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Hoffman Amps Forum image Author Topic: What do these do ????  (Read 14597 times)

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Offline SILVERGUN

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Re: What do these do ????
« Reply #50 on: February 03, 2013, 10:58:25 am »
Thanks......I completely understand and just wanted to make sure I was seeing what you're seeing.

I know that if I'm going to take a "creative" approach to implementing big change, than I'll have to take a solid troubleshooting approach to figure out what is wrong with my creative approach  :icon_biggrin:.......this is how I'll learn

I'l slow down,,,,make sure the schematic matches reality,,,and double back over all of the paths.....that's all I can do for now
It's still fun, especially if I can figure it out.........sometimes it helps to have another set of eyes on it, and i really appreciate you taking the time to look it over. :thumbsup:

Offline HotBluePlates

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Re: What do these do ????
« Reply #51 on: February 03, 2013, 11:10:07 am »
Yep, we all go through those exact same learning processes.

I won't get into my first electronic build project, a way-too-complex distortion pedal. I had creative and wrong wiring (mostly just wrong), and the only sound it ever made was a motorboating put-put-put.

I threw the thing in the trash years before I knew enough to try to figure out how badly I messed up on the wiring.

Offline kagliostro

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Re: What do these do ????
« Reply #52 on: February 03, 2013, 12:18:51 pm »
Quote
the only sound it ever made was a motorboating put-put-put

Putt Putt Boat

 :icon_biggrin: :icon_biggrin: :icon_biggrin:

K
The world is a nice place if there is health and there are friends

Offline HotBluePlates

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Re: What do these do ????
« Reply #53 on: February 03, 2013, 12:39:20 pm »
Yes, that was the only sound my first electronic project made.

Not a good result for a distortion pedal that was supposed to split the guitar signal into 4 frequency bands, distort each individually and at different amounts, then recombine for the output to the amp.

Beginners sometimes pick projects that seem really cool but are way over their heads (and skills). Not that I was ever foolish enough to fall in that category...  :l2:

Offline SILVERGUN

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Re: What do these do ????
« Reply #54 on: February 04, 2013, 12:13:22 pm »
OK, I was able to stick my head in there on my lunch break,,,,the good news is I figured it out  :happy1:

The really bad news is: It was a killer ROOKIE mistake:
That 1M resistor we were discussing earlier,,,turned out to be a 1K  :lipsrsealed: :sad: :embarrassed: :cry:

I pulled it out of a 1M drawer, checked it (it read .998 K), and I never questioned it again,,,,until I was taking resistance readings and it punched me right in the face.....at least my troubleshooting took me right to it.....just can't believe I did it in the first place  :BangHead:

Well, I also realize that if I would've taken a clear picture, at least you guys would have caught it by the color bands....I've seen sluckey do that on a number of occasions, and have great respect for that ability.....I'd still have to break out my Radio shack color band wheel  :sad:
I also turned the pots around and got the wiring right, and changed the description in my wiring pic......(changed bottom of pot view to TOP)

Out of time for now, but I'll be back later with a performance report!
« Last Edit: February 04, 2013, 12:39:10 pm by SILVERGUN »

Offline SILVERGUN

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Re: What do these do ????
« Reply #55 on: February 04, 2013, 04:53:59 pm »
TIMBO,
After play testing it for a half hour, I figured I'd give my first impression opinion,,and it's positive... :icon_biggrin:
For me this works because it's a different way to turn my single channel head into a 2 channel head,,,with a footswitch
It also makes me want to build THAT amp to see how close I am to how it is supposed to sound...BUT I think I have created a good example of it here  :thumbsup:
Input volume does exactly what it should do and sets the amount of gain going into the third stage (for me I wouldn't even need a knob there because it's gonna be, set it and forget it-= FULL ON (maybe useful to level off different guitars....I only have 1 input).....it sets the input gain, and for me to keep my amps original character,,it'll be set pretty high....(maybe a good spot for an internal trim pot in my amp)
The Balance control sets the difference of gain headed into that third stage, that will be effected by the position of the switch.....
switch open= FULL SIGNAL  (with 1M "blocking" signal from going to ground)
switch closed= LOWERED percentage of signal that you have dialed in with Balance control (switch being closed provides a path to ground for whatever percentage of the signal you have chosen with the Balance pot)

So it's basically a switchable/controlable pre-amp gain control.....it did introduce some (slight) noise and I attribute that to some ugly lead dress and the fact that I completely disregarded the grounding scheme and just used the chassis...(it still wasn't as bad as I thought it would be)

If I was building THAT amp,,,I would be sure to include it....and if someone asked me for a "solo boost MOD" I'd run this one by them
I'll need a little more time to decide if it WILL stay here (leaning towards yes),,,,BUT an awesome by-product of doing this mod has been the fact that my amp now sounds better with the tonestack moved and the addition of the cathode follower and utilizing what was an unused 12AU7 triode.....so WIN-WIN

Thanks for bringing this to my attention, and like I said before, I am very glad I joined in to learn about this option  :thumbsup:

Offline TIMBO

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Re: What do these do ????
« Reply #56 on: February 05, 2013, 01:17:08 am »
Thanks for the leg work SG, I too am glad i asked the question. There so many of these addons that you want to build them just to see what they do and only to be disapointed to find that they were just a gimmic.

Schem attached is just the basic idea so far but will probely add passive FX loop as usual. :icon_biggrin:

Something i would like to try is to use the spare V2 triode and add it to V3b to make a kind of overdrive  :think1:

Offline Tone Junkie

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Re: What do these do ????
« Reply #57 on: February 05, 2013, 02:13:09 am »
Timbo looks like you and SG are having some fun. I  think I will go heat up the soldering iron myself (G).
Bill                                                                                                :happy1:

Offline TIMBO

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Re: What do these do ????
« Reply #58 on: February 05, 2013, 03:07:24 am »
Bill, if you keep running around like that your gona hurt yourself  :l2:


Thought i'd throw this out idea out there as a possible ADDON
« Last Edit: February 05, 2013, 03:39:37 am by TIMBO »

Offline SILVERGUN

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Re: What do these do ????
« Reply #59 on: February 05, 2013, 08:21:50 am »
There so many of these addons that you want to build them just to see what they do
Yeah, that's my life story right now......everytime I think I'm close to done with this amp,,,I read something that I want to try...

In this case, once I was able to see the function, I knew I had to try it....and since I was already looking for a reason to move the tonestack around, I just jumped on it.......I hope Tubenit is proud of me,,,,and not wondering if i've lost my marbles  :dontknow:
I really enjoy sharing the info. that I learn,,, because I have learned so much from guys like T who have taken the time to share so much :thumbsup:

When this thing is finally done, I want to know that I didn't settle, without touching all the bases

Nice schematic  :huh:........take a look at what jojo had me try on my TurboWreck, to add gain in those later stages:
http://www.el34world.com/Forum/index.php?topic=14575.msg138871

Offline slavax

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Re: What do these do ????
« Reply #60 on: February 13, 2013, 10:54:19 pm »
FWIW- The Page video from Albert Hall "Prelude" is an adaptation of an E Minor Prelude by Chopin.  It's pretty cool what they did with it but they didn't do the 2nd half of the piece which gets into much more chromatic harmony.  Does sound like Jeff Beck.

 


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