Dumble tube choices

[passfan]

Hey guys, what are you using and what do you lilke. Trying to get an idea what to get for my first build. I've got telefunkens and mullards for the preamp but I'm at a loss as to output tubes. Thanks

[David Root]

Dumble liked NOS Sylvania 6L6GC at one time. I tried an NOS quad in my #124 ODS and did NOT like them in that amp. Compared to the short tube RCA blackplate, they are thin, cold, lacking in low end and thoroughly unengaging.

To be fair, in a stage situation cranked up, (this is a 100W amp), they would cut thru the mix I'm sure, including a neanderthal drummer.

I have built four D-circuits, the #124, a second generation #13/#40 hybrid, a Bluesmaster and a #183 and I like the RCA blackplate 6L6GC in the 124 and especially in the 2nd gen., which is only 50W, Xf4 Mullard EL34 in the 183, and vintage '50s Sylvania 6L6GA in the Bluesmaster, which is a 4-power tube version about 60-70W or so. I tried NOS Tung-Sol 5881s in the Bluesmaster and although the clean tone was good I didn't care for the OD tone.

No experience with current production except reissue Tungsolski 5881s, which are close in tone but wouldn't last as long as the original NOS. They don't cost $350 for a quad either though.

YMMV.

On the preamps, based on your stash, I would use a longplate Mullard in V1, a '60s shortplate ditto in V2, and either another longplate Mullard or a ribbed or smooth longplate 'Funkin in the PI. Amperex (the real ones, Heerlen Holland factory) are also nice in Dumbles, I settled on those in the 2nd gen. amp.

[Max]

These are the tubes fitted and (most) labelled (gold or silver) by Alexander Dumble that I remember to have seen in original Dumble amplifiers:

Preamp:
Mullard ECC83, GE 12AX7, GE 12T7, GE 12AU7, EI 7025 (80ies Telefunken clone), Amperex ECC83, Mullard EF86 (last version), GE12BH7, GE12AY7, GE 5751, Philips 7025, Sylvania 7025.

Power amp:
GE 6L6GC, Philips Sylvania 6l6GC STR, Sovtek 5881, GE 6550A, Chinese KT88 from the late eighties.

Cheers,

Max

[Structo]

In my 50w amp I had a pair of blackplate RCA 6l6GC that sounded wonderful.

As for new production I liked the Winged C best in that.

In my 100w ODS I have only tried new production and so far the TAD 6l6STR sound good and haven't drifted too bad.

The Tung Sol 6l6STR that I had sounded OK but they drifted quite a bit apart.

I think it was more where I bought them then the tubes themselves.
Some dealers burn in then match while others just match the tubes without burning them in, which contributes to drift later I believe.

I got the TAD's from Doug's Tubes, he burns his tubes in then matches them.

The Tung Sols were from The Tube Store and I don't think they burn the power tubes in and the ones I got drifted.

I'm biasing at 32ma which is only about 48%

[David Root]

Thanx for that long list, Max. One other I can think of is
ODS #183--GE 12AX7WA.

Tom, the latest Tonequest magazine has an interview with the guy in Germany that runs TAD. Very interesting stuff. Then they review his premium tubes very favorably including the short bottle 6L6GC-STR.

[Max]

ODS #183--GE 12AX7WA.

David, yes, these are what I named "GE 12AX7" in my list. In some of these ODS between #150 and #200 I met EI ECC83/7025 and Sovtek 5881 that had been fitted and labelled by Alexander Dumble.

Have a nice day!

Max

[passfan]

Are we talking about the GE "long plates" here. I also have some 12ay7's and some Brimar 12AT7's. Great stuff guys and has helped me immensely.

[CHIP]

The GE's are short plate.

[Max]

Are we talking about the GE "long plates" here.

Here are some pictures of the versions I did find in original Dumble amps fitted and (most) labelled by Alexander Dumble:

GE 12AX7 https://www.tubeworld.com/12ax7age70.jpg
GE 12AY7 http://cf.mp-cdn.net/64/de/25c3f902f7a8 ... d17f76.jpg
GE 12AT7 http://www.wellgainelectronics.com/imag ... RU1885.jpg
GE 5751 http://www.dougstubes.com/media/catalog ... an5751.jpg
Mullard ECC83 http://www.vintagehofner.co.uk/gallery/ ... ecc83.html
Amperex ECC83 http://www.tubemongerlib.com/gallery2/d ... olland.jpg
EI ECC 83 http://www.tubemongerlib.com/gallery2/d ... olland.jpg
EI ECC83 http://www.freewebs.com/antreas555/IAN-TELOS%20006.JPG
GE 12 BH7 http://www.freewebs.com/antreas555/IAN-TELOS%20006.JPG
GE 12AU7 http://www.freewebs.com/antreas555/IAN-TELOS%20006.JPG
Mullard EF 86 http://www.pamandandy.demon.co.uk/valve ... f86-03.jpg
Sylvania 7025 https://www.tubeworld.com/12ax7wajhs66.jpg
Philips 7025 http://cgi.ebay.com/ws/eBayISAPI.dll?VI ... 0282272382
GE 6l6GC http://www.tubemongerlib.com/gallery2/d ... +-+USA.jpg
Philips Sylvania 6L6 STR387 http://www.7-string.com/ebay/STR387.jpg
Sovtek 5881 http://www.tube-town.net/ttstore/images ... /759_0.jpg
GE 6550A http://cdn.head-fi.org/e/e6/e64e29fc_6550ge70.jpeg
Chinese KT88 http://www.jacmusic.com/KT88/KT88-Shuguang.jpe

Cheers,

Max

[talbany]

Max
If you and others here don't know..

Sylvania STR 387/415 w/double halo getters are basically the same tube as the 7581a (without the double micas spacers) Most of the 7581's were re-labled 6L6 and carried the STR designation) as in the case with most Mesa's of late 80's) and were a 35w tube (recalculate your bias) and sounded wonderful.. Sylvania also made a single halo type as well as there were several variations of that 6L6 tube type ...Amp manufactures loved these tubes..They were stout well made powerful and travel well..The RCA version was also a good sounding tube but the Sylvania's had a kind of deeper throaty quality about them for me..I also prefer those 7581's be run in quads not pairs..

If you build a second generation (low plate PI) 100w w/skyline stack run through a D-Lator and load it with a healthy quad of 7581 Sylvanias and RCA 7025's you will walk away saying HOLY SHIT.. Have a Nice Day!!

Tony

[passfan]

I have a pair of those STR 415's in a big bottled Rocket with octal preamp tubes and it's a "Holy Shit" amp as well. I'm looking at a quad right now for 250.00 and it's killing me not to buy them.

[Bombacaototal]

I was going through some old threads with a question in mind

I noticed that Alessandro seems to use 5881 (lower dissipation than 6L6 GC, 23Watts) power tubes on his AZZ http://alessandro-products.com/categori ... f-azz-amp/

Chad from Sinewaves seems to like the 7581 (higher dissipation than 6L6 GC, 35 Watts) on his SSS and Mayer amps, which from what I read is more glassy, has a quicker attack but may be a bit harsh/less smooth.

I can see that HAD used on #123 the 7581 but I am not sure this would be his choice for the clean amps?

I am currently using TAD 6L6WGC-STR Blackplate on my Cathode Follower SSS amp. Wondering what to expect by changing it to 7581 (Sylvania/Phillips) or 5881, tonewise (rather than headroom, which is more obvious)

[talbany]

I am currently using TAD 6L6WGC-STR Blackplate on my Cathode Follower SSS amp. Wondering what to expect by changing it to 7581 (Sylvania/Phillips) or 5881, tonewise (rather than headroom, which is more obvious)

Depends on the amp!
The 7581 is a flat clear sounding tube with the push in the upper mids (500 Hz) and a tighter more focused low- end (Works well in an amp with overdrive),which is why some consider them to be a bit sterile and stiff in some clean amps. In an SSS (w/Follower) I would stick with the TAD's for it's scooped mids and extended glassy top end being it's a clean only style amp
The newer 5881's are kind of all over the place depending on the brand?

(Fender's 7581/6L6- STR (Special Tube Request) were designed to operate inverted and in it's combo amps with an added coating on the plates for reduced microphonics and heat dissipation properties along with it's higher power output and added reliability)

BTW. The TAD 6L6WGC's don't really sound anything like the older Sylvania 7581's.

Tony

20200226_013135.jpg

[Bombacaototal]

I am currently using TAD 6L6WGC-STR Blackplate on my Cathode Follower SSS amp. Wondering what to expect by changing it to 7581 (Sylvania/Phillips) or 5881, tonewise (rather than headroom, which is more obvious)

Depends on the amp!
The 7581 is a flat clear sounding tube with the push in the upper mids (500 Hz) and a tighter more focused low- end (Works well in an amp with overdrive),which is why some consider them to be a bit sterile and stiff in some clean amps. In an SSS (w/Follower) I would stick with the TAD's for it's scooped mids and extended glassy top end being it's a clean only style amp
The newer 5881's are kind of all over the place depending on the brand?

(Fender's 7581/6L6- STR (Special Tube Request) were designed to operate inverted and in it's combo amps with an added coating on the plates for reduced microphonics and heat dissipation properties along with it's higher power output and added reliability)

BTW. The TAD 6L6WGC's don't really sound anything like the older Sylvania 7581's.

Tony
20200226_013135.jpg

Great report Tony! I appreciate it. I really like those TAD, would love to buy some old 7581 and 5881 for comparison but cannot justify the cost now. I feel less tempted after your help

[talbany]

I am currently using TAD 6L6WGC-STR Blackplate on my Cathode Follower SSS amp. Wondering what to expect by changing it to 7581 (Sylvania/Phillips) or 5881, tonewise (rather than headroom, which is more obvious)

Depends on the amp!
The 7581 is a flat clear sounding tube with the push in the upper mids (500 Hz) and a tighter more focused low- end (Works well in an amp with overdrive),which is why some consider them to be a bit sterile and stiff in some clean amps. In an SSS (w/Follower) I would stick with the TAD's for it's scooped mids and extended glassy top end being it's a clean only style amp
The newer 5881's are kind of all over the place depending on the brand?

(Fender's 7581/6L6- STR (Special Tube Request) were designed to operate inverted and in it's combo amps with an added coating on the plates for reduced microphonics and heat dissipation properties along with it's higher power output and added reliability)

BTW. The TAD 6L6WGC's don't really sound anything like the older Sylvania 7581's.

Tony
20200226_013135.jpg

Great report Tony! I appreciate it. I really like those TAD, would love to buy some old 7581 and 5881 for comparison but cannot justify the cost now. I feel less tempted after your help

Honestly and IMO swapping tubes in and out of my SSS and to some extent tube types are just not as critical in an amp running AB2 a totally clean amp with a high powered output section.. I've gone through 6L's / KT-88's/KT-100/ 6550 /7581's/ and really didn't notice that big of a difference vs one running AB-1 where I am more prone to getting some output tube distortion out of a LTP PI. If you add on to that the wide tonal variations you get with the Hi-LO filter array along with the extended frequency response from the CF the biggest impact I noticed was going from say the 6L's to the KT'88's or the 6550's was in the low end response due to the larger plates.. I guess my point here is unless your SRV and doing arenas' or your avg gig volume the variation tube to tube is rather small and what variation there is you can pretty much dial in the filters or put it in the subjective category and does not warrant spending a ton of money on a quad of NOS output tubes in an output section designed to not breakup Save those for the ODS's

It's more like choosing a tube for your Bass amp.

Several years back Mojo ran a sale on some Chinese KT-100's like 20 bucks a piece they have been in the amp still sounds big and clean 4 years later

Tony