Silvertone 1484 Simplified schematic drawing attempts (block by block)

Hi,

A while back I bought a bunch of parts to start building a 1484 but I hit a wall probably due to my circuit design skills being pretty poor. I can build pretty well by my design skills certainly need to be honed in on. Moderators feel free to delete the old thread since all I really found out through it was about some lower profile tubes and transformers than the ones that I was using. There also appears to be an LDR of some kind which I prefer not to use. I realized I really just want to try to figure out how to make a simplified version of the 1484 without the reverb and without the tremolo. I could always add those things later. PRR schooled me a while back on my terrible attempt at redesigning the circuit. This attempt is probably just as bad but I don't like getting beat. In fact, I kind of love pulling off what people tell me I can't.

I think I'm best starting off with making a one channel pre amp section without the stacked linked pots for bass treble and vol control. I don't ever plan on plugging two instruments in at one time so why not save on parts by attempting to simplify. Now, I'm not sure how much stuff I can actually pull out of this circuit but it seems like there is so much stuff that I don't want. I'm really just after the sound of the 1484 at near max volume with the bass and treble knobs cranked. I'm not after it's IMO bad tremolo or reverb sound.

Anyway enough of my jargon. I think you guys get my point. I want to take this block by block, starting with the preamp, moving on to the interstage section, and ending with the power output.

Here is my attempt at the pre-amp section. I would really really appreciate it if someone felt kind enough to point out my mistakes and to help me figure out how to make this work.

Thanks regardless,

I think that is basically OK as far as it goes. It's pretty much a straight copy. You will need an output stage of some sort.

My only concern is that you are looking for the sound of the original so there is an assumption that it is created in these two stages. That may or may not be true. However, it is true that distortion in tubes is generally proportional to signal level and the signal level in the first two stages will be quite modest plus the first stage has some NFB around it which will also reduce distortion. Bottom line is the first two stages are unlikely to be responsible for the sound you are after. It is more likely to be created in the power stages of the amp you are basing this on.

The only way to find out is to build one and listen to it.

Cheers

Ian

Ian's advice is particularly relevant to this Silvertone amp.  They were built with infamously small output transformers which certainly influenced the sound.  Some also claim that the cheap masonite (or whatever) cabinets their speakers used was a big part of it!

I would also suggest looking at the physical construction of the circuit. Point to point on tag strips riveted to thin steel chassis with wood end brackets will sound different than eyelet board in a stouter chassis.

I am confused.I thought you were building a simplified pre amp as per the topic title. Why are you now including the power output stages?

Cheers

Ian

EDIT*

I revised the thread title and I deleted a few posts. I'm trying to keep this thread organized.

buildafriend said:

Would it be better to make a new thread for my last drawing? Or should move this all into one thread?

Thanks,

Click to expand...

Pass. Start by telling us just what you are trying to achieve and then we can advise you.

Cheers

Ian

ruffrecords said:

Start by telling us just what you are trying to achieve and then we can advise you.

Cheers

Ian

Click to expand...

I believe he stated in the first post that he wants to build the 1484 amp minus the reverb and tremolo.  Why he is re-drawing everything in pieces is beyond me.

I tried drawing it all at one time. I'm starting to wonder how much I can actually simplify it. The power supply is so weird.

> The power supply is so weird.

They had only low-voltage diodes, and a great price on lower-voltage caps.

Don't do it that way.

PRR said:

> The power supply is so weird.

They had only low-voltage diodes, and a great price on lower-voltage caps.

Don't do it that way.

Click to expand...

Hm, from a mass production standpoint that makes sense.

Thanks for looking PRR. Can I trouble you by asking how you would go about  this build if you were me?

I would really like to simplify it.. I want the sound without all the extra stuff. I understand the masonite and strange power supply are most likely a big part of the sound so i'll be sure to sure to keep those in the build but I'm not after reverb, tremolo, or a second input section. That requires so much more money, and takes more time for stuff that I don't want. The power supply seems so engineered for the overall design. It makes me wonder if I am actually forced to build it exactly as the original schematic has it +/- some more minor changes. 

Would the circuit work the way I have it drawn above? I'm assuming not, but I can't help but wonder how far off it is.

1482 is a simpler amp that a lot of people still dig today,

http://silvertoneworld.net/schematics/silvertone_1482.pdf

from

http://silvertoneworld.net/amps.html

it's the one with the weird speaker cutout and the vertical control panel,

Power unit for Fender 5F6a Bassman will do the job.  Bit over 400V DC, ample 6VAC. Trim the bias to Silvertone specs (probably anything that works).

PRR said:

Power unit for Fender 5F6a Bassman will do the job.  Bit over 400V DC, ample 6VAC. Trim the bias to Silvertone specs (probably anything that works).

Click to expand...

http://www.thevintagesound.com/ffg/schem/bassman_5f6-a_schem.gif

Hm.. interesting how it seems like it could totally work. The push pull section voltages look relatively usable, its practically the same output. I would just need to tap off of the right spots and add or subtract a few resistors. This seems like a great suggestion and it's making me think about selling the silvertone power transformer and buying a bassman one. I also kind of like the idea of this frankenstein design. I'll let my gears turn on this idea for a bit.

thanks guys  ;D

funky music  thru the 1482>

https://www.youtube.com/watch?v=cpZuO3KiYpw

PRR said:

Power unit for Fender 5F6a Bassman will do the job.  Bit over 400V DC, ample 6VAC. Trim the bias to Silvertone specs (probably anything that works).

Click to expand...

Okay so smush this into this?



Should I just plug it all together and see what happens?

I would math it out but I have an irrational fear of ohms law.

CJ said:

funky music  thru the 1482>

https://www.youtube.com/watch?v=cpZuO3KiYpw

Click to expand...

I've now had this song stuck in my head for 2 days.