Correct resistance for pots with EMG pickups? Not 150k and 500k?

prowla

So, a Tone pot of 500k where it should be 25k is consistent with the described behaviour of only approx 0-1 working, ie. about 10% of the travel.

Since 25k is 20% of 500k; it's probably less than 0-1 on the scale: 0-0.5 would give approx 25k (subject to component tolerances).

ICBM

prowla said:

So, a Tone pot of 500k where it should be 25k is consistent with the described behaviour of only approx 0-1 working, ie. about 10% of the travel.

Since 25k is 20% of 500k; it's probably less than 0-1 on the scale: 0-0.5 would give approx 25k (subject to component tolerances).

Exactly.

With the volume control, it’s basically that a very large resistance quickly develops between the input and the output, which ‘unbuffers’ the signal and allows the cable capacitance to suck away all the treble - just as it does with a passive pickup, but you’ll actually notice it much more because unlike with a passive pickup, it doesn’t happen when the control is up full so you’re back to the full brightness.

If I remember rightly, the standard tone cap value for EMGs is .1uF too, so you’ll need one of those as well if they’ve used a typical (smaller) passive value.

skullfunkerry

ToneControl said:

WezV said:

i think it will always look like that with a finish like this.

I can believe it. It's not awful, I just think gloss would look better

All of the satin/matt finish guitars I've had have developed shinier patches from use, so I'd imagine a couple of hours with a polishing cloth would give you a finish that you prefer? Or maybe even super fine micromesh, although I'm not sure about that...

Kittyfrisk

ICBM said:

Funkfingers said:

The H-B Amarok

Amarok?

I hope they paid Mike Oldfield for that...

ICBM

ToneControl said:

the volume pot goes up a bit in resistance at the centre of travel, I assume the circuit preceding it is having an effect

Actually, I missed this post earlier - if you measured the resistance in circuit from the jack output to ground, then in fact a high reading of 135K is what you would expect with a 500K pot (a quarter of the pot resistance, plus the pickup resistance of about 10K - the EMG circuit output might be 25K or more), so that in fact sounds like they've used two 500K pots, which would be more what I would expect since they might have just seen it as a 'humbucker guitar'.

Either way, it's wrong and changing them to 25K should fix the problem.

Kittyfrisk said:

ICBM said:

I hope they paid Mike Oldfield for that...

[Hideous VW oversized Tonka Toy]

Them too...

Funkfingers

Please disregard my comments earlier about solderless connections in the controls area. Your guitar will only have them on the underside of the pickups. The factory wiring error suggests traditional hard-wired soldered connections throughout the controls area. 

TBH, given the slightly El Cheapo grades of cable often used in Indonesian guitars, it is probably wisest to replace the entire loom. Keep a sprung leaf selector switch. Dump the enclosed-in-a-box type.

One advantage of old-fashioned hard-wired A25k pots is that you get to choose the capacitor value on the tone control. (The stock EMG value blows chunks.) An .022 or .047uF should do nicely.

The only place where Solderless™ connections might be advantageous is for the second pot. This would probably need to be integrated into the harness via an EMG 157c Buss Board. Thus, you could easily change from a Passive Treble roll-off to the active VLPF or a pre-amp level booster. If you never use the tone control, you could even have two volumes.

ToneControl

Funkfingers said:

Please disregard my comments earlier about solderless connections in the controls area. Your guitar will only have them on the underside of the pickups. The factory wiring error suggests traditional hard-wired soldered connections throughout the controls area. 

TBH, given the slightly El Cheapo grades of cable often used in Indonesian guitars, it is probably wisest to replace the entire loom. Keep a sprung leaf selector switch. Dump the enclosed-in-a-box type.

One advantage of old-fashioned hard-wired A25k pots is that you get to choose the capacitor value on the tone control. (The stock EMG value blows chunks.) An .022 or .047uF should do nicely.

The only place where Solderless™ connections might be advantageous is for the second pot. This would probably need to be integrated into the harness via an EMG 157c Buss Board. Thus, you could easily change from a Passive Treble roll-off to the active VLPF or a pre-amp level booster. If you never use the tone control, you could even have two volumes.

I thought about fitting a dual-gang bass and treble active EMG BTC tone control on another EMG-equipped guitar

I have separate bass and treble knobs on one guitar, works very nicely

ToneControl

ICBM said:

ToneControl said:

the volume pot goes up a bit in resistance at the centre of travel, I assume the circuit preceding it is having an effect

Actually, I missed this post earlier - if you measured the resistance in circuit from the jack output to ground, then in fact a high reading of 135K is what you would expect with a 500K pot (a quarter of the pot resistance, plus the pickup resistance of about 10K - the EMG circuit output might be 25K or more), so that in fact sounds like they've used two 500K pots, which would be more what I would expect since they might have just seen it as a 'humbucker guitar'.

Either way, it's wrong and changing them to 25K should fix the problem.

Kittyfrisk said:

ICBM said:

I hope they paid Mike Oldfield for that...

[Hideous VW oversized Tonka Toy]

Them too...

yeah, I think they just saw the humbuckers

I saw a review for an Indonesian-made Harley Benton LP-clone with active cheap Thomann pickups, that also said they'd fitted 500k pots

They've offered me £50 discount, I'm trying to decide over the weekend if I like the guitar enough, or whether I should return it. 
Overall it's a lot of discount, since it was a B-stock. I suspect the colour has been a problem, they are selling this colour cheaper than the other colours. The guitar is really well made though

Funkfingers

B-Stock can mean defective/damaged or, sometimes, it means a customer return. 

Assume the former. Thomann could have a whole batch of Anorak guitars with the incorrect pots. Estimate the cost of obtaining the correct parts PLUS professional removal/installation. Fish for that level of discount.

ToneControl

Funkfingers said:

B-Stock can mean defective/damaged or, sometimes, it means a customer return. 

Assume the former. Thomann could have a whole batch of Anorak guitars with the incorrect pots. Estimate the cost of obtaining the correct parts PLUS professional removal/installation. Fish for that level of discount.

B-stock normally means ex-demo AFAIK

anyway, I reckon they probably all have the wrong pots
they only have a few models with these EMG Hot 70 pickups

They've come back with an OK discount, but not a great one, so I'm going to try out the guitar again tomorrow and say yes or no, those pickups are amazing, but I don't like the colour much, the guitar is very well built though

Funkfingers

Has somebody at Thomann admitted that all examples of the model have the same wiring error? Is it just the blackburst ones? Is it just your example?

If you like the guitar but dislike the colour, return it before ordering another example in different colour finish.

ICBM

ToneControl said:

They've offered me £50 discount, I'm trying to decide over the weekend if I like the guitar enough, or whether I should return it.

I would accept that. It’s very unlikely to cost more than that to change two pots, even at top shop rates.

ToneControl

Funkfingers said:

Has somebody at Thomann admitted that all examples of the model have the same wiring error? Is it just the blackburst ones? Is it just your example?

If you like the guitar but dislike the colour, return it before ordering another example in different colour finish.

I'm just guessing based on the fact that other guitar models have reviews saying that they used 500k pots on Roswell pickups
Harley Benton SC-Custom II Active Vintage BK – Thomann UK

Funkfingers

ToneControl said:

Says flamed maple veneer, but there is no 3D appearance

The veneer is probably all of 1mm thick. (Check around the pickup cavities edges or the pot shaft holes.) PRS SE veneer tops are the same. Insufficient depth to provide any visual excitement.

PetGerbil

Shouldn't they have the quick connect pots anyway ? If you're paying for a guitar with an "EMG Retro Active Hot 70" set, then surely you would expect to get the pots and all the connections that come with it. That's part of the "set"
You could understand if they were Thomann's "own brand" active pickups, but they're not. They're EMG's, and EMG's come with the quick connection set. (which isn't cheap to buy on it's own.)

*/edit
After a bit of a search, It seems that guitars sold with EMG's often don't have the gubbins in some/all cases...
Doesn't really affect me, but...what a swizz!!

Funkfingers

ToneControl said:

other guitar models have reviews saying that they used 500k pots on Roswell pickups

That is worrying. It implies either that the Roswell low impedance humbuckers have an external pre-amp stage (like Reflex pickups used to) or that H-B doesn't know what it is doing.

The published spec on the Thomann website could be correct in every detail (I hope not!) or it could have been hastily cobbled together by cutting and pasting from another product description without checking the details.

•

Changing to the correct value pots is well within the capabilities of a home repairer. Before ordering, find out which pot shaft length you require to reach through the guitar's top. 

ToneControl

Funkfingers said:

ToneControl said:

other guitar models have reviews saying that they used 500k pots on Roswell pickups

That is worrying. It implies either that the Roswell low impedance humbuckers have an external pre-amp stage (like Reflex pickups used to) or that H-B doesn't know what it is doing.

The published spec on the Thomann website could be correct in every detail (I hope not!) or it could have been hastily cobbled together by cutting and pasting from another product description without checking the details.

•

Changing to the correct value pots is well within the capabilities of a home repairer. Before ordering, find out which pot shaft length you require to reach through the guitar's top. 

6-string Active Humbucker Pickup / Alnico 5 – Roswell Pickups
Looks like the pickup preamp is internal, the voltage input is required


Ironically, Thomann has a very well written 9 page guide to guitar pots, including the use of 25k for active pickups:
https://www.thomann.de/gb/onlineexpert_page_potentiometers_summary.html

ICBM

PetGerbil said:

Shouldn't they have the quick connect pots anyway ? If you're paying for a guitar with an "EMG Retro Active Hot 70" set, then surely you would expect to get the pots and all the connections that come with it. That's part of the "set"
You could understand if they were Thomann's "own brand" active pickups, but they're not. They're EMG's, and EMG's come with the quick connection set. (which isn't cheap to buy on it's own.)

*/edit
After a bit of a search, It seems that guitars sold with EMG's often don't have the gubbins in some/all cases...
Doesn't really affect me, but...what a swizz!!

I wouldn’t want the Quick Connect stuff, it’s a pain in the backside. The only connector worth having is the one on the pickup itself so you can swap types easily.

I can see why they wouldn’t want EMG to supply the pots, it would increase the cost compared to buying them in bulk, and every penny counts at this end of the market.

But they should use the correct values.

WezV

Funkfingers said:

ToneControl said:

Says flamed maple veneer, but there is no 3D appearance

The veneer is probably all of 1mm thick. (Check around the pickup cavities edges or the pot shaft holes.) PRS SE veneer tops are the same. Insufficient depth to provide any visual excitement.

You must have x-ray eyes  


The figure in wood is only visible at the surface.

Funkfingers

"I'm a personality prototype. You can tell, can't you?"