Christopher Cross' other Dumbleland 300SL

[Max]

the DL being a 12BH7/7025 combo and the SSS being (predominantly)7025/7025.

So perhaps I remember wrong. I always thought that Brandon posted:

DL 150W: 12AU7 > 12BH7

SSS 150W: EJ version 7025 > 7025 ..... SRV version: 12AU7 > 12BH7.

AFAIK the circuits would be very similar and are interchangeable with balance and re-bias so this should go under tube compliment correct?

So I misunderstood what you posted here concerning the PI >driver circuit of an Odyssey? I ask, because I always thought that in your opinion the 12AU7 > 12BH7 circuit of an Odyssey 100W has a different structure (and not only different tubes) than the 7025 > 7025 circuit of a SSS 100W?

And from this (misunderstanding?) I always concluded (up to now) that in your opinion the structure of the 12AU7 > 12BH7 circuit of a DL 150W is different from the structure of the 7025 > 7025 circuit of some 150W SSSs, too.

And based on this (misunderstanding?) I concluded that in your opinion the structure of the 1 x 12AU7 > 2 x 12BH7 circuit of this DL 300SL is different from the structure of the 7025 > 7025 circuit of some 150W SSS.

So if your opinion is, that the structures of all the PI > driver circuits in all these Dumble amps (SSS 100W, Odyssey 100W, DL 150W, SSS 150W, DL 300SL) are identical and only the tubes used in these identical structures are - for whatever reasons - different, than I simply misunderstood what you posted concerning all this up to now. If so - I'm sorry for any confusion that my misunderstanding might have evoked.

BTW: IMO the OT of this SRV SSS 150W posted here looks rather similar to the OTs of DL #009 and of the DL 150W of Jackson Browne - now probably owned by John Mayer (you'll find pictures of these DLs posted in some other threads here). And based on its output-impedance switch, this SRV-SSS 150W has at least a different OT (4, 8, and 16 ohms switchable) than the SSS 150W described in the SSS 150W data sheet posted here ("4 and 8 ohms switchable").

... details - details - details ...

Cheers,

Max

[Aaron]

I remember reading somewhere that the Dumbleland was the "guitar" version of the Winterland. So if that might be a possibility, then there is another version of the 12AU7-12BH7 PI- Driver. Dumble is quoted saying that SRV's amp is more of a bass amp voiced for guitar.

Aaron

[talbany]

So I misunderstood what you posted here concerning the PI >driver circuit of an Odyssey? I ask, because I always thought that in your opinion the 12AU7 > 12BH7 circuit of an Odyssey 100W has a different structure (and not only different tubes) than the 7025 > 7025 circuit of a SSS 100W?

I cannot tell you all the details right now as much of that info is on another computer and not with me right now but I'll try and do the best with what I remember.
Again if I remember the Odyssey was AC (Capacitor) coupled and do not think it was running in true class AB2 (sinking grid current) and yes is a different method of driving the output section..I think the Winterland used something closer to a Williamson type driver..Again not true Class AB2..I was referring to DC coupled only..SVT style

And from this (misunderstanding?) I always concluded (up to now) that in your opinion the structure of the 12AU7 > 12BH7 circuit of a DL 150W is different from the structure of the 7025 > 7025 circuit of some 150W SSSs, too.

Once again all SSS's I have seen so far were DC coupled and running in class AB2 ala SVT

And based on this (misunderstanding?) I concluded that in your opinion the structure of the 1 x 12AU7 > 2 x 12BH7 circuit of this DL 300SL is different from the structure of the 7025 > 7025 circuit of some 150W SSS.

I don't know?..Is this DL AC coupled or DC coupled?
Could it be that the 12AU is the PI and the 2x12BH7's are run in parallel for added current like Jelle mentions here

I see two tall tube sockets: if I were to venture a guess, I would say that these are two parallel 12BH7 cathode follower drivers to maintain sufficient current supply into those 6550s.

So if your opinion is, that the structures of all the PI > driver circuits in all these Dumble amps (SSS 100W, Odyssey 100W, DL 150W, SSS 150W, DL 300SL) are identical and only the tubes used in these identical structures are - for whatever reasons - different, than I simply misunderstood what you posted concerning all this up to now. If so - I'm sorry for any confusion that my misunderstanding might have evoked.

That's correct!!.. 12bh7/7025/12Au7 in any combination (generally Dumble uses BH7 for the driver/ 12au/7025 for PI) can be run in either AC or DC coupled circuits..
However I was reffering to just class AB2 DC coupled (like used in the SSS)..Any one of these tubes can be used in any combination in the same DC coupled circuit (like 002)and only require a re-bias and balance...They will however feel and sound different due to gain factors Mu and current capability

So the magic question is..Drum roll....................Is this DL AC coupled or DC coupled!!!!

BTW..According to Bruce who was in SRV's SSS he says SVT output section

I see you guys discuss the 150 watt Steel String Singer a lot. I once worked on Stevie Ray's live gear and he had a 300 watt SSS with six 6550 power tubes. Can't say it was sort of like and SVT because it was an SVT power amp. The head contained an Ampeg SVT power amp chassis with the Dumble Fender style preamp. Basically a 300 watt Twin? Not sure if this amp was something weird but I have never seen another like it.

This tells me his was running AB2..
Sorry it's late and this is as detailed as it get's right now..

All The Best!

Tony

[Max]

I remember reading somewhere that the Dumbleland was the "guitar" version of the Winterland.

AFAIK Alexander Dumble offered - at least for some time - a version of the Dumbleland 150W for guitar and a version of the Dumbleland 150W for bass. AFAIK both use the same kind of tubes for their PI-stage and their driver-stage

AFAIK the "Winterland" discussed in this forum is the forerunner of the Dumbleland version for bass.

AFAIU what talbany posted here concerning this "Winterland", Alexander Dumble used the same OT in this Winterland as you'll find in both versions of the Dumbleland 150W, but in both versions of the Dumbleland 150W he used the UL-connections of this OT in a different way than in the Winterland discussed here.

So if that might be a possibility, then there is another version of the 12AU7-12BH7 PI- Driver.

Up to now I've never heard or read the opinion of an experienced tech, that you'll find different versions of the 12AU7 > 12BH7 circuit in different versions of the Dumbleland 150W.

But up to now I thought (probably based on some misunderstanding?), that talbany thinks that all the 12AU7 > 12BH7 circuits you'll find in all the 100W and 150W Dumble amps with this PI > driver tube complement (12AU7 > 12BH7), have a different kind of stucture, than all the 7025 > 7025 circuits in all the 100W and 150W SSSs with this kind PI > driver tube complement (7025 > 7025).

But perhaps someone here building and/or offering for sale different versions of SSS 150W "replicas" or "clones" (or however one likes to call them), can shed some light on this topic by simply explaining the differences between these versions and the reasons for these differences in detail? Then perhaps my "cryptic non-tech-descriptions" of Dumble specs may become dispensable - even if this should spoil some amusement. I've some personal interests I like better than clowning for Jelle's amusement.

Cheers,

Max

[talbany]

Max
would it be that Dumble preferred the current handling capabilities of the BH7 to drive the grids of the larger 6550's 150w/300w (DC coupled) amps,and perhaps the 7025/12AX enough to drive the 6L's in the SSS's that utilized that tube..

This makes some sense for me .. Does it for you?
BTW..MY SSS has 4KT-88 valves (150w) and I use a 12AX7 and a 12AT7 for the driver and works like a charm!!..I do not care for the BH7..feels more like a Bass amp than a guitar amp to me!...Stiff

Tony

[Max]

Max
It would seem to me that Dumble preferred the current handling capabilities of the BH7 to drive the grids of the larger 6550's 150w/300w (DC coupled) amps,and perhaps the 7025/12AX enough to drive the 6L's in the SSS's that utilized that tube. This makes some sense for me .. Does it for you?

The 12AU7 > 12BH7 in an Odyssey 100W are driving 4 x 6L6, too.

And the 7025 > 7025 in e. g. some SSS 150W and in the ODS 150W, and in the EF86 Dumbleland 150W all are driving 4 x 6550A, too.

So I don't know if your argumentation is consistent from an engineering point of view.

Cheers,

Max

[talbany]

Max
It would seem to me that Dumble preferred the current handling capabilities of the BH7 to drive the grids of the larger 6550's 150w/300w (DC coupled) amps,and perhaps the 7025/12AX enough to drive the 6L's in the SSS's that utilized that tube. This makes some sense for me .. Does it for you?

The 12AU7 > 12BH7 in an Odyssey 100W are driving 4 x 6L6, too.

And the 7025 > 7025 in some SSS 150W and in the ODS 150W, and in the EF86 Dumbleland 150W all are driving 4 x 6550A, too.

So I don't know if your argumentation is consistent from an engineering point of view.

Cheers,



Max

I am not making an argument here..I like you am trying to figure out why Dumble preferred the 12BH>12au in some amps and 7025>7025 in others..
Clearly they both work (engineering stand point)..Could be personal preference from his customer..Some people like 12AT for PI others 12x7..Same sort of thing here.. This IMO would have to be something you would need to ask Dumble..

Again the PI/Driver in the Odyssey is a DIFFERENT design/circuit!! Not like the SVT type found in the SSS's
Again..Do you know if this DL amp is AC coupled (like Odyssey) or DC coupled like an SSS/SVT
Thanks!!
Tony

[Max]

Again the PI/Driver in the Odyssey is a DIFFERENT design/circuit!! Not like the SVT type found in the SSS's

AFAIR the schematics posted here up to now we only know, that the PI/Driver in the Odyssey is different from the PI/Driver of some SSS's 100W.

Do you know if this DL amp is AC coupled (like Odyssey) or DC coupled like an SSS/SVT

To avoid misunderstandings:

I'm no tech. So IMO it would be inappropriate to claim, that I know this. This said:

I'm rather sure, that the 12AU7 > 12BH7 circuit (and not only the tubes used) in the Dumbleland 150W amps is different in a general way (and not only in regard to some values of some resitors or capacitors) from the PI > driver circuit (and not only the tubes used) in all the Dumble amps (100W and 150W) with a 7025 > 7025 PI/driver.

And I am rather sure, that if there's a SSS 150W with a 12AU7 > 12BH7 circuit, this will the be the same kind of 12AU7 > 12BH7 circuit as the one used in the Dumbleland 150W amps.

But I'm not completely sure if this structural difference I wrote about is the one that you call AC coupled vs. DC coupled .

I don't know if the PI-driver circuit of this DL 300SL is what you call "AC coupled" or what you call "DC coupled".

Cheers,

Max

[talbany]

Awesome
Thanks Max!!

BTW..Here we talked a little about the differences in the output section of the Odyssey a while back!
https://tubeamparchive.com/viewtopic.ph ... ht=odyssey

Good Night
Tony

[Aaron]

Found another pic of SRV's blue light SSS.
If the 3 valves next to the 6550's are the P.I - Driver, notice the middle one is taller.

Aaron

[67plexi]

The only reason I'm interested in the serial number the SRV SSS Blue indicator light amp has two changes.
one the transformer set's are not Peavey Roadmaster both failed in #5/#7 SSS due to the underrated filament supply. And the Roadmaster did not have 4/8/16 OPT taps. Two the extra reverb driver 12AX7.
Max is 100% correct on the PI. PI-1 ( 12BH7A) and PI-2 (12AU7) utilized on SRV builds.
I'm just trying to understand the evolution of the 150 SSS amps. I'm aware that each SSS 150 is its own no two amps are the same. Dig the AC cooling fan.

Steve.

[Max]

And the Roadmaster did not have 4/8/16 OPT taps.

IMO the PT and OT in this 150W SRV SSS look very similar to the tranformers (OT with 4/8/16 OPT taps) used in some Dumbleland Special 150W amps I've seen in person or on pictures.

Cheers,

Max