# Lemonade Drive report



## Mark (Jul 19, 2021)

I have my board at the stage where all the parts are in and I can listen to it.

It nails the sound Page gets. However, I found myself thinking it didn’t have enough bass so I replaced the 2.2uF bypass caps with 4.7uF caps as recommended here. Thanks for the tip by the way.

I wasn’t fond of the 100K log filter pot at the input, the cut end is pretty bunched up. I put a linear pot in and liked it better.

I’m thinking that I would like more range in the bass cut, maybe a 470 or 1000pF?

I was thinking the same thing about the treble response. There is a 3.3nF cap to earth shunting highs. That too could have a pot to add more highs. I think it would be too raspy without the cap, but the right value pot might be a good thing.

Any thoughts?

Regards 

Mark


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## music6000 (Jul 19, 2021)

Mark said:


> I have my board at the stage where all the parts are in and I can listen to it.
> 
> It nails the sound Page gets. However, I found myself thinking it didn’t have enough bass so I replaced the 2.2uF bypass caps with 4.7uF caps as recommended here. Thanks for the tip by the way.
> 
> ...


What voltage are you getting on the Drain on 2n5457?
The original uses a Trimmer!


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## Mark (Jul 19, 2021)

Good call M6000, the VDD is 8.35VDC on the battery that I’m using and the voltage on the drain is 6.97VDC.

I do have a 10K pot. I can remove the 6.8K and sub the pot in to determine the correct resistor value.

I assume the idea is to have half the rail voltage on the Drain.

I will give that a go. I don’t imagine the timbre will change, but there will be more headroom.

Regards 

Mark


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## Mark (Jul 20, 2021)

Okay, I removed the resistor and used the 10K pot. It wasn’t even close to being half the rail. I end up using a 100K trim pot and at about 19K (will have to double check) I had half the rail on the drain. 

I played through the pedal and it was much the same sounding as far as I can remember, though the response of the filter pot was now exactly opposite where there was now too much bass cut and not enough bass on the rotation of the pot. 

I will put the log pot back in, though I like the idea of being able to add more treble to response of the pedal. 

Thanks again for your help.

Regards 

Mark


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## music6000 (Jul 20, 2021)

Mark said:


> Okay, I removed the resistor and used the 10K pot. It wasn’t even close to being half the rail. I end up using a 100K trim pot and at about 19K (will have to double check) I had half the rail on the drain.
> 
> I played through the pedal and it was much the same sounding as far as I can remember, though the response of the filter pot was now exactly opposite where there was now too much bass cut and not enough bass on the rotation of the pot.
> 
> ...


One would have to question if your 2N5457 is legit, I dialed mine @ 4.5v = 7K6!


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## Mark (Jul 20, 2021)

music6000 said:


> One would have to question if your 2N5457 is legit, I dialed mine @ 4.5v = 7K6!


Well, 7.6K is very close to the stock 6.8K, so that makes sense.

I disconnected one side of the pot and the drain resistor is 20K which is quite a bit higher.

Here is photo of the 2N5457 in the board. 





Thanks for your assistance.

Regards 

Mark


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## Mark (Jul 20, 2021)

This is the board, it still has to be cleaned etc.





Regards 

Mark


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## music6000 (Jul 20, 2021)

Bass guitar FET preamp
					

Which first stage FET voltage drops by 50mV?  You are welcome to fiddle with the Source resistors if you must(!), but I wouldn't. We're already substantially impaired trying to do this kind of work with no oscilloscope, and you already have the gain that you want (remember, Drain-res/Source-res...




					www.diyaudio.com
				



Scroll down until you come to this:




Did you get it of ebay? ********
Do you have any way of testing to see if it is genuine.


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## Mark (Jul 20, 2021)

I bought the 2N5457 from Pedal Parts Australia. I don’t know where these guys got them from. So are you saying they are duds?

Who is a recommended seller?

I haven’t read the whole thing yet as it’s a bit long winded.

Regards 

Mark


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## music6000 (Jul 20, 2021)

Another bogus seller!


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## Mark (Jul 20, 2021)

Thanks I’ll remember that.

Regards 

Mark


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## Feral Feline (Jul 20, 2021)

music6000 said:


> Another bogus seller!
> 
> 
> View attachment 13852


Just to clarify, crystal-like, you're just saying FXI Electronics is a junk peddler, that "Another bogus seller!" was NOT a response to the previous post's mention of Pedal Parts Australia...?


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## Mark (Jul 20, 2021)

I would like to point out that I have used Pedal Parts Australia before and I have found them to be very good to purchase from. I think Music6000 was referring to pop up eBay sellers.

The issue here is FET’s. It seems quite a few people have had issues with FETs judging by the links in this thread.

What are your thoughts on FET’s and the results I have?

I had thought of contacting PPA, but it’s not his problem really. He does sell a kit for a Dr Boogie, and may be able to offer some advice, but I’d like to know the right questions first.

Regards

Mark


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## twebb6778 (Jul 20, 2021)

I've only ever had good experiences with Pedal Parts Australia, their parts have always been legit and decent prices too.


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## Mark (Jul 20, 2021)

twebb6778 said:


> I've only ever had good experiences with Pedal Parts Australia, their parts have always been legit and decent prices too.


But what is your take on the FET in my Lemonade board?

PPA isn’t the issue.

Regards 

Mark


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## music6000 (Jul 20, 2021)

Feral Feline said:


> Just to clarify, crystal-like, you're just saying FXI Electronics is a junk peddler, that "Another bogus seller!" was NOT a response to the previous post's mention of Pedal Parts Australia...?


Like Tayda, Pedal Parts Australia get supplies from China, they have Good components & they have bad components.
If I see a 2N5457 with BC27 code, I would guantee it's a Fake!
About the only safe 2N5457 now is the Mouser Lead free version!


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## Mark (Jul 20, 2021)

Music6000 could you provide a link to this part so I don’t order the wrong part?

I hate ordering from Mouser as the postage is expensive.

Thanks again to those offering assistance.

Regards 

Mark


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## Mark (Jul 21, 2021)

This is what I was seeing when testing the 2N5457. It doesn’t seem terribly meaningful though.

Any thoughts?








Regards 

Mark


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## music6000 (Jul 21, 2021)

Mark said:


> This is what I was seeing when testing the 2N5457. It doesn’t seem terribly meaningful though.
> 
> Any thoughts?
> 
> ...


That is standard with this model for jfets.
 It is a jfet you have but with the the most repetitive Batch number on the Internet, who knows if it is a genuine 2n5457 which is out of spec.
As you reported, you could not get half the voltage with a 10k pot & 6K8 is fixed value so it is a Fake or out of spec jfet!
This has been a common fault with 2N5457 & J201 being phased out!


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## music6000 (Jul 21, 2021)

Read my report & update on this Build from nearly 2 years ago :





						M800 Overdrive
					

Awesome JCM800 Emulation !!! All the Trimmers were adjusted to 4.5v & it was meh, 4.75, 5v, 5.25v & 5.5v, Louder with no Gain! Old School, Strummed a Chord & tuned each Trimmer by ear. Critical Trimmer is the Tone trimmer, This effects overall EQ & gives it the Power of The JCM800 sizzle! The...




					forum.pedalpcb.com


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## Mark (Jul 23, 2021)

Great report, where did you get the real deal J201’s from?

I noticed PedalPCB has the small boards to use SMD components but are out of stock.

I was listening to the Lemonade Drive and wondered if having the bias off a bit was part of the pedals charm?

What did you find.

Regards 

Mark


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## music6000 (Jul 23, 2021)

Mark said:


> Great report, where did you get the real deal J201’s from?
> 
> I noticed PedalPCB has the small boards to use SMD components but are out of stock.
> 
> ...


This is my own Eyelet Board design.
I have 7K6 at 4.75v
My input cap was increased from 4n7 to 8n2 & 3n3 was increased to 4n7.
The Red Led is Bypass & Green is On :


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## Mark (Jul 23, 2021)

I love the way you finish your pedals, I’m reading Chuck’s articles at the moment.


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## Mark (Jul 25, 2021)

I measured around my JFET today. The gate was 0VDC as you’d imagine, the source was 0.145vdc and the drain was 4.17vdc with the 20K drain resistor.

Doing a simple bit of maths, if I am to have VCC/2 on the drain, the Id would have to be 661uA with the 1K source resistor.
This means the Vgs would have to be .661vdc. 

Regards 

Mark


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## Mark (Jul 25, 2021)

This diagram does confuse me a bit. It is very much like a thermonic valve where lower Vgs means more current flow.

If I have 0VDC on the Gate and 0.145VDC on the source I have a Vgs of 0.145VDC. According to the common drain source diagram. I should be seeing 3mA with that Vgs. This doesn’t make sense as if I had 3mA going through a 1K resistor I would have 3V on the source resistor.

If there is s simple error in my logic, please point it out to me.

Regards

Mark


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## Mark (Jul 26, 2021)

Mark said:


> View attachment 14039
> 
> This diagram does confuse me a bit. It is very much like a thermonic valve where lower Vgs means more current flow.
> 
> ...


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## Mark (Jul 26, 2021)

I decided to have a go at measuring Vgs (off) and Idss. 

I used a power supply that supplied 9.3VDC, the 10M resistor on the source that measured 10.1M, and a 1K resistor on the Gate which measured 996 ohm. 

I have five 2N5457 JFETs this are Vgs and Idss figures.



(1) 0.543V, 1.57mA

(2) 0.506V, 1.95mA

(3) 0.509V, 2.19mA

(4) 0.464V, 1.7mA

(5) 0.471V, 1.46mA

Is that what you would expect to see from 2N5457’s?

I suspect not. 

Regards 

Mark


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## Mark (Jul 26, 2021)

I have two quite old J201’s which I measured.

(1) 0.881vdc, 0.553mA
(2) 0.856vdc, 0.550mA

From what I’ve read these are good values, not sure why yet, but they are bound for the Boogie Monster.

Regards 

Mark


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## Mark (Jul 28, 2021)

I decided to take the measurements a bit further today. I used the simple FET tester to check the Vgs(off) and Idss, then I put the FET into the circuit on my breadboard.

Basically, I found the higher the Vgs(off) and Idss the closer the 2N5457 was to operating in the desired area.

2N5457   Power Supply = 9.36VDC

Vgs(off)     Idss     Vgs (in cct)     Vd

0.466v      1.7mA     0.18v          8.12VDC
0.511v      1.5mA     0.20v          7.97VDC
0.538v      1.9mA     0.19v          8.05VDC
0.452v      1.4mA     0.16v          8.25VDC
0.530v      2.2mA     0.21v          7.95VDC

J201. 

Vgs(off)     Idss      Vgs(in cct)     Vd

0.885v   0.553mA     0.257v       7.61VDC
0.858v   0.550mA     0.253v       7.64VDC

I thought the J201’s would have had a lower voltage on the Drain than they did. Mind you, I have seen circuits using J201’s using 100K trim pots on the Drain. 

It seems with 2N5457 JFET’s in this circuit, the higher the Idss the better fit the FET is.

Thoughts?

Regards

Mark


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## Mark (Jul 28, 2021)

Still reading up on FET’s, the calculator implies the source resistor is too large to have the Vd at 4.5vdc. With the data I had it states the Rs would need to be 390 ohms.

JFET calculator


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## HamishR (Jul 29, 2021)

I don't know if this helps but I just remembered I built a few of these on vero a while back, and the advice then was to make Q1 have an hfe of around 270-300, with bias at 4.5V.  It could be a 2N2222A, a BC108 or a BC183 - probably others too. I always used a 2N5457 as Q2 with 4.6V on the drain. Whenever I've built them like this they have worked beautifully. Cool pedal.


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## Mark (Jul 29, 2021)

Thanks Hamish R for your reply, much appreciated.

As seen in my attachment, the difference between the Fairchild 2N5457's and the Motorola 2N5457's is night and day. 

A huge thank you to Phil for supplying with the Motorola 2N5457's, having the right part makes a huge difference. There is one JFET which is perfect for this circuit. 

Regards

Mark


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## Mark (Aug 10, 2021)

One thing that I have noticed is if the battery gets down to 7vdc the pedal sounds like the bias is off. 

I think this pedal is better off being run from a power supply.

Regards 

Mark


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