[Advent experiment - mod - much better sound IMO]

Pete, I finished a 22K 6dB version for a friend to run between his preamp and power amp and upon listening neither he nor I can discern any difference. Is it possible I fried a component with too much heat from the soldering iron? On some of the connections I only placed a heat sink to protect the nearest component. Would that cause a lack of audible difference?

[Advent experiment - mod - much better sound IMO]

For some reason the picture I posted of the circuit in diagram form no longer shows. Here it is again, attached.

I have to build a new BSC for between a preamp and amp as a friend needs one for his system.

[Advent experiment - mod - much better sound IMO]

Just wondering if you notice that the Advents appear to disappear with the BSC?

At least for me, once I heard a system that could pull off the disappearing act I

just had to have it. I find the lack of enough BSC results in a boxy sound like

bass/mid-bass from a box, and too much in the 1 to 4 K range causes a harsh

edgy sound. On the other hand when it's right there is just realistic music in the

room.

Those small Mom and Pop shops are refreshing to see, not many of them left. Do

they do mail order?

Other than having some lingering problems with my room which I will address with some more acoustic treatments, I would have to say that, yes, the Advents become less apparent with the BSC. Advents are pretty good with proper placement to begin with. But when you locate them into the room yielding an incredible soundstage the BSC really helps with the sound. I'm really appreciating my vinyl right now and can't wait to get my HK Citation Eleven back as it should provide another improvement.

I don't know if this mom and pop is organized enough to know what they even have in stock, except that when you ask for something the old guy seems to know where he might have it. If you want you could PM me and I could give you his phone number. I'm sure he would welcome the business.

[Advent experiment - mod - much better sound IMO]

Pete and Marty,

I have all my materials together to build my BSC, but my problem is finding time right now and I know I'll have a few questions before I proceed. I know I won't get to it for about a week or two, but if Marty really wants to hear the loaner BSC, and the 6dB unit is appropriate, I'll mail it. If you want it PM me your address.

[Advent experiment - mod - much better sound IMO]

Corrected version.

[Advent experiment - mod - much better sound IMO]

Is this right?

Not even close huh? I think I might have the capacitors and resistors mixed up.

[Advent experiment - mod - much better sound IMO]

Good to hear! For me Advents just "lock in" with BSC.

Let me offer a bit more about my motivation here. My parents bought a pair

of the early Large Advents around 1972 or 73. We did some detailed spec and

review comparing, my brother being highly analytical (2 years into an EE degree

at the time) and having an excellent ear.

We got them after a listening demo, because of the good price and excellent

performance. My brother pointed out the flaw in the midrange when we got them

home after we did some extended listening. And I reluctantly agreed with him,

eventually strongly agreeing. I thought as a young teen that someday I'll try to

figure out what caused the problem. I expected it to be a complex woofer cone

resonance problem or serious crossover issue, that most likely couldn't be fixed

without a new driver. It was logical to think that the smart guys at Advent would

have fixed it if it was possible.

Now years later, I intended to dig into them when I took my parents' speakers to

refoam them. I decided to quickly try the BSC (I had built the BSC for AR-2ax's

that I was listening to out in the room) and was shocked by how it seemed to

completely fix the midrange issue. It was hard to tell the difference between the

Advents with BSC and my commercial reference system at moderate listening

levels, very hard.

Yes it is the 6 dB version from post #41 in this thread:

4.7K Version, these values are for RL = 47K or typically an EPL or tape monitor

loop:

R1 = 4.7 K, C1 = .0047 uF

6db: C2 = .068 uF R2 = 4.3K

C1 can be two .01 uF green mylar caps from Radio Shack in series.

C2 can be a .047 uF and .022 uF also from Radio Shack in parallel.

Just so happens that I have a good supply of .068 uF, .01 uF, and 4.3K resistors

here. I forgot to include them in my rush to send it to you. I'll get them off

to you soon. Figured I'd wait to see how you liked it.

Have you tried different settings of the tweeter control? Where do you like it best?

As I may have mentioned somewhere posting here that I've had my New Large Advents since 1980 that I purchased when I got a new stereo after several years without. What influenced me was a trip to the stereo store in 1974 with a friend when he bought a new stereo and got original Large Advents, an amazing 30 wpc Sony receiver and an AR XA turntable. With his setup I never really noticed the midrange problem perhaps because he had them almost flush against the wall so there were less baffle issues. Of course all I had it to compare to were my own BIC Venturi Formula 4 speakers driven by a 28 wpc Sansui reciever and sourced from an old Fairchild turntable with Thorens arm, a friend's Bose 901s powered by Phase Linear 400 and another's Altec Lansing Voice of the Theaters powered by Dynaco tube stuff. Then I worked with a guy who introduced me to stacked double original Advents driven by a Phase Linear 700. I thought then that that had to be about the ultimate. In 1980 I bought New Large Advents with some new Harman Kardon gear and they have stuck with me all this time. It was just within the last couple of years that I decided to put together a kickass vintage stereo around stacked double Advents. I ended up refoaming my Advents and getting four more pairs, one pair of U4s to match mine, two pairs of U3s that needed some work, and a pair of beautiful mint A4s. I had never really identified the midrange issue until I decided to put Advents out into the room. Over all this time I've always considered the Advent a pretty flat speaker and have treated it that way by setting the tweeter switch on Normal rather than Extended or Decrease. As I listen to more varied sources on my system with the BSC in place I am amazed that it could make such a difference. Whew! Sorry about the longwindedness.

Pete, I will gladly accept your spare components and will wait to build my circuit until they arrive. I found a deal on some very nice gold plated RCA jacks at the local Mom and Pop electronics store and have had the box for several weeks. The place is pretty funny, looks like he has stuff in there about as old as he is. Thanks again Pete.

Is this right?

[Advent experiment - mod - much better sound IMO]

Pete B, got your BSC hooked up today. First impressions are that this is a definite improvement. I have my bass, midrange and treble controls flat and the speakers set at normal. Voila! The bass is much improved, sounds better than when I had my bass control at 3 o'clock. The midrange is also much improved; smoother sounding yet very revealing of the nuances of the human voice or instruments like saxophones. And I think you are right about the high frequency boost you applied to this unit. Things also sound better with this boost employed. My ears need all the help they can get with high frequencies.

What is the schematic for this unit, with I believe the -6dB BSC and whatever high frequency boost you used? I don't need the switch to defeat the high frequency boost. Thanks much! As soon as I build mine (this weekend I hope) I will return it or pass it on if someone here expresses an interest to try it out next.

Stacked double New Large Advents rock with 200 watts per speaker and Pete's BSC!!!!!

[All Advent questions answered]

The Advent/1 is an 8 Ohm speaker. I would try to match all your speakers to 8 Ohms if some are selectable. Then with your Niles SS-6 if you are using more than 2 pairs of speakers just push in the impedence magnification button (marked PROTECTION).

[Advent experiment - mod - much better sound IMO]

I don't know if this question has been asked yet or not, but is there someone that will make these circuits for the electronically challenged? Time, effort and materials would gladly be compensated. Thanks. Or are they are fairly easily made with a soldering gun? I have two pair of New Large Advents that I want to stack.