12004 Build with some general guidance

[YMI5150?]

yeah, you can save a lot of $$ if you deviate just a bit from what everyone knows is good mojo. That cap was from a US supplier. also the bay.

Here's the final board shot. just need to groud the PI can and add power cord. will post initial voltage readings next week. no doubt some board values will change based on how it sounds/feels. FYI, the chassis isnt bent, its artifacts from iphone panarama

final board shot.jpg (98.36 KiB) Viewed 8743 times

[vanhalen5150]

That looks great Kevin!

[julkke]

Looks great! Kinda funny to put that NFB pot so far to the preamp but I guess it adds some mojo.

[neikeel]

These are handy but expensive:http://www.ebay.co.uk/itm/SET-OF-NOS-IS ... 121wt_1399

This is one of Al's listings:http://www.ebay.co.uk/itm/8-1-2W-1-3W-P ... 804wt_1399

[YMI5150?]

Well she's all wrapped up and ready to roll. A few things worth mentioning to summarize this thread.

Troubleshooting
There will always be some level of trouble shooting. this build went very well and i got lucky that there werent any witches to hunt down. The first was during initial power up and taking measurements, some pins were lacking. turns out the OT was no producing. The mind was going through the steps of everything possible. Daunting. Thank GOD I thought to check the fuse impedence first. OL. Swapped the fuse and wha la. Lesson - just be cause it looks good, doesnt mean it is.
During cap forming, VDC across the resistor wouldnt drop well. Ran this by a few of the inner circle. thanks for Valvestorm for helping identify the PI cap was struggling to form. Props to Robert for seeming to always be available and ready to help out.

Tone Shaping
This is the good part. I just spent 4+ hours non stop swapping parts to taste. Drove home the point that each of these beasts are unique and its a waste of time to try to copy someone else's recipe. DF knew this when he shared what he did. Also explains why one would hang onto a good one when he found one and never let go of it....

I wont get into details of what i ended up with but will say i threw a 2k pot in series with an 820r on v1b to shape things. that's a very powerful method and there's a lot of good there. I also completely removed the cap on v1a. things really fatten up and its something to experiment with.

This one will find its way to a new home in the near future but not before some clips from it. gotta get my recording rig going on this new machine.

[vanhalen5150]

Got a pic of how you added that pot?.

[YMI5150?]

No. I threw it in like to find a value I liked with this build. Then removed it. I soldered center wiper lug to v1b post, and an 820r to the input lug, leaving the others disconnected. 2k value swept the whole range of options.

As the value incrsases the low end frequency point that gets boost increases so if you're looking to tighten up that low e string this is a good place to start. I like 2.2k and 2.7k values with this build. Will depend in other things like guitar wood, strings, pickup, OT, and tubes....

Eric stopped by for a beer last night and checked the build out. Its definitely got the goods. I set it up for wall voltage. Plates are right at 400 vdc. For grins I plugged it into the variac without rebiasing and it was tonal bliss. A bit more sag, compression and warmer high end. I wasn't a believer in the importance of the variac until last night. I also don't believe Ed tweaked his amp to run off the variac. I think he was a wicked smart kid who thought the variac might help with volume issues and plugged it straight in and ran with it. My hypothesis anyway.

Possibility for some clips tonight.

[vanhalen5150]

Ok, I guess what I was getting at was did you use a small trimmer pot? Like use on the bias?

[YMI5150?]

Basically yes. The only 2k I could find was a bit big and bulky compared to our bias pots but had same functionality. Email me if you wants to send you one

[axeman]

Post a clip YMI5150?

[YMI5150?]

Soundcloud sure drops some low end but you get the gist.

ran this through the variac at ~92 VAC as well.

https://soundcloud.com/ymi5150/vh-montage" onclick="window.open(this.href);return false;

https://soundcloud.com/ymi5150/rwtd-short-clip" onclick="window.open(this.href);return false;

[JimiJames]

holy crap!

[Tone Slinger]

Damn thats CLOSE ! Cant really say anything negative about that. One thing that I find with slaving clips (this sounded slaved) is that 'droning' type sound on certain notes/licks, like the c-b-c notes on the A string in 'ATBL' for instance. I noticed that Stans & Jnew's has that, as well as all other slaved setups I've heard. Like the mids are 'stuck' and not quite blooming. It is like a 'shift' from the resonant center or something. It's slight, BUT noticable. Ed obviously wasnt slaving back in the day.

Still, that is one of the best clips around, great job

[vanhalen5150]

Slaved?

We need a sticky down here for clips only. Lot of good clips that are killer coming out in the last while. They get lost.

[YMI5150?]

yes, slaved. details are next to the clip in sound cloud.

thx Andy. i cringe when i hear the wheels fall off in a few spots but its good enough for gvt work...

i'm not sure i agree that its obvious Ed didnt slave for the first record. i think the compression says the opposite. my personal amp has less thud than this one and many others. i'm trying to dial that out of this build but right now its a moot point. its brand new and lots of parts need to settle in. these are brand new EH fat bottles as well. I think they give a bit more bottom end than the originals. It's got the goods for sure.

obviously these clips were tailored to target the first record with all the verb. sounds good with good headphones but not so much through an iphone speaker. make sure to listen with at least buds in, and crank it!

here's a "b side" that's not much but I suppose is ok to post here for you guys. its the normal channel the way i modify it to make it more crunchy and useful. works well for the second record and a lot of other classic rock. less sizzle and a bit warmer.

https://soundcloud.com/ymi5150/sgmad-slow" onclick="window.open(this.href);return false;

and a spin on 316. worth documenting what it sounds like rolled back a bit and how balzy it is when you let it feed back. a monster!

https://soundcloud.com/ymi5150/wicked-417" onclick="window.open(this.href);return false;