"New Diode" / "Tweaked" KTR?

[Fingolfen]

Has anyone traced one of the newer KTR's with the "new" diodes and "adjustments"? I'm assuming the base circuit is the same, just some values that may change because of a different Vf on the diodes.

 

[Fingolfen]

Personally I’d like to see also so we don’t have to keep sourcing GEs. Imseparately, I recently did a test with an in-progress build to see if I could get the same sound with bat46. Just swapping diodes I’d say it’s noticeably different. I added a 100R in series with the diodes (to soften them, in theory), then also a 4k7 resistor in series with C11 (pedalpcb Kliche schem). The reason is that the 100R in series with diodes raised the clip threshold slightly, making the dirt path louder for a give gain knob setting. This additional R should bring it back into balance with the clean paths (4k7 found by ear, but may need to tweak). I had to get that build to a friend, but soon plan to do another full build with these mods to confirm, and I may end up tweaking those R values.

I hear what you're saying - Germanium diodes can be difficult to source and work with. I'm building a series of G2 clones, and those are even worse because you have to worry not only about Vf but leakage current as well.

 

[spi]

If he was going to tweak components to work with different diodes, he should've chosen 1n4148s.

 

[Robert]

I hear what you're saying - Germanium diodes can be difficult to source and work with. I'm building a series of G2 clones, and those are even worse because you have to worry not only about Vf but leakage current as well.

I like germanium in one stage, silicon in the other.... I don't pay a bit of attention to leakage in this configuration, although it's not "authentic" I suppose.

 

[Fingolfen]

I like germanium in one stage, silicon in the other.... I don't pay a bit of attention to leakage in this configuration, although it's not "authentic" I suppose.

I'm going to experiment a little. I wanted to try and nail the "authentic" first before I went with mods.

 

[K Pedals]

Really?

The D9E I have are either a pale green stripe or a bright blue stripe:

View attachment 29440

They come with one blue stripe and some have a blue and red stripe…
All Russian diodes color scheme could have an extra red line on them…

Those green striped are not Russian… I think they’re probably 1N34a’s…

 

[Fingolfen]

Green ones could be... they were orphans that may have ended up in the wrong bin...

 

[MobyOctopad]

They don't look like D9Es to me. They look like some of the newer 1N34A diodes I've picked up recently and used on a recent Klon build:

View attachment 29421

Compare to the 1N34A from an earlier build:

View attachment 29422

VS. one with yet another 1N34A variant:

View attachment 29423

Yeah, was going to say that the pair in the newer KTR look exactly like the 1N34As StompboxParts currently has in stock. Though, they said this batch tested at ~.35-.41v at 1ma whereas the extra super-duper special 1N34As seem to have tested at .35v at 5ma, if memory serves correctly.

 

[Fingolfen]

Yeah, was going to say that the pair in the newer KTR look exactly like the 1N34As StompboxParts currently has in stock. Though, they said this batch tested at ~.35-.41v at 1ma whereas the extra super-duper special 1N34As seem to have tested at .35v at 5ma, if memory serves correctly.

I've tested several of the new StompboxParts ones on my DMM and they're all coming in ~0.35-0.41V - not sure what amperage my DMM is running, though.

 

[benny_profane]

The DMM Vf reading of diodes is rather meaningless unless you know the test current. Even then, it just gives you a snapshot—a particular Vf given a particular current. Diodes are not like resistors. They are non-linear devices. So, all of the talk about the Vf of the Klon diodes doesn't impart meaningful information. You'd have to see the I-V curve to characterize them and know how they'd respond.

 

[Fingolfen]

The DMM Vf reading of diodes is rather meaningless unless you know the test current. Even then, it just gives you a snapshot—a particular Vf given a particular current. Diodes are not like resistors. They are non-linear devices. So, all of the talk about the Vf of the Klon diodes doesn't impart meaningful information. You'd have to see the I-V curve to characterize them and know how they'd respond.

I sort of have to go quick and dirty at this point. Do you have a set up you could recommend that would generate a good I-V curve? I've dealt with a fair amount of electrical test in my industry, but semiconductors are a world apart from testing discrete components.

 

[Robert]

I have tried every ge diode I could get my hands on, they literally all sound the same to me.

A friend of mine can hear the difference in his amp when using one of those $33 Mercury Magnetics AC cords....

 

[Robert]

Can't you?

 

[Robert]

If I need a spectrum analyzer to hear the difference I'm good....

 

[benny_profane]

I sort of have to go quick and dirty at this point. Do you have a set up you could recommend that would generate a good I-V curve? I've dealt with a fair amount of electrical test in my industry, but semiconductors are a world apart from testing discrete components.

Semi-conductors like transistors and diodes are still discrete. Linearity or active/passive has nothing to do with that.

You would either need a setup where you’re controlling the current through device under test (DUT) and keep notes, or a test instrument like a Peak Atlas DCA75 that has curve tracing capabilities. With the DCA75, you have to hook it up to a computer to generate the graphs.

 

[Big Monk]

I use a klone daily and have built a handful. I have tried every ge diode I could get my hands on, they literally all sound the same to me. They are only audible the more you turn the gain up because of the dual gang pot usage. most people use it with the gain between zero and 11 o'clock. I don't know how most people can here a difference, it's just clean tone you are hearing and at low gain settings it's likely the buffer has a greater impact than the diodes. The fv is the only difference I could tell made an impact and that was only when the gain was past noon. WTF do I know though, I don't have Eric Johnson ears.

I think you nailed it. Forward voltage is the thang.

Also, how hard could it possibly be to find a modern productio. Diode with that forward voltage?

I was looking for Ram’s Head diodes in a specific Vf range the other day and found a modern unit being sold by the tens of thousands in mouser in 5 seconds.

 

[Robert]

Dude is like "I can't believe the difference this 12 gauge AC cord makes" ....

But your amp is plugged in to a 14 gauge extension cord....

 

[Big Monk]

If I need a spectrum analyzer to see the difference I'm good....

Fixed that for you…

 

[Big Monk]

A friend of mine can hear the difference in his amp when using one of those $33 Mercury Magnetics AC cords....

You mean a former friend of yours…

 

[Robert]

Well.... I don't do amp work for him, let's just say that.

 

[ICTRock]

this reminds me of that local guy with the chokes on his instrument cables. could swear there's a couple greybench vids about the klon diodes on the youtubes