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Old 16th June 2011, 07:20 PM   #141
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Originally Posted by ChrisA View Post
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
The cost I calculated does not include shipping. The Fender Champ actually uses four 5 cent rectifiers, five including the one for the power lamp, but let's not nitpick. If you could provide a parts list so that I can build one of these for $100 it would be most appreciated.

Transformers from Musical Power Supplies are no cost savings compared to Triode USA.
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Old 16th June 2011, 07:23 PM   #142
TheGimp is offline TheGimp  United States
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I just looked at a spreadsheet I did on a 5F1 derivative using a 6P1P, 6N1P, 6K49VG pwr transformer and P-T31 OPT. The total inculding "Moonlight" Tone control and Jewel lamp was less than $85 (excluding shipping). An Edcor XSE10-8-4K which sounds better only adds $5.

I used a SS power supply.

Most of the prices came from Antique Electronic Supply. Power transformer from Allied.

I'd be willing to bet Fender only has MSRP/3 in the Champ 600. Standard mark up is 3X from mfg cost to MSRP.

Last edited by TheGimp; 16th June 2011 at 07:27 PM.
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Old 16th June 2011, 07:29 PM   #143
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Originally Posted by TheGimp View Post
I just looked at a spreadsheet I did on a 5F1 derivative using a 6P1P, 6N1P, 6K49VG pwr transformer and P-T31 OPT. The total inculding "Moonlight" Tone control and Jewel lamp was less than $85 (excluding shipping). An Edcor XSE10-8-4K which sounds better only adds $5.

I used a SS power supply.

Most of the prices came from Antique Electronic Supply. Power transformer from Allied.
That's not a 5F1 copy. A 5F1 does not use a 6P1P, 6N1P. The 6K49VG is the wrong voltage.
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Old 16th June 2011, 07:36 PM   #144
ChrisA is offline ChrisA  United States
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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.
No, I think there is more variation between player then between genre. There are some very well know players on youtube. One counter example your statement is t a you tube video where Richie Blackmore is interviewed and he shows how he plays his (way to well known) Smoke of the Water riff. They have close up detail shots and he talks you through it. What's surprising is this is done "finger style" no pick with a light touch on the strings. He "lets the amp do the work" The most recognisable metal riff on earth and he does it with a playing style borrowed from classic guitar

Also on you tune is Joe Satriani himself showing how to play some shredding metal rifs and, same thing, a very light touch. In fact he says that lifting the fingers on and off each string makes so much noise (compared to his playing) that he mutes each string with right hand when he must move a fretting finger. The amp has such a huge gain that otherwise fretting a string would make a huge noise. He holds the pick with thumb and index finger and uses the other three fingers mute fretted but unplayed strings. Most ordinary humans can't do that at his tempo so they play louder to clover of the fingers on the strings noise but he says you can't play fast if you take time to dig into each string, so he goes light on the pick and mutes unplayed strings. No way can I do what he shows, Then he continues on about unconventional chord progressions an "F minor, g9 or something like that". Then tells his students to "just improvise over those chords and keep muting" and adds, "I can't do it if I have the think about it, needs to be automatic."

you tube is great, there are a lot of want-a-be types on you tube but if you look some well respected top musicians too.

Last edited by ChrisA; 16th June 2011 at 07:41 PM.
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Old 16th June 2011, 07:54 PM   #145
TheGimp is offline TheGimp  United States
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That's not a 5F1 copy. A 5F1 does not use a 6P1P, 6N1P. The 6K49VG is the wrong voltage.
I didn't say copy, I said derivative.

B+ is close to 325V which is close enough to 340V which is what I've seen on 5F1 schematics.

I counted $7 for each tube which is close to what you can get JJ 6BQ5 and 12AX7 for.

So, the price is reasonable for what I've state.
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Old 16th June 2011, 07:57 PM   #146
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I don't think there should be a max power limit, if someone can do 15W and meet the budget why not? One can trade off features for power.......Some are going minimalistic and others? Possibly 5 tubes George? WOW!
.

I have employed a lot of creative shopping. My spreadsheet says I can build a 5 tube P-P amp that makes about 10 watts in "cranked Marshall" mode for just under the $100 limit. That is way too loud for a practice amp, so there will be a built in "power soak". Anyone who has spent nearly 40 years as an engineer in a big company knows that a spreadsheet can say whatever you want, so I will start building it when all the parts get here. Tubes? Lets just say that the sockets cost more than the tubes.

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"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.
Very true in the HiFi world. Not true in the guitar amp world. That lovely Champ left class A back in Kansas when you plug in a stomp box and ram a volt of input down its throat. Class A is a dream when the OPT saturates too.

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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.
If you build it the way Fender did in the 50's it will cost $$$$. If you use a 6AU6 driving a 6AQ5, use a N-68X, a cheap filament transformer, and a $13 OPT you can build it well under the $100 limit. With some creative re-engineering I can make a "Champ" for about $60 not counting cabinet or speaker. The little Champ transformer from Triode isn't to great either, its not much bigger than a 12AX7. It will saturate and force deviation from class A though, especially when you stuff a KT88 in a Champ. Don't do that with the stock Champ. You WILL smoke the power transformer.
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Old 16th June 2011, 08:03 PM   #147
TheGimp is offline TheGimp  United States
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and no it wasn't a theoretical amp only in a spreadsheet.
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File Type: jpg 5F1_Russian_.JPG (206.3 KB, 262 views)
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Old 16th June 2011, 08:06 PM   #148
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Originally Posted by TheGimp View Post
I didn't say copy, I said derivative.

B+ is close to 325V which is close enough to 340V which is what I've seen on 5F1 schematics.

I counted $7 for each tube which is close to what you can get JJ 6BQ5 and 12AX7 for.

So, the price is reasonable for what I've state.
A 12AX7 cannot be purchased for $7 in single quantities from any reputable dealer. If you have a source I would really appreciate knowing about it.
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Old 16th June 2011, 08:13 PM   #149
TheGimp is offline TheGimp  United States
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Ok, so I'll go with 9.75 for a JJ 12AX7 and 9.40 for a JJ EL84 from AES (I can get them cheaper but this was the first price I hit).

That puts the cost at 87.94 plus shipping.
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Old 16th June 2011, 08:19 PM   #150
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Nice work, I like it!
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