Tap Settings on P12 or LP140m

[jimbones]

I design and build my own speakers. My current speakers lowest impedance is at 200hz and is 6 ohm. It is nominally an 8 ohm design. my amp is set to 4 ohm tap. on my P12. Is it hard to change to 8 ohm? Also what should I expect when I swap it to 8 ohm as that would appear to be the correct setting. Would it be better?

Note that I spoke to Jeff at CJ and he says to set to the minimum speaker impedance. So if you have an 8 ohm speaker that dips t 3+ or 4 ohms he said to set to 4 ohm tap.

Thanks
Jim

[admin]

My general understanding is that typically you want to set the amp to the lower rating if possible. Some CJ amps don't need to be altered and can accommodate 4 and 8 ohm speakers. I'm not familiar with the P12 specifically so not sure if that needs any rewiring.

[AnotherJohnson]

If the low magnitude of Z is really 6 Ohms, the Real component may well be lower than 6 Ohms.

Nevertheless, you probably ought to try both 4 and 8 to see which you prefer.

CJ sets all their modern amps up on 4 Ohms.

On many models after CJ abandoned the different external taps, when you get inside there is a diagram that shows how to rewire for other loads.

If I were you, I’d go with 4 Ohms. But you should hear for yourself. The diagram is on this board. If I run across it I’ll post a link.

[AnotherJohnson]

Here’s an old post with the color code.

If you search the forum for this

CJ output transformer cable color (2) (2).pdf

You should find a link from Roberto that gives the color code for transformer taps.

I was not able to copy the link here. Maybe Roberto or Admin could establish the link.

For 4 ohms
Yellow +
Gray. -

2 ohms could also be of interest
Yellow +
Orange -

8 ohms
Yellow +
Black/White -

I think someone reported that this color code is actually on the transformers.

[AnotherJohnson]

https://www.conradjohnsonowners.com/vie ... 500#p10500

[SolderSlinger]

Changing the output configuration also required changing the feedback resistor. If you look on this site in the Schematics section, you'll find information on the corresponding correct value resistor to use with a 2, 4, 8, or 16 ohms connection. As a caveat, CJ does not recommend using a 2 ohm configuration.

[jimbones]

All,

I spoke with Jeff at CJ he said leave it at 4 ohms.

[AnotherJohnson]

All,

I spoke with Jeff at CJ he said leave it at 4 ohms.

Yup.

[tonye]

You just described the closet in my home office.

I think of it as an Audio Museum... Marantz 2325, 4415 (with full quad paraphernalia), Akai 980AS, Sansui 7500, Kenwood KA3500/KT5300, stacked NAD monitor amps, FW F5, Akai quad open reel, etc.... then on the floor of the office.... and the spare amps in the living room racks....

Yikes, never mind.

But I like such things.

[Joe Appierto]

I had a Marantz 4300 back in the day. Four mono 40W amps went to 2 x 100 in stereo. Sweet sounding without being cloying good detail but not what you'd call transparent. Still wish I had it at times but I bet at this point (50 years on) a whole bunch of stuff would've been replaced along the way.

[AnotherJohnson]

I had a Marantz 4300 back in the day. Four mono 40W amps went to 2 x 100 in stereo. Sweet sounding without being cloying good detail but not what you'd call transparent. Still wish I had it at times but I bet at this point (50 years on) a whole bunch of stuff would've been replaced along the way.

If you’d like to have one, there are several on eBay as I write this. Cool Quad Receiver.

[Joe Appierto]

Thanks, AJ. I'm going to read through them more out of curiosity than the chance of buying one but still...

It was part of the system my (now ex-) wife and I bought when we were first married back in 1974 as a wedding present to ourselves together with 4 Cerwin-Vega speakers (211R), a Dokorder 7140 4 channel reel-to-reel and a Pioneer PL61 turntable. Jeez a lot of memories (good ones) over the years with that sound system part of them.

[tonye]

I had both the 2325 and 4415 fully rebuilt... (actually all of my vintage units were rebuilt). Took all the boards out, replaced everything that looked suspicious AND ALL capacitors, taking into account that different circuits need different types of caps. Biased and calibrated everything. The only place were we "upgraded" any parts was with the power supply caps, with more modern units with higher ESR. Put incandescent lights (no LEDs, yuck), although we put somewhat lower wattage lamps in the 4415 to protect the vellum.

The 4415 has an SQA1 decoder, the wired remote and an external CD-4 demodulator. Every works except I could not verify the quad decoding since I didn't want to mess with my Linn set up.

The 2325 had some lifted traces in the tuner multiplex board so we had to fix that. We could not test the Dolby circuitry. Everything else works per spec.

( All of my other vintage units were similarly rebuilt ).

I find the 4415 to be fun with its dimension control. It creates some fun sounds but I can do the same thing with a Sony EP9ES decoder wired as a tape deck.

The 2325 puzzles me. I find its sound to be on the ponderous, heavy side. Sure it has lots of power but it feels very "old". Mind you, it's fully up to factory spec, and that's the sound we used to have then. I don't know why people are paying such crazy numbers for it. It's must be nostalgia, image and ignorance, I guess. Think Led Zeppelin's Rain Song.

The Akai 7500, OTOH, is a much better sounding unit... think Steele Dany. A much better value, even if it's high speed transistors are kamikazes and unobtanium ( it took four months to find a replacement set ) if you can find one rebuilt as mine was.

To be honest, I find a used CJ MF2100 ( I got one ) with a simple preamp a much better sounding proposition. The MF2100 sounds really good, it's will deliver a solid 100/200wpc into 8/4 speaker loads... has no problems with Maggies.

I guess people are gullible fools.

About those "40 watt amps". I had a 2240 receiver... I gave it away because that's the one amplifier design that is not so good. The ones to have are the 2220B, 2270/75 and 2325, plus the matching quad receivers.

[Joe Appierto]

For the time it sounded good to me. Had both the SQ module that fitted in the bay underneath the unit and the standalone CD-4 demodulator, too. The Pioneer turntable was fitted with a Pickering cartridge (XUV-4500Q I think) so the frequency response extended to 45kHz and the demodulator was therefore functional for the RCA-based 4-channel records. Bought the system at Crazy Eddie's Kings Highway store in Brooklyn except for the turntable which we purchased while on our honeymoon in Jamaica.

I have no electronics skills at all so updating and fixing equipment as you do is entirely out of the question for me -- always has been.

[admin]

Man I love that brushed steel design of the 70's. My parents had a Fisher hi-fi stereo back in the day. Sure sounded great to me when I was growing up. Not sure if I would be impressed with the sound now but at that time it was amazing. Had big box speakers that you could crank up to ridiculous volumes (because at that time as a kid I thought the louder it gets the better it must be).

[AnotherJohnson]

For the time it sounded good to me. Had both the SQ module that fitted in the bay underneath the unit and the standalone CD-4 demodulator, too. The Pioneer turntable was fitted with a Pickering cartridge (XUV-4500Q I think) so the frequency response extended to 45kHz and the demodulator was therefore functional for the RCA-based 4-channel records. Bought the system at Crazy Eddie's Kings Highway store in Brooklyn except for the turntable which we purchased while on our honeymoon in Jamaica.

I have no electronics skills at all so updating and fixing equipment as you do is entirely out of the question for me -- always has been.

My wife and I bought our first system together in 1975, at Mr. Toad’s Sound Concept in Johnson City, TN.

I remember explaining the importance of buying something “good enough for the long haul” so that we would be looking for an upgrade any time soon.

The TT was an upper entry level Garrard. The receiver was a Scott R33AS I think. Wiring was all cheap rca and zip cord. The speakers were sealed box Advent knockoffs, maybe from Boston Acoustics. The cartridge was probably $20, Stanton or Pickering … an upper lower priced offering.

We kept that system going for a decade. But I did have to buy Radio Shack solder sucker, wick, soldering iron, etc, and replace output transistors at the kitchen table,

Around 1981, after a couple of good career moves, we set up a better system based on Cerwin Vega, Onkyo, Technics, Pioneer, etc. By 1984 I was hooked and set up a hobby level dealership for several high end lines in our living room. By 1987 I knew that the side hustle of dealing to get access at wholesale was a bad idea. Better to find someone else who was working the same problem and buying from him at wholesale to help his cash flow. Great friendships developed unrelated to the audio gear.

Ah, the memories

[Joe Appierto]

Lamp wire and rca patch cords that came with the equipment was mainly maybe only what was available at the time. Then Monster speaker cable from Atlantic Stereo, AudioQuest Ruby interconnects from J&R Music World, TARA Space and Time TFA ordered from Audio Advisor and thus began my slide down the slippery slope. Still wouldn't trade those memories for anything.

[roberto]

CJ output transformer cable color (2) (2).pdf

(267.22 KiB) Downloaded 92 times

Hola, here is the output transformer wire color