Dumbleland Overdrive Special!!!

[Bombacaototal]

Since we are on Dumbleland topic, does anyone have any more intel on this specimen?

[Max]

Since we are on Dumbleland topic, does anyone have any more intel on this specimen?

Because of the 11-step filters (similar to the filters in the later SSS 150W amplifiers) I would suspect that this is one of the later Dumbleland Special 150W amps with serial numbers above about # 010. A rear view could perhaps clarify this, as at least some of these later Dumbleland Special 150W amps had different 4/8/16 ohm output transformers than the early ones with a serial number up to around # 010 (e.g. DL-150W #009). In this respect, a look at the output transformer from behind would perhaps be informative, even if the serial number of this Dumbleland Special could not be identified exactly.

... Since the Dumbleland 300 uses primarily an SVT output transformer and is 2/4 ohms is kind of a no brainer..it does however share the same AC driver as the 150W versions and does have Dumbleland on the chassis so good point! ...

Which amplifier do you mean by "it"? The Dumbleland 300SL or the Ampeg SVT or both? Here’s a schematic of the Ampeg SVT: https://ampeg.com/support/files/Schemat ... matics.pdf

[Bombacaototal]

Thanks Max, good observation on the step filters. The knobs looks fairly unfamiliar, and for some time I was even wondering if this is a genuine Dumble. Also the wording"step filters" versus just "filters". Unfortunately that's the only picture I have. Interesting to see the led on top of the pilot light, must be for one of the relays, like PAB

[Max]

It could of course be that these potentiometer knobs are no longer the original ones (as is the case with the DL-150W #009, for example). On the other hand, you can also see unusual potentiometer knobs on other Dumblelands (for example DL-150W #008).

"unfamiliar ... wording": The Dumbleland Special 150W # 008, for example, says "Tone Expander" below the two filter buttons and "High" and "Low" above, and (by the way) the DL-150W # 008 has very different dimensions than others Dumbleland Special amps.

[Bombacaototal]

It could of course be that these potentiometer knobs are no longer the original ones (as is the case with the DL-150W #009, for example). On the other hand, you can also see unusual potentiometer knobs on other Dumblelands (for example DL-150W #008).

"unfamiliar ... wording": The Dumbleland Special 150W # 008, for example, says "Tone Expander" below the two filter buttons and "High" and "Low" above, and (by the way) the DL-150W # 008 has very different dimensions than others Dumbleland Special amps.

That's true and we'll pointed out, thanks Max. Do you happen to have any good outside pictures of 008, besides that one that he is tilted with the Alligator?

[Max]

For example, the front of DL150W #008 is shown on page 90 of "A DUMBLE BOOK by Jesse Schwarz".

[talbany]

Which amplifier do you mean by "it"? The Dumbleland 300SL or the Ampeg SVT or both? Here’s a schematic of the Ampeg SVT: https://ampeg.com/support/files/Schemat ... matics.pdf

"it" being the Dumbleland Special 150W (4/8/16)

Both the Dumbleland Special and the Dumbleland 300 w/( BH7/12AU7) combo is AC coupled

Both the SVT and SSS are D.C coupled (SVT uses a BH7 and Dumble used a 7025) to drive the grids of the 6550's..

https://ampgarage.com/forum/viewtopic.p ... 26#p426026

Tony

[Max]

... the Dumbleland 300 w ... is AC coupled ...

Does anyone here know of any facts that would support the hypothesis that the Dumbleland 300SL is "AC coupled"?

[Bombacaototal]

... the Dumbleland 300 w ... is AC coupled ...

Does anyone here know of any facts that would support the hypothesis that the Dumbleland 300SL is "AC coupled"?

I personally think that the 300SL is DC coupled like SVT and SSS amps, evidenced by the two bias pots on the back. But no hard evidence other than that

[talbany]

... the Dumbleland 300 w ... is AC coupled ...

Does anyone here know of any facts that would support the hypothesis that the Dumbleland 300SL is "AC coupled"?

Max?..Here we go again
Is it possible it's DC coupled? sure! This is Dumble we are talking about here
If what I know about the driver is not accurate please let everyone here know?.."

"Fact" since you have actually been inside an "Ungooped" Dumbleland 300SL I would love to be proven wrong or is this some secret info your not willing to share here?

facts?

- In the ungooped DL 300SL I had a chance to look into, the dynamic balance control was on the PI board inside the amp and not at the back panel.

- If you find the time to look at the pictures on Bill Morgans (before:Yukihiro's) site, you will notice, that on both 300 SL's the hole for the "Balance" control is closed.

But I understand that, as ic-racer wrote, this project was ment by him just for the fun of discussing guesses anyway (btw: nothing wrong with such a kind of hobby IMHO)

But if "Dumble small talk" is the goal of this thread anyway, of course I understand, that my reminders, that to end up with a fine 300SL clone, some kind of precision would be of some advantage, have missed the whole point. No problem, sorry for my misinterpretation.

BTW: In regard of entertaining and amusing small talk topics, the question if Alexander is a "genius" or not, is for my own taste one of the most boring topics I can imagine. But of course: tastes are different.

Cheers and have fun

Max

https://ampgarage.com/forum/viewtopic.p ... 386#p79386

Tony

[Max]

... Is it possible it ... [Max: Dumbleland 300SL] ... 's DC coupled? sure! ...

Thanks for the clarification.