Budda SD30 to Naylor SD60 preamp?

[sonofmickel]

Has anyone done this?
I am still a NOOB but it's all starting to make sense. I have a Budda SD30 that is nice but mello on the drive and smooth on the clean channel. Would like the more open sound of Fusionbears SD60. That amp sounds nice!

I have removed a leg of the Plate bypass cap on the Budda but the amp became "strident" way too much highs let through and still not the "punch" of the Naylor. Looks like there is a low pass filter into the second gain stage on the Budda I will remove a leg of that and see if it makes much difference.

[sonofmickel]

I gave up on the Budda-mod. Not worth it.
Instead I cobbled a "beaks-n-feet" Naylor SD60 preamp into my donor chassis. It is definitely a different flavor than the Budda, a little more open sounding and more grit. The Budda is what it is and that's a great thing, no need to change. I would, however, like to de-thicken the Naylor circuit just a little bit.
Would the .001uf/560k distort less lows if it were a 500p/470k?
Also I have some different Naylor schems, one has a 470p/560k after the second plate, that's a treble peaking circuit(yes?). Basically looks like a JCM800 again. I guess I'll have to get dirty and see what happens.

[jamme61]

I have the sd18 which I love. You could try changing the 220k plate resistors to 100k it will open up the sound make a little brighter . There's also a cap on v2? Trying to remember- that shunts higs to ground I think it's.002? Again not sure of value, half the value of that cap. For more highs. Jeff bobber told me about that one, great guy. Then the biggest thing with the budda is to use your guitar volume to work the amp, it works great. Hope this helps

[sonofmickel]

Thanks for the tips. I have since sold the Budda and changed my Naylor build into something based on the "Minimalist HRM" schematic floating around here.

[Darkbluemurder]

The Minimalist HRM is great. I have it in my rebuilt JMP 1959 SLP. Does everything from slight crunch to high gain with a twist of the gain knob.

Cheers Stephan

[Gaz]

Did either of you guys ever draw up a schematic of your EL84 SuperDrives? I always wondered what they did in the smaller versions. I have a schem that is mostly correct for the 80w version. Similar pre to the Naylor, but cathide biased quad of 6L6s and paraphrase PI, different loop, etc. Thanks!

[jamme61]

From memory and looking at a sd80 schematic I have- it looks like the same exact preamp.

[sonofmickel]

Yes, that is the schematic. As far as I remember, it matched everything my SD30.

[Gaz]

Thanks for the replies. I thought maybe they would have changed it a little. Do you remember by chance what the power tube voltages were, and bias?

[erigm]

Did either of you guys ever draw up a schematic of your EL84 SuperDrives? I always wondered what they did in the smaller versions. I have a schem that is mostly correct for the 80w version. Similar pre to the Naylor, but cathide biased quad of 6L6s and paraphrase PI, different loop, etc. Thanks!

Hi Gaz,

I drew that schematic of the Budda 80watt. Can you tell me what parts aren't correct? I don't have the amp in my possession anymore to compare, but I'd like to know if I made a mistake. Thanks.

Eric

[Gaz]

Oh, cool, nice work! I actually don't know myself. My statement was based off of what others have said about your schematic (which is the only one I've ever seen, btw!). I don't remember where I read it, but I think they inferred the errors were small. I think I also remember someone pointing out some drawing errors as well on EL34world...

[erigm]

That's cool. I was just curious. I wasn't really sure i got the switching circuit right … so that's mainly why I was wondering. They are nice amps though.

[Gaz]

This is the one thread I'm thinking of:

http://el34world.com/Forum/index.php?to ... #msg124356

And now that I think of it, I think I originally downloaded the schem when you posted it at SLOclone!

Thanks.

[erigm]

Thanks for the link Gaz. Regarding that thread:

Yeah, I'm not sure about those 10ohm bleed resistors in the power supply either … that value does seem low … but I was just trying to read off the components. The 1k/50watt series resistor is what was in there though.

It looks like they finally figured out the PI, so that's good.

The hard part was trying to trace the switching relay traces without having access to the bottom of the PCB. A lot of continuity testing went on there!

Eric

[TimmyP1955]

What did they change in the SD30II? I like that amp.