New Amp build

I've ordered the kit for my next build. If you're interested in following then click the link. I've made a 2nd blog site foramp building in general. This will allow me to begin new posts within the same blog and you won't have to keep following new links.

http://tonebone-ampbuilding.blogspot.com/

First video of the 2 Stroke

I have the amp chassis connected to my old Fender M-80 amp. The Fender has a 12" speaker and it sounds nice however, with this amp/speaker combo there is virtually no clean sound. The tubes begin to distort with the volume set to 3 and up.

http://www.youtube.com/watch?v=Lr_nh0Wc3Y4&feature=email


I have since picked up a used Fender amp/cab. the solid state amp doesn't work so I pulled the chassis out and I'll use it to make something else. In the mean time in the cab I put in my Emenince Wizard to begin the break in period.

The sounds are a lot different than the M-80 in the video link above. This speaker is capable of providing cleaner sounds at higher levels. You cannot hear the distortion with this set up until around 5 or 6 on the amp, but the distortion it produces in my opinion is not as nice as the M-80.

SHE'S ALIVE!!!

I have been trouble shooting for the past couple of weeks and I have finally got this amp up and running.

I had sound coming from it, but it was super low in volume and it sounded like it was distorting the speaker.

It turns out that I had a bad solder connection on the middle of the circuit board. A couple of weeks ago I took the amp to a local amp tech (he offered to look for free) and he pointed out that I had one electrolytic cap in backwards. In amplifiers there are some caps with a positive charge sign + and they need to be connected correctly. Luckily for me, it wasn't a large one that could have exploded.

When I turned that cap around I didn't make a good enough solder connection. With the help and suggestion of Robin at http://tubeampnetwork.ning.com/ he told me to turn the amp over, turn the power on, and take a chop-stick and move the wires around and listen for a bad connection (keep one hand in your pocket or behind your back if/when you do this). That poking around helped me find the bad solder joint.

It sounds great so far. I have not cranked the volume up because - 1. the speaker is new and needs to be broken in and 2. everyone in the house is already in bed.

So far it sounds nice with clean sounds. The boost function makes it brighter in both the up and down position, but a different amount of bright sound so the switch provides 3 distinct sounds. I'll need to get a youtube account shoot some video and posts the sounds.

It Works

Well sort of.

I made the suggested changes the amp tech told me to do, but it didn't help. So I hit a couple of the solder joints again, but the biggest change I did was to connect the white (8ohm) output tranformer wire directly to the speaker output - I basically disconnected the switch.

I am getting a guitar sound out, but it is very soft (low volume). It needs to be louder and infact for a brief second it sounded like it became louder almost like something that wasn't fully connected made sudden contact.

I know it's working and now I just need to do some more trouble shooting.

Fixed and about to fire her up

Here what I've fixed:

The very first thing the amp tech noticed was my ground connection at the power transformer - The weren't connected so I actually had no ground.

Then as we were looking he noticed one electro cap that was in backwards - it was a small one; not one of the large ones that can explode. As we were talking I noticed another small one that was backwards.

He also found a couple of weak solder joints and two of them he was able to disconnect with a tug. He recommended that I put a little more heat and solder on a couple of places.

Overall, he said for a first time build it looked pretty good at least as far as soldering and running the wire. He wants to hear it after its finished. Since it is near tax time, I probably won't buy the cabinet until after April 16. - I hope in mid May to order it.

Here are the pics.

In each of these first two pics there is a black capacitor. On these caps at one end there is a small + sign. Those + signs need to be towards the bottom of the board. If you look at some earlier pics I posted you can see two big one on the far left of the board and those + are a LOT easier to see.

In this pic you can see the ground connection inbetween all of the wires. It is fastened to one corner of the power transformer. I made the ground connections to each of the lugs so they are all ground together, but I didn't make a connection from those lugs to the actual ground. There is a small wire in there, but it's hard to see unless you know what you're looking for.

I'm ready to fire her up. I'll take one (or 2) last looks and put the tube in and power her up!

Found some Problems

I just got back from my local amp tech/repair shop - he offered to take a quick look and see anything obvious that may be wrong.

He found some things right off the bat and I'll begin working on them later this evening. Most of the fixes are easy, but there are two things that I may or may not have to remove the board containing all the caps and resisters. I have two caps that were in place with the wrong polarity. Fortunately, they are small caps and not the big ones.

I take some pics and post of my mistakes and the fix.

Fired it up and...

Ok I fired up the amp last week and nothing! I've been trying to trouble shoot it for the past week. Here are a few of my mistakes that I have fixed but there is still no sound. I say no sound, there is a slight hum in the speaker, just no sound from the guitar.

I had the wrong input jack. I don't know how I missed this - The output jack I used only had two prongs and the correct jack is a switched jack with three prongs.

I found a wire that may have been shorting the circuit. It was the wire going from the volume pot to the tone pot. When the pots were screwed into the chassis the connections touched the brass grounding plate. I moved the wire around to the bottom side of the pots.

That's the latest update. I'll be out of town all next week and I think when I get back I'll have to take it to my local amp tech and see if he can help me.

I did buy the speaker today. I bought a 12" Eminence Wizard speaker from http://www.nationalspeaker.com/ as they are 6 miles from my house. After taxes the cost was $85

Few more pics

Here are a few more pictures

It is Finished!

I finished the last bit of soldering tonight!

Here are some pics

The next steps are to double and triple check all of my connections for both the correct wiring and to check the solder joints. A cold solder joint has a dull appearance. All of the solder connections should be shiny.

As for plugging in and fireing up. Well there are some safety concerns. First amps, even small ones like this produces lethal voltages. Some safety precautions are in order.

I need to make a circuit in the power cord to check for problems. Here is a quote from the Aikens Amp web site, "make a fixture with a light bulb in a socket that is in series with one side of the AC line - if the amp has a major short, the light bulb will light up instead of blowing the fuse or vaporizing your new power transformer."

In fact, go to the web site and read their whole safety page found here: http://www.aikenamps.com/SafetyTips.html

It has some great advice that could save your life.

I have to go out of town this week, so I won't get to fire this puppy up for at least a week - I need to buy the stuff to make the safety curcuit. It shouldn't be long now!!

Tools for the build

I thought I'd take a minute and list some basic tools needed for this job for those who are considering this build or any amp build. Keep in mind this is my first build so I'm not an expert.

• Wire cutter & stripper.
• Small screw driver - phillips and standard depending on what type of mounting hardware you buy.
• A small set of needle nose pliers - I have a set of small tools I bought at sears a long time ago and I think they still sell them. See the picture below. The long needle nose ones have been extremely helpful in bending cap/resistor wires.
• Drill - The main thing for this amp was that I had to drill a hole for the ohm switch. For the twisting of the wires it is helpful, but you can build a small amp like this without it. If you build an amp with a bigger chassis and longer wire runs then it would definately help.
• Soldering iron - a variable temp iron. Why variable temp? For the light electronic parts you don't want to burn them up with a high watt iron, but when making ground connections to the chassis you need a hotter iron. If you have two irons already then this doesn't matter. I picked up this soldering iron for around $50 + shipping here: http://www.howardelectronics.com/xytronic/379.html and this place has it for $40 + shipping http://www.assemblyoutfitters.com/shop/item.aspx?itemid=2163 It also helps to have a tip with a fine point because some of the connections are small.
  

Off the top of my head that's a basic list. Here are some pics

Chassis work

I finished drilling the new hole in the chassis for the ohm selector switch. Here is a picture of the new switch mounted and also the wiring I did last night of the fuse, lamp, and power switch.

Begining assembly

After cutting the power transformer's wire to length I found that it is easier to strip the wire and tin the leads with the pt out of the chassis. That's what I worked on last night. After tinning the leads I soldered the fuse wire, lamp, power switch, and the first 2 leads to the power tube - the 6.3v.

Coming from the pt the two green wires go to the lamp and then on to the power tube socket numbers 2 and 7. These wires supply the need 6.3 volts.

The black wire from the pt goes to the fuse. The other side of the fuse will be a black wire from the cord that plugs into the wall.

For the power switch I made an optional change that is not mentioned in the book. This option comes from the updated notes by Dave Hunter. I replaced the on/off power switch with an on/off/on switch and I wired the pt's blue wire in the up/on position which will supply 125 volts and the down/on position will supply 120 volts to the amp. According to hunter the extra 5v will not hurt the amp and will actually give a slightly different sound. I'm all about versitility.

The last thing I worked on was a resister between lug 5 & 6 on the power tube socket - I almost missed that. This is actually the hardest fitting resister I've had to do yet because the distance is smaller than the resistor itself. I suggest not cutting the wires until after bending them in place and making a good mechanical connection. This would have been easier making this connection with the tube socket out of the chassis. I soldered them while in the chassis - do it before you put it in the chassis and before wiring any other wires to the socket.

I'm still working on drilling a hole in the chassis - I need to buy a bigger drill bit and I hope to go to sears or ace today and get that.

No pictures of last nights work which is probably fine since I just cannot seem to get any really good pics from that camera. I will take and post some as I make a little more progess.

EDIT: Output Transformer

In my last post I mentioned drilling the chassis in order to place an impedance switch in the circuit.

I could skip the switch and wire either the white or the yellow wire directly to the input jack. If I did this I would only get the following:

White wire: one 6L6 = 8ohms speaker
Yellow wire: one 6V6 = 8ohms
one 6L6 = 4ohms

There is also an optional green wire that you can read about in the book.

Power Tran & Output Tran

The Power Transformer wires have been measured and cut to length and so has the Output Transformer wires. I'm going to have to drill into the chassis for an impedance switch for the speakers.

This switch will allow me to run one of these set ups: one 6L6 power tube = 8ohms
one 6L6 = 4ohms
one 6V6 = 4ohms
one 6V6 = 8ohms

I've already purchased a 6L6 and I plan to run it into an 8ohm speaker, but in the future I may try and go with a 6V6 into an 8ohm speaker as this will give a tweed Champ or Princeton like sound.

My next step is to cut a hole in the chassis to allow that switch to fit and then I can finally begin assembly and solder... Not too far away from powering up!!

Power Transformer

The volume and tone pot has each been made ready by soldering them together and adding the .0047uF capictor to the tone control. Also the input jack and the on/off/on boost switch is now connected.

The circuit board is pretty much complete, the pots, the on/off/on switch, and the input jack are prepped and now I'm prepping the Power Transformer at this point. I've read the book and re-read the book to help me understand all of the steps.

Another great thing to look at prior to doing this step is to watch Gabby of "sound garage tales" wire a power transformer. Here is a link to his videos - make sure you watch all 4 of them:
http://www.youtube.com/watch?v=hKu4HG2q-iQ&feature=related



I've twisted some of the wires together so they will stay sort of neat looking as they run to their connection point.

I placed the wires to be twisted together into a drill and slowly twisted the pair together. This makes a nice even twist.

You need to be careful because you do not want to over twist them - they could actually break.

The next step will be to mount the PT into the chassis and measure and cut the wires to length. Perahaps I'll do that tomorrow night or thursday.

Solder, Solder, Solder

The last shipment of parts arrived today - not including a cab and speaker. Those will be ordered later.

I finished dry mounting the components onto the board then I double checked them and cut the wires that will run under the board.

Here is a good tip I read some place: When mounting the resistors and caps place the values up so you can read them. This helps when double checking prior to soldering.

I soldered all the components. I didn't follow the instructions in the book exactly. The book suggests soldering the board without the leads that will go the tubes and to vol pot and input jack. The book suggests wiring the components and adding them to the board later. I did just the opposite. I soldered the leads to the board then placed the board inside the chassis, mounted the vol, tone pots, input jack and switches and then cut my lead wires to length.

Tomorrow I'll do the same with the leads that go to the tubes. Right now it's late and I'm tired. Here are a couple of shots of the soldered board sitting inside the chassis.

No work today

I didn't actully work on anything today, but I did order what should be the last of the electronic parts. All that is left is the cabinet and speaker. I'm going to go with a single 12" speaker which is different from what is in the book plans. The design originally called for one 10" and one 12" but the new kits that can be purchased uses just the 12"

I've dry mounted the components that I have. I will re-check before I solder (possibly thursday) and I need to plan out where connector wires will go and running connector wires under the board.

I want to have it all planned out before I solder.

One note for those who plan to build and not buy from a kit: It helps to be a detail person. Double check before ordering that you are ordering the right parts. Also, it may help to buy the chassis first. The mistake I made was ordering the tube sockets and not knowing what size hole was in the chassis plus their mounting specs. Also when ordering I didn't double check my quantities and I accidently ordered one 9 pin tube socket when I meant to buy two.

More Parts Arrive

More parts arrived this morning from Weber Speakers which can be found here: http://www.tedweber.com/

I ordered the 5F2 chassis which is basically a Fender Princeton chassis, a Weber Power Transformer (W022772), and a couple of caps/resisters - Zoso cap which is a correction to the book. The cap on the tone control is supposed to be .0047uF which is what I ordered.

The chassis appears to be top quality. I thought I was going to have to go out and buy a deburring tool, but all of the edges feel as if they have already been deburred. However, the chassis kit did not come with mounting hardware (screws/bolts etc...) so I will problaby carry the parts over to my local ACE hardware store and see what I can find.

I also have to place one more order for the output transformer (OT), a switch (out of stock for first order), another 1Meg Ohm pot, and one more tube socket (I forgot to update the quantity before I ordered). I'll order these from Antique Electronic Supply.
Here are some pics of the parts that arrived today.

Beginning of 2 Stroke Amp Project

This amp project comes from Dave Hunter's book, "The Guitar Amp Handbook" published by BackBeat Books 2005. There is a kit available for this amplifier and it can be ordered from Victoria Amps via http://www.myspace.com/twostrokeampkits
I did not order the kit. Instead I ordered the parts pictured here from Antique Electronic Supply found here: http://www.tubesandmore.com/

Yesterday I received the first shipment of parts for this amp project.
The parts have been placed into a holder to help keep them a little organized.

The chassis kit and some other parts are scheduled to arrive tomorrow.

Here is a close up shot of the Sprague Atom Cap.