MHartman SSS layout questions

[samsarod]

Hi,

I’m wanting to build a Steel String Singer clone, and will be using user MHartman’s layout, which I have attached I’m not sure if MHartman scans AmpGarage much, so I thought I’d post a few questions to the community here.

In addition to the MHartman layout, I also found the following pdf files on AmpGarage: “mhartman_sss_preamp_v11_482.pdf”, and “mhartman_sss_poweramp_v11_906.pdf”. They are apparently written by an “L.Victor”, and they contain a couple, just a couple, differences with the layout itself. There are also a couple of other handrawn schematics that say “MHartman” on them, but they have many differences to his layout.

With that stated, has anyone successfully built an SSS using MHartman’s layout?

Are all the pre-amp tubes in MHartman’s layout 12AX7’s, including the cathode driver tube (some models have a 12BH7 there)? I believe the output tubes are 6L6's as opposed to 6550's?

I haven’t found a post that explicitly states the pre-amp tube types for the layout, and the layout itself doesn’t state it either. This appears to be a layout of SSS #002?

Is there anybody making an SSS chassis (6 nine-pin, 4 octal tube holes) for hobbyists? I can live without that if need be. I have an old Dual Showman Reverb chassis and twin reverb power transformer. Just thought I’d ask.

Any help would be appreciated.

Thanks,
Sam

[larsvictor]

Sam,

you can see and hear this amp on youtube.

https://www.youtube.com/watch?v=9-PctgbrjSg

Please feel free and write me a PM if you find any mismatches in the schematics.

Regards
Lars

[Synchu]

Yep. On the layout the reverb driver tube cathode connection to the board is missing and 4.7M resistor should be wired to the 10k resistor...
Schematics should have taken care of this.
Niki

[larsvictor]

Hi Niki,

Thanks. Good catch with the missing cathode wire in the layout.
I see a connection between the 10k and 4M7 resistor in MHartmans layout. Its the green jumper from pin 2 to 7 on the driver tube socket.

Lars

[mhartman]

Hi guys,

Thanks for the interest in this amp. I have attached a revised version of the layout (thanks for the feedback on this) and in pdf version so everything is crystal clear at 100% zoom.

For a bit of background, I built a couple of years ago when there wasn't much SSS info available. I originally built it with a standard Dumble Phase Inverter and then, after I had the amp running without issue (or so I thought), I rebuilt the PI into the SSS version seen here with the post-phase inverter driver. It took a bunch of experimenting to get it right (mostly due to some lacquer that flaked off of the PT and kept arching on me and turned out to be a red herring). Once I got the bias right and the post-phase inverter tube working right, I was psyched -- it sounded really glorious. I kept the amp and tweaked on it for six months or so and then sold it off to a musician named Ryan Jarvis, who gigs and records around LA. As far as I know, he is still enjoying it. I've built 3 SSS inspired amps now (including this one), each with a different design based on different Dumble SSS amps -- two 100w amps and one 150w -- I much prefer the 100w amps because they still have a little give to them and they are easier to lug around.

I hope that the updated layout helps!

Mike

BTW, the tubes are 12AX7 everywhere except V3, which is designed for a 12AT7 (or equivalent). That being said, you can do 12AX7 all the way across if you want a bit more reverb.

[dorrisant]

Thank you for the improved drawing Mike! Sourcing parts for this one now.

Sam, welcome to TAG.

[mhartman]

No problem. Enjoy your build!!

[norburybrook]

oh dear, I think this might be my next build...........................


Damn....I thought the Kemper would stop all this....


Can I ask where you get the filter switches, chassis and what's the reverb transformer ? (I presume a standard fender twin one)

oh and is there a schematic?



Marcus

[dorrisant]

Filter switches can be had here in the US at Mouser...

http://www.mouser.com/Search/ProductDet ... R2511F-17S

I don't know about what to do across the pond. Maybe the link above will help a bit though.

Schematics that are referenced above are here:

http://ampgarage.com/forum/viewtopic.ph ... c&start=90

*Edited to put the schematics in question on this post.

[norburybrook]

thanks Dorrisant

mouser deliver to the UK via a European outlet, I use them a lot.


What about chassis? I presume it's a lot longer than the standard ODS


cheers

marcus

[dorrisant]

I am going to use one of these... Going to have to punch some more holes and reconfigure the layout a bit... but that just makes it more fun to me.

https://www.cedist.com/products/chassis ... -amplifier

[Synchu]

Hi Niki,

Thanks. Good catch with the missing cathode wire in the layout.
I see a connection between the 10k and 4M7 resistor in MHartmans layout. Its the green jumper from pin 2 to 7 on the driver tube socket.

Lars

Might be, will check what I did, layout and the schematics.
Niki

[mhartman]

thanks Dorrisant

mouser deliver to the UK via a European outlet, I use them a lot.


What about chassis? I presume it's a lot longer than the standard ODS


cheers

marcus

The chassis I used was 22.25". With that size, the can end up at 24", which is just about perfect in my opinion.

Mike

[samsarod]

Thanks to everybody ....especially Mike (MHartman)! Sorry if I pestered you a bit about it. I have just received my X-Mas gift of knowledge from you all!

I'll probably stick with the Dual-Showman Reverb chassis that I have. For now, the cab will be a semi-closed back 1X12" with an EVM-12L.

Woot!!

-Sam

[dorrisant]

Right on Sam. Are you gonna post some pics and info on your bid? It's kinda the thing to do around here.