Has anyone heard of the old Wharfdale E70 made back in the 80's?

[Old bones]

This is what I have found. I am glad I haven't yet built the enclosures.


Wharfedale service diagram


Original E70 crossovers


Suspect replacement


Steve's circuit

 

[Galu]

The commercial E70 crossover is a bit more complex than the kit crossover as it does some response shaping.

The suspect crossover does not have the correct crossover frequencies. In the Speakercraft booklet, these are stated as 800Hz and 7000Hz.

You appear to have been sold a pup!

 

[Galu]

I am glad I haven't yet built the enclosures.

I can supply the Wharfedale Speakercraft enclosure plans should you require them.

 

[kgrlee]

I was Graham Bank's gopher when he designed the E70s.

IIRC, Steve's xover is correct. The other 2 inductors are to do with the twiddle knobs which are unnecessary. E70 does VERY well in DBLTs even on classical music and this is with the knobs at full.

The important inductor is the 3.25mH feeding the bass. The original has a short 19mm Diameter ferrite core. Don't use the cheapo (?) ones you can buy with long 9.5mm D cores. Better still, use an air-core but this will be BIG. The 0.2mH & 0.5mH should be air-cored like the original.

Replacing the caps with films is good.

If you score an E50 with a mangy cabinet, consider re-housing the bits in an E70 box of 3/4" ply with the treble above the single midrange. Better all round.

 

[krivium]

Old Bones check your pm please.

 

[Old bones]

The commercial E70 crossover is a bit more complex than the kit crossover as it does some response shaping.

The suspect crossover does not have the correct crossover frequencies. In the Speakercraft booklet, these are stated as 800Hz and 7000Hz.

You appear to have been sold a pup!

Yes, I believe that is the case.

 

[Old bones]

I can supply the Wharfedale Speakercraft enclosure plans should you require them.

That is very kind of you. It would be useful as I have only a couple of images of a Speakercraft brochure. Does it include a circuit diagram of the xover?

 

[Old bones]

I was Graham Bank's gopher when he designed the E70s.

IIRC, Steve's xover is correct. The other 2 inductors are to do with the twiddle knobs which are unnecessary. E70 does VERY well in DBLTs even on classical music and this is with the knobs at full.

The important inductor is the 3.25mH feeding the bass. The original has a short 19mm Diameter ferrite core. Don't use the cheapo (?) ones you can buy with long 9.5mm D cores. Better still, use an air-core but this will be BIG. The 0.2mH & 0.5mH should be air-cored like the original.

Replacing the caps with films is good.

If you score an E50 with a mangy cabinet, consider re-housing the bits in an E70 box of 3/4" ply with the treble above the single midrange. Better all round.

Thank you so much for your advice. If I am going to see this project through I need as much (factual) info as I can get. If you recall anything more please post it or pm me.

I had no idea there would be so much help on offer here. So many so called experts have slagged off the E70s it is nice to find there are people who love(d) them as much as I did.

 

[Galu]

It would be useful as I have only a couple of images of a Speakercraft brochure. Does it include a circuit diagram of the xover?

I will scan the kit cabinet plans and kit crossover diagram later.

The kit crossover is the same as the one shown by Steve, but has two component value differences which I identified in post #39.

 

[Galu]

As promised:

 

[Old bones]

Many thanks for that Galu. A few more missing parts to the puzzle.

 

[kgrlee]

IIRC, the 2mH bass inductor feed and 2R2 treble resistor feed are correct.

Old Bones, the only tip I can think of at the moment is to build the cabinets in handed pairs with the treble units 'inside'.

Are you using the original units?

So many so called experts have slagged off the E70s

The Wharfedale Super 8/
About 2/3 down on this page is a true story about the E70 and 'Bat Ears'. If you have a copy of the very first HiFi Choice on Loudspeakers, you can work out who 'Bat Ears' is. There were other famous reviewers and 'ears' in this story who shall all remain anonymous

 

[Old bones]

IIRC, the 2mH bass inductor feed and 2R2 treble resistor feed are correct.

Old Bones, the only tip I can think of at the moment is to build the cabinets in handed pairs with the treble units 'inside'.

Are you using the original units?

The Wharfedale Super 8/
About 2/3 down on this page is a true story about the E70 and 'Bat Ears'. If you have a copy of the very first HiFi Choice on Loudspeakers, you can work out who 'Bat Ears' is. There were other famous reviewers and 'ears' in this story who shall all remain anonymous

Now I am totally confused.
The inductor values I have before me don't agree.

Bass inductor- 2mh, 3.2mh, or 3.25mh

Mids inductor- 2.0mh or 0.5mh

Treble inductor- 0.2mh or 0.5mh

I have found these values from various sources including photos of an actual crossover.
One thing is certain. It is going to be an expensive gamble whichever way I slice it. The
3.2mh if that is what I need is going to be very hard to find. I looked on about a dozen
websites last night and couldn't find one but I expect some high end company would be
willing to make a couple of "specials".

I don't have any original parts and have been reluctant to buy parts on ebay stripped from
decades old speakers that are probably at or near the end of their life. Thanks again for your input.

The saga continues.

 

[Galu]

No need for confusion at the moment on the crossover front. The kit version shown in post #50 obviously worked adequately well with the original kit drivers and forms a basic starting point for experiment.

Have you noted kgrlee's confirmation about the values of the bass inductor (2mH) and the treble resistor (2R2)?

However, I am confused on the driver front. We have no details of the drivers you own or intend to purchase. The crossover may have to be tweaked to accommodate cloned or substitute drivers.

 

[kgrlee]

Bass inductor- 2mh, 3.2mh, or 3.25mh
Mids inductor- 2.0mh or 0.5mh
Treble inductor- 0.2mh or 0.5mh

Bass is 2mH
Mid 0.5mH
Treble 0.2mH

The other inductors were to do the twiddle knobs ... re-surrecting 40+ yr old memories working on these speakers.

I don't have any original parts and have been reluctant to buy parts on ebay stripped from decades old speakers that are probably at or near the end of their life.

Alas, the xover is ONLY valid for ORIGINAL E70 & E50 units.

If you are using other units, your xover should be COMPLETELY different.

About the only thing one can say is that if your replacement 10" unit has about the same Thiele parameters, particularly Mms & Qtot, the E70 box will give good bass.

Speakers usually don't go bad. If 40 yr old units are not rubbing and have no obvious physical damage, they are probably good for another 40 yrs.

 

[kgrlee]

Alas, the xover is ONLY valid for ORIGINAL E70 & E50 units.

If you are using other units, your xover should be COMPLETELY different.

Old Bones, can you post some info & links about your units?

GRS BT3-8 3-3/8" Bullet Tweeter

I think at least the treble unit (probably a good clone) is still available.

 

[Old bones]

OK, here goes. I have these units which I was led to believe would be equivalent or upgrades to the original Wharfedale drivers.

Tweets- Monacor DT 107

THIELE-SMALL-PARAMETER
Resonance fs fs: 1200 Hz
Mechanical Q Qms: 0.85
Electrical Q Qes: 2.23
Total Q Qts: 0.62
DC-Resistance Re: 6.4 Ohm
Coil Inductance Le: 0.1 mH
Moving Mass Mms: 0.22 g
Sound pressure dB: 89 SPL

Mid range- Peerless Fabrikkerne (I) Ltd - M10NG - 4"

FS 80 Hz 90hz
Re 5.8 ohms 3.4 ohms
Qms 2.14 4.6
Qes 0.57 0.6
Qts 0.45 0.5
Vas (SD) 11.306 litres 4.1 litres
Mms (SD) 4.12 grams
Cms (SD) 0.92 mm/N
BL (SD) 4.63 Tesla-M
SPL ref (SD) 92.5 dB [Re] 88db
Impedance 4 ohms
Power 60w rms

Woofer- Celestion TF1020

General Specifications
Nominal diameter (mm/in)...................................... 254/10
Power rating (AES, W rms) ......................................... 150
Nominal impedance ( Ω ) ................................................. 8
Voice coil diameter (mm/in)........................................ 51/2
Magnet type............................................................ Ferrite
Magnet weight (kg/oz)..............................................1.2/42
Chassis type................................................. Pressed steel
Sensitivity (dB).............................................................. 97
Frequency range (Hz)........................................... 60-3000
Coil material ............................................... Round copper
Former material.................................................. Polyimide
Cone material ..................................... Kevlar loaded paper
Surround material .......................................... Cloth-sealed
Suspension ............................................................. Single
Xmax (mm/in)...................................................... 2.0/0.08
Gap depth (mm/in)............................................... 8.0/0.31
Voice coil winding width (mm/in) ....................... 12.0/0.47
Small Signal Parameters
D (m/in) ............................................................ 0.21/8.27
F s (Hz).......................................................................... 75
M air (g/oz) ...................................................... 3.65/0.129
M md (g/oz) ...................................................... 24.80/0.87
Q ms .......................................................................... 4.00
Q es ........................................................................... 0.41
Q ts ........................................................................... 0.37
R e ( Ω ) ...................................................................... 5.40
V as (lt/ft 3 ) .......................................................... 26.6/0.94
Bl (Tm) ................................................................... 13.40
C ms (mm/N) .............................................................. 0.16
R ms (kg/s) ................................................................. 3.35
L e (mH).......................................................................0.49

 

[Old bones]

Old Bones, can you post some info & links about your units?


I think at least the treble unit (probably a good clone) is still available.

I must say, the tweeter in your link looks pretty much identical to the original, and certainly is moderately priced.

Oops! I just had a go at ordering a pair. The shipping is double the cost of the drivers on top.

 

[Galu]

"I have these units which I was led to believe would be equivalent or upgrades to the original Wharfedale drivers."

And you were also recommended this crossover circuit to match those particular units listed above - is that correct?

 

[kgrlee]

And you were also recommended this crossover circuit to match those particular units listed above - is that correct?

Old Bones, who recommended this and the drive units to you?

There's loadsa info I need to digest from your drive units but here is a first stab.

- Monacor unit is FAR too soft. Try the unit I suggested.
Celestion Bass is
- Too stiff : Fs on original is about 35Hz
- Too heavy : Mmd was well under 20 gm
- Bl about right but Re was 4R8

But your biggest problem is finding a good midrange. I'm not sure why you've got 2 sets of figures for this Peerless unit but it needs to be a lot louder too. The M10NG is a BASS unit

You said in a previous post that you've already got a box built and had tried out what you'd bought and found it wanting. Do you still have the box? Is it close to the original?