How to get a good sound out of JR 149s

[Mandryka]

What are people's experiences with JR 149s?

I have a pair being driven by a Quad 520 . The sound is not very satisfactory -- it sounds "amplified." I wonder if people have found a really successful amp for them.

Someone I know loves the sound he gets out of them with a Leak ST20. That's 10W per channel. But it turns out that he listens very vert close and very quietly. I want to be able to listen in a smallish room -- 15'x15' -- though not to loud music -- a harpsichord or a handful of voices max or a few string instruments max.

And then there's the question of positioning. Does anyone think that the wall brackets Jim Rogers produced are a good idea for the sound? I have mine on stands but close to a wall, 10'apart.

Oh my source is an old Deltec Bigger Bit DAC; no preamp.

I'm toying with the idea of getting a PASS Aleph 30 clone for them.

It may be that these speakers were designed for nearfield monitoring and it's just not possible to get a satisfactory room filling sound from them.

[Barry]

The Quad 520 offers over 10x the power of a Leak Stereo 20, so you could be overdriving the JR149s. We have a couple of Members here who use JR149s, perhaps they will say what amplification they use with them.

I have a Quad 520f which I use in my second system for Av duties. They power Bowers & Wilkins DM2As, and I don't notice the effect you describe.

[Mandryka]

Can you explain "overdriving"? I assume it's not just a matter of playing them at too high a volume.

It looks like Rogers recommended up to 100W amps, which is, I agree, a bit surprising!

https://www.hifiengine.com/manual_library/jr-loudspeakers/jr149.shtml

[Barry]

Using an amplifier which has a power rating well in excess of the speakers requirement. But if you say Rogers recommend amplifiers up to 100W for the JR149s, than the 135W of the Quad 520 will make little difference. Where do you have the two input gain potentiometers set on the 520?

[Mandryka]

Where do you have the two input gain potentiometers set on the 520?


Oh good question! I have them set very high, close to maximum.

[Mr. C]

I have two pairs of JR 149's including a still sealed new pair.

Using an amplifier that is more powerful that the rating on the speakers is MUCH preferable to using an under-powered amplifier and pushing them in DC.

The JR149's work well with 30 quality watts, as they do with 200Wrms amplifiers, it is a case of being sensible and remembering that turning any speaker up beyond its comfort zone will cause problems for the speakers and possible amplifiers.

I have used many amps with these speakers, even the little Belcanto Ref150S sounding very nice, Puresound A30 no problem, better to have more good clean power available than required rather than boarder line max power that could cause clipping/DC issues, speaker cones do not like square waves!

[Mandryka]

Using an amplifier which has a power rating well in excess of the speakers requirement. But if you say Rogers recommend amplifiers up to 100W for the JR149s, than the 135W of the Quad 520 will make little difference. Where do you have the two input gain potentiometers set on the 520?




Oh good question! I have them set very high, close to maximum.

Well I just turned them from 11.00 to 3.00, and it seems to have made quite a positive difference. �� Thank you.

[Mandryka]

including a still sealed new pair.



Extraordinary! How come?

[Mr. C]

My uncle left me to me in his will in 1992, they are circa 1977 from Laskys's I believe, have been offered various sums over the years, but will not part with them as just before I go, I am sure some e-bay collector will find a museum for 20th century audio that will pay a small fortune for them!

Not being a fan of the 1950's 'Hello and welcome to the BBC' style of plummy mid band sounds they do not flat my boat, however they are plenty of fan's out they that adore their presentation.

[Mandryka]

Has anyone tried them with a really top amp? A class A beast.

[Mandryka]

My uncle left me to me in his will in 1992, they are circa 1977 from Laskys's I believe, have been offered various sums over the years, but will not part with them as just before I go, I am sure some e-bay collector will find a museum for 20th century audio that will pay a small fortune for them!

Not being a fan of the 1950's 'Hello and welcome to the BBC' style of plummy mid band sounds they do not flat my boat, however they are plenty of fan's out they that adore their presentation.

You have to find a way of making sure that the original ribbed foam doesn't corrupt. You can buy a reproduction ribbed foam from the USA but I notice that there's only one set remaining.

[spendorman]

It's likely that the reversible electrolytic capacitors need replacing if not already done. They can increase in capacitance a lot, and do other things as well.

[Mr. C]

Yes they can sound good with a quality class 'a' solid state

[Mandryka]

It's likely that the reversible electrolytic capacitors need replacing if not already done. They can increase in capacitance a lot, and do other things as well.

That's easy to act on, would you expect a sound improvement?

[spendorman]

That's easy to act on, would you expect a sound improvement?

A lot will depend upon the position in the circuit of the capacitors, if the ones across the bass unit have risen in value (likely) then the mid and whatever top that should come out of that unit will be reduced.

The ones in series with the tweeter, if they have increased (also likely) this will have the effect of putting lower frequencies through the tweeter.

The effects are more than this though, the capacitors also begin to act like resistors.

Falcon probably still do a capacitor replacement kit for the 149.

Just checked, still there;

https://www.falconacoustics.co.uk/rogers-jr149-crossover-capacitor-set.html

[Alex_UK]

Always fancied a pair of these... But I'm supposed to be downsizing my collection... :)

[Wakefield Turntables]

1. Recap the X0 with the higher tolerance capacitor kit.t
2. Rewire them with decent purity copper.
3. Tighten the drivers and rotate them in case of sag.
4. Tighten the torsion bar in the speakers.

And a few other bits that you could do....

[graham67]

Your quad will work well with a sympathetic passive or buffer pre. As it has the adjustable gain switches it will help matching too. I have heard excellent sounds with a not dissimilar quad 405, so your 520 should be a good match with the 149.

[Light Dependant Resistor]

Hi
The 100k pot for each channel of your 520 should be wired out of circuit, to be the same as a power amplifier.

I also have JR149 and they sound great with a Quad 306 per channel.

My Quad 306 have been modified to establish 10ma of current at the base of T2 - I did a thread on this a bit earlier, it uses a LM329
https://www.analog.com/media/en/technical-documentation/data-sheets/129329fd.pdf
instead of the 6V8 zener at D12 ( d3 in a 306 ) ad hoc providing 100ma To get 10ma I am using a LM317 accessing its adjustment terminal as a current source.
I referenced HiFi engines schematic for a Quad 520F that is very close in design to the Quad 306

This forms my every day system to assess audio. The 149 and Quad amps with a few minor changes are a very good combination when used with
LDR attenuation.

Hope that helps.

[Mandryka]

Using an amplifier which has a power rating well in excess of the speakers requirement. But if you say Rogers recommend amplifiers up to 100W for the JR149s, than the 135W of the Quad 520 will make little difference. Where do you have the two input gain potentiometers set on the 520?

Adjusting the potentiometers made a big difference, I owe you one!

[Mandryka]

O
Hi
The 100k pot for each channel of your 520 should be wired out of circuit, to be the same as a power amplifier.

I also have JR149 and they sound great with a Quad 306 per channel.

My Quad 306 have been modified to establish 10ma of current at the base of T2 - I did a thread on this a bit earlier, it uses a LM329
https://www.analog.com/media/en/technical-documentation/data-sheets/129329fd.pdf
instead of the 6V8 zener at D12 ( d3 in a 306 ) ad hoc providing 100ma To get 10ma I am using a LM317 accessing its adjustment terminal as a current source.
I referenced HiFi engines schematic for a Quad 520F that is very close in design to the Quad 306

This forms my every day system to assess audio. The 149 and Quad amps with a few minor changes are a very good combination when used with
LDR attenuation.

Hope that helps.

Thanks, there’s interesting ideas there there.

[Mandryka]

These speakers have bass drivers which are about 4.5 inches diameter. Has anyone tried subwoofers with them?

[Mandryka]

Or how about stacking them?

If anyone with a pair is near me, I’m in London, and would like to try stacking them, I’m up for it!

[spendorman]

Or how about stacking them?

I double stacked Spendor BC1's, that worked.

I double double stacked (that's four per channel), B&W DM2a's, that worked.

I have two pairs of JR149's, not tried double stacking, yet!

[Mandryka]

I double stacked Spendor BC1's, that worked.

I double double stacked (that's four per channel), B&W DM2a's, that worked.

I have two pairs of JR149's, not tried double stacking, yet!

I hope you’ll try it out and let me know, it could be a really good thing and cheap and easy to accomplish.

[Light Dependant Resistor]

I double stacked Spendor BC1's, that worked.

I double double stacked (that's four per channel), B&W DM2a's, that worked.

I have two pairs of JR149's, not tried double stacking, yet!

Lucky you :) maybe when you try this have the T27 closer to each other. It would mean having leads at the top
of the top speaker.

[spendorman]

Lucky you :) maybe when you try this have the T27 closer to each other. It would mean having leads at the top
of the top speaker.

Unfortunately, I'm not going to try double stacking the 149's just yet, some serious things in my life need to be resolved first.

Suspect that double stacking JR149's would work. Only possible trouble is connecting them in parallel, nominal impedance will be half, OK for most amps, but not all.

The reason I went for four DM2a's per side, was that a series / parallel connection, would bring the nominal impedance back to 8 Ohms.

[Light Dependant Resistor]

Unfortunately, I'm not going to try double stacking the 149's just yet, some serious things in my life need to be resolved first.

Suspect that double stacking JR149's would work. Only possible trouble is connecting them in parallel, nominal impedance will be half, OK for most amps, but not all.

The reason I went for four DM2a's per side, was that a series / parallel connection, would bring the nominal impedance back to 8 Ohms.

When comes time, a stereo power amp per channel might be the answer. In my own set up I am presently using 2x Quad 306, presently using one channel of each amp, so a channel per amp is spare
for stacking speakers.

[spendorman]

When comes time, a stereo power amp per channel might be the answer. In my own set up I am presently using 2x Quad 306, presently using one channel of each amp, so a channel per amp is spare
for stacking speakers.

I had thought of that, should really be similar amps, it would not be good, one inverting and one non inverting. I've got four nice Quad 303's, and three A&R A60's, so that's not a problem.

[Barry]

Vertical stacking the DM2As is IMO not successful. If you have the tweeters close together, the bass is confused; if you position the bass drivers together the image suffers badly.

[Lawrence001]

Unfortunately, I'm not going to try double stacking the 149's just yet, some serious things in my life need to be resolved first.

Suspect that double stacking JR149's would work. Only possible trouble is connecting them in parallel, nominal impedance will be half, OK for most amps, but not all.

The reason I went for four DM2a's per side, was that a series / parallel connection, would bring the nominal impedance back to 8 Ohms.If you want 8 ohms impedance won't one speaker per side work fine, and be far less complicated!

Sent from my BLN-L21 using Tapatalk

[Light Dependant Resistor]

If you want 8 ohms impedance won't one speaker per side work fine, and be far less complicated!

Sent from my BLN-L21 using Tapatalk

Yes indeed, however 2 arranged stacked speakers that are pretty well identical, represent a great opportunity to get a bigger sound.
Where another amp like 2x stereo 303 , or 306 are used there are then amplifier channels to cater for this different but beneficial arrangement.

If we look at dispersion from speakers - the ESL57 by Quad is a great model to get ideas from, we see the middle of the speaker is the treble panel and
two bass panels per side are used. It is no coincidence the Gale 401 also copied this same idea with 8 inch acoustic suspension drivers either end and
a Peerless midrange and Celestion tweeter in the middle. Move ahead many years and MBL use the same principle, using moving magnet rather than
moving coil drivers. Hence a stacking arrangement like using JR149 should try tweeters facing each other and bass drivers either end... well that's the theory.

[Lawrence001]

Yes indeed, however 2 arranged stacked speakers that are pretty well identical, represent a great opportunity to get a bigger sound.
Where another amp like 2x stereo 303 , or 306 are used there are then amplifier channels to cater for this different but beneficial arrangement.

If we look at dispersion from speakers - the ESL57 by Quad is a great model to get ideas from, we see the middle of the speaker is the treble panel and
two bass panels per side are used. It is no coincidence the Gale 401 also copied this same idea with 8 inch acoustic suspension drivers either end and
a Peerless midrange and Celestion tweeter in the middle. Move ahead many years and MBL use the same principle, using moving magnet rather than
moving coil drivers. Hence a stacking arrangement like using JR149 should try tweeters facing each other and bass drivers either end... well that's the theory.I was only joking. He only mentioned a requirement for 8 ohms impedance not an increase in SPL, scale and (subjective) dynamics.

Sent from my BLN-L21 using Tapatalk