May 142016
 

I am delighted to say that the vintage Altec-Lansing A5 Voice of the Theatre Project is now moving forward again!

Jeff's A5 VOTTs as restored by Gary Fischer.

Jeff’s A5 VOTTs as restored by Gary Fischer.

In the first phase of the project I commissioned Gary Fischer to restore a vintage pair of Altec-Lansing A5 Voice of the Theatre loudspeakers, which I described in three parts: Part 1, Part 2, and Part 3.

Many thanks to Gary Fischer for his excellent restoration of the A5 VOTTs!

Jeff's A5 VOTTs without grills.

Jeff’s A5 VOTTs without grills.

For my restoration, I chose two 825B bass horn cabinets, two 16 Ohm 515B Alnico low-frequency drivers, two N-500-D ‘Dividing Networks’ (crossovers), two 1005B 10-cell horns, and two 16 Ohm 288C Alnico high-frequency compression drivers, which is a classic Altec-Lansing A5 Voice of the Theatre combination of components from that period.

Resistors and capacitors, and inductors, oh my!

To adapt Frank L. Baum’s famous line by Dorothy in the Wizard of Oz, “Lions and tigers, and bears, oh my!”, when you enter the haunted forest of DIY circuit modifications, you too (like me) might in trepidation say, “Resistors and capacitors, and inductors, oh my!” Until you actually meet them, that is, and then like Dorothy when she meets the Cowardly Lion, you might decide that resistors, capacitors, or inductors are really no threat at all, and can actually be quite a nice addition to your audio adventures – that’s been my experience.

In the second phase of the project, the plan is to build external crossovers based on the crossover circuit developed by Jean Hiraga using those fearful resistors, capacitors, and inductors, for the combination of the 16 Ohm 515B Alnico low-frequency drivers and the 16 Ohm 288C Alnico high-frequency compression drivers, along with a couple of creative modifications suggested by our good friend Yazaki-san included for good measure.

Important Note: All of what I am describing is for the 16 Ohm version of the drivers, if you have 8 Ohm versions of the drivers you’ll need the Hiraga schematic optimized for 8 Ohm drivers, which is not shown here.

Hiraga-san inspired 16 Ohm A5 crossover with Yazaki-san mods.

Hiraga-san inspired 16 Ohm A5 crossover with Yazaki-san mods.

You can see Modification 1 and Modification 2 that Yazaki-san drew in the schematic above.

Modification 1: In the first modification Yazaki-san incorporated an impedance compensator into the low-frequency part of the Jean Hiraga inspired circuit, which you can see in the upper right-hand of the diagram above.

If I understand this modification correctly (I’ll ask Yazaki-san to clarify just in case), it is similar in concept to the SPEC RSP-901EX Real Sound Processor that I wrote about for Positive Feedback in Issue 78, which reduces fluctuations of loudspeakers’ impedance over the frequency spectrum, making them sound more clear, natural, and musical throughout their range.

In this modification a 10uF capacitor (C4 in the diagram above) is placed in series with a 20Ω 12W resistor (R6 in the diagram above) between the +/- low-frequency outputs from the crossover.

Yazaki-san recommended a 20Ω 12W Ohmite Brown Devil resistor for R6 in this application, which I ordered from Digi-Key Electronics (I ordered the B8J20RE-ND 20Ω 8W version as they didn’t have a 12W version in stock).

Ohmite Brown Devil 20Ω 8W resistors for Modification 1.

Ohmite Brown Devil 20Ω 8W resistors for Modification 1.

As I brushed the mental cobwebs aside from 6 months ago when we started the planning for this crossover project, I realized I did not have a suitable 10uF capacitor to use in the C4 position, so I’ll have to ask Yazaki-san for a recommendation on what to get.

The plan is to first construct the crossovers without Modification 1 in the circuit, so I can hear the crossovers without Mod 1 to establish a baseline, and then I’ll add it into the circuit so I can articulate the sonic & musical effects it has on the circuit. Yes, I’m slowly learning not to make too many changes at once, so I can tell what’s going on with a circuit!

Modification 2: Unlike the stock Altec N-500-D crossover, Jean Hiraga’s A5 crossover design doesn’t include a way to adjust the level of the high-frequency horn so you can more easily match it to a room, a feature which I’ve found to be very handy with the Altec N-500-D crossovers of my ‘Stokowski’ A7 VOTTs.

I discussed with Yazaki-san how we might approach including adjustability as a design feature in our A5 crossover project, and he proposed a very clever addition to the high-frequency circuit using vintage Clarostat variable resistors, which he was able to find in Japan, and then sent them to me as part of a ‘crossover kit’ he made up for me. Thank you Yazaki-san, you’re the best!

Clarostats for impedance compensation of the high-frequency circuit.

Clarostats for impedance compensation of the high-frequency circuit.

In Modification 2 Yazaki-san replaces the original R3 24-Ohm 50W resistor in the high-frequency circuit with three resistors in series, an R3-1 Ohmite Brown Devil B8J10RE 10Ω 8W resistor, the Clarostat variable resistor, and an Ohmite Brown Devil B12J10RE 10Ω 12W resistor, as depicted at the left middle of the crossover schematic above, with the components shown below.

Clarostat variable resistors with Ohmite Brown Devil resistors.

Clarostat variable resistors with Ohmite Brown Devil resistors.

With the arrival of the six custom 6.6uH inductors from Solen Electronique I mentioned in my last post, I thought I now had all the components I needed to start breadboarding the crossovers, but then I realized I was still missing some key capacitors that I still needed to order.

So my first step was to inventory all of the components I had in-hand for the Altec A5 VOTT 16-Ohm crossover project, and then order what I still needed.

The complete list of components for the A5 VOTT crossover project are listed below, and those highlighted in yellow I still need to order. Once I get those ordered I’ll update the list so you know what I decided on for a given component.

C1 18uF: Yazaki-san suggested connecting several capacitors in parallel to achieve 18uF. I don’t have these, so I’ve asked Yazaki-san for a recommendation on what to order. I also asked me buddy Pete Riggle for his thoughts on a recommendation, as Pete just built some Hiraga-san inspired 8-Ohm crossovers for his A7 VOTTs that turned out great. Pete graciously offered to loan me the caps needed so I could start breadboarding.

  • 10uF/600-800VDC wax or mineral oil capacitor
  • 4uF/600-800VDC wax capacitor
  • 4uF/600-800VDC mineral oil capacitor

C2 10uF: Yazaki-san suggested connecting capacitors in parallel to achieve 10uF as he did for C1.

  • 4uF/600-800VDC wax capacitor
  • 4uF/600-800VDC mineral oil capacitor
  • SPEC CORP 1uF/200VDC C50309-2105K (included in Yazaki-san’s crossover kit).
  • AZ Cap Blue Cactus 0.47uF/600VDC C50309-6474K (included in Yazaki-san’s crossover kit).
  • AZ Cap Green Cactus 0.47uF/600VDC C50313-6474K (included in Yazaki-san’s crossover kit).
  • SPEC CORP Ruby-Mica 0.022uF/500VDC MC-223DA (included in Yazaki-san’s crossover kit).
SPEC CORP 1uF/200VDC C50309-2105K capacitors.

SPEC CORP 1uF/200VDC C50309-2105K capacitors for C2.

AZ Cap Blue Cactus 0.47uF/600VDC C50309-6474K for C2.

AZ Cap Blue Cactus 0.47uF/600VDC C50309-6474K for C2.

AZ Cap Green Cactus 0.47uF/600VDC C50313-6474K capacitors.

AZ Cap Green Cactus 0.47uF/600VDC C50313-6474K capacitors for C2.

SPEC CORP Ruby-Mica 0.022uF/500VDC MC-223DA capacitors for C2.

SPEC CORP Ruby-Mica 0.022uF/500VDC MC-223DA capacitors for C2.

C3 0.82uF: Like C1 and C2 several capacitors are paralleled to achieve 0.82uF.

  • AZ Cap Blue Cactus 0.47uF/600VDC C50309-6474K (included in Yazaki-san’s crossover kit).
  • AZ Cap Green Cactus 0.33uF/600VDC C50313-6334K (included in Yazaki-san’s crossover kit).
  • SPEC CORP Ruby-Mica 0.022uF/500VDC MC-223DA (included in Yazaki-san’s crossover kit).
AZ Cap Blue Cactus 0.47uF/600VDC C50309-6474K for C3.

AZ Cap Blue Cactus 0.47uF/600VDC C50309-6474K for C3.

AZ Cap Green Cactus 0.33uF/600VDC C50313-6334K for C3.

AZ Cap Green Cactus 0.33uF/600VDC C50313-6334K for C3.

SPEC CORP Ruby-Mica 0.022uF/500VDC MC-223DA capacitors for C3.

SPEC CORP Ruby-Mica 0.022uF/500VDC MC-223DA capacitors for C3.

C4 10uF: This is the capacitor part of Yazaki-san’s Modification 1 that I described above. In Mod 1 a 10uF capacitor is placed in series with a 20Ω 12W resistor (R6) between the +/- low-frequency outputs from the crossover to reduce fluctuations of loudspeakers’ impedance over the frequency spectrum.

  • 10uF capacitor

R2 140 10W: In case you’re wondering where R1 is, there is no R1 in the Hiraga-san crossover schematic. To get R2 140 10W Yazaki-san recommended a series resistor connection of 100 Ohms & 40 Ohms Ohmite Brown Devils. Digi-Key didn’t have the 10W versions in stock so I substituted 12W versions.

  • Ohmite Brown Devil B12J100E-ND 100 Ohms 12W
  • Ohmite Brown Devil B12J40RE-ND 40 Ohms 12W
R2 140 10W with

R2 140 10W achieved with Ohmite Brown Devil B12J100E-ND 100 Ohms 12W in series with Ohmite Brown Devil B12J40RE-ND 40 Ohms 12W.

R3 24 50W:  In Modification 2 Yazaki-san replaces the original R3 24-Ohm 50W resistor in the high-frequency circuit with three resistors in series, an R3-1 Ohmite Brown Devil B8J10RE 10Ω 8W resistor, the Clarostat variable resistor, and an Ohmite Brown Devil B12J10RE 10Ω 12W resistor, as depicted at the left middle of the crossover schematic above, with the components shown below.

  • R3-1 Ohmite Brown Devil B8J10RE 10Ω 8W resistor (included in Yazaki-san’s crossover kit).
  • R3-2 Clarostat variable resistor (included in Yazaki-san’s crossover kit).
  • R3.3 Ohmite Brown Devil B12J10RE 10Ω 12W resistor (included in Yazaki-san’s crossover kit).
Clarostat variable resistors with Ohmite Brown Devil resistors as used in Mod 2 for R3.

Clarostat variable resistors with Ohmite Brown Devil resistors as used in Mod 2 for R3.

R4 100 10W: Ohmite Brown Devil B12J100E-ND 100 Ohms 12W.

Ohmite Brown Devil B12J100E-ND 100 Ohms 12W resistors for R4.

Ohmite Brown Devil B12J100E-ND 100 Ohms 12W resistors for R4.

R5 10 20W: Ohmite Brown Devil B12J10RE-ND 10 Ohms 12W

B12J10RE-ND 10 Ohms 12W for R5.

Ohmite Brown Devil B12J10RE-ND 10 Ohms 12W for R5.

R6 20 12W: This is the Ohmite Brown Devil resistor part of the low-frequency impedance compensator addition by Yazaki-san that is described above in Modification 1, where a 10uF capacitor (C4) is placed in series with a 20Ω 12W resistor (R6) between the +/- low-frequency outputs from the crossover to reduce fluctuations of loudspeakers’ impedance over the frequency spectrum..

Ohmite Brown Devil 20Ω 8W resistors for Modification 1.

Ohmite Brown Devil 20Ω 8W resistors for Modification 1.

L1, L2, and L3 6.6mH inductors: It took Solen Electronique only 4 days to make up the six custom 6.6mH inductors for the project and send them to me. 6.6mH inductors are a non-standard value, so I ordered the S166.8 6.8mH versions and Solen custom wound them to 6.6mH for me at no extra charge. What great customer service!

Solen custom 6.6mH inductors for the A5 VOTT project crossovers.

Solen custom 6.6mH inductors for the A5 VOTT project crossovers.

Ok that’s the end of the list for capacitors, resistors, and inductors.

McMaster-Carr setscrew lugs: I want to use copper McMaster-Carr setscrew lugs for direct wire-on-wire connections wherever possible, so there’s zero performance loss, like I did with the Duelund-WRSE project. The setscrew lugs are great to work with, and allow easy component swapping for comparisons. I think wire-on-wire connections are probably better sounding than having the additional materials of intervening connectors that the signal has to go through. Pete Riggle recommended I use straight-tongue copper setscrew lugs, 14-8 AWG, #10 stud, from McMaster-Carr, part number 6923K61. I’ll place an order when I know how many I’ll need.

Wire: I’ll use Western Electric WE16GA wire in the crossover where wiring is required.

Ok, now that I’ve gone through my inventory of parts for the A5 VOTT crossover project I know what’s still on my shopping list:

For C1 18uF: 

  • 2 x 10uF/600-800VDC wax or mineral oil capacitor
  • 2 x 4uF/600-800VDC wax capacitor
  • 2 x 4uF/600-800VDC mineral oil capacitor

For C2 10uF: 

  • 2 x 4uF/600-800VDC wax capacitor
  • 2 x 4uF/600-800VDC mineral oil capacitor

For C4 10uF: This is the capacitor part of Yazaki-san’s Modification 1.

  • 2 x 10uF capacitor

I’ve asked Yazaki-san, Pete-san, and Ron-san for ideas for the capacitor shopping list above, so soon as I hear back I’ll go capacitor shopping, then all I’ll need is the McMaster-Carr setscrew lugs.

Many thanks to Yazaki-san for all his great ideas for the A5 VOTT crossover project, and his generosity in sending me a ‘crossover kit’ to help kick-off the project! Thank you, Yazaki-san!

A big thanks to Pete who offered to loan me the needed caps on the list above to get me started on breadboarding.

Much more to come, and thanks for stopping by!

 Posted by at 4:11 pm

  23 Responses to “The A5 VOTT Project Commences: Resistors and capacitors, and inductors, oh my!”

  1. HI Jeff

    just a little bit of advice , apologies perhaps too late now, but iron core inductors in my opinion are much more natural sounding than the air core versions, after numerous trials, with much more realistic tone, sorry I know you have already bought them and indeed I could very well be wrong for your project. But I do feel the Altecs need a little bit of taming and teasing out of more tonal shades (certainly with my A7 that is), which is why I will keep my A7 but also try the very efficient Orangutan 096. which might just do that and have the Bass I long for. But who knows your crossover may well be a revelation in all these areas. And I will once again humbly follow you in your crossover project. with my tail hanging down between my legs.
    I eagerly await your findings.as we have near identical systems.

    All the Best Luke from the UK

    • Hi Luke,

      I was absolutely blown away by Pete Riggle’s A7 VOTTs last week. Pete built a variation of the Hiraga crossover that he adapted to the A7’s, and he used iron core inductors, so you may be on to something there. Pete’s A7 system is one of the best hi-fi systems I’ve ever heard. It was love at first listen for me.

      Pete also has some capacitors that he’s discovered that area really something special, and that is part of his secret for good sound too I think. It doesn’t hurt that Pete has six decades of experience modifying and designing loudspeakers, and once owned a loudspeaker company.

      His A7’s are rich, warm, musical, and utterly captivating to listen to music with. If I can get my A5’s sounding that good I’ll be in heaven!

      Best,

      Jeff

      • HI Jeff

        as an A7 owner with a 416 woofer, do you think Pete might be able to share his Higara mods. I know the Higara crossover was specifically for the 515/288/1005.

        Many Thanks Luke

        • Hi Luke,

          I’m sure Pete would be happy to share with you how he adapted the Hiraga-style crossover to the A7. Pete has put a lot of thought into his crossovers, done modeling of the circuit using SPICE, and done a lot of tuning by ear. By the way, are your A7’s 16 or 8 Ohm?

          Pete’s email addy is peteriggle@msn.com. Send Pete an email and tell him Jeff sent you, I’m sure he’d be glad to help.

          My A7’s are 16 Ohm, but once I get finished with the A5 crossover project, I’d like to adapt Pete’s Hiraga-style crossover design to my A7’s as well.

          Keep me posted on how it goes!

          Kind regards,

          Jeff

          • thanks Jeff for that,

            Mine are all 16 ohm. I had the bass port reduced by 50% and that made a huge difference to the clarity of the bass notes. I also copied your enclosure and put more padding inside the box behind the woofer horns. This improved the tone and detail as well as separation no end. Finally i added RCA 6l6 to my mc30 and I am in two minds about the tonality being better than the reissue Mullards. The latter got damaged by the way due to my own fault, but are very cheap to buy. I recall from memeory that they had wonderful tone and a huge sound stage as well as great PRAT. Yves kindly added in the Arizona caps to my MC30’s so i guess i am still keeping up with you!!. Now one change you have not mentioned is the pre tubes in the mx110??? I changed them from the Tungsram that was in them to Telefunken. The sound has great clarity speed and separation now. Tonal warmth has not improved greatly but note decay and finer inflections are so much more obvious. At long last the UK have Arizona caps so i will be experimenting with them in the mx110 shortly.

            All the best Jeff I look forward to our parallel worlds of adventure, although my world is always a few weeks behind yours as you are always the innovator first!

          • Hi Luke!

            I told Pete about your desire to do the Hiraga-san crossovers for your A7’s, and he said he’d be glad to offer any insights he could. Pete told me he had to do very little to adapt the Hiraga crossovers to the A7’s, so just send him an email, and he can walk you through it.

            After I get my A5 VOTT crossovers completely sorted out, I think I’ll build a pair for my ‘Stokowski’ A7 VOTTs too, as I’m really impressed with the result I’m hear both on Pete’s A7’s and my A5’s.

            You mentioned you liked the tone of the iron core inductors best, which iron core inductors are you using, I may have to give that a try.

            Here’s some of the tubes I’ve got under the bonnet of the MX110:

            V13 (phono pre left) & V14 (phono pre right) – 12AX7/ECC83 Telefunken smooth plates.

            V15 (L&R 2nd AF) – 12AX7/ECC83 Telefunken smooth plate.

            V16 (L 3rd AF) & V17 (R 3rd AF) – 6U8 RCA’s replacing the stock Tele’s.

            I’ve got a urge to try some vintage Mullard ‘Tropical Fish’ caps in my MX110 too, so ordered some up. In fact I’d like to do a survey of the best vintage tone caps if I can round them up a couple more, like the Sprague Black Beauty & Bumblebee caps, which would round out a vintage tone capacitor survey really nicely. We’ll see what happens.

            The Yazaki-san mods in my MC30’s were really superb with the Arizona Capacitors, so I imagine you’re enjoying the result!

            This sure is a lot of fun playing tone games!

            May the tone be with you!

            Kind regards,

            Jeff

  2. Hi Jeff, Im exited to follow your progress with the VOTTs 🙂 A couple of days ago I unexpectedly I got the option to buy ( exchange for other hifi stuff) a pair of A5s. I did not hesitate one second. I got A5s with the ferrite 8 ohm drivers, 515g and 299, 828 cabs and the 1505b horns. The 828 cabinettes are somewhat battered but can be restored, I totally love the 1505Bs. The crossovers are Hiraga inspired. The A5s replaced my Altec 604-8gs in 620 cab. copies using Werners filters for the 604. Initially I used hypex nc400 monoblocks and was only moderately impressed, then I connected my Ladyday Signature 300B SET 91s and got totally blown away. Cosmetically, especially the cabinettes need some work and I know the 828s can be beefed up, but Im already captivated by the rich, energetic and powerful, but still thorougly musical way the A5s conwey all kinds of music.
    Regards
    Kjartan

    • Hi Kjartan,

      It sounds like you got a really great pair of A5 VOTTs! That’s fantastic! I love the looks of the 1505B horns, and I tried to find a pair, but at the time I was looking there were none to be had.

      My buddy Stephaen has a pair of 604’s that Pete Riggle built a pair of cabinets & crossovers for, and they really are fantastic. Pete really can get some great sound out of Altecs.

      Keep me posted on your A5 adventure, an thanks for adding the great comment!

      Kind regards,

      Jeff

  3. Yes Jeff the 1505s where the main attraction. I have only seen a couple of auctions for single 1505 horns on ebay for several years. The 1505 makes it possible to listen in realitive nearfield, their not as directional as some of the smaller altec horns, which need a lot of space to gel well vith the woofer front horn. I did not tell the whole story on the woofers as I need to choose between 515g and 416c, one or the other pair of woofers where a part of the deal. Now Im testing the 416c. I use either Quicksilver mid monos with 6l6s ( i preferred kt88 with the Altec 604s) or my 300B SET 91s and a passive pre (Slagle autoformere) to take the pre out of the equation.
    Regards
    Kjartan

    • Hi Kjartan,

      I’m listening to both my A5’s and A7’s in the near field and they sound great, no problem with integration here. I’m not familiar with the 515G, but I sure do like the way my 515B Alnico low-frequency drivers sound with my 288C Alnico high-frequency compression drivers and 1005B horns, it’s a really nice match. Let me know which bass drivers you end up preferring.

      Sounds like you’re having a fun time, keep me posted on your adventure!

      Kind regards,

      Jeff

  4. Hi Jeff,

    Great article on a fine rebuild and modification of a great American classic loudspeaker. I appreciate your approach toward this DIY project by first establishing the finial circuit and values with Yazaki-san’s assistance, and then following that with defining a Bill of Materials. This is the approach many of my DIY friends and I take with projects. With proper planning, one can avoid having to obtain multiple shipments from various parts suppliers, or buying too many non-essential components. The Bill of Materials along with the schematic form a checklist for the process of properly assembling a circuit. Having the components on hand allows the DIYer to properly and efficiently lay out the components before committing them permanently to a circuit. Sometimes, speaker crossover circuits benefit from a 2-3 tier physical layout to keep connections as short as possible and minimize the chances for short circuits or possible electromagnetic interferences.

    Prototyping also helps. Using some plywood or solid wood sheet, some zip tie mounts and other hardware like terminal strips, stand-offs, etc. can go a long way to experimenting with the everything until you have the results you really want.

    • Hi Rich,

      Thanks for the suggestions, mucho appreciated. I’m using pretty much the same approach with the A5 crossovers that I did with my Duelund-Westminster crossovers, in fact I’m reusing the plywood breadboards from that project for the A5 project – recycling!

      I really like the McMaster-Carr setscrew lugs for making connections on the breadboards, as it makes it really easy to swap components in and out. I did a little more soldering on the A5 breadboards that I did on the Duelund-WRSE breadboards (where I actually used zero solder joints), but it’s still fairly easy to swap in and out parts for evaluations.

      This sure is a blast!

      Cheers,

      Jeff

  5. Hi Jeff. I m really interesting with your A5 project so that why i m building a pair of a5 use the same parts which you use. I got almost everything except the spec ruby-mica 0.022 uf. I try to contact yazaki-san but dont hear anything from him. Ithink he really busy, so if i cant order the ruby-mica 0.022uf, do you have any advice for me? Which one i can use and still keep the “real sound” for A5? Thanks you a lot
    Cheer
    Kevin

    • Hi Kevin,

      That’s fantastic! I’m really enjoying my A5 project, and I think you’ll have a grand adventure as well.

      My crossovers are still a work in progress, but I’m glad to share my latest insights with you.

      The first is to use the Duelund DCA16GA for wiring the drivers and for the crossover wiring (which I’ll be talking more about in the near future).

      I recommend that you omit modification 1 on the Hiraga crossover circuit shown here. We tried it, but it was not a good match to the A5’s.

      I am experimenting with resistor values at R3-2 in modification 2, and I’ll have a revised recommendation for that value in the near future.

      Also, I have been experimenting with port dimensions in the low-frequency horns, which I hope to describe more fully in the near future.

      Finally, I recommend you hold off on the ruby mica couple capacitors at C3, as I may have some exciting news to share about capacitor choice for C3.

      My A5’s are really sounding nice at the moment, but I believe they have much more to offer, and I have mapped out a course to get there.

      Stay tuned, and I’ll have more to say over the course of the next few weeks.

      Thanks for stopping by!

      Kind regards,

      Jeff

      Kind regards,

      Jeff

      Stay tuned, I hope to be able to focus more on the development of the A5 crossovers shortly.

    • Hi Kevin,

      A follow up to my last response to you: I said, “Finally, I recommend you hold off on the ruby mica couple capacitors at C3, as I may have some exciting news to share about capacitor choice for C3.”

      Well you can scratch that comment, as I tried another capacitor alternative at C3 and the experiment didn’t work, despite my high expectations. Stick with the combination of Arizona Capacitors and the SPEC Ruby-Mica cap, it’s a really great combination. I thought I had something that could compete with or beat that combination, but nope.

      I haven’t heard from Yazaki-san for a while, so he’s probably busy on a project, so I’d just try emailing him again, he’s really good about answering.

      Keep me posted on your A5 project and be sure to let me know about any discoveries you make!

      Kind regards,

      Jeff

      • Thanks you Jeff. In case i don’t hear any thing from Yazaki-san, do you know any where i can order for the ruby mica capacitor?
        Kind regards
        Kevin

        • Do you think it good idea to use Sprague .022 @ 400 VDC Bumble Bee PIO Capacitors at c3?

          • Hi Kevin,

            As much as I love the Sprague Bumblebee caps, I don’t think they’d be a good choice for C3, as I think the result would be too laid back. I would just try it without the mica cap and see how that works (quite well I would imagine).

            Best,

            Jeff

        • Hi Kevin,

          I don’t know where you can get them except for Yazaki-san. I checked Parts Connexion and Hi-Fi Collective and neither had them listed.

          Hopefully you’ll hear back from Yazaki-san.

          Kind regards,

          Jeff

  6. Hi Jeff. I came my friend house last Sunday and he gave me pair autotransformer! Do you ever think to use a autotransformer in your A5 crossovers? I would to do it but dont know how to use it. hope this idea is working to make the A5 better. Thanks you Jeff for everything you did to make the A5 VOTT sound better
    Kinds regards
    Kevin

    • Hi Kevin,

      I think you ought to give them a try and see what happens! I do have a pair of Werner Jagusch’s autoformer based crossovers for my A5’s, but I haven’t had a chance to revisit them since I first got them.

      My Hiraga-san inspired crossovers are coming along nicely, and I’m closing in on a final version. I want to experiment a little with resistors in the high-frequency circuit, and then I think I’ll be done except for building something that looks a little nicer, and rewiring it with the Duelund DCA16GA.

      Let me know how the autoformers work out!

      Kind regards,

      Jeff

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