Which Fender Deluxe Circuit?

[Glowin Plates]

Hello

I am considering building an amp using a Fender Deluxe Circuit.
I am unsure weather to use the older circuit (TV front) with the 6SC7 for the preamp and PI.
Or the "newer" circuit employing the 12AY7 and 12AX7.
I am after a warm cleaner sound as I (try to) play jazz.
I want to use my old 10 Watt Goodmans speaker so lower power might be better.
Has anyone gone down this road and care to share?

[OneyedK]

I can't say I've travelled down that road, but I have a fair bit experience in servicing these things.

First of all, the use of 6SC7 versus the 12AX7/12AY7 does not make all that much difference.
What makes a difference is the PI.

5A,B,C,D3 used paraphase PI's, these can sound really great, but often ask some fine tuning of components. Not exactly plug and play diy.

5E3 was the oddball in the series, as it used the cathodyne/split-load/concertina PI, depending on the guitar/pickups you are using, this might be the best choice.

6G3 and up use long tail PI, so that's basically a mini silver bassman/bandmaster. They also use global feedback, something I wouldn't recommend for jazz. Since the balance (or unbalance if you like) between non-inverted and inverted outputs can be tuned, these circuits are great for blues and classic rock.

And the most important thing is the output transformer.
Since higher frquencies are less important to a jazz player (you would end up turning the treble completely counterclockwise), the best way to go is a relatively cheap oversized transformer. 2-4 times the expected power of the amp.
Someting like the Hammond 1750NA (they say it's a Marshall replacement, but who cares) or an Edcor XPP25-8-7.6K

[Glowin Plates]

Now I look at my book closer they do list the 5E3 schematic.
I am using a humbucking Benedetto in the neck position for a pick up on a
carved archtop guitar so it's a bit prone to feedback.
I have to buy a OP TX for this project so that was a timely tip.
Thanks for that.

[OneyedK]

Another tip:

Loaded FENDER 5E3 TWEED DELUXE
--> go for the carbon comp resistors

I like the MiniMax principle, minimal effort, maximal result, you can always start the tweaking later (if needed).
Stuff from turretboards is pretty well made...

[RTF671]

Ah, the good 'ol 5E3 is a good base to start from to make a good guitar amp. However, some areas should be improved upon considering many new technologies have changed things since then. Now the question is, what do you want?

Considerations:
-Push/Pull or Single ended?
-Reverb and/or tremolo?
-Input stage?
-SS or valve recto?
-Tone controls?

My advice versus what you specified you're after:

Push/Pull 6V6 pair with a cathodyne phase inverter just like the 5E3. That will have a warm guitar tone and allows the use of a tube rectifier (Tube rectos don't affect single ended amps because they draw max current always).

Reverb is always pleasant, but somewhat more difficult to add to amps for someone who hasn't done it before. Tremolo on the other hand is easy to add (takes a single triode, which is half a typical dual triode).

The input stage has 4 inputs for this amp. Do you need four inputs? Each 2 inputs get its own gain stage. If you cut it down to 2 inputs you can recover half the valve (which can be used for other things like tremolo )

If Jazz and warmth are your goal then you should keep the tube recto. With the 5Y3 you will get power supply sag but it takes the 5Y3 nearly a half second to swing the voltages.

Now somewhat of a concern is tone controls, the original Deluxe was lacking in this area. In order to get good tone controls you will have to add another tube (a 12AX7/AU7 would be best).


Think upon this and consider what else do you want to add/change. The 5E3 is a good tried and true design but does still have areas for improvement.

[Glowin Plates]

Yes some good points.
I'm not really worried about reverb or tremolo and only really need a
single input.
I allready built a cabinet around an existing 12" Goodmans 10 Watt speaker
and a old radio/phono chassis with a p-p 35L6 pair of sockets.
Which happily will work for 6L6 tubes also.
So the deluxe circuit seems a good match.
If I can build a great sounding practice amp I will be happy.
If it sounds better than my Princeton doubly so.

[OneyedK]

Originally Posted by Glowin Plates

If it sounds better than my Princeton doubly so.

What kind of Princeton do you have?
(have a look inside the cabinet, on one of the sides the reference number of the schematic used is marked on the paper that states what tubes are used)

[jjman]

Old model Deluxes are not commonly felt to be "clean" or "jazz" amps. However I don't care for "clean-jazz" amps anyway, regardless of the style of music being played.

The 5E3 is very common to build since it's fairly simple and can sound fantastic.

[OneyedK]

Originally Posted by jjman

Old model Deluxes are not commonly felt to be "clean" or "jazz" amps.

The 5E3 is very common to build since it's fairly simple and can sound fantastic.

Yep, I agree.
But this is a new built, so Glowin Plates doesn't have to settle for an undersized and not remotely balanced output transformer like Fender did.
And because of the component and voltage tolerance, some deluxes are biased hot (as they should be) and some deluxes are more centre or cold biased. (talking préamp tubes here)
Same goes for the power tubes, autobias, yes, but seldom biased the way they should be.

All those things can be tuned to create a perfect (and this depends on the player and his ears) tone.

[RTF671]

OneyedK is right, the more subtle and appropiate alterations can make the tone better. Some people get lost in the "vintage" way of doing things when they really just went with cost-effective methods.

A bigger OT will provide a cleaner responsiveness overall. It can even be oversized to provide even more effect.