ODS #183 PCB build.

[telekingdom]

Sorry, but it's not a 'generic claim'. It's absolutely factual. The schematic(s) is incorrect.

As far as leaving the 'cryptic pronouncement', well yeah, I'm tempted to leave it just as is. I reached out by PM for some pretty darn generic help and didn't get so much as a FU as a reply here.


I don't feel like I owe it, or that the correction is deserved, to be frank. Such things should be reasonably reciprocal IMHO, but maybe I should start?

...my preference is to be helpful. I'll attach a pic of the correct wiring. It does make a ton of difference.


Edit: I'll propose an exchange of information. I originally asked if there were additional pictures of 183 that talbany could share. I'll ask the same (of anyone able) even though they're no longer needed.

For the record, I have zero affiliation of anything/anyone commercial etc. Just an enthusiast. PM me if you're game.

[talbany]

I originally asked if there were additional pictures of 183 that talbany could share

I never received this request from you? either by PM or in one of your posts..So how did you send it?
I answer all my PM's

I reached out by PM for some pretty darn generic help and didn't get so much as a FU as a reply here.

BTW.Nobody here (including me) is entitled to any or all info they ask for (including PM's). It's generally a ask and hope proposition here. I've found the more you contribute and help out the builders here the better your odds..IMO
Tony

[digi2t]

Hi ijedouglas, hi digi2t, hi everyone,

Checking the layout of AA Electronics # 183 I noticed a difference with the layout of Tony Albany owned by TAG, the connections of the Rock / Jazz switch are different, the right contact in the Jazz position in Tony's Layout is connected to the left center of the switch while that of AA Electronics is connected to the left Jazz.
I think the error is in the layout of AA Electronics.
Before turning on the soldering iron, I hope someone will get some answers.

Franco

Hi guys,

First off, I don't think there are "errors" per se in one layout or the other where the layouts are concerned. I've been staring at the two Rock/Jazz configs for a while now, and what my eyes see (and my brain is telling me) it's six of one, or a half dozen of the other. Both configurations seem to achieve the same switching paths. If I'm wrong, then please correct me, by all means.

On a different note, I would like to point out a possible weakness in the bias network. I'm speaking from experience here, having my 183 clone almost go up in smoke the other day. I was happily strumming along, testing a new OD pedal, when I was suddenly overpowered by a smell of hot tolex. The power tubes were all red plating. I shut everything down quickly, and after letting it cool down for the day, I tore back into it. Out of all the possible culprits for the red plating, the only thing I could find in my troubleshooting was the possibility of the bias pot trace/wiper not providing adequate continuity, thus letting the grids go hot (closer to ground).

The way the network is set up, any failure through the bias pot will automatically allow the grids to float or get pulled hotter, which needless to say, is not a "good thing". As such, I took a page from Merlin's book, and added a 100K resistor across lug 2 and the bias voltage supply side lug of the bias pot. In case of a pot failure, the grids will be pulled safely negative, and not left to go hot or float.

I rebiased, and put it back into service. It looks (and sounds) like there was no damage done to the power tubes. No further red plating either.

[jazzbass]

Hi Digit,

I have analyzed the layout of Martin Manning and that of AAElettronics and I have seen that both lead to the same result (at least I think if the eyes do not deceive me).

The suggestion to add a resistance between pins 2 and 3 of the BIAS potentiometer is excellent.

I have a problem that I have to solve quickly with my # 183 otherwise I will burn some speakers: sometimes, it seems for an excess of low frequencies, the speaker sounds as if the coil is touching the magnet. I don't play loud, the bass pot is at 4 or 5 and no pedal is connected to the amp. This thing worries me because I made various assumptions and went over some welds but no action was decisive.

I think I need your help to cure this problem.

Thank you
Franco

[martin manning]

I have analyzed the layout of Martin Manning and that of AAElettronics and I have seen that both lead to the same result...

You will see a couple of different arrangements for the R/J switch wiring in the layouts published here (compare 124 and 183). Electrically they are the same. And, truth be told, I drew some of the boards, and Tony Albany drew the controls and wiring in the layouts.

I can't imagine the amp causing the speaker voice coil to rub in that situation, unless the speaker has been damaged. Does it occur when playing your 183 through another speaker? A parasitic oscillation might be the cause, but without hearing it I can't guess.

The way the network is set up, any failure through the bias pot will automatically allow the grids to float or get pulled hotter, which needless to say, is not a "good thing".

That's true, although such failures are rare. For peace of mind, the bias supply can be made so that it will fail "cold."

[talbany]

Electrically they are the same

This is exactly the same thing Shad told the garage.
Later there was some comments made that perhaps the reason for the different wiring on the R/J switch was due to the fact that the earlier 4 th generation amps (124) had a on/off/on switch which provides a boost feature in the off position where some of the later serial number amps had an on/on switch. We don't know if this is why Dumble wired the switch differently since he won't answer my calls and does not post here

BTW. If anyone here wants to make the claim that something in the layouts are "not correct" or wrong the correct way to approach this would be to tell us what about it was wrong? exactly! and back it up in either a schematic or have some pictures or an in depth description, something to base your findings on and not just it's wrong or there is a difference?..This way I will be more inclined to take the time to investigate further someone's claim or complaint about the layouts This is the 3rd or 4th time this has come up.

Thanks
Tony

[jazzbass]

Hi Tony, Hi Martin,

Martin write: I can't imagine the amp causing the speaker voice coil to rub in that situation, unless the speaker has been damaged. Does it occur when playing your 183 through another speaker? A parasitic oscillation might be the cause, but without hearing it I can't guess.

Martin, yes, it happens with a Celestion12 65, with a Celestion 12 Heritage, with 2x12 Celestion Alnico Blue.
I play at moderate volume in order not to damage the speakers that cannot bear the 50 watts of the amp and also because the room where I play is small.

I cannot record the problem because it is not regular, sometimes this crackling sound comes out of the speakers, I stop immediately and turn off the amp, change the speakers and the sound resumes regularly until you hear crackling sounds even with these speakers .....

Grazie
Franco

[martin manning]

Later there was some comments made that perhaps the reason for the different wiring on the R/J switch was due to that the earlier 4 th generation amps had a on/off/on switch which provides a boost feature in the off position where as some of the later serial number amps had an on/on switch.

Looks to me like a middle "off" position will result in PAB using either wiring.

[martin manning]

I cannot record the problem because it is not regular, sometimes this crackling sound comes out of the speakers, I stop immediately and turn off the amp, change the speakers and the sound resumes regularly until you hear crackling sounds even with these speakers .....

This sounds like a failing component. Does the crackiling occur only when you hit the strings? Does it occur in both clean and OD modes? How old are the filter capacitors?

[talbany]

Later there was some comments made that perhaps the reason for the different wiring on the R/J switch was due to that the earlier 4 th generation amps had a on/off/on switch which provides a boost feature in the off position where as some of the later serial number amps had an on/on switch.

Looks to me like a middle "off" position will result in PAB using either wiring.

Thanks Martin it looks like all of this has been discussed here before.
https://ampgarage.com/forum/viewtopic.p ... ch#p232641

Tony

[jazzbass]

I cannot record the problem because it is not regular, sometimes this crackling sound comes out of the speakers, I stop immediately and turn off the amp, change the speakers and the sound resumes regularly until you hear crackling sounds even with these speakers .....

This sounds like a failing component. Does the crackiling occur only when you hit the strings? Does it occur in both clean and OD modes? How old are the filter capacitors?

Hi Martin,

I know that it is difficult to understand what causes the problem from a brief description, now I am on vacation and when I return I try the amplifier again writing in what condition and when the problem occurs but I seem to remember that it started when I played an A note on the 4 ° string or F on the 5th string in the OD position.

I suspect it's a bad capacitor in the tone stack, it's like a very low frequency is putting the speakers in trouble.

I replaced the 250K bas pot (indicated in Tony's layout as 311K) with a 500K one (as indicated by ceriatone) and the bass has improved a lot the problem has decreased but it has not disappeared.

Franco

[digi2t]

Later there was some comments made that perhaps the reason for the different wiring on the R/J switch was due to that the earlier 4 th generation amps had a on/off/on switch which provides a boost feature in the off position where as some of the later serial number amps had an on/on switch.

Looks to me like a middle "off" position will result in PAB using either wiring.

Thanks for the confirmation. I was pretty sure I was seeing it right.

As for the bass pot, I used a 300K in my builds. The bass is present, but not overwhelming. Besides, I tend to like amps that are a bit darker sounding. Perhaps why I tend to lean towards playing guitar through bass amps. I think at the end of the line, it's really in the ears of the beholder.

[jazzbass]

Hi Digit, hi Tony, hi everyone,

who can i contact to order a 300K bass pot?

Alternatively, where can I find the explanation on how to interrupt the trace of a 500K potentiometer to make a 300k one?

Thanks for your answers, I am learning a lot by reading the pages of Ampgarage.

Franco

[pompeiisneaks]

From what I've read, but never done, you can carefully scrape the carbon on the trace around the circle of the pot to decrease the resistance, or is it increase? I've never done it. Basically you have to carefully open the pot, and scrape away some of the carbon to change the resistance. just don't 'break' the carbon trace or you've ruined the pot. You could buy a few cheaper pots to practice with? Or if you have some old ones laying around that weren't as great, noisy etc, then you could practice there...

~Phil

[ijedouglas]

Scraping the trace increases the resistance.

Instead of scraping the trace and potentially destroying or reducing the lifespan of the pot, buy a bunch of 500K pots. Typically the values are all over the show and you can often find one that you need. I have also tried different pots from 320K to 450K and prefer anything between 360K - 400K.

Try a few different values and see what you like