Search found 1593 matches

by bepone
Fri May 10, 2024 6:29 am
Forum: Dumble Discussion
Topic: Couple of #183 derivatives
Replies: 66
Views: 10638

Re: Couple of #183 derivatives

Here is something what happened after in the amp.. failure on 450V elcos in the preamp section (they were new Kemet - Long life - ex Rifa) ? Very strange, i didnt measure wall voltage before.. maybe little bit over 230? Looks like caps took surge voltage during cold start (power and standby switch p...
by bepone
Fri May 10, 2024 4:53 am
Forum: Dumble Discussion
Topic: Couple of #183 derivatives
Replies: 66
Views: 10638

Re: Couple of #183 derivatives

For the past weekend we had some festival dedicated to vinyl and tubes, where was amp played.. i took nude and rude version without box.. Very nice experience.. maybe little bit too fatty/creamy sound with 1x12" Alnico Cream.. room and people damped the heights so better in the start to have more mi...
by bepone
Fri May 10, 2024 4:45 am
Forum: Garage Talk
Topic: Psycho-fonics - Blind testing
Replies: 2
Views: 39

Re: Psycho-fonics - Blind testing

I wonder if anyone can actually call out a tube by hearing it. not possible.. also there is wide range of manufacturing types and shapes..but you can hear the differences.. and NOS are at least 30% better than modern tubes.. Altough i have good luck with 12AX7 JJ, often they are good enough-till-gr...
by bepone
Wed May 08, 2024 5:31 pm
Forum: Technical Discussion
Topic: ID this tube?
Replies: 6
Views: 167

Re: ID this tube?

ECC81 most probably , need to put tube on the tester to see the currents
by bepone
Wed May 08, 2024 5:18 pm
Forum: Garage Talk
Topic: The rack is Back?! Maybe not for everyone, but at least for me !
Replies: 9
Views: 386

Re: The rack is Back?! Maybe not for everyone, but at least for me !

about tube preamps.. they are here all the time, real built and durable.. not those pcb+processors garbage types.. they have 0 value it is actually a shooting in his own legs to go this route, but they will realise after some years what a fail this is..IMO
by bepone
Wed May 08, 2024 5:14 pm
Forum: Garage Talk
Topic: The rack is Back?! Maybe not for everyone, but at least for me !
Replies: 9
Views: 386

Re: The rack is Back?! Maybe not for everyone, but at least for me !

Hey Bepone, Thanks for the clarification. My plan is not to drive the amp with a multi effect, but rather to have a lot of flexibility between preamps and power amps coupling. I have a musicman PT and OT that I would like to couple them with any preamp to get the feel of those 700V without building...
by bepone
Fri May 03, 2024 8:29 am
Forum: Technical Discussion
Topic: JTM45 Build, looks alive but no sound,
Replies: 7
Views: 245

Re: JTM45 Build, looks alive but no sound,

if there is a scope, then is easy..

1. remove NFB wire
2. put 100mV signal on the input
3. trace to the output tubes pin 5

blind shot..i suspect there is no gnd wire on some tubes, missing
by bepone
Fri May 03, 2024 8:23 am
Forum: Dumble Discussion
Topic: Transformer transplant
Replies: 25
Views: 641

Re: Transformer transplant

So my questions are: That original wiring of the speaker jack, grounded with the bias pot, is that correct, or is it a design flaw from the manufacturer?? yes If so, this makes me question the rest of the grounding scheme in this amp, so I'll then have to take a deeper look at the rest. Could you p...
by bepone
Thu May 02, 2024 8:20 am
Forum: Dumble Discussion
Topic: Couple of #183 derivatives
Replies: 66
Views: 10638

Re: Couple of #183 derivatives

last 2 days update on the OD sound and tweaks..while clean is correct, OD wasnt so.. i have found OD sound too fuzzy for my taste, not amusing in any way... on the lower register.. tweak to cure that - both OD potentiometers changed from 100k to 250k..(actually they are like that in 183 schematic, n...
by bepone
Tue Apr 30, 2024 1:11 pm
Forum: Dumble Discussion
Topic: Couple of #183 derivatives
Replies: 66
Views: 10638

Re: Couple of #183 derivatives

i have put mixed NOS and modern , for output Philips Miniwatt brown base EL34 :P
IMG_20240430_112609.jpg
by bepone
Tue Apr 30, 2024 11:06 am
Forum: Dumble Discussion
Topic: Couple of #183 derivatives
Replies: 66
Views: 10638

Re: Couple of #183 derivatives

Amp tested clean very very nice, drive under testing, tranformers are good! Nothing too much, normal attack, normal bass , normal treble
by bepone
Mon Apr 29, 2024 5:02 pm
Forum: Dumble Discussion
Topic: Couple of #183 derivatives
Replies: 66
Views: 10638

Re: Couple of #183 derivatives

mounted transformers on experimental chassis..
IMG_20240429_190011.jpg
by bepone
Mon Apr 29, 2024 2:12 pm
Forum: Dumble Discussion
Topic: Couple of #183 derivatives
Replies: 66
Views: 10638

Re: Couple of #183 derivatives

i saw.. i saw..
by bepone
Mon Apr 29, 2024 12:21 pm
Forum: Dumble Discussion
Topic: Couple of #183 derivatives
Replies: 66
Views: 10638

Re: Couple of #183 derivatives

busy last week in winding small 14VAC transformer for DC heaters of V1-V2 and relay switching.. Carsbro PT doesnt have this option... now baked under the sun few h, black paint on laminations, vintage brown presspan on the bobbin,
IMG_2024042.jpg