Questions/Build Log: Soldano SLO 100 Clone

[ViperDoc]

Just out of curiosity, what transformers do you all prefer for this type of build, then? Thanks.

[professormudd]

Just out of curiosity, what transformers do you all prefer for this type of build, then? Thanks.

When I was researching, I found a lot of people talking about the O'Netics being wonderful, albeit expensive. For me, aside from the mechanical hum, these transformers seem great electrically... Unfortunately the guy who sells them hasn't left me with the greatest confidence.

Other options I have read up on include Heyboer. I sent them an email asking if they can do an SLO Power transformer and I am awaiting a response. I will report back when they do.

[professormudd]

Your PT is vibrating mechanically--been there. Some PTs are born "unbalanced" and just want to hop around at 60Hz. You have two choices: tighten securely to the chassis (sometimes this makes it worse, because then the chassis serves as a sympathetic resonator and makes the noise louder), or isolate from the chassis with rubber grommets (may not be practical because the PT is too heavy). However, this mechanical vibration won't be audible at the speaker (you can actually try plugging in a speaker now, with NO tubes installed, and listen for hum). So hopefully when you button the chassis into the cabinet, the noise won't be bothersome.

I ended up replacing the 2-1/2" screws and lock nuts that were securing the end bells since I think one of the screws and/or nuts were stripped enough to prevent completely tightening. While I was at it, I put some neoprene washers under the flanges and tightened the transformer back down. This seemed to help quite a bit. The transformer is still audible, but not nearly as loud as it was.

[bepone]

maybe will pass

[ViperDoc]

Just out of curiosity, what transformers do you all prefer for this type of build, then? Thanks.

When I was researching, I found a lot of people talking about the O'Netics being wonderful, albeit expensive. For me, aside from the mechanical hum, these transformers seem great electrically... Unfortunately the guy who sells them hasn't left me with the greatest confidence.

Other options I have read up on include Heyboer. I sent them an email asking if they can do an SLO Power transformer and I am awaiting a response. I will report back when they do.

Thanks, Professor. Heyboer has never done me wrong. My only guff they tend not to send wire diagrams with them, albeit a minor inconvenience. They sure sound awesome.

[FourT6and2]

I used O'Netics in my SLO Clone and they were 100% quiet.

Just a thought... did you sand off the powder coating of the chassis at all the necessary places? All of the pot mounting holes, some of the switches, jacks, ground point connections, etc. It could be a grounding issue if you did not. Also, there are a few holes that must be isolated from chassis ground as well, using special insulated washers.

[professormudd]

Yes. I did. Everything is grounded properly where it needs to be and isolated where it needs to be.

[fred.violleau]

Hey guys, very interesting thread and I hope the remaining vibration is settling over time.

Quick question as I am planning my build (SLO 100watts) what caps would you use?
For the preamp, I read Vima MKT, Orange drops 6PS, Mallory (but almost impossible to find), sozo...
As for resistors, would you recommend vishay carbon film resistors or metal film?

Thanks for your opinions!

Fred.

[bepone]

first tube: dale metal film in anodes , grids, cathodes // bypassed with MKT
all other tubes : anodes MOX 2W or Dales, signal carbon film
PI grids MF, cathode MOX, all other CF
caps: 6PS

result /chassis and cabinet experimental :
https://www.youtube.com/watch?v=kyi_vo1MTOs

[Reeltarded]

Hey, that works pretty well! I like the range that it starts to take off in. I try to keep mine lower in the mids too. I want it to howl instead of squeel.

[TUBEDUDE]

Slipping 2mm sorbothane sheet under the mounting tabs helped quiet several xfmrs recently.

[LOUDthud]

Yes. I did. Everything is grounded properly where it needs to be and isolated where it needs to be.

That power supply board is an example of how NOT to layout a PCB. One of the wires to the main rectifier runs way too close to the mounting screw in the corner. You should use a Nylon screw and standoff there. The center tap snakes around before it gets to the main filter caps where is should go first. Then there are two caps in series with no equalizing resistors. It's a nightmare!

SLO_bad.GIF

[fred.violleau]

first tube: dale metal film in anodes , grids, cathodes // bypassed with MKT
all other tubes : anodes MOX 2W or Dales, signal carbon film
PI grids MF, cathode MOX, all other CF
caps: 6PS

result /chassis and cabinet experimental :
https://www.youtube.com/watch?v=kyi_vo1MTOs

Sounds Killer! Thanks Bepone!

Just to be clear MOX = metal oxyde and MKT = Vima, right?

Fred.

[angelodp]

I had this mechanical vibration in my Marshall Lead amp build. It was one cold solder in the power supply. It was imperceptibly subtle in terms of visual inspection. I reflowed and gone. Your build is at such a high level that perhaps this is not a possible issue, but it might be worth a check.

[bepone]

Sounds Killer! Thanks Bepone!

Just to be clear MOX = metal oxyde and MKT = Vima, right?

No problem,
Mkt was 1uF foil i think was ERO, and mox yes metal oxide.
I heard one slo clone with all the mox 2w everywhere and sound was creamy!
So i have put few in anodes for the effect and other how i liked (carbon film) and first tube all MF because is generating Signal/noise ratio ,
so must be noise free,