yes.... I Know....I'm starting a #183 build!

[donvan]

if I crocodile clip across the clean out to the OD will that bypass the relay safely so at least I know the OD is OK?

M

That's a good test.

[norburybrook]

OK, I think I might have a dry joint on V2b I swapped valves and it jumped into life but is crackly and intermittent also the plate and cathode voltage is erratic there so something is slightly iffy.


I'm going to reflow that side of the valve.


thanks for the help so far, it's very close now

I even managed to get the primaries the correct way and also the LED's

M

[donvan]

Sounds like you're almost there!

[norburybrook]

I've got something funky going on with V2. the plate voltage on the output side is swinging between 150 and 325 and the cathode voltage is swinging too up to 2.2v. the valve is also glowing a lot brighter than the other two.

I've got a gnarly, chopped fuzz type distortion now when I play, I suppose that's progress.

i'm calling it a day now.

I'll try again in the morning.

Cheers



M

[pompeiisneaks]

You could get your DMM on volts AC and measure the signal output after the coupling caps in clean, see about what it is, then check with the relay engaged for the OD side and see if you're getting about that amount at the other side of the relay output, if so it's dumping somewhere after that, if not it's the relay.

~Phil

[norburybrook]

You could get your DMM on volts AC and measure the signal output after the coupling caps in clean, see about what it is, then check with the relay engaged for the OD side and see if you're getting about that amount at the other side of the relay output, if so it's dumping somewhere after that, if not it's the relay.

~Phil

The relay seems to be working as I have OD now but as I said V2b is acting a little strange and I'm getting sort of gated Fuzz type distortion.


M

[pompeiisneaks]

D'oh missed that, sorry hehe.

~Phil

[xtian]

getting sort of gated Fuzz type distortion

"gated" always directs me to check the grid-to-ground reference resistors. If the grid is left floating from ground, you can get unpredictable gating and clipping.

In the #183 OD section, that would be the OD input trimmer, and the OD drive pot.

[norburybrook]

getting sort of gated Fuzz type distortion

"gated" always directs me to check the grid-to-ground reference resistors. If the grid is left floating from ground, you can get unpredictable gating and clipping.

In the #183 OD section, that would be the OD input trimmer, and the OD drive pot.

thanks I'll check those in the morning.


M

[norburybrook]

Xtian , bang on..the drive pot was missing the ground to the bus wire. It's all sorted now. perfect.

Time for bias tweaks , p.i. balance tweaks and OD trimer tweaks.

OK voltages etc.

B+ 460vDC

V1: 189v-195v Tungsol

V2: 195v-198 NOS ruby

V3: 300v- 305v sovtek LPS

OD trimmer 23k


EHX 6CA7(EL 34) Valves aren't particular well balanced, I have biased at 30mv-36mv


going to let it settle in today and maybe do some tube rolling later on.

Time to build a footswitch and a cabinet.

[norburybrook]

pics.

IMG_20190124_115544-01.jpeg

IMG_20190124_115535-01.jpeg

IMG_20190124_115352-01.jpeg

IMG_20190124_115103.jpg

MC

[martin manning]

Looks great! Interested to hear your impressions on the sound.

[norburybrook]

thanks Martin.

First impressions;

clean is somewhere between my #102 and Bluesmaster. the OD is a lot more 'overdriven' than my #102 it's bordering on 'Santana' ish which I suppose is where the ODS was heading by this point in its development. It's very beefy, the 150w OT and the 4x 6CA7's along with a very well spec'd power transformer probably help. It's tighter sounding than the Bluesmaster in the low end, it's great sounding amp though ,very clear and no harshness.

Again , I'm never really sure what makes them sound different. perhaps it's those cool black metal film resistors


I'm going to go with a black, cross bar tolex cabinet with the black 'striped' fender grill cloth just like the original#183 along with the 'gold script' logo



M

p.s. from an aesthetic point of view I don't really like the white flown wire to the on /off switch would it be better to run it along the floor of the chassis? it will be crossing a lot of other wires though and I was worried about noise. the amp is very quiet as it is.

[Reeltarded]

Lovely amp! Give it a few days and replays and tell me which of all you love most, please.

Really great looking.. good job!

In all my experiences, I don't think you should worry about the flying wire. If you move it and find a problem.. that's a bother, but otherwise shouldn't be any problem. It will be routed along the upper shielding when in the cab.

[norburybrook]

Lovely amp! Give it a few days and replays and tell me which of all you love most, please.

Really great looking.. good job!

In all my experiences, I don't think you should worry about the flying wire. If you move it and find a problem.. that's a bother, but otherwise shouldn't be any problem. It will be routed along the upper shielding when in the cab.

thanks Miles.

Actually yes of course it will be on the bottom when in it's cab I've got clients in the studio for the next 4 days so i'll be busy.

start of next week I have a few days off and will start to see what this amp likes and doesn't like.

I still don't like the PAB on most ODS amps, it's probably designed for people who play high output neck humbuckers as it cuts the low end. probably be good for cutting high gain tones maybe. Not my thing though.


M