My OPT comes from a 60's Reel to Reel player. How legal is that? LOL. Output tube was an ECL86. It looks too small for 4W though. I thought about using a transformer cover to cheat the grand jury. Bah. Not worth the trouble. What I'm not going to do is to buy a crappy transformer that I don't need. My other parts are legal - bummer.
Anyway, I'm going to be busy building an F5. Probably I will also build my little guitar amp just to compare it with the work of others. I wish all of the other participants the best of luck. My vote will be fair - no hard feelings.
I don't remember too much, it was about 15 years ago. I was surprised to find out just how few parts were inside the amp. It was a little practice amp about a foot tall, maybe 8 watts. The chip was cratered and I didn't really know what it was. At the time we had chip company reps visiting us daily trying to sell us chips. I work for Motorola, designing cell phones at the time. I got a hand full of everything National Semiconductor made with the right pinout, and tried the biggest one (TDA2030 maybe). It worked and the kid never blew it up again. He lived next door and played in a death metal band. The Peavey was for when his parents were home. It sounded far better than my daughters Gorilla. He had a full stack for the band. Don't remember what kind, but it wasn't a popular brand. I never heard the Peavey through the big speakers.
I was in a 3 year long vocational high school electronics program back in 1967-1970. It was 3 hours / day for the last 2 years. There were two of us students that did all sorts of stuff, and our teacher was really cool about it. I think he liked learning just what would happen when you turned the knob to the right as much as we did. We had no budget, but we got donations from all over so the donor got a tax write off. We got tons of stuff from Homestead Air Force base, including hundreds of metal 6L6's. Yes, I can make a metal tube glow red! Where do you think I learned how to melt tubes.
I just remembered that I have a dead Park (Marshall) 100 watt head in my warehouse. I guess I'll have to fix it to test some speakers. Lets see 100 watt Marshall, 15 watt speaker..........
Win or not, it doesn't matter to me. Its about time I took a crash course in guitar amp building. I used to make a lot of them, but that was at least 15 years ago. I fixed a few while my daughter lived at home, and the metal head lived next door. Most of the guitar players and ALL of the tube heads were taken out when they laid off 355 people in one day at work. It seems that all the fun, just died on that day, now its just a job.
So weigh it, measure the impedance, and find a similar transformer that can be bought somewhere and use that price. From BST's post:
The idea of using junkbox parts, or parts already on hand, and then tallying the equivalent current purchase price, is an excellent suggestion. I didn't realize that there were many prospective builders who have a problem with slow parts deliveries.
I'd like to make a proposal with regards to demonstrating the amps.
Although many of us are musically gifted, there are those of us who's greatest musical skill might be tuning an FM station (myself included).
It would be nice (helpful to some of us) if some of the more gifted would produce a wave file or other of the output of their guitar (buffered only) which could be used as the input of an amp for demonstration purposes.
If several people with different styles (Clean Lead, Heavy metal, Blues, etc) would do this, it would be possible to do more of an apples to apples comparison.
If enough people would do this, a demo cd could be made to show off the strengths and weaknesses of the designs.
Although many of us are musically gifted, there are those of us who's greatest musical skill might be tuning an FM station (myself included).
It would be nice (helpful to some of us) if some of the more gifted would produce a wave file or other of the output of their guitar (buffered only) which could be used as the input of an amp for demonstration purposes.
If several people with different styles (Clean Lead, Heavy metal, Blues, etc) would do this, it would be possible to do more of an apples to apples comparison.
If enough people would do this, a demo cd could be made to show off the strengths and weaknesses of the designs.
In Canada I would likely be looking at Just Radio's (Canadian Vendor) for things like Caps, Resistors & much lower localized shipping expense.
Also, that particular transformer is made in Chicago, there might very well be a Canadian vendor that sells them for less.
Check some of the guitar amp parts websites.
That is a Magnetic Components Inc. Product, they market the Classictone series of transformers that are getting very popular.
Yeah, I read that. I also read what he wrote today. He'd changed his tune. Parts should be available to everyone. I have no problem with the rules, but I have several vintage OPT's good for the job... why buy another one? To win? Makes no sense to me.
I know that. I know you love experimenting and this is going to be fun. OK, I will post my project but it will be out of contest. Just for educating purposes.
As I said before, I respect the rules.
Just using them as an example. I probably have most of what I need to get me going, might bring in one special order transformer at the local parts shop at the retail price. I'll look up Just Radio's, thanks.
ChrisA, the rules apparently do not address speakers, so I see no reason not to use the speaker that shows off the amp the best. If a 12" Legend makes your amp sound great, go for it, IMO. The idea is still good sound, after all. As TubeLab pointed out, there will be a practical limit to size, but if a 12" Eminence works, do it. You'll probably need the whole 5 watts, of course...
I'm shocked, shocked, I say.
I've never looked into the Champ 600 before. It looks nice and it looks like a good mod candidate. What is really impressive it that it goes up to 12! That's one louder than 11! Hmm, just how big a speaker can you cram into that thing anyway?
I wasn't remembering that correctly. I ordered $169 worth of parts. Since my order was for over $100 they gave me "UPS 3 day for the price of ground". They charged me $28.20 to ship a 3.3 pound box. This is such a deal. Tracking shows it went from Tempe to Phoenix to San Diego to Ontario CA it is now in Portland Oregon. They claim it will be delivered here in Ft. Lauderdale Florida tomorrow! Allied charged me $18 to ship $45 worth of transformers, Antek was cheap $11 for 3 transformers. Once I get Mouser, Digikey and ESRC done, my hundred buck amp will have over $100 worth of shipping in it!
Last night I ordered some parts from Parts Express. The shipping came to $14. Their ordering page said If I spent $17 more I would get free shipping. So it looks like I got one of those Peavey Blue Marvel speakers for $3. If I don't like it I can always hook it up to something really loud and see what it takes to blow it up.
Just for interest,
If you record guitar o/p for a dirty lick, clean lick, jazz lick, soul lick... they will all be clean..lol The amp makes the different sounds. Guitar O/P is not distorted just higher and lower volume.
However, recordings of each style with no compression might work. You would have to fiddle with the amp settings to get the desired distortion and each track would have to have the actual amp sound to follow it so you could compare to try and mimic it.
Good idea though!
Regards
M. Gregg
What I was thinking was along the lines that heavy metal players tend to turn up their output on the guitar as well as the amp. And they tend to hit the strings harder, all resulting in a significant increase in output compared to lead or jazz.
So the differnce in playing style is accompanied by differences in drive to the amp.
In addition, there are differences in chord usage vs note playing which would effect harmonic and intermodulation content.
No?
So the differnce in playing style is accompanied by differences in drive to the amp.
In addition, there are differences in chord usage vs note playing which would effect harmonic and intermodulation content.
No?
Yes you are correct minor 7th's and power cords are different etc. However you would need a recording of the expected sound as heard by the player to test.ie compare to the sound from the project with the signal going in of clean guitar. I guess you could then listen to the recorded sound of each project amp with each sample as adjusted to get the "best" sound compared to the original.
I know you wont get a Fender/ Marshall sound, however its a fixed reference point. Then again someone might..LOL
Regards
M. Gregg
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Okay My 2 cents worth on power supplies. In a guitar amplifier the power supply needs to sag under load for the folks who like to turn up the gain so high that when they turn around and face the amp stack it feeds back and squeals! The sag in power supply acts as a compressor and allows then to play the feedback!
I have found my output pentodes. They should allow me to get similar distortions to the common power pentodes used in normal guitar amplifiers but these run at lower voltage and put out 2 watts when pushed. They will drive a standard 70V speaker to line transformer very nicely. So at under $4.00 ea N.O.S. my output stage including sockets is under $15!
I have found my output pentodes. They should allow me to get similar distortions to the common power pentodes used in normal guitar amplifiers but these run at lower voltage and put out 2 watts when pushed. They will drive a standard 70V speaker to line transformer very nicely. So at under $4.00 ea N.O.S. my output stage including sockets is under $15!
Just for interest,
Mini amps
Vox AC4 Vs Orange
YouTube - Vox AC4 vs Orange Tiny Terror. Comparison. Great audio!
http://wn.com/Vox_AC4_vs_Orange_Tiny_Terror_Comparison_Great_audio! <<<try track 13# Hideaway how does it compare with track 12
Regards
M. Gregg
Mini amps
Vox AC4 Vs Orange
YouTube - Vox AC4 vs Orange Tiny Terror. Comparison. Great audio!
http://wn.com/Vox_AC4_vs_Orange_Tiny_Terror_Comparison_Great_audio! <<<try track 13# Hideaway how does it compare with track 12
Regards
M. Gregg
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I'll describe is amp in some detail because it's very good at what it does and retails for $149 and that INCLUDES the cabinet, speaker silk screened front panel and some profit for both the reseller and Fender. I think one could build a Champ 600 clone $100. I don't think it cost Fender $100 to built it
You might be able to cram in an 8" speaker. I've seen it done but it is tight. It comes with a "Fender" brand 6" that might be built by Jenson. I installed a switching jack so if I plug in a speaker cable it disconnects the built in speaker. So I set the Champ on top on a 1x12 cab. For home use the Champ on a 1x12 goes up loud enough to be heard outdoors if playing in the living room. It is a "Fender clean tone" amp. If you want "crunch" you need an overdrive pedal or at least my Strat needs one. perhaps a Gibson with a humbucker could over drive the amp? I built a tube based overdrive "pedal" and with that I can get a Ritchie Blackmore "Smoke on the Water" tone that is fun to play for all of 3 minutes
The Champ 600 is easy worth $149 just counting the cost of the parts inside. It is built in a PCB but it is a very low density layout with large size axial lead components and wide PCB traces. Circuit is dead simple, two 12AX7 gain stages with TMB tone stack between but no pots, they used fix resisters but still the same TMB topology. Then the last grain stage to a volume control then a single ended 6V6 (metal envelope) power tube. The OPT is small but surprisingly the bass from the low open E string is strong. The cabinet is heavy MDF with tolex covering. There is some hum and noise if you turn it up. Some day "ill replace a resistor in the power supply with a 9H choke to address hum and re-work the heaters. but I use it as a practice amp and at those low volume setting the hum/noise is very low.
If you were looking to win this competition a Fender Champ clone with cab and speaker built for under $100, might pull a lot of votes. It would not be hard. Webber sells speakers like the one inside the Champ 600 for $25 each and a cab built from Home Depot #2 pine adds all of about $3 to the price.
My experience is that there is no correlation to how hard strings are hit and music genre.
Many metal plays are simply hot fast noise boys that are either slamming or speed & or sweep picking. Tapping & sweep pickers actually tend to have a light touch, lots of finesse. Same Genre, entirely different style.
Now SRV for instance, Blues/Rock, big fat strings, and he is really digging in on notes.
Some of the best acoustic work (or my favorites) those guys really dig in as well. Guys like Tommy Emmanuel routinely keep strings at the edge of failure.
Several boutique and replica amp vendors use a recorded chip to do exactly as suggested.
Input the same clip into multiple amps to show the basic differences in sound.
A good example of this is with Clark Tweed Amps, Listen to the clip of the Webster, then listen to the clip of the Beaufort.
Clark Webster
Clark Beaufort
Same clip, but obvious differences are present.
The universal clip idea though valid does have its virtues, but it also has another problem,
Input Reproduced sound then recorded & reproduced again. A lot can be lost Vs actually sitting there with an amp.
My old Saying/Joke, I do not need to sound good, I have (insert favorite software here) to eq, edit and master.
Funny but true.
I sold an amp I built to a lad a few years back, He bought it based on the clip he heard in my listing.
Recorded completely dry, flat/neutral eq's, guitar to amp, sm57 mic
Dimed Champish circuit, Stones- Cant you her me knocking.
about a week after he got it I get an email along the lines of I can not get the song to sound like the recording. Its distorted enough, but the tone is just weird. I think somethings wrong with the amp or speaker.
After a couple emails something occurred to me, He did not know how that tune was played. I sent him instructions on open G tuning. A few days later he responded back with a clip, Nailed it!
CE is fast with UPS 3day service, I ordered my stuff Monday and its scheduled to be here by the end of business today;
Tempe, AZ -Phoenix, AZ
Phoenix, AZ-Albuquerque, NM
Albuquerque, NM-Louisville, KY
Louisville, KY-Chicago, IL
Chicago, IL-Hodgkins, IL
Hodgkins, IL-Dekalb, IL
Out For Delivery
The judging based on audio clips should be a very small percentage of the challenge, it is far to subjective, and there are enough variables that it pretty much makes in impractical.
I look at this as a resource thread, already a great list of vendors & sources have appeared and it clearly shows that the "under $100.00" parts aspect can be achieved.
Now its the creative design aspect that should really be interesting.
Tubes not commonly seen in guitar amps are about to become valid contenders as well new and unusual twists on age old designs.
Some are going minimalistic and others? Possibly 5 tubes George? WOW!
At least this will not turn into another Epiphone Valve Junior Mod Thread. I remember when those first came out, so cheap that even if you blew it up it was a fun mod platform.
You can still buy those(heads) all day long on ebay for under $129.00
I just priced out the components, including transformers, tubes, sockets, resistors, capacitors, jacks, switch, volume pot, power jack, fuse holder, etc. to build a copy of the Fender 5F1 circuit. Not including the chassis, cabinet, or speakers, the cost is about $150.00. The transformers were sourced from Triode USA which seem to be the least expensive.
This is not based on "quantity" pricing. If I am missing something please help me out here. I did not price out the Fender 600. Maybe the cost savings is because the 600 uses a solid state power supply? I'm not seeing it.
"Sag" only matters on a push pull class AB amp. On the smaller single ended amps, maybe the kind built for this contest these would be running in Class A. A Class A amp actually draws more current when the input is muted.
If you are trying to go for the $100 budget, single ended is atractive because there is only one output tube. If you go that route "sag" is a non-issue.
Yes, the "600" uses two 5 cent rectifier diodes. I'd go with a chassis made from a cookie baking sheet from the 99 cent store. Check out "musical power supplies" for output transformers. Power transformers hard to find at low cost. Maybe back to back heater tranformers?
Shipping is the killer for building just one amp. it's easy to pay $6 to ship $5 worth of parts but if you order $100 in parts the shipping is free. Lilely you could build 20 champs for under $2,000