Couple of #183 derivatives

[bepone]

several testing of anode metal film resistors in all stages,
results, very similar or no difference in sound between 90'ties Dralorics SMA green types, and 80/90ties Resista MK3's, i think they came from the same facility.. so i proceed with SMA 0411 Dralorics, easier to find in Europe

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to be noted in this project i liked more sound with 10nF 715 pp coupling cap instead of 50nF polyester after V1b and 2n2 instead of 20nF in entrance of PI!

this project is lmost finished i have arrived to the point that i'm satisfied with everything.. i have only one more idea.. with one exotic OT...

[bepone]

One (very) old build returned to small service, unusual build, preamp all on PCB, layout different than Dumble 183.. Toroidal and Power transformers, all iron DIY .
Used the opportunity to update all essential components in the preamp, all plate and signal resistors(MK3+Draloric) and capacitors (715+6PS), feedback resistor (MOX NTE) in preamp to more "Dumble friendly" compositions..lead dress fixed.. amp on the overdrive lacked bass (because initially was created for 4x12" box, now is on 1x12"), and treble was not so good..

Sound became very good, sweet middle , a lot of sustain, strong bass, (toroid surprised me) box is 1x12" G12-65, short clip:
https://www.youtube.com/watch?v=MOOK2OELTQA

[Stephen1966]

One (very) old build returned to small service, unusual build, preamp all on PCB, layout different than Dumble 183.. Toroidal and Power transformers, all iron DIY .
Used the opportunity to update all essential components in the preamp, all plate and signal resistors(MK3+Draloric) and capacitors (715+6PS), feedback resistor (MOX NTE) in preamp to more "Dumble friendly" compositions..lead dress fixed.. amp on the overdrive lacked bass (because initially was created for 4x12" box, now is on 1x12"), and treble was not so good..

Sound became very good, sweet middle , a lot of sustain, strong bass, (toroid surprised me) box is 1x12" G12-65, short clip:
https://www.youtube.com/watch?v=MOOK2OELTQA

Sweet

[bepone]

few more clips of "wooden" amp:
rock:
https://drive.google.com/file/d/1cpwPRj ... sp=sharing
blues:
https://drive.google.com/file/d/1clQXbv ... sp=sharing

[bepone]

the same amp clean sound:
https://www.youtube.com/watch?v=jfrlNg7i5bc

[10thTx]

the same amp clean sound:
https://www.youtube.com/watch?v=jfrlNg7i5bc

Man, that is really NICE! Thanks for sharing it!

With respect, 10thtx

[bepone]

thanks! will be more

[bepone]

Very long story of 100w /muddy/ from the beginning of this theme.. converted to 50w and so on..new pcbs components.. changed 3-4 Ot's..changed from 6L6 to EL34.. i was happy on clean.. but o OD i get some ugly FUZZZ distortion.
One month ago i wound one more output transformer for 2xEL34 installed, hoping that was from OT.. happy with very tight bass on clean, but still fuzz on OD..

I have lost 3 months without improvement, changed anode resistors , cathode, signal, PI, resistor from metal film to CF, CC.. also g2 from ceramic 5w to carbon film.. tried to reduce value of coupling capacitors from V1b, also from V2a and b.. nothing helped, fuzz was just more pronounced, because i have cut the bass.

Every day i was trying something more and every day i left the amp by side, and continue with 100 other projects in parallel... Tried to reroute lead dress too. Pulled all the wires in the air, connected on fly. Fuzz was there. So it is not from the wires and lead dress.

I was sure that is in OD channel, because clean was ok.

One day i was telling to myself, why you are loosing time and life.. is easy to change all the components on the board in OD section.. it is just 1/2h work. So started. Anode , cathode, resistors caps. Cathode bypass caps. Supply electrolytic for OD section from new Kemet 22uF to 20uF F&T.
Started, no fuzz!! Classic rock tone on 183' amp with LP.

Shock, where i have lost 3 months for nothing . Probably is faulty cathode bypass cap, or cold solder(also wonder because i'm very careful with that)..Now all new and resoldered, all working almost perfectly (need some fine tuning now)..
I have returned Kemet/Rifa 22uF back to confirm that is electrolytic cap supplying this stage, but it wasn't. In the same time i can confirm that Kemet is little bit more harsh for some reason and has different bass character than F&T! Returned F&T, also reducing value to 10uF to experiment. Now back to fine tuning, redo all changes i was doing all the time- for nothing.

Will be new rotation of NTE mox resistors, Carbon films etc etc. Treble cap i will return to ceramic, now is mylar+mica.

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Writing all of that maybe will help to somebody.. I like sound of 183 with only minimum, a very light dose, almost unnoticable, but nice, amount of fuzz component in OD, all other scenarios are mistake or some fault. I should take this route from beginning

[bepone]

new round of experiments!
i was in china and cheaply produced some pcbs locally...
new pcbs actually there are only holes, for eyelets insert, with little bit of copper around so cam be used also without eyelets
bought somw materials from all around thw world and starting again some 183 and variants (bluesmaster probably)

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[bepone]

MK8s, MK3's, NTE's, Dralorics, Pihers, some EJ parts too to disturb sequence.. Nichicon axials which becaming obsolete also...

[bepone]

this project will go on in strange way.. some chassis and torroids are recovered from one other amp and will be used here, experiment, but i want only top end results!
failure or success we will see...

in the same time, opportunity to test new boards

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[beasleybodyshop]

Quite the journey Bepone! Rebuilding previous builds with "better" components is like a D style amp builders rite of passage lol!

Have to say I'm really impressed with winding your own transformers. That just seems like wizardry to me! Loved the clips you posted as well.

[bepone]

Quite the journey Bepone! Rebuilding previous builds with "better" components is like a D style amp builders rite of passage lol!

Have to say I'm really impressed with winding your own transformers. That just seems like wizardry to me! Loved the clips you posted as well.

thank you for the kind words, I hope that something interesting will come out of this as well those toroids were working well before,

p.s. for the output tranformer it is not so difficult, winding machine is heavy part

following some standard practices, laminations are also available nowadays in small quantites, bobbins too

[donvan]

... So started. Anode , cathode, resistors caps. Cathode bypass caps. Supply electrolytic for OD section from new Kemet 22uF to 20uF F&T.
Started, no fuzz!! Classic rock tone on 183' amp with LP.

Did you replace all of these parts before finding out that you had solved your fuzz issue? Or, did you replace a couple of these parts, listen, replace more parts, listen, etc?
I'm wondering how you decided that it was the cathode bypass capacitors and not one of the other parts that were the issue?

Thanks,
Don

[bepone]

Did you replace all of these parts before finding out that you had solved your fuzz issue? Or, did you replace a couple of these parts, listen, replace more parts, listen, etc?
I'm wondering how you decided that it was the cathode bypass capacitors and not one of the other parts that were the issue?

Thanks,
Don

i did all components together. this fuzz maybe was result of faulty component or bad solder i wasnt sure at the end.. something was