Infinity IRS Beta Mods Query

[msb64]

I managed to track down a set of IRS Beta speakers earlier this year, and was thinking about upgrading dated (20+ years) crossover components. I was wondering if anyone out there has any good component recommendations? I am looking for good bang for the buck mods, and have heard that Sonic Caps might be worth looking into. Any other ideas or information sources would be greatly appreciated. I have included a picture of one of the mid/high tower crossovers, plenty of space on the board and should be easy to work on. Thanks in advance!

 

[inertial]

Hi,

I have had in the past IRS Delta, the little brother of the BETA 😀

I was a infinity passionate and have used it for confrontate with my DIY speaker.

Yf you have enough money you could be replace that "iron" core inductors with Solen air-core, sure very expansive

Replace also those big electrolityc caps with cheap MKT like Bennic or others.
Imho the solen are ok because they marriage very well the openess of the EMIT-SEMIT, sort of complementary IMHO.
Resistors in the signal path I like Mills.
Rotative L-pads are another point......they are very useful ...but resistor Lpad are better.

Have fun 😀

Cheers,
Paolo

 

[sreten]

Hi,

It seems a fairly serious attempt already at crossover quality.
The bipolar electrolytics should be replaced if > 20 years old.
They are all bypassed, replacement seems the best option.

🙂/sreten.

 

[inertial]

You are right Sreten,
but msb64 wants high-end upgrade, cost-no object ! So why do not put that electrolitycs out of the window and replace with enormous MKT? 😀

Cheers,
Paolo

 

[sreten]

but msb64 wants high-end upgrade, cost-no object ! So why do not put
that electrolitycs out of the window and replace with enormous MKT? 😀

Cheers,
Paolo

Hi,

In my experience (and others) with quality speakers changing
bipolar electrolytics to other types can unbalance the speaker
if the electrolytic is in a critical position, if it is not, why bother ?

As they are old the electrolytics should be replaced, the other
capacitors should be fine. If upgrading the network is wanted
the position and purpose of each capacitor should be found,
and then possibly "upgraded" accordingly.

Usually more attention is made to series rather than parallel
capacitors, e.g. take a parallel zobel network, try and work
out how a higher quality capacitor would improve matters .....

🙂/sreten.

 

[inertial]

Sreten,
If I well remember the LOW Enim has a big cap NP in series.
sure the balance can change, this is the reason to try to improving a sound that IS NOT perfect .
and to be honest, imo electrolitic caps sucks, even if bypassed ! 😀
Last , I think msb64 could try and will judge for itself
Please, then report his impression also 🙂

Cheers,
Paolo

 

[sreten]

Last , I think msb64 could try and will judge for itself
Please, then report his impression also 🙂

Cheers,
Paolo

Hi,

Its all JMO and of course msb64 can do whatever he likes.
But e.g. chucking loads of money on big and therefore expensive zobel
capacitors for bass units is a very debatable activity for the sensible.

🙂/sreten.

 

[msb64]

Thanks for the input everyone. By good bang for the buck I mean maximum return for each dollar invested. Like most things in life you reach a point of diminishing returns, and you end up paying a lot more for just a little more gain. I figure my weakest link right now is probably my cd player, an Arcam CD73T. Although a decent sounding unit for it's price, I would not consider it a high end unit. Other equipment includes a Threshold FET10 preamp, Threshold S/500e to power the bass towers, and a fairly modified Hafler DH200 (as per Pooge article mod from the 80s) with WonderCaps/Bypass caps, metal film resistors, large outboard power supply with torroidal transformers, large PS caps etc. I wouldn't mind upgrading the caps in the Hafler as well, one of the reasons I was asking about Sonic caps or whatever brand might be of benefit and cost effective. I have heard a little bit about special diodes and rectifiers for amplifier applications, but it would be nice to hear from someone who has actually had hands on experience with them. I am currently using Audioquest Midnight speaker wire on all towers, and custom made interconnects based on RG174/U cable. I haven't even opened up the bass servo box yet, but I imagine it has components similar to the speaker crossovers. It looks like winter has set in here, so its a good time for some nice indoor projects. 🙂

 

[inertial]

Msb,
can you please post the crossover schematic of the beta's towers so all will be more clear. Please indicate the NP cap and the MKP and the iron core inductors.

I agree with you, that CD plaier is under the level of your system;
Have you considered to add a serious DAC? I see every day persons who sell his wonderful DACs for a few bucks in the audiogon website 😀

Cheers,
Paolo

 

[infinia]

I have heard a little bit about special diodes and rectifiers for amplifier applications, but it would be nice to hear from someone who has actually had hands on experience with them.

Regarding amplifier "upgrades" Don't do it... unless it has been well established by a competent amplifier design engineer. I see allot (most all) of the stuff on various forum web sites regarding rectifier diode (fast diode) substitutions that is plain wrong and can result in sonic degradation in fact.

 

[inertial]

Hey msb64,

Just curious . It seems to be strange you have putted the Threshold on the bass towers and the Hafler on the "sat". Do you confirm?


Are you satisfied with the imaging of your Beta?

Cheers,
Paolo

 

[Ron E]

The Electrolytics are worth replacing as others said - but there is nothing wrong with Solen caps - before you spend the money on boutique caps you should do a listening test for yourself.

Build little circuits with several different brand caps of the same value, then switch between them and see if you hear a difference.

 

[msb64]

Thanks for the heads up on the diodes, one less thing for me to worry about then. I am running the Threshold S/500e on the bass towers, because it has good clean power to spare, should be around 500 watts or so for that impedance load. I tried a Threshold S/300 Series II on the mid/high towers, but I found it to be somewhat cold and sterile sounding. I ran it for about 3 weeks straight, and then switched back to the modified Hafler. At medium to high levels the Hafler definitely sounded much nicer to me, warmer yet still with excellent detail. The original Hafler DH200 was a $500 Cdn kit that I built back in the early 80s and did sound fairly decent for an entry level power amp. The modified version is definitely a very different animal though, it is hard to believe that it is essentially the same amp. I used the Pooge-2 article in the April 1981 issue of Audio Amateur as a guideline for the mods, and then went a little further by moving the whole power supply outboard in a separate enclosure, doubled the current capacity with torroids, almost tripled the main capacitance and fabricated a heavy gauge umbilical cord with military style connectors at the amp and power supply. WonderCaps were used throughout the signal path. At the time I had a set of new IRS Deltas to help evaluate the new changes, and the change was huge. I brought home a brand new Threshold S/300 at the time to compare, but couldn't justify its $6500 Cdn price tag at the time. The modified Hafler sounded as good or better than the Threshold, but the Threshold had way more power. I even brought it down to our local Infinity dealer back then to evaluate it with some high end components, even the owner said I definitely has something there. I find the same thing now with the Betas, the Hafler sounds excellent, but starts to sound somewhat strained at higher levels. I do have an original issue Threshold S/350e I want to try on the mid/highs, but need to change speaker cable ends to be able to hook it up. At the price you can get Hafler DH200 and 220s nowdays, they do make a nice little project amp. I would love to hear one of the Musical Concepts modified units, and am thinking hard about trying their boards on a spare DH200 I currently have. I will see if I can find the crossover schematic, as I did receive some literature with the speakers, I will post it if I have it. The Betas are very amazing, both in looks and sound. They have a tendency to make you want to turn up the volume and then they create a wall of sound, the speakers essentially disappear. The biggest physical drawback I have is the lack of room size for them. My current room is only 14 feet wide x 30 feet long, and they really should have a room twice as wide to do them justice. I have been giving some serious consideration to lifting the house and putting in a full basement to create a room big enough. Thanks again everyone for your input. Mike

 

[msb64]

My Beta schematic is exactly the same as that listed on the following excellent site, just add the www

infinity-classics.de/infinity/technik/manuals/IRS_Beta_technical_sheet.pdf

 

[inertial]

As I was suspected,

The Low enim have 2 NP caps in series and iron core in series also 🙁
Imho the schematic have something of wrong. 600 microF MKP in series to the ENIM is not possible. Check your value please and report us.
You are canadian, Solen.ca has good offers for big capacitor Bennic and Solen 400v.....and also for air coils.......

Cheers,
Paolo

 

[msb64]

You are correct, the diagram does not show the proper values for the min midrange caps. The one listed as a Solen 500 ufd cap appears to be a 50 ufd cap according to the silkscreen on the backboard. The cap itself is securely glued in place and the specs are not visible but it is at least 1/3 to 1/2 smaller than the 100 ufd Solens so that should be accurate. The one listed as a WonderCap 100 ufd cap in parallel is actually a 10 ufd cap, and the markings are plainly visible. There are only 4 NP caps per speaker, a 20, 35, 150 and 300 ufd cap, the only markings visible on these show T.I. Any recommendations for good replacements for these? Consensus appears to be that the Solen caps are decent, can the same be said for the WonderCaps or are they also worth hanging on to? I don't mind replacing the caps if it will make a noticeable difference. The same applies to the caps in my mid/high amp.

 

[msb64]

Here is my current layout, sure wish I had more room width. There really isn't enough room to do the speakers justice, but it is all I have to work with right now. My goal was to set up a decent sound system, but have it so that others besides myself could enjoy it too. I ended up tearing down 3 walls to make enough room for the table, and installed an engineered 480 lb beam to replace the main support wall. I also tore out a bedroom and my last 2 built in closets to give the audio equipment more space as well. It is still a work in progress with a long way to go, as time and funds permit. All work has been performed by myself so far, other than assistance with the painting. None of my pool playing friends have complained about the sound quality yet 🙂 Thanks everyone for your helpful input.

 

[inertial]

Msb64,

Imo Solen are ok, wondercap are hiend-caps, but I must insist: those 4 NP are "junk", swap with at least Bennic MKT, they are special offer at
www.solen.ca . ( the two biggers are in series on the LEMIM ; the 2 little are so little you can sure afford the little cost ).
One of the most venerable Hi-end speaker system of 20 years ago( in italy they costed a lot of money) sure deserve this little upgrade!

Cheers,
Paolo

 

[msb64]

Hi Paolo

In your previous post you mentioned that there were some good DACs and CD Transports up on audiogon from time to time. What brand/models would you recommend that I should be considering for a good match with my current setup?

Also, thank you for the tip on solen.ca.
I will definitely look into replacing the NP caps in the Betas, and I plan on using some of the Solens in my next Hafler builds as well.
I think I will try some of the Sonic caps too in one of the units for comparison.

The air coils I would have to give good consideration to, besides being fairly costly they are also fairly large. It will take some careful mounting to get those units into the enclosure and properly secured against unwanted vibration.

 

[inertial]

Hi msb64,

IMHO a wadia would be ideal with the Betas.
A friend of mine have a 25 and I like it very much. also integrated wadias are good stuff.
For separates I like the old Teac P2s and CEC also. Old Rocksan with belt drive are good sounding also ( attessa ).

I' m glad you are in work to follow my suggestions about Solens.
Looks also the Bennic yellow MKT in the special offer.

I hope you make soon the new room for your listen because the Beta have to stay far from the rear wall, but you sure know this better of me ! 😀

Cheers,
Paolo