Block End Build

[Strat78]

It's taken forever gathering all the parts especially the boards and I still don't have the irons! I wasn't sure about the orange board material at first, but now I like it allot, plus they were fun to cut and stake (I will never pay somebody ells to make my boards again)! Its kind of silly using block ends for a Dickinson spec, but given how fat the tone will get with the RS choke (20Hy), I thought it would be a good compromise between a super lead and jtm 45/100. I'm going with classic tone irons for this.

[JimiJames]

Looks great soo far. Betcha can't wait to get the feel under your fingers.
Like those Top Hats.

aye, don't you have another one a' them slider's ? ...keep the block ends !

[axeman]

No bias 1 ohm resistor? Why? I hear it changes the tone of the amp?

[Strat78]

Looks great soo far. Betcha can't wait to get the feel under your fingers.
Like those Top Hats.

aye, don't you have another one a' them slider's ? ...keep the block ends !

I dont think I've heard a 45/100 that I did not like, so this build has been an on going dream to complete. Jimi, I've got a pile of old carbon slider pre-sets, but their values render them kind of useless for our purposes. I have 2.2meg, 500ohm and one 5k. My plexi clone has a 27k slider with a 5.6k bias resistor to put it into a useful range, however with the other values
I don't know where to begin to match them with the right resistor. Perhaps adding one in parallel with the slider will make the 2.2megs work safely. You guys are better with the math than me so any suggestions would be apreciated. I searched high and low for the block ends, so they are pretty special to me. Looking at the picture,
I have a mish mash of nos piher 1/2w resistores, but only you guys could pick up on that. I've finally settled on a heater wire dress that I like with very relaxed twists, though they are very snug up against the chassis and noise free in other build. I stopped using the 1ohm resistor for biassing because Terry Killgore said it was gay! Actually, I find biassing the old school way is pretty easy and I also heard that the tone is less effected (better) as well, who knows. If an amp is for someone ells, I would use the 1ohm for safety reasons.

[emmjaydubya]

I've been waiting and here it is!! Looks amazing!

So the filter cap in the pre is 32/32? I was thinking of using lower filtering with a 16 or maybe a Rifa 22 on mine. Maybe less ghosting with the higher pre filtering on yours? And the little blue snubber cap on the power board, what is that? Mallory? I've been racking my brain on figuring out what to use there. Are the boards Brian H.? How about the trannys?

Oh yeah, how's the knee doing?

[Strat78]

That little snuber cap is a .047 1200v Ashcroft. It's all I had lying around, but it should be fine. That is an Erie 32/32 in the preamp, I might go to 15/15 if the 20H choke makes it too stiff. I think 22uf Rifas would be just right in that possition, I just wanted the look of that old cap. I got those boards from Brian H when he was clearing out his stock a while back. I drilled every single hole by hand (no drill press). I've going with Classic Tone tranny's, or maybe Marstran, I'm trying to strech my budget so I can pick up a head cab too, but I'm open to suggestions. I have two unused M e r r e n tranny's to trade if anybody is interested (132 OT and T2562 PT).
The knee is doing well but for the first time in two years, I'm systemically feeling normal again much to the delight of my family. Never mind fighting a staff infection for a year and a half, It takes forever to get your head cleared out after going under anesthesia, I went under twice in the last six months. Oh, and opioids turned me into a nasty son of a bitch.

[mightymike]

Looks beautiful..

[neikeel]

The knee is doing well but for the first time in two years, I'm systemically feeling normal again much to the delight of my family. Never mind fighting a staff infection for a year and a half, It takes forever to get your head cleared out after going under anesthesia, I went under twice in the last six months. Oh, and opioids turned me into a nasty son of a bitch.

Glad to hear you are getting better!
Funny the Morphine PCA I had once just took the pain away and made me sleep, it was the weird psychedelic dreams for a couple of weeks after that were bad!

Nice build, my 7026 is on the slow burner, I have Marstran trannies

[Xplorer]

wow ! very nice !

you said that the 20 hy choke will make it fatter ? i mean can you describe the effect of a 20 hy choke over a 3-4 hy ?

i'm about to start a second jtm 45/100 as soon as i get a transfo from Brian, and i might consider the 7026 Dickinson way, why not ? i'll maybe try.

why did you choose the 7026 ?
how is it supposed to react, over a standard 45/100 please ?
i've heard clips of this 7026 but ... it's a lot of fuzz and univibe, sounding great.

are the 7026 mods supposed to be noticeable just about the volume ? noticeable at ten ? or below ?

cool, i didn't know about the 1 ohm résistors, really an effect ?

sorry for all my questions lol

[JimiJames]

Fantastic , isn't it !
Anyway rgalpin did a choke comparison with clips IIRC called "No Pepsi" rockstah did some R&D as well.
I learned alot there. Thanks !

[Xplorer]

oh ! that's right ! i remember now. thanks !

here :

http://www.soundclick.com/bands/default ... dID=694440" onclick="window.open(this.href);return false;


the 10 hy seems more loose, while the 3 hy is more tight.
How do you guys know that the Dickinson used a 20 hy ?
i think i have almost all the parts for it, even the 32 + 32 old RS preamp cap. and some old 470 ohms RS wirewound résistors.
same OT as a standard one ?
i asked if possible a 510 v tap on the power transformer, added between the 490v, and 560v ( which i doubt i'll ever use ) .

So what are the last news about your build strat78 ?

[mightymike]

For me, it waw more of a feel thing than a tonal thing; with the higher 10 Henry feeling more stiff than the 3H. It's hard for me to hear that difference listening to those clips, but I remember the difference having done the experiement and liking the more open less filtered tone of the 3h. That's what I used on my 45/100 and never realized that some say it was a 10h on the Dickenson amp.

[Strat78]

I'm kind of building this amp around an old RS 20h choke for the reasons that are described in Roe's article:

"The choke (inductor) on these early amps appears to have been the Radiospares 20 henry choke often seen on the early Marshall schematics. The Radiospares choke is different from the Drake and Dagnall chokes used later. The Radiospares choke is rated for 20h and 70mA, whereas the Drake and Dagnall are rated for 3 henry and 100mA. It also has a have a high resistance (690 ohms) compared to the later chokes (110 ohms). This high resistance gives more voltage drop across the choke than with the later chokes. When running the amp hard, screen voltages (and preamp voltages) will sag more, giving a softer response with more breakup."
I think it's the 690ohms that takes this in a different direction than the chokes rated much lower with lower H. Maybe Roe can elaborate on this.
At any rate, I briefly had the 20h choke in a 12xxx and it sounded wonderful, very robust yet squishy. It's silly using a block end with this choke much less using the 7026 layout, but lets hear how it sounds when I finally get around to grabbing a couple of irons and finishing her up. Why is it that these 45/100 builds seem to span over several years with us guys.
http://www.youtube.com/watch?v=oSs6DcA6dFI" onclick="window.open(this.href);return false;

[mightymike]

That's really interesting. You make me want to try this. What is your source for a choke of these specs?

[Strat78]

That's really interesting. You make me want to try this. What is your source for a choke of these specs?

Yep, it is intriguing! I was able to get mine a couple years ago off ebay, but I did notice that Classic Tone is making one that look like it is spect pretty close:
http://www.classictone.net/40-18059.html" onclick="window.open(this.href);return false;