Questions/Build Log: Soldano SLO 100 Clone

[professormudd]

Greetings all...

I have been slowly but surely accumulating the necessary parts to build out a Soldano SLO 100 clone and I have finally decided to get started.

Back in February I ordered a chassis from Russia right before the conflict started. I was worried it would never arrive, but it managed to land at my door a month or so later. I had also acquired a PCB set from C3 via ebay as well. I sat on this board/chassis set for a while before I decided to pull the trigger on ordering more parts.

They were expensive, but I went ahead and ordered a set of Onetics transformers from C3 as well. It took about 3 weeks to receive them since Mr. Reeder had some things going on that prevented him from getting them out sooner.

While I waited for the transformers I went ahead and scoured Mouser and Amplified Parts for the rest of the components needed. I carefully built out my shopping carts for a bit over a week before I pulled the trigger on placing my orders. Despite my best efforts to get everything in one shot, I still ended up needing to order a single pot and pay shipping that cost more than the part itself.

I believe I am all set for now and have started my assembly. I will be taking this pretty slow because I am not in a hurry and I want to get it right. I decided to go ahead and put the power supply board together first. I also decided to forego the use of turrets for the various outboard connections from the power and preamp boards.

I need to drill for the transformers since the chassis did not come pre-drilled for them. I plan to orient them as pictured unless anyone foresees any problems with that. I am basing this off of photos I have seen of other SLOs.

In all of the previous build I have done, the OT and PT are oriented perpendicular so as to avoid induced hum. Is that only a problem if the end bells face each other?

[mhuss]

I think the orientation is more important when they're right next to each other (a la Marshall). At opposite ends of the chassis, I don't think you have to worry about it too much.

[professormudd]

Thanks for the input.

[bal704]

If the placement of the xformers is in doubt, you might try the headphone trick to see if there is any induced hum.

[professormudd]

I went ahead and followed the advice of doing a headphone test... Well, I used a guitar speaker. Anyway, I did not find any problem with having the transformers in line. I also think it looks pretty nice. After I got the transformers mounted, I went ahead and wired the power tube filaments along with the bias test points. After that I decided to start populating the preamp board so as to reduce the amount of little mouser baggies I had taking up space.

I mostly went with Panasonic and Vishay capacitors for the preamp and Rubycon for the power supply. Resistors are nearly all Vishay/Dale with a few variances.

Next for me, I plan to finish wiring the preamp filaments followed by the ground buss for the potentiometers and connecting the output transformer to the rotary switch and the power tube sockets.

[bepone]

Pt is mounted in the worst possible way. Why is like that? It is shooting magnetic field directly in preamp tubes..

PXL_20221023_191414379.MP.jpg

[xtian]

No issue. The PT is close to the power tubes, but I've never found that a problem.

[professormudd]

C3 amp chassis come oriented in the same fashion: http://c3amps.com/index.html

As well, it looks like Soldano sold them oriented in the same fashion for at least a little while. Cursory searches on google show lots of clones and actual Soldanos oriented in this way, with end bells facing each other, and with 90 degree offsets.

[martin manning]

That is the way the originals were mounted. https://nevismusic.wordpress.com/2014/0 ... read-this/ Hiwatt also mounted the PT and OT on opposite ends of the chassis with the coil axes parallel to each other, horizontal rather than vertical, though..

[bepone]

No issue. The PT is close to the power tubes, but I've never found that a problem.

maybe correct, but still is wrong and IMO technically need to be addressed, in its roots. It is shooting in preamp tubes in high gain amp

[bepone]

10 yrs ago i had Soldano amp, maybe i have pictures somewhere, now i'm curios to see what he did inside

[professormudd]

Welp, I think I have complted the wiring portion of this build. As of this moment it is still Schrodinger's amp, though since I have yet to power it up. I will probably power it up in the morning. It is nowhere near as neat as other SLO builds I have seen, but for the time being I am pretty proud of how this build came together. I will be sure to post back after I have powered it up.

[roberto]

R U still alive?
To me it seems a nice built considering it’s your first SLO.
Please report your impressions and don’t rush on doing mods. SLO is a particular beast and needs time to explore all nuances it is capable of.

One of the best sound I’ve got from it is removing the bright switch on the OD gain pot, and use the gain at 2 to 3 . Warm, full, dynamic and very punchy.

[professormudd]

Finally got around to powering this amplifier up, no tubes installed. Man, this power transformer is pretty loud. In stand-by immediately after powering it up it holds a pretty steady hum. I can feel the transformer vibrating. Other amps I am used to an initial bit of PT hum when I power it on, but it will fade. This is not fading out. I left it on while I checked voltages and it stayed pretty steady. I tightened all of the screws on the PT, but that didn't seem to help as they were all pretty tight already. Any thoughts on how I might address this?

[Roe]

I think the orientation is more important when they're right next to each other (a la Marshall). At opposite ends of the chassis, I don't think you have to worry about it too much.

I've tested this with headphones a few times, and you can clearly hear the difference normally