Dirtbag Troubles

[tenwatt]

Okay, I'm getting excited now.  After pushing the ICs down it's sounding GOOOOOOOD.  The only dilemma is if I punch a power chord firmly it breaks up and sounds all fuzz like.  I only rolled the "Gain" trimmers up enough to get the oscillation but should I back them off a bit to get rid of that?

The whining in the "Delay" pot is still there BUT it goes away when I touch the "Level" pot.  I'm thinking that it's a grounding issue that will go away when I box it.  Do you guys agree?

[LaceSensor]

Ill give that a stab in a sec
Here are my reported voltages

VC - 8.99V from a DC brick

IC1 TL072cn
1-4.82
2-3.96
3-4.72
4-0
5-4.37
6-4.83
7-4.83
8-8.98

IC3 TL072cn
1-4.82
2-4.82
3-4.72
4-0
5-4.67
6-4.83
7-4.83
8-9.97


IC8 TL072cn
1-4.82
2-4.82
3-4.67
4-0
5-7.31
6-7.46
7-8.05
8-8.98

IC6 TL072cn
1-4.15
2-4.15
3-4.04
4-0
5-3.67
6-5.04
7-5.26
8-8.98

IC7 TL062cp
1-3.3 to 5.6
2-4.68
3-4.6 to 4.9
4-0
5-4.68
6-4.33 (strangely jumps down from 4.9 ish, repeatable when remove and add DMM probe...stays at 4.3)
7-4.5 to 4.7
8-8.98

IC4 CA v3205D
1-0
2-4.31 to 4.32
3-4.66 to 4.67
4-4.68
5-8.28
6-4.30
7-3.93
8-7.90

IC5 CA v3205D
1-0
2-4.31 to 4.32
3-4.49 to 4.50
4-4.50
5-8.27
6-4.30
7-4.15
8-7.90

IC2 SA571N
1-1.28
2-1.80
3-1.80
4-0
5-1.80
6-1.79
7-7.43
8-1.80
9-1.80
10-8.05
11-6.37
12-1.81
13-8.98
14-1.80
15-1.80
16-0.27

IC HCF 4047BE (datasheet same as a CD4057...)
1-4.58
2-4.38
3-4.38
4-8.99
5-8.98
6-8.98
7-0
8-0
9-0
10-4.45
11-4.45
12-0
13-4.58
14-8.98

Test done with BAL at noon, Bias 1 and 2 at Noon, Gain 1 and 2 at Full Anticlockwise.

Thanks for all help and patience

FWIW I also did beans tests earlier

- Pin 7 of IC1 had clean signal, clear, non distorted
- Pin 7 of IC8 again had signal, bit louder than IC1
- Pin 7 of SA571n had a fuzzy sound


When messing around earlier I noticed also that I could only get echos with a lot of pick strength / attack.

Cheers

[gtr2]

If your testing out of box it will "whine" a little.

Josh

[LaceSensor]

fudge me

I dunno whats going on.

But it works now.
needs fine tuning repeats a bit fuzy
but shit
its works

holy damn
still be interested to hear what people think of the voltages?

[Scruffie]

fudge me

I dunno whats going on.

But it works now.
needs fine tuning repeats a bit fuzy
but shit
its works

holy damn
still be interested to hear what people think of the voltages?

I'd say there's a little bit of inconsistency, probably in line with the bad joint or IC not properly in socket that caused your issue in the first place, generally in the right ball park though.

Okay, I'm getting excited now.  After pushing the ICs down it's sounding GOOOOOOOD.  The only dilemma is if I punch a power chord firmly it breaks up and sounds all fuzz like.  I only rolled the "Gain" trimmers up enough to get the oscillation but should I back them off a bit to get rid of that?

The whining in the "Delay" pot is still there BUT it goes away when I touch the "Level" pot.  I'm thinking that it's a grounding issue that will go away when I box it.  Do you guys agree?

Using Humbuckers? Yeah a BBD will clip when smacked with a power chord, especially with high output pickups, that's the nature of them.

You might be able to dial it out though yeah, keep messing with the Bias & Gain trimmers untill you get a nice balance. As I said, Gain 1 & Bias 2 will interact so that's a spot to tweak back and forth untill you get the correct balance. Of course not neglecting the other bias trimmer, the post gain trimmer shouldn't be affecting clipping so much.

Then as Josh said about the whine.

[LaceSensor]

Think it was just seating all the ic again. Didn't touch any solder.

On the look for a 240pf mica cap now,or a known good ceramic.
Speaking of whine my eh poly chorus does the same thing at high delay settings.
And I had clock noise tenable by delay pot setting on my aqua puss fixed that by shielded cable on the output in addition to the input.

[Scruffie]

Think it was just seating all the ic again. Didn't touch any solder.

On the look for a 240pf mica cap now,or a known good ceramic.
Speaking of whine my eh poly chorus does the same thing at high delay settings.
And I had clock noise tenable by delay pot setting on my aqua puss fixed that by shielded cable on the output in addition to the input.

Yeah it will and does happen at high delay times, the only way out of it is to buffer the clock lines (as the very first Deluxe Memory Mans had the 4049 before it was omitted as it's not entirely necessary) or use more BBDs so the clock doesn't have to work as hard.

I thought you had a socket for your 240pF cap from the picture I saw? Can't you just select a 220pF out of your ceramics?

[LaceSensor]

Yeah I will tomorrow, in bed now.
Just be nice to have the mica, or a tested 240pf

Checking my pots to get accurate values was an eye opener.
100k some were low as 85k up to 110k
Got 99.8k and 100.3k though hehe

[tenwatt]

Is a silver mica recommended over a ceramic?

[Scruffie]

Is a silver mica recommended over a ceramic?

Silver mica will just be closer in tollerance I imagine, if it's working fine with a ceramic, it's working fine.

That component has no bearing on the audio at all, it merely sets the maximum delay time.

If you get enough delay time then it's probably close enough in value, if you feel there should be more delay time, it may be too low, if you get whine at the max delay setting, it may be over the value... you can just not set the delay pot that high though.

A capacitor of 5% tollerance is reccomended on the schematic (although EHX ignored this and deluxe memory mans regularly had around 400ms Delay according to a test I read, which I can beleive) 10% is acceptable and will most likely be fine, ceramics tend to have 20% so it is a little risky unless you can measure it or you are not overly fussed about getting the max delay time or having to back off the delay pot a bit.

As i've said many times though, the Delay pot value, 5k6 resistor and that cap all have a bearing on the delay time, not just the cap.

[LaceSensor]

No worries I'm just hoping to have the most accurate value.
I bothered to test pots and used 1% resistors where possible inc the 5.6k
Can't wait to gt this boxed up


Thanks for all he support

[LaceSensor]

boxed this up now, having a mess with the trimmers again.

even with the cleanest trims on the Bias1 and 2, it still seems to get overdriven easily
the repeats are not clean even by analog delay standards, especially the very first repeat.

I have the Gain trimmers almost off to try and help with it.

otherwise its all functions and does sound lovely, just need to keep trimming I spose.

[tenwatt]

boxed this up now, having a mess with the trimmers again.

even with the cleanest trims on the Bias1 and 2, it still seems to get overdriven easily
the repeats are not clean even by analog delay standards, especially the very first repeat.

I have the Gain trimmers almost off to try and help with it.

otherwise its all functions and does sound lovely, just need to keep trimming I spose.

I'm having the same issue.  It's a little more sensitive than I first thought.  Adding OD is NOT an option.  Higher notes are not as bad but lower notes are pushed easily into fuzzy repeats.  I tried my single coil Tele and the problem is the same.  Any suggestions?

Did the whine go away when you boxed it?

[LaceSensor]

Hi

no the clock noise whine is still there past 2pm on the Delay knob.

not present in bypass though which is encouraging.

Maybe the mods bean suggested earlier would help, not sure.
Wanna wait for some feedback from him hopefully its forthcoming.

Cheers

[tenwatt]

Hi

no the clock noise whine is still there past 2pm on the Delay knob.

not present in bypass though which is encouraging.

Maybe the mods bean suggested earlier would help, not sure.
Wanna wait for some feedback from him hopefully its forthcoming.

Cheers

Does the whining stop for you when you touch the "Level" pot?