This early summer I have built a Bassman 5f6a amp, using chrome chassis, fiber board, vintage cloth wires and also vintage carbon resistors. I've tried to make it as close to 50s examples.  For the electronic assemble guid I followed Mojotone instruction picture showing all the connections, wires etc. Amp was finished and working but there few issues, first one was the hum. To eliminate it I have rewired preamp grounding, basically I removed ground bus and followed the picture of original Bassman from 50s. I used grounding mainly of the pots and one change made significant elimination of the hum, was to separate filter caps ground from preamp ground and connect it to power section ground point. I dont know why Mojotone on the instruction connected filter caps with preamp grounding.

After that, there was no hum, but... There was still appearent type of scratchy noise, even when all controls set to minimum. I was able to localted it to the PI section and lastly to the carbon resistor (10k) of long-tail circuit. Replaced with metal resitor removed this noise and now amp is completly silent on its own.

One more chnage I have made to the original 5f6a circuit was the Presense control, which with original schematic any pot move was producing scratching noise. See my 5f6a schematic to see the configuration with is silent one. 

After 1 year of keeping my own built 5e3 clone chassis on the shelf, finally I have put in some work with the help of my father to finish it. I called it Deluxe 57, which is a replica of 5e3 - Fender Deluxe from '57. Cabinet design and dimension were kept to the original specs as well as electronic circuit. I am very satisfied with the result, the amp looks really nice and sounds amazing. Yes, after a few years, now I have to admit, 5e3 is one of the unique amp I have played, it has its own character.

Most of all, I like its response to the player's articulation, strumming softly - amp is clean, hit it harder and I get unique overdrive.

This spring I have finished my 5e3 custom amp, OldClub 57 with two modifications compared to the original circuit. To my surprise this amp sounds incredibly good, it has lots of basses, full mids and clear high tones. Thanks to the master volume control I can play in my apartment and enjoy its sound. 

Spring reverb & tremolo tube effect unit is my second project this year, almost finished.

Next I will build 3 small single-ended custom amps on request.

Then, I have my ToneClassic64 project to be finished, chassis is ready and playable. This will be an amp head and cabinet holding 1x12” speaker.

And after  that, I will finish my 5e3 clone for which I already have a finished and working chassis. Hold on, there is one mode I have applied to this amp, which is master volume control in place of second output speaker jack. You can see this extra control on the picture below. 

Winter is passing...and soon spring spring will come. I have played over and over OldClub 57 - 5e3 based and I have to admit, I am enjoing this amp more and more. Over cold and snowy time, I have assembled few circuits for finishing once the worm and sunny spring days will come.  

I have already made one attempt to build amp based on classic circuit 5e11 which I dropped as the result was not satisfactory - compared to 3 stage pre-amps like princetone reverb create. 

Now, I tried once more and this time went for 5e3 circuit which is very similar to 5e11 , but has 2 separate input pre-amp stages build on 12ay7 (or 12ax7) and interactive volume, tone controls.

My design includes 2 inputs - normal and bright vs 4 inputs as 5e3, but still two channels later mixed following volume pots.  I added also Master Volume so that amp is usable in the appartment.

I had to try for many times to figure out different setting for the volume and tone controls to find some interesting setting which gives really nice tonal results, example, guitar plugged into Bright input, Volume normal set to 9-10 (out of 12), Volume bright set to 2-3 (out of 12) and tone set to 11-12 (out of 12), such setting gives plenty of basses and sparckling high tones with reduce mids, very balanced. I thought such sound was not possibler to get out of such as simple circuit.

Will continue trying out my version of 5e3...

My previous reveb n tremolo unit effects where built combined Fender 6G15 circuit followed by Supro cathod bias tremolo. This time I have used for tremolo the Fender 6G12 vibrato part circuit following reverb section.

...

Few points to be considered to built no-hum tube amp...

Over those years of designing and bulding tube guitar amps, I have collected few important points in order to built no-hum amp. Of course no-hum is imposible but at least level of hum is so low that it can not heard unless you would put your ear to the speaker.

1. Heater transformer output referenced to the ground 

2. Twisted tube heater wires entering tube socket perpendicularly  (heater wires are going above tube sockets)

3. Heater wires cross with signal wires more less 90 degrees to each other, basically they cannot be parallel

4. Power transformer is far away from signal input

5. Output speaker wires are twisted and away or shielded from input and preamp section - I am placing outside of the chassis 

6. Circuit is built to follow nautral amplification stages , so each preamp stage is place after another and no crossing back, power section at far end from input typically close to power filters cap section

7. Signal wires going into the tube are always shielded

8. Signal wire going out from the tube before coupling cap does not need to shielded - no issues

9. Grounding is super important - avoid ground loops - e.g. shield of signal cable is connected on one side only to  the ground

 To be continued...

5e3 the story of there and back again...

Finally spring season has came and now I am be able to do some wood craft. First, I have built cabinet for the reverb&tremolo effect and guitar combo. Reveb & Tremolo chassis is ready to be installed, but I went into new combo amp electronic assembly.

My new project idea was to re-create circuits based on the 50's - Fender Deluxe 5e3 so that I can hear its sound and compare it with the latest design from the 60's. 

5e3 has a 2 stage preamp including tone and volume control followed by cathodyne phase split driving pair of 6v6s in push-pull setup. I was always wondering how come this super simple design can produce the unique tone which is so desired these days - by few at least.

I had to try it myself... and so I did.

Since my chassis is prepared for single input, I choose to build Vobrolux 5e11 - 2x12ax7, 2x 6v6 and 5y3 rectifier. 5e11 is basically a single bright channel of 5e3 with tremolo. 

 Tests of 5e3 done and logically simple circuit produced a very simplistic sound, very shallow, full of mids, not exposed basses and high tones. Very poor result compared to designs from the 60's. Cranked amp was rather farting and overdrive was pretty harsh. 

Another logical thought, no wonder why Fender extended the circuit in later 60's  designs - just to get better sound.

Let's evolve 5e3 by steps, to get the sound...

I have removed the tremolo circuit and built another in between the preamp stage with a bypassed cathode resistor. 

This gave me 3 stage preamp, with just tone and volume controls, I did not change the cathodyne phase split and power section 2x6v6.

Turn on and test... sound gets now full basses and high tones where noticeable, still too much of mids and way too much of saturation, but now the sound was very rich with different frequencies and much more interesting for the ear.

3 stage preamp added the missing basses and high frequencies to a level which could compete with mids. 

Conclusion, now I know, 5e3 is just famous for its legend. Sound though, is very simple, dominated with mid frequencies and overdrive is harsh. For me, who plays at home mostly 5e3 is not giving the desired sound rich in different frequencies and crisp overdrive. 60's designs are far better in the sound experience and deliver the iconic overdrive, very well known from famous bands from the 60s. 

New  project comming ...

Finally spring has came and I will be able to do some wood craft. I plan to build cabinet for the reverb&tremolo effect and combo cabinet for the amplifier holding 12 inches speaker to play with something close to 5e3.

Spring is getting closer so why not prototyping spring reverb unit?

Winter is passing... I have decided to try and test a standalone tube reverb unit based on 6G15 Fender model. Since 6K6 are no longer around thus I used 6V6, while other tube 12AY7 and 12AX7 remians. This type of reverb unit gives really unique sound. Indeed, having such in fron of the amp I was able to reproduce sound of Dick Dale or Shaddows. 

It has some draw backs like adding bit of noise or decreasing of volume and top end.  Will work more on it over next weeks to make it super silent and also try to add tremolo, like a Milkman reverb/tremolo unit...

Bassman this time... rather not. It will be a Bluesman?

After trying another master volume circuit and testing more, I decided to go with my moded 5e3 or priceton (no) reverb 64 ... way better result and superb tone! Below is the circuit schematic.   

Bassman this time...?

It is a second time I am approaching Bassman circuit. Few months before I have made 5F6 circuit but decided for 5E3, for few reasons:

1) master volume was not working preperly - it did not shut the volume completely down at 0 position. I used simply pot that shunts together two signals before enter the power tubes. Since signals waves are in oposite phase, so they should cancel each other.   

2) sound at lower volume levels was having too much basses, overdrive was bit harsh compared to sound from moded 5E3

What I was about to change this time to make it work? 

For the master volume I dedicded to use dual pot 250k Ohm which shunts grid to bias - following this schematic: https://robrobinette.com/5F6A_Modifications.htm#Master_Volume

One more change I planned to make is to use pair of 6V6 rather then 6L6 to make it less powerfull and of course smaller & lighter (smaller  transformers).

...and so I did.

Result

Master volume worked this time perfectly! In the sense of conroling volume down to 0. 

Bass response is quite overwhelming with Low pot at 30%+ - this is first impression after first run with guitar. Good part is that Low at 0 level nicely remove basses, which helps when gain is at 90-100% and overdrive signal.

Top frequencies are cut off at master volume set to 10-20% with Gain at 70-100% - this lead me to add 100pF cap over gain pot signal, which increases high freqs at Gain below 70-60%.  Perfect top freqs response I can get when Gain is set pretty low 20-30% and Master Volume is open at 100%. This leads me to the conclusion that potentially Master Volume is causing high freqs to be cut off.

General impression

Clean sound of this circuit - I love it, with 100pF bypass cap over gain pot signal I have enough top and plenty on bass a hand. 

Overdriven sound - bit harsh, not enough top and still bit too much basses, this could be balanced with more high freq like I could achieve with by other amps (BassVerb, RoadSixy, RoadRider, ClubMaster)

I will make one more attempt to change Master Volume circuit and if that not going to help I will modify this amp to 5E3 with eq which got great sound....

ClubMaster finished

Last adjustments made to the circuit to support 5881 and 6L6 tubes. I have decided to try 5881 tubes as in early Bassman. Compaing with 6L6s, I got impression that 5881 produce bit warmer  tones. Such difference wont be noticable on the recordings.

Top metal control panel installed and ClubMaster is finished. 

ClubMaster almost there...

ClubMaster is a 30 watts amplifier based on pair of 6L6s - with late 50/early 60s 3 stage pre-amp in a vintage style cabinet covered with original lacquered tweed...  

RoadRider at last finishing touch...

RoadRider is my next vintage style amp. 30 watts based on pair of 6L6s - with late 50/early 60s 3 stage pre-amp with amazing tonal response. High, basses and mids - all under control of 3 band EQ. Changing between Normal and Bright channel with a matter of switch. Spring reverb adds space to the sound so if you close your eyes when playing you can get impression you are on stage in music hall. 

Cabinet style inspired by Valco National although not looking exactly as tweed cut is different. Shellac lacquered finish imitated aged look with exquisite result...

RoadSixty finished, time for new project plans...

RoadSixty is already and singing. Its sound is very rich and bit different compared to the bigger 30 watts amps based on 6L6 - brighter I would say still with nice basses and mids - all under control of EQ. Its weight makes a huge difference to mobility, it can be easily moved around. I still enjoy watching this small vintage style amp as the cabinet finish is so nice.

So,... I have made plan for my next project coming back to larger amps with reverb which sound so far is THE BEST to my ears, cabinet style inspired by Valco National...

Cabinet for my new amplifier is ready

Despite of rainy days I have built cabinet for my new amplifier. Tweed, vintage style and shellac lacquered made it look like an old stylish box. This time I have added decorative stripes. I love it.

Inside cabinet I have mounted 8 inch Jensen C8R speaker 8 Ohm, tested with BassVerb'59 and the sound was SUPERB! Can't wait to assemble electronics, classic fender 60s pre-amp (deluxe type) with 2 6V6s in power section should make a deal. This time without any switches just 3 band eq, gain and master volume. Soon I should be able to tell whether small cabinet and 8 inch speaker can also sound great and produce big tones...

New project - full tone in easy to grab and go cabinet...    

My next idea is to build handy amp guitar combo without sacrificing tone.

BassVerb '59 - a 30 watts TV vintage style guitar combo is ready   

Finding best speaker combination, brought me back to single 12 inch C12Q  Jensen giving excellent sound with warm basses and chime tops. 

Produced sound match perfectly with the finished cabinet, tv style covered with original tweed shellac lacquered. 

All together I am very satisfied with the result, it gives a lot of fun playing guitar on this amp - BassVerb 59

New cabinet TV vintage style covered with original tweed - built

I was quite busy last weekend,  during which I have built the cabinet for my new amp, vintage TV style to hold already assembled and tested electronic. Cabinet fits 2 Jensen C8R - 25w each speakers. After first tests with the circuit in place, it turned out that left speaker (looking from the front) is interacting with output transformer, casuing significant hum, generated even without connected speaker jack. While other speaker remain silent. 

Next step is to change the configuration of the speakers and see if hum will disapear, if not then I will use single speaker for which I have also preapred a holding board. 

Bassverb 59 cuircuit is ready for first test!

Just finished assembling Bassverb 59's electronic cuircuit and placed it in my custom designed chassis . Today I'm will test it and check the result. It will have 2 speaker outputs, 8 and 16 ohms, for test I will use 8 ohm with single speaker but for the it cabinet I will use 16 ohm with 2 speakers.

Mods compared to Bassman 59 circuit: single input, bright switch, drive switch, spring reverb and master volume.

Tubes: 3 x 12AX7, 2x 6L6 fixed bias (adjustable)

Planned:

2x Jensen 8" C8R speakers with capacity for ~50 watts of output power.

Cabinet sized to W45cm x H40cm x D28cm, pine wood, finger joined, vintage TV style box, covered with tweed.

New project is on the way... Bassverb 59

Spring has come and its time for new project. I have started a new amp build with an ambition to recreate bassman 59 tones based on its circuit with modifications like single channel only, bright switch, drive boost switch and spring reverb. 

Some early specs:

Tubes: 3 x 12AX7, 2x 6L6 fixed bias (adjustable)

2x Jensen 8" C8R speakers with capacity for ~50 watts of output power.

Cabinet sized to W45cm x H40cm x D28cm, pine wood, finger joined, vintage TV style box, covered with tweed.

Push-pull 2x 6L6  with classic pre-amp Fender style circuit

This time I have decided to build bit more powerful amp based on two 6L6s in power section with pre-amp similar to Bassman or Princton reverb as my version includes reverb. Since Old Pepper give superb sound both clean and overdriven I wanted to hear how the 2x 6L6s could sound. I have placed the amp chassis in the Bambino cabinet with single 12" Jensen CQ12 speaker. Probably will design 2 or 4 speaker cabinet in spring to also get exp. of playing through more than one speaker.

... and my new built amp gives incredibly powerful tone! Of course I have added master volume control to be able to overdrive the amp at home, else I could not crank it up as it easily get 30+ watts.

Control panel: 1x instrument input, clean/drive mode switch, 3 band EQ high, mid, low, eq bypass switch, reverb and master volume.

Tonal range is very wide controlled by 3 band eq plus different positions of gain control. It starts with very bright, compressed tones into creamy, full of basses while still maintaining bright clear high frequencies.

Overall I'm still amazed and enjoying its sound...

Old Pepper Black Tweed, 20 Watts of pure valve sound got new turret board incl. carbon resistors

Previous tag board worked very well but did not presented itself well thus it could be seen as unprofessional.  Sine Old Pepper is a top quality handmade valve amp, it deserves also a nice turret board, so there it is... 

New Black Tweed finished and become Old Pepper 

I am really glad from the effect of covering tweed with color lacquer, it came out darker than I was intended. Vintage style cabinet: h43 cm, w40 cm and d26 cm. It holds 10" speaker WGS Veteran. Still few things left to finish the cabinet and then to build the heart of the amp - chassis and electronics.

Bambino 10 Watts, lacquered tweed tube amp with reverb and 3 band eq - ready

Guitar combo amplifier, single 6L6 in power section and 3x12AX7/ECC83 in preamp section dring spring reverb - Roma 5. This amp cabinet holds 12" Jensen speaker C12Q which sings perfectly as it has enough room insied, its size is 48cm height, 41 cm width and 28 cm depth with open back.