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#1
EDITED TO FIT WHAT IS ACTUALLY GOING ON

I'm am building an amp that will have two funtions. It will be both a guitar and bass amp. It is going to be 2 channels. One channel will be the preamp of an Orange OR120. The second channel is the same as an Ampeg portaflex, as is the poweramp. I am going use a 12AT7 for the phase inverter rather than the 6SL7 like the ampeg. I will put a switch on the back that allows you to switch between a 5AR4 rectifier or silcion UF4007s. I am using an optical relay I found on Ted Weber's site for channel switching. I am adding a boost circuit also that can also be used for a tube driven effects loop. The EQ for the Ampeg side is from a different ampeg that has a Mid control.

Everything is on order or in already. The features are as follows:
Channel 1- 12AX7, Bass control, FAC control (mid shift), Treble Control, Gain control
Channel 2- 6SL7, Bass control, Mid Control, Treble Control, Gain Control
Phase Inverter- 12AT7
Effects loop/ Boost - 12AU7 with Send and Return controls which act as two more gain stages when in "Boost" mode
6L6 power section (50w)
Switchable solid state or tube rectification
Master Volume and Master Presence

Aesthetics:
Transparent Gray plexi front panel
Flat Black chassis
Brushed aluminum knobs
Black enclosure w/ white stripe down the the top center

Pics of it thus far:



Last edited by end_citizen at Jan 10, 2009,
#2
You can buy an inexpensive plexiglass scoring tool. Score it about 15 times and then snap it at the edge of a table or put a 1/2" dowel under the score and press down on both sides. This will not work if you are trying to cut off a few inches though. So you could try using a tablesaw with a plywood blade and a zero-clerance insert. A bandsaw with a fine blade and zero-clearance insert would be ok as well.
#3
I'd suggest an SS recitifier over a tube recitifier.
Quote by satchgear
I tried it out in store.

Great neck, nice n light, good tuning stability. Overall a good guitar. I didn't but it cause I generally only buy guitars over a grand now.
#4
^that's totally a matter of opinion. Anyways why not have the option of two, that's what the TSer is doing. It's smart.

Have you attached the transformers yet? Did you test for them for the best positioning?
#5
Quote by kurtlives91
^that's totally a matter of opinion. Anyways why not have the option of two, that's what the TSer is doing. It's smart.

Have you attached the transformers yet? Did you test for them for the best positioning?


About the rectifier: That's why I'm doing it, to have both. I like versatility because I'm kinda ADD when it comes to tone.

As for the transformer question, yes. I have the demensions of all parts, and I figured out where I want everything to go. I currently have the chassis all drilled up. Well not all drilled up, just the front and back panel. I also have the holes where the wires go in drilled and grommeted. I know where the tubes will go, but I won't drill until the sockets get in, just in case something was a misprint online. My main concern was working on a turret board layout, but I think I'm satisfied with what I have.
#6
Ya thats why I said the switch was cool.

What is the headphone trick?

This is the best way to find the quietest place to put a reverb, output, driver, or any other signal transformer to get the least hum. CAUTION: THIS INVOLVES WORKING ON THE AMP WITH WALL VOLTAGE PRESENT. WALL VOLTAGE CAN BE FATAL.
First set up the power transformer. If it's not installed yet, all the better, but if it is, this will still help. If the PT is not installed, wire up the primaries to a power cord, but do not wire up any secondaries-- tape the ends of the secondaries. If the PT is installed, fine, just make sure there is no circuit on any of the secondary leads (pull all tubes, and disconnect leads and tape them as necessary).

Now set up the signal transformer (output, reverb, whatever). Hook one set of OT secondaries (your choice, but I usually go from ground to the highest impedance tap, don't worry about impedance matching here!) to a set of headphones. Tape the primary leads.

Put the headphones on, plug in the power cord, and start moving the signal transformer around. Try it all over the chassis, and also rotate it. While you might expect the least hum with the transformers as far from each other as possible and at right angles (and that may be the case for you), it might come at an odd angle and/or position. Sometimes the least hum occurs when the transformers are side by side. When you find the quietest spot, use a permanent marker to mark where the mounting holes should be.

If you have more than one signal transformer, repeat this for each one. When you're finished, unplug the PT. That's it!
#7
This thread will be amazing once the build progresses further and will probably be the most advanced amp build on here although you're not building everything from the ground up.
Quote by DeathByDestroyr
What the hell is a G&L.



Quote by Flux'D
Gay & Lesbian I think, the box smelled funny
Greg what did you send me??
#8
Thanks. I'm trying to get finished before school starts back up in 9 days.

I'm not sure what you consider "building from the ground up." All I won't do on this build is the schematic, which I tweaked anyways. This isn't a kit if you have that impression.

I expect a lot to come in by Tuesday, but I have to work all week. I just finished the cabinet. The tolex job isn't great, but it is way better than my last build.
#10
Here are some new pics. You can see all the capacitors (except 3 I forgot to order) are soldered to the turret board. I also have all the tubes, but as you can see I also forgot to order a socket for the GZ34/5AR4. I expect all the resistor, a couple more pots, and a few switches to be in tommorow or Friday. It doesn't look like I'll be done by the time school starts.





Obviously just the tubes and front controls are the only things in the right place here.
Last edited by end_citizen at Jan 7, 2009,
#13
How thick is the plexiglass that you're installing?

If it's any thicker than 1/8", you aren't going to be able to use a scoring tool. The best way to do it is to get a scroll saw with a fine toothed blade and zero pitch. I'll get you the exact model # when I get home. Cut about 1/2" outside your cut line with the scroll saw and then you will need to use a router with a 1/2" shank flush cut bit. Do a couple test cuts before you tackle the main project. The goal with cutting the plexi is to make the passes as quick and as clean as possible so that it doesn't melt. What I did was set the router speed to max and then moved at about 1 foot per second. This gave me the best cut with very little tool marking on 1/2" plexi.

See my 'fuzzy killer' links for the results.
Guitar:
Dean Vendetta 3 - Dave Mustaine Livewires

Amplifier
Carvin X100B - Bias Mod - Tungsol 12AX7's - JJ KT77's

I have built the most badass 212 that puts all others to shame
Last edited by MeanwiththeDean at Jan 8, 2009,
#14
Quote by Invader Jim
I hear that turretboard, when exposed to enough moisture/humidity, can become a single conductive sheet. Is that true?

Yes

Depends on the material used for the board though. Also it is never so bad as the whole board becomes a conductor. I have seen 50V from a unused turret to ground, that's pretty bad.

Common on old Fenders that use fibreboard. Some say though the electric fields surrounding components and slightly conductive boards add to the sound. I agree with this to an extent...
#15
Like Kurt said, it depends on the material. What I used is the same epoxy that is used for copper clad Printed Circuit Boards.

I got a lot done today. I have the chassis painted and the plexi cut and drilled. I'm just waiting on some resistors, a socket, a couple of pots, a switch, and the optical relays.

In honor of this build/kinda required- I bought a cabinet today with a 15" Electro Voice, and a Fernandes bass. They sounded great together in the store with a monster Ampeg SVT powering it all. I hope to get close to that, plus have a nice guitar amp
#18
Quick question: Does anyone know if I can use the 5v taps that I'm not using on my transformer to run this:
http://www.xoxide.com/12linespcoca.html

I think it'd be awesome to have that behind the clear plexiglass. I'm also kinda worried that I may get some AC interference from it though. Any thoughts?
#19
Quote by end_citizen
Quick question: Does anyone know if I can use the 5v taps that I'm not using on my transformer to run this:
http://www.xoxide.com/12linespcoca.html

I think it'd be awesome to have that behind the clear plexiglass. I'm also kinda worried that I may get some AC interference from it though. Any thoughts?



They need 12V going in, so no unless you build a charge pump or a voltage multiplier or something...

Regarding transformers...I've build 10+ amps by hand, I place the transformers using an oscilloscope (wired the same as the headphone trick, but so I can SEE the magnetic interference, not hear it like in the headphone trick). The PT radiates the EMI. Most of the EMI is coming from the bells of the PT body (the smooth rounded parts). To keep the hum to a minimum, point the bell of the PT away from the OT, and then have the OT's core oriented 90 degree off of the PT core (so, the bell of the PT faces away from the OT, and the bell of the OT faces the PT). Keep them a couple of inches apart and it should be dead quiet (from an EMI point of view).

I hope that made sense...I reread it and my brain went

Let me know if you need any other help, I should be able to work through most things with you. PM if needed, I'll check back when I can. For now, time to cook dinner.
Quote by kcdakrt
DLrocket89 makes my ug experience better!


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#20
^I assumed that it wold just glow with less intensity, but I'll take your word for it, as I am not entirely sure how that style lighting works. I have decided on how I will indicate channel switching and boost. I think I'll leave it a surprise for now.

More important stuff. I thought my Weber order was at the post office, but I have school until 5pm. The post office closes at 4pm, but my awesome girlfriend picked it up for me...

It was just art suplies for my sister (an art major). I didn't realise how slow Weber was at shipping, but it may be due to the fact that there was recently an ice storm through that part of the country. I was hoping to inventory everything that I forgot to order my first go around today, but alas I have don't have that order to inventory. I also have Macroeconomics homework and Calculus II homework.
#21
Quote by end_citizen
^I assumed that it wold just glow with less intensity, but I'll take your word for it, as I am not entirely sure how that style lighting works. I have decided on how I will indicate channel switching and boost. I think I'll leave it a surprise for now.

More important stuff. I thought my Weber order was at the post office, but I have school until 5pm. The post office closes at 4pm, but my awesome girlfriend picked it up for me...

It was just art suplies for my sister (an art major). I didn't realise how slow Weber was at shipping, but it may be due to the fact that there was recently an ice storm through that part of the country. I was hoping to inventory everything that I forgot to order my first go around today, but alas I have don't have that order to inventory. I also have Macroeconomics homework and Calculus II homework.



Yeah, Weber is good w/ prices and availability, but I think he's a pretty small shop. It's worth the wait.

I'm pretty sure that the problem you'd have with the lighting is that it would run w/ a 5VDC setup, but it wouldn't have enough voltage to get the light started...

Might be worth a shot playing around w/ though, who knows.

BTW, it's great to see another person building amps here. I just finished a smaller one, the thread should be floating around...
Quote by kcdakrt
DLrocket89 makes my ug experience better!


Member of the official GB&C "Who to Listen to" list

Kit Amp Building Tutorial
#22
end_citizen, have you permanently bolted down your transformers yet? if not, you should rotate your PT 90 degrees, I PROMISE you will like you amp better. right now, they're positioned to couple together via EMI about as worse as it can get...if you don't do something about it, you'll have a loud and obnoxious 60Hz hum, with overtones of 120Hz and 240 Hz. Worst part is it'll sound loudest when the amp is turned down...

Actually, it'll make the noise with no output tubes in the amp...been there, done that w/ a build, not good.

Even if you have to redrill the chassis and leave a few holes, it's worth it.
Quote by kcdakrt
DLrocket89 makes my ug experience better!


Member of the official GB&C "Who to Listen to" list

Kit Amp Building Tutorial
#23
I got the heaters wired up yesterday. I also have it fit in the box properly.

I'm still waiting on my Weber order. Has anyone ordered from there before? I know they are supposed to have quality parts, but is the shipping usually slow? I sent them an e-mail trying to verify that it has been shipped, but I received not reply.
#24
I got a lot done today. My Weber shipment came (sans switch boards). Turns out Ted has been sick, and he's the one who puts together the optical relays. They have shipped though, and according to FedEx, they will be here Wednesday. I don't have a camera at the moment, but you aren't missing much yet.

I have taken inventory and I have forgotten to order the Send/Return pots on the loop/boost, 3 caps, about 6 resistors, and I ordered the wrong 3PDT switch for the rectifier selector. I will order all this through mouser because I know that it will be here fast. Hopefully I will have this done by next weekend
#26
^Sorry, my last post explains. I don't have a camera at the moments. And BTW, I did turn the PT so the EMI is not interfering as much with the OT.
#27
Quote by end_citizen
^Sorry, my last post explains. I don't have a camera at the moments. And BTW, I did turn the PT so the EMI is not interfering as much with the OT.



I fail, sorry about that. Glad you rotated things, you're going to like the amp a LOT more.



keep us updated! I'm starting the heater wiring in my new amp in a couple of minutes...
Quote by kcdakrt
DLrocket89 makes my ug experience better!


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Kit Amp Building Tutorial
#28
We had the ice storm of the year. Since we were only 27 or so days into the year, I felt I could say that.
So I've been without electricity for over a week. I still don't have power, but I'm up the college using there computer. I just placed my (hopefully) final mouser order. Maybe this amp will be running by next weekend. I've got lots of homework to catch up on in the mean time
#29
Quote by end_citizen
We had the ice storm of the year. Since we were only 27 or so days into the year, I felt I could say that.
So I've been without electricity for over a week. I still don't have power, but I'm up the college using there computer. I just placed my (hopefully) final mouser order. Maybe this amp will be running by next weekend. I've got lots of homework to catch up on in the mean time


I haven't touched mine in a week. Put in 60 hours last week at work, plus homework (getting a master's degree on the side). Haven't done anything but work, sleep, and do homework since my last post.
Quote by kcdakrt
DLrocket89 makes my ug experience better!


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#30
I got the rest of the parts in yesterday. I was very surprised. I ordered Tuesday. They appear on Wednesday. I paid for 7-8 day shipping. If I had power, this would be great. Now it's just kind of depressing. I have everything (to the best of my knowledge) that I need, but I can't use it.
Last edited by end_citizen at Feb 7, 2009,
#31
I got a lot done today. The whole board is done. I do not have the boost/effects loop built though. I have a lot of wiring to do though. I have the rectifiers and power section wired. I the way school is though, I'll probably not be able to work on this until next weekend or the weekend after that.

Two side notes: There are a lot of English people here, so help me settle a bet. In America we buy what are called English muffins. Are they just called muffins over there?

#2. My dad should not play Metal Gear Solid 4. I bet I could be a lot further along if I didn't have to get through all the hard parts for him.
#32
I've not been able to work a lot on this because of school. That last post had some random thoughts, eh?

I got quite a bit done today, but I don't have my camera. I was concerned about the power section so I did a modification to that in the name of safety. I couldn't get the board as far away from than the chassis as I would have liked. So I now have the two capacitors sticking through the chassis. This enabled me to raise the entire board a much more comfortable height. I have installed the switch boards. I have all the controls wired as well. I just need to hook up the power to the different sections as well the input. I don't have enough shielded wire at the moment, so I won't be able to finish until I have some more.

I hope anyone who read that paragraph was interested, otherwise I apologize
#33
I thought I had everything. Turns out my knowledge of rectifier tubes was not up to snuff.

I've got an inductor and some more caps on order and supposed to be here by the 17th. I've also got some shielded wire on the way. I probably only needed about 3 feet, but I ordered 30 feet so I shouldn't run out soon.
#36
Glad to see forward progress...sometimes it's hard to get going again on things.
Quote by kcdakrt
DLrocket89 makes my ug experience better!


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#37
Tell me about it. This project is only being worked on after I get homework done. I'm bad about procrastinating on homework though. I really want to hear this amp though, so it will get done, but I won't guess at a date anymore.
#38
An Update:

I had everything done (I thought). I plugged it in, and nothing. No hum, no nothing. It is probably something I did wrong on the output transformer, but I won't be able to get back to until after finals week (May 4th-9th).
#39
Quote by end_citizen
An Update:

I had everything done (I thought). I plugged it in, and nothing. No hum, no nothing. It is probably something I did wrong on the output transformer, but I won't be able to get back to until after finals week (May 4th-9th).


Can you post a couple of gut shots of it? HAving a second set of eyes on it always helps...
Quote by kcdakrt
DLrocket89 makes my ug experience better!


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#40
HUGE-ish, LARGE-ish, SUPER IMPORTANT-ish update:

It works for the most part. I can get guitar through the amp. The sound is not good right now and I have the following problems:

1. My volume control doesn't work (it's loud).

2. I had to disconnect my switching boards because I was getting way too high of voltage to them for some reason. I might have fried them I don't know. Right now I'm only able to use the first channel.

3. My bias voltage isn't negative. When I take a reading it is 20v. It is cathode biased though, so I don't know if this is normal.

4. When I have the amp on tube rectification it blows fuses.

I will work on these problems in the order I listed them. I need some help with #3 though. I can't remember the website I got the schematic off of, but pm me with an email address and I can send you the pdf if you'd like to help.
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