's opinions and questions.

* Different power tubes and bias WILL affect the tone and feel of a real SLO...

* EL34's could damage the amp/transformers (per Mike Soldano). Yes, it has been done....but not worth it.

* Factory Depth is very noticeable no matter what tubes you run.

* Sovtek 5881/wgc "wafer bottoms" biased around 28ma yield the best tone and performance.

* JJ-12AX7's sound pretty darn good in V1, V3, and V4.

* Try an EH-12AX7 in V2, and Sovtek LP in V5....along with the above JJ's.... I've landed on this combination after HOURS of tube rolling. This gets me great tones from Warren Haynes to George Lynch.

Other tubes may work and sound ok, but the above combination and bias setting is what a lot of us long-time SLO owners/players stick with.

Don't you find that the Depth mod doesn't make any difference when the master is past 1.5 or 2? Had one stock and one with both depth/Haynes mods..depth didn't do much once turned up a bit.

 

[SLOgriff]

I've had probably (13) different SLO's, half had the Depth mod. The Depth is always noticable at any volume....maybe more so at lower volume levels.

If you have an SLO with Depth, turn it "0" which is totally out of the circuit. Then turn it to 11:00 o'clock and then 2 o'clock as you're playing....there is definitely a difference in low end and feel. It also changes the midrange some depending on the setting.

 

[Mr. Willy]

I've tried them all, 6L6 and variants including KT66. Best to my ears were the Sovtek wafer bottom 5881s. Not tried 34s which would require modding. But there's a reason Mike puts those wafer bottoms in. Cheap, reliable and they sound great. Bias around 28ma and you're set. Pre tubes, I've played with lots of combos and the Chinese 8th gen sounded best, with a Jan AT7 in the pi spot. Had my last SLO last year, that's my experience.

I'm gonna agree with this. I've tried both the wafer bottom Sovtek 5881's and JJ6L6GC. Didn't care for the 6L6's at all. It scooped too much of the midrange out. Wasn't as compressed (in the good way) or as aggressive. I rolled a few NOS around in the preamp spot and just went with 9th gen Chinese. I thought they sounded the best. This is for me though. Some other players might like the combinations I didn't.

 

[RockyStar]

Thanks everybody for the input. I really appreciate it.

It looks like the Sovtek 5881 wafers are the way to go in the power section.

 

[Jdub]

Ive heard good things about these ...

I used those for a year or so in the late 90's early 2000 . They were warm and soft around the edges so to speak. I liked them at the time but ultimately, after twenty years of using the SLO and sampling many tubes, I always go back to the stock Sovtek 5881 that MJS uses. No need to mess with it.

 

[Mesa\Kramer]

The Power tubes need to be able to handle the SLO's high plate voltage and the stock Sovtek's are of few built to handle
Most other 5881's can not support the 500+ needed

 

[Giga]

Just the regular stock Sovtek wafer bottom 5881s. All the power tubes are gonna sound the same for the most part in the SLO. Its power section is hi-fi and not meant to really break up at all. Unless you're running it on 8+, in which case you're deaf.

That's more or less MJS statement on the subject too but my ears definitely tell me something different...

Giga

 

[FourT6and2]

Yeah, I mean the tubes do sound different. But not different enough to really put that much effort into it. You can get the same tonal differences by just messing with the EQ knobs on the front of the amp. For the SLO, might as well just run the stock power tubes and focus your efforts elsewhere. If one disagrees, cool. But to me it's just a waste of time and money and effort to worry about power tubes in an amp like this. Even in my other amps, not a huge difference to be honest.

My Ares came with stock JJ 6L6GC. I swapped them out for super awesome mega cool NOS Sylvania 6L6GC STR-387s. The freakin' demi-god of NOS 6L6s apparently. And honestly... very little difference lol. Yeah yeah yeah, me ears are shot and I don't know what real tone is. Hahaha. But really... I think most people just have a touch of placebo effect going on.

 

[RockyStar]

Yeah, I mean the tubes do sound different. But not different enough to really put that much effort into it. You can get the same tonal differences by just messing with the EQ knobs on the front of the amp. For the SLO, might as well just run the stock power tubes and focus your efforts elsewhere. If one disagrees, cool. But to me it's just a waste of time and money and effort to worry about power tubes in an amp like this. Even in my other amps, not a huge difference to be honest.

My Ares came with stock JJ 6L6GC. I swapped them out for super awesome mega cool NOS Sylvania 6L6GC STR-387s. The freakin' demi-god of NOS 6L6s apparently. And honestly... very little difference lol. Yeah yeah yeah, me ears are shot and I don't know what real tone is. Hahaha. But really... I think most people just have a touch of placebo effect going on.

Agree....in many cases tubes don't always make a huge difference from one brand to another in the same tube type family. It is when you switch tube types that changes can be more severe....example an el-34 to a 6550 or something like that.

Anyway, I will tube with the 5881 wafers and try a few pre-amp variations in places that make sense and enjoy it. I have no interest in chasing the 3% that could be when the 97% is already bad ass.

 

[FourT6and2]

Yup. There ya go.

 

[Racerxrated]

Yeah, I mean the tubes do sound different. But not different enough to really put that much effort into it. You can get the same tonal differences by just messing with the EQ knobs on the front of the amp. For the SLO, might as well just run the stock power tubes and focus your efforts elsewhere. If one disagrees, cool. But to me it's just a waste of time and money and effort to worry about power tubes in an amp like this. Even in my other amps, not a huge difference to be honest.

My Ares came with stock JJ 6L6GC. I swapped them out for super awesome mega cool NOS Sylvania 6L6GC STR-387s. The freakin' demi-god of NOS 6L6s apparently. And honestly... very little difference lol. Yeah yeah yeah, me ears are shot and I don't know what real tone is. Hahaha. But really... I think most people just have a touch of placebo effect going on.

Well, I can tell you for sure that in a Mesa Mark, at least in my case the red and purple stripe III I had, and my present 2C+ that those Sylvania's make a WORLD of difference to my ears. I mean a ton. And I've now acquired enough that my Strategy 400 is fully tubed with them. And again sounds that much better than the Mesa 425s they replaced. But that's my only experience with the Sylvania's. Marshalls can be very sensitive to tube swaps with 34s. But other 34 based amps, not much if any difference between vintage Mullards or cheap JJs.

 

[CEG85]

I like an RFT in V1, 5751 in V2, Shugaung (older ones) in V3-V4, Sovtek LPS or new Mullard in V5. The Shuguangs should have the square getters (the orig SLO pre tube), the newer ones with round getters are brighter/harsher. The reduction in gain from the 5751 lets me run the gain higher which reduces the effect of the bright cap which for me is a good thing. There's a dude on TGP selling RFT pres for decent price, let me know if you need contact.

I haven't rolled that many power tube types. I have a set of discontinued Shuguangs (called Red Box, Lord Valve has them, not expensive) in there and every time I try a different tube those Shuguangs win.

+1

I'm using RFT ecc83 for v1 in a Marshall 1959 super lead
Nos Chinese 12ax7 v2 (square getter)
Sovtek 12ax7lps v3

I've tube rolled a lot in this amp and this seems to be the best combo I've come across.
Those old school 80's Chinese 12ax7's sound killer.

As far as power tubes go, I like JJ's and TAD/RUBY el34's.

 

[mikey]

Another vote for Sovtek 5881s. I've used TADs, Winged C etc. and wound up back with the 5881. I've tried some NOS types in the preamp with good results, but the Sovtek LP and LPS do work pretty well. I wasn't a fan of JJs in the preamp, kind of dull, lackluster response to my ears.

 

[Rick Lee]

Ok, I'm doing this job now and have some questions. I put in the wafer bottom Sovteks and am using a EuroTubes bias probe, the one that reads out the plate voltage on the lower display and dissipation on the upper one. I always get over 500V plate. I biased it last night to 34.5mA after leaving it on for about 30 min. and playing through it pretty loud.

Today I fired it up and was getting 25.5mV after about a minute and am now getting 29.6mV after a good 10 min. Do I need to burn these tubes in with the amp on standby for a day? It's a matched quad from Antique Electronics.

Also, the EuroTubes table says 5881s are good for 23 watts. So if I divide the 23w by the 506 plate voltage, 70% of that is 31.8mV. If I go by the more common 25w, I get to 34.5mA, which sounded a little better to me when playing.

Where to go from here?

 

[mikey]

I bias my SLO around 50-55%. Mine was colder than that from the factory and still sounded great. I think of 70% as more of a maximum vs. a target setting. I do bias my Marshalls a little hotter but they're a different animal.

 

[Rick Lee]

But what's with these plate voltages? The chart on Antique Electronics's page says these tubes are rated at 500v. If I bias it colder, the plate voltage will go even higher than 506v, which is already high for these tubes. And do I go by 23, 23.5 or 25w per tube?

 

[SpiderWars]

But what's with these plate voltages? The chart on Antique Electronics's page says these tubes are rated at 500v. If I bias it colder, the plate voltage will go even higher than 506v, which is already high for these tubes. And do I go by 23, 23.5 or 25w per tube?

A couple of posts itt have said 28mA. I wouldn't worry about the voltage too much, that's one of the reasons to use that tube (because it's mostly worked over time).