Poor man's Fender tweed amps

[omphalopsychos]

Just wanted to add one thing. I switched the preamp tube from a 12ax7 to a 12ay7. The outcome was less muddy bass and slightly more headroom and clarity. I recommend!

[Herbie]

I just got a 5f1 in a large cab with a 10" speaker yesterday. It was a prototype by a guy starting a custom amp business. He did a very clean soldering job and it sounds terrific. You guys would kill me if I told you how little I paid for it.

Attachment 55647Attachment 55648

Now THAT is neat work! Oh my!

[Gitfiddler]

Since the title of this thread is "Poor man's Fender tweed amps...", let me suggest the "Extremely poor man's version.

Fender Silverface Musicmaster Bass Amp! (Hint: Only plug in guitars. Never plug a bass into this rig!!)
The tweediest sounding version is the later model. All it has is Volume and Tone, runs two 6V6 tubes and a single 12AX7, pumping out 12 loud watts and it rocks old school! It is priced between $400 - $500, but since it was a beginner bass amp, condition is all over the map. Look for a clean one if interested. Mine has been modded to give it a bit more headroom and better tone; plus it now has a Cannabis Rex. With only an EQ and Reverb pedal, this little amp is ready for small-medium clubs. Tons of tweedy fun for not much cash.

Fender Silverface Musicmaster Bass – Ampwares

[Mike Anderson]

Thanks! In the price list he does seem to sell combos with Mather cabs, no idea if he'll let you choose the cab and price accordingly. Only one way to find out! That said, might go with a kit + Mather cab and DIY the thing - taking all necessary (to the point of overkill) precautions since I'm a noob.

[iim7V7IM7]

Give Jim a call. He will explain what your options are in terms of no cabinet or a cabinet by Peter etc. Peter posts his cabinet prices on his website as well.

Thanks! In the price list he does seem to sell combos with Mather cabs, no idea if he'll let you choose the cab and price accordingly. Only one way to find out! That said, might go with a kit + Mather cab and DIY the thing - taking all necessary (to the point of overkill) precautions since I'm a noob.

[Tal_175]

Noise floor depends on a lot of things, including component choice, layout, and lead dress. And it is possible to build a Champ with ZERO hiss and hum, but you won’t do it with carbon comp resistors and slavishly following the Fender schematic and layout.


steven

So I guess it's fair to say that it's practically impossible for a first time builder to achieve zero hiss and hum following a schema based on Fender design using components that come with the kits suggested in this thread.

[stevo58]

Maybe, maybe not. Carbon comp resistors will produce hiss, there’s no way around it. The original design uses pretty lightweight power supply filtering, so you have ripple coming through. This was a student amp and was as cheap as possible, and electrolytics were expensive. The heaters use the chassis for one side of the connection (although I doubt any of the kits do this). To get it dead quiet you would, for example, switch to high-quality metal film resistors (e.g. Dale RN65), elevate the heaters by tying a center tap to the 6v6 cathode, and increase the filtering. As a start.

But you should be able to get a fairly quiet amp out of a kit. It probably won’t be did-I-turn-this-on-it’s-not-making-any-noise-oh-there-it-is quiet though.

Steven

[Tal_175]

Ok so I went to my local store that had one 57' Champ. I played it for an hour or two, loved it and bought it!
I even had it set up with an external 12 inch cab in the store to see how it would sound with my Princeton cab. It sounded good, but I like the 8 inch cab it comes with just as much. I played tweed amps before and I've wanted one for a long time but I just needed to play more before justifying forking out the cash.
Thanks for all the suggestions. Building one seemed very tempting but I just finished building a guitar, it's very time consuming. As much as I like doing projects, they disrupt my playing/practicing schedule, so I said no more projects for a while.
Boutique makers are tempting too, but I could play the fender model in the local store before buying which is a big advantage. I wasn't going to not buy from the store and order online after having them jump through hoops for 2 hours, as I've relationship with my local guitar stores.
Anyway I love the thing. Pure soul. Great with pedals too. Amazing O/D tones.
Tweed Deluxe was too expensive. May be that would be my next project. NO. I didn't say that.

[stevo58]

You made an excellent decision. Have fun with the amp.

steven

[Tal_175]

Thanks. It does have a little 60 cycle hum. It comes after the amp warms up, whether or not a guitar is plugged into it. The hum does not get louder with the volume, stays the same. It's quiet enough that it's not heard over even quietest guitar sounds. But loud enough to be heard in a dead quite room no matter where you stand if you're paying attention to it. During the day over the normal background noise of the city I don't notice it. After volume passes 9 there is a bit of hiss too. It doesn't bother me. I guess these are normal for a 5f1? Part of the champ charm?

[stevo58]

Pretty normal. Hum is coming from the heater chain (tubes have to be hot to work, so there is a 'heater' which ... heats). Constant volume means it's coming after the volume control. The Champ is a single-ended amp, which in this case means one tube (the 6v6) is producing all the power. In a push -pull amp (generally any amp with more than one power tube) the output signal is split into positive and negative parts (highly simplified and inaccurate description) and each part is amplified by its own power tube, and the heater hum (from the output section) cancels itself out. This doesn't happen in a Champ. You can completely eliminate hum in a Champ but it requires significant modification and would destroy the amp's value, and isn't worth it.

The hiss comes from the type of resistors used in the amp. Hiss can also come from the preamp tubes. In my experience Russian 12ax7s often are hissy. You're not going to change the resistors, but it is definitely worth your money to buy a good NOS 12AX7 - RCA, GE, Sylvania, TungSol, and so on. It will be expensive but preamp tubes last a long time, and you only have one in this amp, and it makes a big difference.

Steven

[radiofm74]

Congrats! I can only say that tweed champs are a lovely thing. I have a 5F1 Mojotone kit (which I had expertly assembled by my excellent amp tech so as to be noise-free) and it’s a wonderful little amp. Wth my DeArmond or with my tele it produces all sorts of wonderful swing and western swing tones.

So: small, light, great tone, quiet enough to play at home with good tone, loud enough to play in a duo, or with horns and double bass (tried that… a blast), or possibly even in a combo with a fairly quiet drummer.

Enjoy it!!

[Tal_175]

Update on my Champ. The amps hum has gotten worse over the past week. Now it's loud enough that I can hear it over guitar when I play gently at volume about 3 (just to give an idea about the loudness). Otherwise I Iove the amp. I don't know how I lived without a Champ all these years.
I'll bring it back to the store and let them have a listen. I wonder what the store's tech will think. I understand that with Champs some noise is acceptable. But I believe the noise has gotten passed that reasonable limit. Gets worse after an hour or so play.
The amp is still in the return window but I don't want to return it. If they consider this within the window of "acceptable noise for Champ". I'll have to find a good tech to eliminate the noise.

[Longways to Go]

Have you tried swapping out the preamp tube?

Every Fender tube amp I've ever purchased new came with noisy tubes and greatly benefited from a tube swap.

[Hammertone]

Or just get one of these - a little 1x12" Koch SE6:
-Class A, runs either a 6V6 or EL-84;
-runs either at 6 watts or 2 watts
-compact, with some useful features.
-speaker outs can drive a 4/8/16 ohm cab

[John A.]

Update on my Champ. The amps hum has gotten worse over the past week. Now it's loud enough that I can hear it when I play gently at volume about 3 (just to give an idea about the loudness). Otherwise I Iove the amp. I don't know how I lived without a Champ all these years.
I'll bring it back to the store and let them have a listen. I wonder what the store's tech will think. I understand that with Champs some noise is acceptable. But I believe the noise has gotten passed that reasonable limit. Gets worse after an hour or so play.
The amp is still in the return window but I don't want to return it. If they consider this within the window of "acceptable noise for Champ". I'll have to find a good tech to eliminate the noise.

If the noise is getting worse, that's a sign that something is wrong with the amp; that's not normal amp behavior. IME, a "healthy" amp might start out with some hum and noise, but this would fade as it warms up, not get worse.

John

[Tal_175]

The amp is new and it has 2 years full warranty. Tubes have 1 year. So I'll wait and see the outcome of the warranty process before replacing any components.
I'm completely in love with Champ, so I wouldn't consider getting any other amp as a replacement at this point.

[radiofm74]

My tech changed the layout slightly (especially the placement of the transformers) to reduce hum. My champ is as quiet as a mouse

[Greentone]

Your Champ hum could be a ground issue at the input. I had a guy bring me a Champ once that was humming big time. Turned out that the input grounding was getting dodgy. I resoldered things there and the amp got real quiet.

[DRS]

VHS (the new ones made in Asia, not the old high gain Fryette made ones)

[Longways to Go]

The amp is new and it has 2 years full warranty. Tubes have 1 year. So I'll wait and see the outcome of the warranty process before replacing any components.
I'm completely in love with Champ, so I wouldn't consider getting any other amp as a replacement at this point.

FWIW, tube swapping doesn't cancel any warranty, as the original tube can be plugged right back into place.
The whole process takes only a moment if you have easy access to the tubes. A little longer if they are caged or buried inside the cabinet. I'm no amp guru, but I do know that when it comes to tube amps, the tubes are the first suspect and by far the easiest cure.

[Tal_175]

FWIW, tube swapping doesn't cancel any warranty, as the original tube can be plugged right back into place.
The whole process takes only a moment if you have easy access to the tubes. A little longer if they are caged or buried inside the cabinet. I'm no amp guru, but I do know that when it comes to tube amps, the tubes are the first suspect and by far the easiest cure.

That's true. I have changed tubes before in my other amps. The reason I want wait until the tech sees it is, if the tube is faulty it'll be covered by the warranty and I won't have to pay for it.

[Tal_175]

Just an update on the amp. I took the amp to the repair department of the store I bought it from last week. They just got back to me. Unfortunately, as I expected, they said they contacted Fender and the official word is that the 60 cycle hum is to be expected with these amps. The tech said he replaced the power tube and the hum is a little bit quieter but it's still there. He said he himself was surprised after seeing the price tag of the amp that it wasn't quieter. I understand that there is nothing else the store can do at this point (as part of the Fender warranty).
Anyway, I haven't picked up the amp yet but since the noise has gone down I might be able to live with it happily. If not, I'll need to get the amp modded so it runs quiet. If it comes down to it, is it there a standard method to fix the 60 cycle hum noise in these amps? Stevo58 mentioned heaters as the cause of the noise. Is there an easy mod for that? Greentone mentioned grounding connection. The tech said he checked all the wiring. So probably in this case this wasn't the issue.
Would modding the heaters change the tone? Should I not mess with it and find a good tech? (that's if I still find the noise too much for my liking)

[stevo58]

Retiring the heaters is only one of a number of things, and by itself won’t bring much.
When I build a single-ended amp, generally I will do the following:

All all these things are things which, in my experience, reduce hum. Others will have different experience.


- wire the heaters as suggested here - The Valve Wizard.

- tie the heater center tap to the cathode side of the power tube cathode resistor

- use a rheostat to balance the two heater sides

- add a large electrolytic to shunt AC from the 6V6 screen grid to ground

- split signal ground into high and low current halves. High current grounds to chassis near the PE, low current grounds as far away from that as possible, close to the input jacks.

- position the output transformer for minimum interaction with the power transformer.

- I will generally use heavier power supply filtering than used in a stock Champ. Generally I will use a 22u reservoir cap, followed by a 40u and several 20u nodes. I’ve used up to five nodes in a Champ with reverb and tremolo.

I would never make these mods to your amp. It would be simpler to build a new one.

make sure you are judging hum with no guitar plugged in, so you don’t confuse hum induced in the pickups and cord with amp hum.

I think you either have to accept it, or return it.


That said, it is possible to build a zero-hum single -ended amp. I have done so many times.

Steven

[Tal_175]

It has the hum without a guitar plugged into it. Hum doesn't change when a guitar is plugged. Also hum doesn't increase with the amp volume. Just a hiss in introduced when volume above 8-9.