Vintage Hi Fi and my little CF amp

[elgrau]

JJ wrote:
"A word of caution: Those 12" woofers are only rated 100 watts RMS. The problem is they sound so good and distortion free no matter how loud you play them until POP! "

I can relate to that, jj....recently "opened up" the m1.0t mkII opt2 a bit "too much" in my garage system and even tho the sound was not at all distorted, when the Floyd's "Welcome to Machine" came ON, the extreme LF ripped the cone from the spyder of one of my EPI 400 tower's (old) 6.5" drivers....and these (original) drivers seem to be very scarce on ePray lately (unlike the 8" drivers): only one was listed recently and I had to pay $46 (plus shipping) to get it... On the bright side I have ~22 of these drivers (12 in a pair of "sphere's", 8 in the 400's and 2 in my daughter's A70's...).

[Magnaryder]

JJ wrote:
"A word of caution: Those 12" woofers are only rated 100 watts RMS. The problem is they sound so good and distortion free no matter how loud you play them until POP! "

I wonder if the units Bob Crites sells are more durable?

ray

[jjptkd]

They are a completely new woofer design created by Mr Crites. Power handling is up to 150 watts RMS from 100 but the first thing I noticed was the surround is an accordion style instead of the inverse standard rubber type, which seems to me like it would limit the Xmax and possibly change the resonate frequency. I emailed him as soon as I seen the new woofers on eBay many months ago asking about the differences and how they spec'd out in comparison to the stock woofers. His reply was that he sent his woofer manufacturer the Forte cabinet and various other specs and this was the driver they came up with as a suitable replacement. I'm not an expert on woofer design and haven't tried these myself so can't say for sure, it would be interesting to compare them to a stock driver though.

[Magnaryder]

I want to thank Jesse Venables(F1Nut) for his help and guidance on 'TheQuest' it was invaluable. Thanks Jesse!!!

This weekend I re-capped my Klipsch Forte speakers with Obbligato Gold series caps in the squawker and tweeter parts of the network. I picked these caps because the word I kept hearing when they were described was analogue and I thought 'that' is what I like to hear. Keep in mind, that until the caps are actually in and running for a good long time you still have no idea what they are REALLY going to sound like. Well since I'd heard good things from quite a few different sources about the Obbligato cap line I thought I'd roll the dice. BTW, big thanks to Tom for the deal on the speaks. We all have budgets to work within ya know and a good deal on the outset makes the modding($$$) a little less painful to part with.

I burned-in the caps for 100 hours as described on the 'Humble Homemade HiFi and Enjoy the Music' websites before I installed them. The Fortes' x-over is mounted to the speaker terminal cup on a circuit board. Getting them free of the speakers required removing the passive radiator to gain access to the speaker leads which use push on connectors and then removing the connector cups. I left the speaker leads intact because I'm going to replace the electrolytic cap (are you fucking kidding me???? and it sounded ok) and resistor in the woofer network with an Obbligato 47uf PSU when the cap arrives. I already have the Mills 50 watt resistor. I'll drill the board and solder the new wire in at that time. I have some heavy gauge 7 nines copper for the woofer and some silver-clad copper for the squawker and tweeters. Someone told me that the audio signal loses a little 'weight' when you use silver wire throughout.

The Klipsch network caps are substantially smaller than the Obbligato caps, like on an order of 4. I used my drill press to open the circuit board holes to accommodate the leads of the new caps, soldered them in then hot glued them to each other then to the board. The board is crowded now and this new cap is huge!! I'm going to look into building a new network board similar to the units offered by BEC and ALK.

DAMN...they made a big difference. The first thing I noticed was how uncluttered and effortless the midrange has become. It didn't sound like the various instruments were really close together or on top of each other before the modding, but now the reproduction sounds more natural.....to me anyway. Each element of the image seems to have spread out across the room. When I listened before, the speakers were the boundaries. Now the soundfield has spread out beyond the speakers a bit. Improvement, I guess. The vocals are airy, but without the halo of echo that I heard surrounding them before. Same with the piano, upright bass acoustic guitars. What I can't figure out is what am I supposed to be hearing? Is there really that much 'air' in the recordings, or....did I 'artificially' insert it?

I'm really impressed by the way Willie Nelson sounds on Mark's CF12 disc. His voice has taken on nuances I'd not noticed before. Holly Cole...the same, although her voice emanates from a larger space. Odd that. The standing bass far more definition and the piano...all I can say is WOW!!! Count me impressed.

My thanks to Jesse, the folks over at the Klipsch Community, ALK and BEC for lighting the way.

Anyway...it sounds good to me. So I guess that's OK. We'll see what happens when I install the Mills Res, wire and the other cap. Might be worth writing about

ray

[engtaz]

Congrats Ray. Jesse is a awesome information bank.

[Zoot Horn]

I used them in my Dared pre-- they are very good caps,, the tone man,,it's about the tone!!! Congrats Ray!

[Magnaryder]

They are a completely new woofer design created by Mr Crites. Power handling is up to 150 watts RMS from 100. I emailed him as soon as I seen the new woofers on eBay many months ago asking about the differences and how they spec'd out in comparison to the stock woofers. His reply was that he sent his woofer manufacturer the Forte cabinet and various other specs and this was the driver they came up with as a suitable replacement.

Looking at the new x-overs from ALK it is a tad different. ALK has an add-on to the network to accommodate the new woofer.

ray

[kingman]

Great post Ray. Are you planning on bringing them to Carverfest this year?

[Magnaryder]

Great post Ray. Are you planning on bringing them to Carverfest this year?

Maybe.... I have a little something in mind. I'll know more after the pre build. I'm waiting on Edcor......and waiting...and waiting. 6-8 weeks to build a transformer?????

ray

[Magnaryder]

Week before last BOTH of my CF amplifiers took a shit. Neither of them would work. f**k f**k f**k me thinks. I called Tom and asked what to try first before I send them to Pittsburgh for repairs. He suggested checking B+ voltages. My amp had been modded by MBSKEAM(thanks Mike!!) lowering the B+ voltages so it would run plain ol' 6BQ5s. I checked along the run of diodes and found nothing...WTF. I looked around and found nothing in the fuse holder. Damn...It was running a minute ago. Replaced fuse and it's up and running. KEWL

The second CF amplifier had lost a channel. Tom suggested taking tubes out of the running amp and substitute the known good tubes and place them in the other amp. Today I thought why do all of that when changing the tubes out of the good channel should work just as well. No Joy...damn. Poking around under the amp I noticed some bad connections. I re-flowed them and gave it another shot. No Joy again. Well this is a pain in the ass. Turned it back over and poked around a little more and found the culprit... A loose positive signal line running from the input jack to the first tag board. Resoldered it, replaced the tubes and still No Joy!!!! WTF!!! I moved the tubes from the other channel in and it works. Hot Damn!! I started replacing the tubes one-by-one and discovered one of little tubes in front had failed. I slapped another one in and I gotz tunes.

I installed a power switch and a bridging switch on the rear panel of the amp that Anders built for me. Both of them work just fine. I'm back in business.

ray

[engtaz]

Congrats Ray

[kingman]

Enjoy the music Ray!!!

[radioeng2]

Good for you Ray, for jumpin' in and given it a go! That's the next logical progression for those that built. The ability to get in and figure out, carefully, what has happened.

Troubleshooting is taking what symptoms we know, dividing up the parts of the circuit and figuring out what would be logical checks. Not thinking of it as a whole bucket of parts, but a few complete circuits that we can check the result of. Physical indications and what could cause it. Then start the portions...AC power? DC power? B+, Filament, bias? Then not quite as easy, the audio signal path. Divide to conquer.

Good job Ray!

Mark

[Zoot Horn]

I really had something witty to say,, but I'm just gonna keep quiet.

Good on you Ray

[hewlew1]

Witty you say. If you perfect that screen door trick I am sure your mind will transend to a whole new level of thinking. I just don't know if it will go up or down