5e1 Cap questions

[Rp3703]

So my brother wants me to build him an authentic 1957 champ as a head. I noticed Fender upsized cap values in subsequent champ models. Should I keep the filtering exact to the original specs or should it be changed for more up to date safety requirements?

Also, what would be the equivalent to the .02/600V coupling caps used in the original in todays market?

[sluckey]

So my brother wants me to build him an authentic 1957 champ as a head.

So use the same value components as listed on the schematic.

Here's a Jupiter brand .02µF/600V
https://hoffmanamps.com/MyStore/perlshop.cgi?ACTION=enter&template&thispage=Capacitors&ORDER_ID=!ORDERID!

[Latole]

I will modify heater circuit for quieter amp. I'll build 2 wires heater with center tap to ground.
Original heater with one side at ground make the amp noisy.

Don't use the .05/ 600v death cap.
Use 3 prongs cord, not 2 prongs
 

[ac427v]

You want to research that choke. It is not a standard fender choke because this design has all the amp's power flowing through it. Some of the single (ended) guys here probably can tell you an appropriate substitute.

[Rp3703]

In this thread, it was debated and concluded that a 50mA 4h choke will work.
https://el34world.com/Forum/index.php?topic=19378.0

[Latole]

Choke ;

https://www.tubesandmore.com/products/transformer-hammond-output-replacement-fender

[Rp3703]

While we're discussing parts, I plan to use a Hammond 290AX (650/550 @ 100mA, 6.3V @ 2.25A, 5V @ 3A) for the PT and a Hammond 1760C (5W @ 3.2,8,16 ohm) for the OT. I know 8ohm is authentic but I figured it might be nice to have more options when pairing this with speakers.

[Latole]

While we're discussing parts, I plan to use a Hammond 290AX (650/550 @ 100mA,

Too powerfull for this amp
And cost more for nothing

Use my link for XFRs
_________________

Update ; my link suggest also the 290AX !!!!  Go with this one

Older reference I have say 70 ma for Champ, look no more available

To resume ; Both transformers you wrote are good choice

[Rp3703]

Hammond makes 3 or so different champ PT's and the AX is the cheapest even though they all seem to have the same specs.

[Latole]

Hammond makes 3 or so different champ PT's and the AX is the cheapest even though they all seem to have the same specs.

I see only two on Hammond.com.
The other one is more expensive because it is a export xfr

https://www.hammfg.com/electronics/transformers/classic/290

[Rp3703]

Thanks for confirming that for me.

No issues going with a multi-tap OT?

[Latole]

Thanks for confirming that for me.

No issues going with a multi-tap OT?

No, it is a better choice.

[j_bruce]

If someone asked me to build an "authentic" Fender Champ I would ask them if they wanted straight from the schematic authentic, or slightly improved (like two wire heater supply and multi impedance output transformer). If someone really wants authentic then they may want the nose of the heater supply and the resulting tonal impact of that noise?? I suspect that a multi-tap OT sounds slightly different than a single tap OT too??

The only deal breaker to me would be not using a three prong power cord and putting the fuse on the hot.

Just my .02
Jerry

[Latole]

You can't built "authentic" Champ

Capacitors are not same.
Transformers are not .
Cabinet wood not.
Speaker not.
And most important ; tubes
They could be close, but not same.

Anybody who know what he is doing and know what is a 1957 Champ will built a clone with all 1957 "defects".

I will not modify a real vintage '50 Champ, a collector item. I wont build a clone with  is "defects"

[Rp3703]

I’m pretty sure I found the same forest Leo got his Champ wood from. I’m having  the tree milled as we speak.

I am looking for as close to original within reason. Even if I could build exact, since the player will never be able to play it side by side with an original, he will never know the difference.

[Latole]

I’m pretty sure I found the same forest Leo got his Champ wood from. I’m having  the tree milled as we speak.


 
I am looking for as close to original within reason. Even if I could build exact, since the player will never be able to play it side by side with an original, he will never know the difference.

Finding a forest is easy, now try finding the few hundred years wood.....

This guitar player don't know what is Champ, a noise in a Champ.I would explain to him before.

If he know something about Champ, he will bought a clone from different builder. I will have more value than a home made.
 
He his the customer, you are the builder and you will have his money. Go ahead.

$1400 for a Victoria

[sluckey]

I know 8ohm is authentic but I figured it might be nice to have more options when pairing this with speakers.

Something to consider... A champ was the cheapest amp Fender made. This included a cheap-ass 8 inch speaker that had very poor low frequency response. When you pair that cheap amp with a good quality speaker you will soon notice low freq. hum that was not noticeable with the cheap 8" speaker. At that point you will likely be modifying the power supply of your "authentic" cheap amp.   

[Rp3703]

"When you pair that cheap amp with a good quality speaker you will soon notice low freq. hum that was not noticeable with the cheap 8" speaker. At that point you will likely be modifying the power supply of your "authentic" cheap amp."

What's the solution for solving that issue now? Fender's $900 reissue looks like they add a fourth filter cap as well as upsizing of the first cap. It also looks like they skipped the choke.

[Latole]

  I know 8ohm is authentic ......

Wrong original is a 3.2 Ohm. Jensen P8Q.

Fender Champ RI use 4 ohms spkr

[Latole]

"When you pair that cheap amp with a good quality speaker you will soon notice low freq. hum that was not noticeable with the cheap 8" speaker. At that point you will likely be modifying the power supply of your "authentic" cheap amp."

What's the solution for solving that issue now? Fender's $900 reissue looks like they add a fourth filter cap as well as upsizing of the first cap. It also looks like they skipped the choke.

You ask for solution ! I write a bout that yesterday.

IMO Fender skipped the choke for cost cutting.
Filter caps in RI ;" better" sound, more punch.

Fender Champ 57 RI

[SILVERGUN]

In this thread, it was debated and concluded that a 50mA 4h choke will work.
https://el34world.com/Forum/index.php?topic=19378.0

Except, your 5E1 was not mentioned.
Using a 50mA choke in that position is not a great idea.
ac427v was giving you good advice in reply#3.


If you are going to use the choke position in the original schematic, I would suggest going bigger.

[Latole]

http://www.classictone.net/40-18040.html

http://www.triodeelectronics.com/22707.html

[Rp3703]

"Except, your 5E1 was not mentioned."

No, they were discussing a Princeton, which is just a 5E1 with an added tone knob.

So if AC427 and Silvergun post that 50mA is not enough and Latole posts links to a 50mA and a 40mA choke marketed as champ replacements, does this mean the debate is back on?

[SILVERGUN]

Compare the schematics to understand the debate.


If Mr. Kuehnel says it's ok, then it's ok with me.
https://www.ampbooks.com/mobile/classic-circuits/fender-champ-5e1/

[Rp3703]

You ask for solution ! I write a bout that yesterday.

IMO Fender skipped the choke for cost cutting.
Filter caps in RI ;" better" sound, more punch.

Fender Champ 57 RI

So looking closer at the 57 RI, I have some questions.

1. The 305V on the second filter cap is same as original but that 470K 2W resistor is not. What's the purpose for putting that in there?

2. Why do you think Fender beefed up the bypass cap by a lot on the 6V6? Was there an issue with the original 25u/50V?

[Rp3703]

More questions.

3. In the PSU, are the diodes before the rectifier necessary?

4. What is the cap and resistor thing on the primary side of the PT?

5. What watt should the HV center tap resistors be?

[Latole]

More questions.

3. In the PSU, are the diodes before the rectifier necessary?

4. What is the cap and resistor thing on the primary side of the PT?

5. What watt should the HV center tap resistors be?

2-  No, they are there in case tube rectifier blow

3- Heat sensing (thermistor, some fuse).   Capacitor noise filter ?

4- 1/2 watt. It is not HV, it is tubes heater winding, LV

2-3  : Perhaps it is required by an American organization as protection ANSI  ?

You are new in tubes amps ?

[shooter]

Why do you think Fender beefed up the bypass cap by a lot on the 6V6? Was there an issue with the original

experiment, put in the original, play til you can't.  double the value - repeat

pretty sure Fenders "motivation" is Benjamin's 

[sluckey]

No, they were discussing a Princeton, which is just a 5E1 with an added tone knob.

Not so. A Princeton 5F2A is a 5F1 with an added tone knob. Significant difference between 5E1 and 5F1. Look at the schematics.

So looking closer at the 57 RI, I have some questions.

1. The 305V on the second filter cap is same as original but that 470K 2W resistor is not. What's the purpose for putting that in there? It's a screen resistor. Limits screen current. This is an improvement over the original.

2. Why do you think Fender beefed up the bypass cap by a lot on the 6V6? Was there an issue with the original 25u/50V? Nowadays Fender buys 22µF/450V bu the truckload. Cheaper than stocking a 25µF/50V.

3. In the PSU, are the diodes before the rectifier necessary? No. Considered an improvement over the original.

4. What is the cap and resistor thing on the primary side of the PT? RT1 prevents high inrush current. High resistance when cold, low resistance when hot. The "Class X" cap is a line filter.

5. What watt should the HV center tap resistors be? Schematic says all resistors 5% 1/2W unless otherwise noted.

All these things are modern improvements to the amp, just like the three prong power cord. But you are straying from an authentic 5E1.

[ac427v]

I've been hoping someone who has built a 5e1 would chime in on the choke question. I have not built that version of the champ. Fender does not specify the choke they used. One builder in another thread used a Hammond 156L. 5 Henries. 75ma. 135 ohms. 1/2 lb. It needs to be robust because it carries the high voltage for the power tube plate and the rest of the amp. Most amp designs do not use a choke and two caps to filter the power tube plates. Expensive but very effective.

[sluckey]

It's a popular mod to add an additional cap/resistor between the recto and plate node in a Champ to reduce hum. A cap/choke would be even better.

[Latole]

 But you are straying from an authentic 5E1.

We are very far from the very small modification of the heaters circuit that I suggested earlier on which members wrote to the non respect of the original Champ '57 circuit. 

[sluckey]

We are very far from the very small modification of the heaters circuit that I suggested earlier on which members wrote to the non respect of the original Champ '57 circuit. 

That is a small change on paper and easy to do on a new build. Actually making the change inside an original tweed style chassis is quite another thing.

[Latole]

That is a small change on paper and easy to do on a new build. Actually making the change inside an original tweed style chassis is quite another thing.
[/quote]

Yesterday I wrote, I'll never mod a original vintage Champ

[Rp3703]

Wow, a lot of replies in just a few hours. So, I took another look at the Fender 57 RI and realized it is actually a 5F1 circuit. So when my brother said he wanted a 57 Champ, he was actually talking about the 5F1. Oops. So now that I'm essentially making a replica of the 57 RI, is there a benefit to adding a choke or should i just use a resistor like Fender did?

[Rp3703]

You are new in tubes amps ?

Not new. I've built 6 or 7 but building tube amps and know what everything does are two different things.

[SILVERGUN]

Everything you need is right here
https://el34world.com/schematics.htm#Hoffman_5F1_Tweed_Champ


The resistor will perform a function that a choke won't in the 5F1

[sluckey]

Everything you need is right here
https://el34world.com/schematics.htm#Hoffman_5F1_Tweed_Champ


The resistor will perform a function that a choke won't in the 5F1

Simply replacing R14 with a choke will not turn a 5F1 into a 5E1. Better take a look at the two schematics.

[Rp3703]

I've got it all figured out. I was originally going to build a 5E1 but now I'm switching to a 5F1. No choke will be used. Sorry for the confusion.

[sluckey]

Now Hoffman's 5F1 is a good candidate. Should be a fun/easy project.

[SILVERGUN]

I was just looking around on ebay and came across this listing. Not a bad deal.
https://www.ebay.com/itm/Combo-Cabinet-For-5f1-Chassis-and-10-Inch-Speaker/184367295930?hash=item2aed25adba:g:D8wAAOSwW4JeQ7X2


I just saw you specified a head in your initial post. Left this up just in case...

[Rp3703]

Yes, this project started out as a head but has now turned into a combo. That is a good deal for a pine cabinet but I was thinking something more like this since the resale is so much better.

https://reverb.com/item/14987098-fender-custom-shop-forest-fire-juniper-57-champ-guitar-amplifier-only-one-built?utm_source=rev-ios-app&utm_medium=ios-share&utm_campaign=listing&utm_content=14987098

Yes, I am kidding.

[bmccowan]

Should be a fun competition to see what sells first. That firewood amp or this $22,000 6G3 that was reportedly modded by Dumble. https://reverb.com/item/8002544-dumble-modded-fender-brown-deluxe-1962

[Rp3703]

Just wanted to say that the amp turned out great. I decided to make my own eyelet board since I wanted something that looked closer to the original. Building the cabinet myself brought the whole project in at around $400(not really sure the exact total since I made my brother pick out and pay for his tubes and speaker which he spared no expense on). I have to say, I'm not really a fan of this amp. It's very dark sounding to me. I was only able to play through it with a Gibson SG and I'm guessing it's geared towards single coil guitars. At least I can say I have built and played through one now. It was a pretty easy project to build. Thanks for everyone's help.

[shooter]

It's very dark sounding

that can be tweaked easy enough;
start with anyone you know's 2X12 or 4 X10/12, good speakers, then evaluate "dark" again, your guitar choice was fine 


to late to hunt a schematic, if V1A has a 22-25uF ecap, swap for 5-10uf, you might get by with 1 speaker

[HotBluePlates]

Choke ;

https://www.tubesandmore.com/products/transformer-hammond-output-replacement-fender

While we're discussing parts, I plan to use a Hammond 290AX (650/550 @ 100mA, 6.3V @ 2.25A, 5V @ 3A) for the PT ...

This amp is built, but for future reference be careful assuming too much from models listed by Hammond, Antique Electronic Supply or Classictone.  First, Fender used the same single power transformer in the blackface Champ, Vibro Champ, blackface Princeton and blackface Princeton Reverb.  Fender used 3 different models of power transformers in the brown 6G3 Deluxe, and at least 4 different models in the blackface Deluxe Reverb.  The PTs in the vintage Fenders I own don't exactly match the Hamond parts listed as replacements.

I know 8ohm is authentic but I figured it might be nice to have more options when pairing this with speakers.

Something to consider... A champ was the cheapest amp Fender made. This included a cheap-ass 8 inch speaker that had very poor low frequency response. When you pair that cheap amp with a good quality speaker you will soon notice low freq. hum that was not noticeable with the cheap 8" speaker. At that point you will likely be modifying the power supply of your "authentic" cheap amp.   

It's a popular mod to add an additional cap/resistor between the recto and plate node in a Champ to reduce hum. A cap/choke would be even better.

I was really hoping he'd stick with the 5E1 circuit...  I wrote up a little survey of available Fender Champ/Princeton schematics, and showed while everyone seems to copy Fender's last Princeton & Champ circuits (they must be "the best" right?), the earlier amps had power supplies that would hum less (whether you go for a choke or a resistor).

[ac427v]

Nice job....that's a beauty! The perfectionist in me says the wirenut has to go. I would opt for something able to handle the jarring that an amp endures. Like solder and heat shrink or soldering to a terminal strip.
What's the next project? I want to see more finger joints.

[Rp3703]

The wire nut was my quick solution for the multi-tap OT I used to allow my brother to try out different speakers if he wants to in the future. I could have installed an impedance switch but I would have had to cut a hole in the chassis. I then thought about using some extra boat motor connectors I had but I'm still worried about the unused leads bouncing around inside and coming in contact with something. In the end the wire nut was what I chose due to ease of operation. Now that you mention it, a terminal strip with each secondary on a different terminal and a spade connector running to the speaker jack would be a safer way to do that assuming the spade connector will connect to the terminals.

No more box joint projects for me. I have limited patience for cabinetry. I have to finish my Marshall 1959 build that has an oscillation problem. It works with the PPIMV but if I dime the PPIMV, the regular volume will only go to three before it goes into oscillation. It sounds good with the PPMIV so it has not been a priority. After that, I need to fix a Bassman 100 clone I built that crackles when vibrated from too much low end. Probably a tube issue. I think I'd like to build an AC30 circuit as a 5 or 15 watt but I will probably take a break from amp building for a few months.

[Rp3703]

The terminal strip was a great idea!