Dumbleland update (was SSS) :D

[jelle]

Hi,

Is that V1a/b or the buffer stage for the pi??

Just like the cathode direct coupled stage for the "200w bass amp" ?


It would be a great tube for that application because it is designed as a high symmetry driver and delivers a lot of gain. 70% compared to a 12ax7.

Interesting stuff. I love this subject!

Jelle

[glasman]

Interesting stuff. I love this subject!
Jelle

Totally OT, Jelle what part of the Netherlands are you located. I will be in Eindhoven on business for 2 weeks at the end of the month. Always fun to chat with tubeheads.

Tot Ziens,

Gary

[jelle]

Hi Gary,

What is totally OT???

You're welcome! Shoot me an email: jwelagen at hotmail.com

I live in Nijmegen. That's about one hours drive from Eindhoven.
Sure is nice to talk to tubeheads.

Hoe goed spreek je nederlands?
Tot ziens in Nederland,
Jelle

[glasman]

Hi Gary,

What is totally OT???

You're welcome! Shoot me an email: jwelagen at hotmail.com

I live in Nijmegen. That's about one hours drive from Eindhoven.
Sure is nice to talk to tubeheads.

Hoe goed spreek je nederlands?
Tot ziens in Nederland,
Jelle

OT = Off Topic

I have been to Nijmegen at few times at the Philips facilities (I work for ASML in Veldhoven).

As far as my Dutch, I understand more than I can speak. I will drop you a note when I get in the Netherlands.

Gary

[jelle]

Hi guys,
I just tried the EF86 preamp and I like it!
It's very hifí-ish, clean and definately SRV- territory. Think 'little wing' and the album 'Couldn't stand the weather' in the 'jazz' mode.
I found out that the NFB is a must to keep the noise down, unlike the ODS. Also I was lucky to have three EF86 tube because one was extremely noisy. I run the signal from the second EF86 through a .047uF into the pi via a standard 1M master pot. AB763 solid state rectified into 15'' JBL K-series.

This is a not sound everybody will enjoy playing! Like playing through a magnifying glass, if that makes sense....
I've always wanted to hear the guitar like it sounds unamplified. This is it!
Electronavalanche: thanks so much for sharing this information. This is exactly why I bought a soldering iron: SSS-sound!

What's the latest news on the direct coulped phase inverter? Is it working and are there schematics available?


Jelle
The Netherlands

[ElectronAvalanche]

Hi Jelle,

thanks for the report.

The SSS PI and post PI CF parts are as follows:

PI: 120k anode resistors

1M grid resistors
820 Ohm cathode, 24k tail resistor

Feedback Loop resistor 100 Ohm , 2k2 on Presence Pot to ground

Post PI CF:
150k CF grid resistors
100k (2W) cathode resistors

Think of the SVT 12BH7: coupling to Bias is with 330k , 30k

Here is a pic attached to make more sense....

I nearly finished that SSS amp, after looking for hours at the photocopied pics I had of the amp, endless planning and stuff, but the amp is lost forever I am afraid....

Electron

[oldmacman]

I've been wondering about the layout of the preamp ever since I saw the mini-pic at http://blueguitar.org/new/pix/sss12ax7.jpg

Can you put up a drawing or photo of how that works, with the tube sockets mounted in the middle of the eyelet board?

Thanks for all the info!

[jay]

I have worked on this amp and it is not an s.s.s. It is more like a dumbleland.
Jay

[jelle]

Hi,


Can you explain the differences between the sss and the dumbleland?
Are there ef86's in a sss?

Electronavalanche:
Thanks for the info!
I can't find the attached picture in your message...
I'm very interested in some sound clips. Great work, very neat looking.
I'm also planning to build a sss. Did you use the reverb section from the ODS reverb schem?

oldmacman wrote;
Posted: Mon Mar 06, 2006 10:41 pm Post subject:

--------------------------------------------------------------------------------

I've been wondering about the layout of the preamp ever since I saw the mini-pic at http://blueguitar.org/new/pix/sss12ax7.jpg

Can you put up a drawing or photo of how that works, with the tube sockets mounted in the middle of the eyelet board?

Thanks for all the info!


I'll try to figure that one out this weekend. So this is a 12ax7 sss, right?
Is the tube socket physically connected to the eyeletboard or is it underneath it? space saving measure? If only somebody would post some hi-res pictures of a sss....
How many tubes are there in a sss?

FWIW, with the enormous amount of gain of the ef86 I was very carefull with the lead dress! A couple of months ago I reworked the lead dress of a couple of homebrew amps which I thought I'd done well but there was a big difference after the lead dress was redone! Nowadays I design the schematic, then the layout on paper(!) and start soldering when I'm happy with it. Works for me.


Jelle

[mlp-mx6]

Please explain how you "improve" lead dress. What are you looking for? What constitutes "good" lead dress? "Bad" lead dress?

[oldmacman]

Here's Ayan's article on the subject:

http://home.earthlink.net/~ayan/leaddress.htm

[jay]

I have had 4 s.s.s. in my shop ,they all used feedback in each preamp stage and they had e.q. switchs. The early ones used cathode feedback and the later ones used feed back like the ods.

[ElectronAvalanche]

@Jay,

which amp are you referring to? Dumblelands usually have more than 4 Output tubes.

The small pic of the 12AX7 shows a SSS as well, me thinks. I think I have seen the complete pic and the amp says Steel String Singer on the front.

The silver alligator SSS with the EF86 is a SSS as well.

@Jelle

the tube sockets are mounted on the chassis. Short wires run from the board to the socket underneath. I really do not know why Dumble choose to do it like this. It is a pain to service and to build. Maybe short leads?

As far as I know the Reverb from Dumbles ODS Reverb amps is identical to the SSS Reverb. But who am I to know!

Electron

[jay]

I have pictures of the amp and know the history, Dumble was so unhappy with that amp he gave it away and than it was traded for a overseas ods
I saw it again when it came back .The letters on the amp are stickon and
and it is not a s.s.s

[Funkalicousgroove]

Nevermind, got it