Please suggest tube amp build + other questions

[FWAU112358]

Hi everyone.
I play jazz on a Fender MIM Telecaster HH.
It's stock, although I have in mind: a) bypass the guitar tone, b) upgrade the bridge pickup.
Right now I'm playing thru GarageBand and headphones.

I'm looking to build a minimalist tube amp to get that ever elusive rich sweet jazz tone.

Question: When I look at a tube amp kit like the 5F1 on MojoTone (http://www.mojotone.com/kits/TweedAmpKits_x/Test-Tweed-Champ-Amp-Kit), I notice that it's described: "it has a nice clean sound at its lowest volumes but introduces an articulate and unique grit as you increase the amp's volume". I'm also noticing that a lot of amps (on YouTube videos, for example) are mic'd. Is this a general characteristic of tube amps in general? Or is this a characteristic of the specific amp model in question? I ask this because I want to select a model to build which will stay clean throughout the range I intend to use it, which is basically "room-sized" (a house room, not a club). To be clear, I'm not interested in an amp that I need to mic in order to hear in a room in my house (this strikes me more as a pre-amp than an amp, right?) I suppose that this would then mean that I'd have multiple amplification stages in the amp??.

Also, I've noticed that one of the higher-regarded production amp series, the Henriksen line (https://www.henriksenamplifiers.com/) claim to be so good because they don't distort the natural guitar sound. They provide a 5 band EQ, but perhaps this is for matching tone to a band or club setting??

Question: In your opinion, is the "sweet rich jazz tone" mostly a product of the guitar system (heavier jazz strings + good neck pickup) combined with pleasing harmonics via the tube amplification, or do specific EQ settings also go into the equation? Initially, I think I'd rather build the amp without EQ and reverb and add after the fact with pedals if I want to go that route.

So, with that in mind, can you recommend a known amp / tube setup / circuit / anything to get started on from which I can buy parts and assemble an amp?

Thanks in advance.
And if my questions are silly or don't make sense, I apologize up front. I'm learning a lot of new things and may have mis-applied what I do/don't know!!

[ajaxlepinski]

Welcome to the fold brother! This is the best guitar/amp forum on the interwebznet!!!


Check out this Django Reinhardt amp page: http://www.djangobooks.com/Category/amplifiers_pickups

When an amp does not distort at high volumes, it means that it has a lot of "headroom".
Many amps "break up" and become "gritty" as you turn the volume up, the quicker they break up, the lower the headroom.
Where (on the dial) and if the amp breaks up can be good or bad, depending on the player's taste.
"Articulate" means that the amp and speaker react quickly to your playing.
A "squishy amp" like my Sunn Solarus, makes notes sound like they blend smoothly together in a nice way, but you lose a bit of clarity.
Transistor amps are generally more articulate and reactive than tube amps.

When making a recording, a microphone near the speaker will generally sound better than a recording made with a room mic.
YouTube videos made with cell phones usually sound awful. Many people want to present their music in the best way possible and using a microphone and recording software is usually the only way to do that.

If you want to play clubs without your amp being mic'd, you may want a higher wattage amp so people in the back can hear you.
Generally, small bars don't have PA Systems. When you play a larger room, a PA is needed and all the insturments and vocals will be mic'd and run through the PA.

All guitar amps have at least one 'preamp" section and an "output" section.
You can buy a "preamp" pedal that can be run direct into a PA system.
Preamp pedals can also be used with a guitar amp. For example; I have a Sunn Model T preamp pedal, that is a clone of the preamp section of the real amplifier. The pedal has two tubes to more closely copy the tone and feel of the real amp. I plug this pedal into the effects return on my Hi-Tone HT103 amp (an amp with tons of headroom). By plugging the preamp pedal in to the effects return, I am using the Hi-Tone's output section to drive the speakers. The preamp pedal (like the preamp section of an amp) does not have enough power to drive speakers.

5 Band EQ's are good to have. They allow you to adjust the tone of the amp (bass, midrange, treble).
Most amps have bass, mid and treble tone knobs.
Many Mesa Boogie amps have 5 band graphic EQ's.
Some basic amps only have one volume knob and one tone knob that sweeps from bass to treble. Some amps only have a volume knob.
Many things affect tone, including where you put the amp (floor, on a chair) to what is in the room (carpeting, wood floors, cement walls, number of people in the room). String selection and sting age affect tone as well. Humidity can affect tone too. Generally, the more control you have over the EQ, the better.

The "sweet rich jazz tone" is subjective and elusive. Most people would say that it is achieved from the combination of the guitar, amp and the player.

Another popular kit supplier is Ted Weber... https://www.tedweber.com/amps/kits

Hope this helps and good luck!

[jgreenwd]

...tube amp kit like the 5F1 on MojoTone (http://www.mojotone.com/kits/TweedAmpKits_x/Test-Tweed-Champ-Amp-Kit)...
"it has a nice clean sound at its lowest volumes but introduces an articulate and unique grit as you increase the amp's volume". Is this a general
characteristic of tube amps in general? Or is this a characteristic of the specific amp model in question? ...

This is a result of limited headroom in all amps (as explained by Ajax). Every amp will distort as it approaches its extremes. Tube amps tend to distort
gradually. Solid state amps tend to distort (historically, at least) very abruptly as they approach maximum output.

...I want to select a model to build which will stay clean throughout the range I intend to use it, which is basically "room-sized" (a house room, not a club)...
...the Henriksen line (https://www.henriksenamplifiers.com/) claim to be so good because they don't distort the natural guitar sound...

The Henriksen JazzAmp is designed to have a "flat" response. That means that whatever goes in, comes out; just louder. That is common in hi-fi and
sound reproduction systems. The 5F1 is not designed for this. It is designed to modify the input that it receives, shaping it with distortion, compression, and
some tone alteration.

You have to decide which path you want to tread.

...is the "sweet rich jazz tone" mostly a product of the guitar system ... combined with ... the tube amplification, or do specific EQ settings also go into the equation?

The EQ settings are part of the system. Some amps just don't allow you to modify that aspect externally.

So, with that in mind, can you recommend a known amp / tube setup / circuit / anything to get started on from which I can buy parts and assemble an amp?

Maybe a Tremolux or Vibrolux. They will have more headroom than a Deluxe Reverb, but will allow you to get some tube compression at room volumes.
Actually, in this situation, I might start with the speakers and cab that I am interested in and work backwards.

[long standing member]

Tone is phenomenally subjective.

That "sweet" jazz tone could have been produced by a lot of factors.

For example, a Les Paul in the 50s/60s = jazz machine; 70s-2010 = rock machine.

50s/60s Fender amps were designed for lots of headroom, i.e., clear reproduction of the guitar = jazz. Players took the Fender amps, drove them louder than what they were designed for, and voila! Rock tone!

I seriously suggest you Google your favorite jazz song produced by your favorite jazz artist and try to figure out what his rig was when he recorded the song.

It'll help you narrow down your search.

[FWAU112358]

ajaxlepinski, jgreenwd, long standing member: thank you for your replies! I've really learned a lot.

Based a lot on this thread I'm going to go in a very modular direction,
that is to say I'll spec & build: preamp + P/S + amp + P/S + speaker cabinet.
That way, I can mix and match and experiment until I find out what I like the best.
Plus, it will be easier to build & debug the smaller components.
I'll be looking for simple tube amp circuits with a flat response and plenty of headroom.
Plus plus, if I understand correctly, I can swap in a production speaker cabinet, like the Henriksen, at a pretty reasonable price (secondhand).

Off to do more research!

[Zozobra]

A good place to start is here:
https://ax84.com/p1/P1_Theory_Document.zip
The forum there is a great resource too.

More advanced but very informative, the book is great too:
http://valvewizard.co.uk/


I for my sins don't know a great deal about what makes a good jazz amp. Maybe post a few clips from videos/songs you like from youtube and I can maybe help

[FWAU112358]

Zozobra: thank you for the references. That online amp doc is amazing; it will take me a while to get thru it.

With regard to what I like... again thank you for that question. It seems so intuitive to ask, but I hadn't considered it.
My first influence with jazz was the band that Diana Krall played with back in the day (circa 2002 +/-, think Peter Erskine on drums).
While I don't always like the songs she chooses, the band and musical integrity is always top notch. She plays with various guitarists,
but I really like this clip (https://www.youtube.com/watch?v=yMlQUq5I-QQ) of Anthony Wilson (even though it's not with her), but it's hard for me to evaluate cleanly since it's primarily picked and I use fingers.

With regards to classics, I would point out Wes Montgomery Round Midnight (https://www.youtube.com/watch?v=MOm17yw__6U).

A bit more contemporary, I would go with George Benson Breezin' (https://www.youtube.com/watch?v=cYYW6A3Q44U&t=204s) - guitar cuts in around 1:12.

And finally, for a really clean peek at what I think would be a very professionally produced awesome tone, check out guitar teacher Justin Sandercoe from this jazz lesson from around 0:42 to 2:00 (https://www.youtube.com/watch?v=DDauV1Ot124) - even though he's talking over a lot of it, the tone is very clear. From 1:47 to 2:00 there is no talking. He has a little bit of "bite" in his sound that I can't quite pin down. (Maybe just a touch of gain??)

So that's basically a montage of the sound qualities I find really pleasing, and wouldn't mind emulating.

It's interesting to note that when I looked at Justin's guitar (referenced above) and ran it thru GarageBand, I could very clearly see what looked like a very even tone distribution between about 100Hz and 5k Hz (all of the spikes were aligned in intensity... ok, maybe the bass were just a little higher). *Then* when I looked at my tone, I saw that the bass was there (100-500 Hz maybe) but the other tones were missing. (Reminder, I'm going directly guitar into GarageBand.)

So I turned off all the effects and worked with the EQ directly. I rolled everything off under 100Hz, then I really ramped up the tones up to 5K, and added a touch of compression. This got me a lot closer to what the EQ looked like while playing, and the sound as well.

This got me to thinking that the sound that I'm presenting to GB is too weak (e.g. needs a pre-amp). Well, duh, this suddenly made sense in the whole context of what I'm trying to achieve. (To be clear, I think I can get a better usage and more closely replicate the sound I want if I present GB with a more amplified version of my original signal.)

I am going to build a general purpose pre-amp which is based on (what I learned) is a very popular internet build, the ValveCaster. Schematic is here, noting that the complete circuit in the link is NOT what I'm building - only the preamp part, and with a 12AU7, not the 12AT7 referenced (http://miaudio.com/category/diy-kits/). I can then run this pre-amped signal thru GB and compare results.

I post breadboard photos and results when I get it up and running.
Comments / suggestions / the many ways I've erred and misinterpreted things are very welcome!

[FWAU112358]

For clarity, I should point out that the original ValveCaster doc is here:
https://cdn.instructables.com/ORIG/FXM/9B6H/IK1FLK5B/FXM9B6HIK1FLK5B.pdf
And that I'm going to build the circuit on the top of page 2,
using a variable PS to experiment with voltages between 9 and 18 VDC.

[jgreenwd]

I've been thinking more about this and I don't believe the ValveCaster will really achieve what you're after. It's a starved plate design, which means the headroom will be very limited. I would try something more like this
http://www.frontiernet.net/~jff/SonOfAlembic/SonOfAlembicF2B.html

It's a clone of Alembic's F2B preamp, which is just a clone of the Fender blackface preamp. This version is 2 channel and adds a cathode follower and line level transformer to each output. I would replace the cathode follower with a mosfet follower and probably make the 2nd channel something different like a Vox topboost preamp.