183 tweaks

[dogears]

So, I listened to my clips of 183 and then compared to my most recent clips of the semi clone I have been tweaking. I found that my earliest clips were most similar. Here are the changes that pushed me further from the tone.

I changed the OD1 cap to a .015 715 from a .05 PS series. I replaced 270pf snubbers (measured around 260) with 33pf.

The clips were a bit brash and raw in the mids.

So, I replaced the 715 600v .015 with a PS series .015. The cap in 183 is very big and must have a Q and dissipation closer to the PS series than the small 715 I used. The amp immediately regained the bassoon like bottom. It is possible that the used 715 cap I installed was not 100% due to repeated soldering.

I also compared the small 33pf snubbers to real 250pf snubbers measuring 245pf or so. I preferred the 245 snubbers.

I set the trimmer to 24K from ground with the amp and OD on.

Here is a quick sample from this morning of the Glaswerks. CSA guitar. Slight delay and verb added. Sonar 8.5.

http://www.scottlernermusic.com/2010/Ph ... Ttweak.mp3

Here is real 183. Recorded with Adobe Audition. Same mics. But, no delay, just verb (totally diff verb than todays clip) And importantly, I believe I was playing a rare 50 year old 335!!!! So, not apples to apples, but to my ear, these clips sound extremely similar and easily could be the same amp.

http://www.scottlernermusic.com/dumble/ ... tLast2.mp3 (OD about half way in.)

Here is another 183 clip demonstrating how different the amp sounds depending on settings and mic position. To show that todays clip and AtLast2 sound much closer than AtLast versus AtLast2.

http://www.scottlernermusic.com/dumble/ ... AtLast.mp3

What say you guys?? I was in no way attempting to copy the AtLast clips. I just plugged in and recorded. I was surprised by how similar they were with ZERO effort and NO EQ at all. All clips were with no master bright cap and no loop or cables.

So to review again, I used a .015uf PS series 600V on OD1 and 250pf snubbers on V2. I'll do a clip later with the small (33pf snubbers or 27pf snubbers) to compare. My gut says I like the 250pf.

[bcmatt]

Wow! It sounds the same to me. Good job!
That's actually pretty amazing.

I really like the sound of the 183 design. I don't think I've seen a schematic though. For instance, I'm a bit confused about any .05 cap around OD1.

Do you have a link to a schematic I can see?

I know you'd like to hear from guys that are more familiar with 183; but I had noted that 183 was my favourate D Style amp.

[JD0x0]

sweet clips scott! Have you tried experimenting with mismatched snubbers? My preference right now is no snubber on the first triode and a higher value on the second triode-500pf (im running 830pf with a telecaster)

seems more responsive and dynamic to me, with plenty of smoothness that can get agressive on demand. Also the amp sounds more open and "roomy" in OD
JMO

[tubedogsmith]

FWIW, I'm messing around with this circuit in an amp as well. What I liked best so far was 330pf snubbers, .05 ps cap on OD1 with a .005 cap on the OD entrance with 4.7m resistor to ground. It still had that cool fat lowend but it didn't mush out on a neck humbucker. I really like the high string sound with this setup as well. Also, the 250K level pot works great with this thing.

[dave g]

Where did the notion that the snubbers were 25pF come from in the first place?

Ampdork originally said:

25pf/1KV snubber....that is not a typo that is what is printed on the caps (250K) and was measured.

250K doesn't mean 25pF. It means 250pF, and the K means that it's got a +/- 10% tolerance

[pinner]

Wow thats close. I need to hear again at home with better speaks, but WOW!

[Mac Daddy]

Sounds nice Scott , But I'm still not hearing the snap & chirp that the Dumble has . Their's a openness , Push that 183 has . I'm just not hearing in other Amps

[markusw]

Where did the notion that the snubbers were 25pF come from in the first place?

Ampdork originally said:

25pf/1KV snubber....that is not a typo that is what is printed on the caps (250K) and was measured.

250K doesn't mean 25pF. It means 250pF, and the K means that it's got a +/- 10% tolerance

I always thought that 251 would be 250pF. Probably, there are different ways of coding caps.

Peace,

Markus

[nix]

Sounds close to identical. Same 'openness' in both amps. Always was a fan of the 250k Level pot and EL-34s. I've got an amp that gradually evolved into something very similar, through my own ears and taste.
Not a fan of the higher filtering however. I'm running two 100uf's as opposed to a pair of 220's or 300's. Not into the stiff power-section thing.

Does your tweaked-amp have a plexi-style output tranny on it?
I'm considering swapping my current Twin OPT for one, though it does sound surprisingly good running EL-34s.

[dogears]

Yep.... Mojotone iron for a Marshall.....

Sounds close to identical. Same 'openness' in both amps. Always was a fan of the 250k Level pot and EL-34s. I've got an amp that gradually evolved into something very similar, through my own ears and taste.
Not a fan of the higher filtering however. I'm running two 100uf's as opposed to a pair of 220's or 300's. Not into the stiff power-section thing.

Does your tweaked-amp have a plexi-style output tranny on it?
I'm considering swapping my current Twin OPT for one, though it does sound surprisingly good running EL-34s.

[ampdork]

OMFG...


Not even going to get into this nonsense again.

The caps are 25pF... That is fact!

Anyone else is making a guess.
Unless I am mistaken there is not even a clear picture of the snubbers that exists??
So what are people basing their guess work on? Anything tangible at all?
I told someone, they told Scott, the rest is history...
Otherwise there would not even be a question of it. All here would assume 250pF or higher....

I took measurements and even showed here how that is done too.

Ugh.... I almost care...

[ampdork]

250K doesn't mean 25pF. It means 250pF, and the K means that it's got a +/- 10% tolerance

Smartpants!

Oh but look......it ALSO stands for 25pf..... So technically your only 50% correct....
http://www.electronics2000.co.uk/calc/c ... ulator.php

And if it ended there I would only be at 50% too....

But I took actual measurements in the amp... Did you?

Looks like I just took a big step up in the percentages of most likely to be correct...

[ayan]

Where did the notion that the snubbers were 25pF come from in the first place?

Ampdork originally said:

25pf/1KV snubber....that is not a typo that is what is printed on the caps (250K) and was measured.

250K doesn't mean 25pF. It means 250pF, and the K means that it's got a +/- 10% tolerance

Not really. The way to read a cap that says "XYZ" (meaning there are generic numbers, not codes), is: XY are the first two digits of the value of the cap and Z is the power to which "10" is raised. Thus, 250 = 25 x 10^0. Being that any number raised to the 0 is 1, then 25 x 1 = 25pF. That's the way these things go... same rule as used to read 3-color banded resistor values. If you have, say, red-green-black (which stands for 250), that means 25 ohms and not 250 ohms -- which would be red-green-brown, or 251.

Gil

[glasman]

Where did the notion that the snubbers were 25pF come from in the first place?

Ampdork originally said:

25pf/1KV snubber....that is not a typo that is what is printed on the caps (250K) and was measured.

250K doesn't mean 25pF. It means 250pF, and the K means that it's got a +/- 10% tolerance

Not really. The way to read a cap that says "XYZ" (meaning there are generic numbers, not codes), is: XY are the first two digits of the value of the cap and Z is the power to which "10" is raised. Thus, 250 = 25 x 10^0. Being that any number raised to the 0 is 1, then 25 x 1 = 25pF. That's the way these things go... same rule as used to read 3-color banded resistor values. If you have, say, red-green-black (which stands for 250), that means 25 ohms and not 250 ohms -- which would be red-green-brown, or 251.

Gil

I have to check my stash of 250pf's, but I swear that are marked 250 and that is it. They are Cera-Mites.

I will verify tonight and drop a picture or two.

Gary

[dogears]

Look, I never disputed Shad. I only said on my build I liked 250pf.