Heybrook HB1 Renovation

[gbcambridge]

I recently acquired a pair of these fine old speakers, Heybrook HB1. (Mine are serial number 011053). The cone surrounds were shot (not unusual) but all else appeared to be OK. However, I wanted to review the crossover and there came the problem.
It appeared difficult to obtain a diagram of the crossover. I finally found one and everything agreed with my actual crossover except that my actual resistor is rated at 15 Ohms, while the published circuit states 18 Ohms. I say "published" ...it is actually a freehand sketch by someone.

So, can anyone advise on this? I am hesitant to change what was implemented but I am curious as to the actual reason the resistor disagrees with the diagram. I have since found a diagram for a Series 2 crossover and there they are also showing an 18 Ohm resistor!

[Greg.]

Considering the small cost involved and your ears being the final arbiter, I would try both values and settle on the resistor that sounds best. Simples!

[colin.hepburn]

Hi George
AH the HB1s remember them well
both maybe right i would try both the 15R and 18R
Will this help

[petercom]

Originally Posted by gbcambridge

I recently acquired a pair of these fine old speakers, Heybrook HB1. (Mine are serial number 011053). The cone surrounds were shot (not unusual) but all else appeared to be OK. However, I wanted to review the crossover and there came the problem.
It appeared difficult to obtain a diagram of the crossover. I finally found one and everything agreed with my actual crossover except that my actual resistor is rated at 15 Ohms, while the published circuit states 18 Ohms. I say "published" ...it is actually a freehand sketch by someone.

So, can anyone advise on this? I am hesitant to change what was implemented but I am curious as to the actual reason the resistor disagrees with the diagram. I have since found a diagram for a Series 2 crossover and there they are also showing an 18 Ohm resistor!

The change from 15 to 18 Ohms was implemented in Series 2 onwards to accommodate a tiny change in the bass unit foam surround performance.

This change will suit the modern production of the Vifa bass unit so, if anyone replaces their bass units with new ones there may be a small benefit from changing the resistor to 18 Ohms.

[Revoli]

Originally Posted by petercom

The change from 15 to 18 Ohms was implemented in Series 2 onwards to accommodate a tiny change in the bass unit foam surround performance.

This change will suit the modern production of the Vifa bass unit so, if anyone replaces their bass units with new ones there may be a small benefit from changing the resistor to 18 Ohms.

Bump.

Roughly when was this? I replaced my base units (in my glorious 38 year oold HB1s) some years (15 ish maybe) ago and just spotted this chat. Is it obvious if look at base units rear?

Thx

[Yellow]

Originally Posted by Greg.

Considering the small cost involved and your ears being the final arbiter, I would try both values and settle on the resistor that sounds best. Simples!

Indeed!!!