Reccomend me easy Teac mods please

gevorg · « **on:** 9 Jun 2005, 07:22 pm »

Hi all,

Other than removing the center channel amp board, is there any other easy mod I can do (or at least one that does not requires soldering)? What does it take to replace the switching power supply to a regulated one?

Thank you in advance for any suggestions!!

gevorg · « **Reply #1 on:** 10 Jun 2005, 08:46 am »

How about using decent APC battery power used for computers?

gongos · « **Reply #2 on:** 10 Jun 2005, 09:26 am »

The easiest thing I can think of is packing it up and shipping it off to have it modded.

mcgsxr · « **Reply #3 on:** 10 Jun 2005, 01:39 pm »

Well, other than removing the center channel, the only other thing I have heard of that makes an immediate impression, is good power conditioning. Not sure if it is worth THAT kind of investment (BPT, Equitech) but I have enjoyed improvements using simple Powervar or Isobar units.

Worth the $25 or so on eBay to find out!

Occam · « **Reply #4 on:** 10 Jun 2005, 02:26 pm »

Felicia-cize it......

gevorg · « **Reply #5 on:** 11 Jun 2005, 05:18 am »

I would definetely get it modded if it wouldn't cost 5 times more! Its not like it would sound five times more (I'm sure not even twice as good). I will consider power conditioning after I'm all done with modding and overall system setup.

Since I have a center channel board lying around, I'll give soldering a shot and see if I can do it or ruin it

What should I replace in it?

Also, does wrapping cables in foil will reduce EMI? (like the one which goes from main board to on/off switch, or from PS to the main board?

mcgsxr · « **Reply #6 on:** 11 Jun 2005, 11:22 am »

One guy around here used some copper flashing (like the stuff for your expensive roof...) and bent it into shape to separate the PS from the amp boards with positive feedback.

You may want to search up my comparison of a stock Teac, a Vinnie power supply modded Teac, and the Bolder Teac I own.

The fully modded, but still AC powered, Bolder Teac is clearly the best amp in the bunch, and easily worth the $$ to me.

Could just be me though - there is no $5-600 amp out there that competes, in my experience.

Gordy · « **Reply #7 on:** 11 Jun 2005, 12:10 pm »

Quote from: Occam

Felicia-cize it......

Will the Felicia handle a 30w amp Occam? If it can, for a mere $30 you can build a balanced power Felicia, which is vastly superior to the admittedly very nice OneAC iso transformers... build two or three and dance with the gods...

Occam · « **Reply #8 on:** 11 Jun 2005, 12:18 pm »

Gordy - You betcha, ya sure....

albee · « **Reply #9 on:** 11 Jun 2005, 05:01 pm »

I noticed a difference using an "Isobar" surge/filter with my Teac. Like mcgsxr said, ebay has gott'em for the right price.

samplesj · « **Reply #10 on:** 11 Jun 2005, 06:17 pm »

One of the mods I've seen for the tripath amps is to remove the cheapie volume pots (bypass with wire or add better ones). This doesn't fit the original poster's no solder restriction, but might be useful for other searchers later and I wanted to ask a question too.

I'm trying out a Teac in my game room for potential modification and use in my critical listening system. Because I needed two inputs for the testing area I thought I'd just throw together a cheapie passive.

I think I've read somewhere that the tripath chips should never have right and left grounds tied together. Is this true? I had forgotten and got an AL chassis and non insulated RCA jacks. What will happen if I do hook the Teac up to this??

Is it time to junk the box and get a plastic one or is the AL safe?

CSMR · « **Reply #11 on:** 11 Jun 2005, 06:45 pm »

Quote from: samplesj

I think I've read somewhere that the tripath chips should never have right and left grounds tied together. Is this true?

Yes. (They aren't grounds on the TEAC.) I did this once by mistake. The machine won't work but it won't blow up either.

Occam · « **Reply #12 on:** 11 Jun 2005, 07:04 pm »

CMSR- For the tripath chips used in the TEAC and the Sonic Inpact, etc... the ouputs are bridge tied load, BTL, and therefore do not have one of the output terminals at ground. Hence, the loudspeaker outputs should never tie any leads together. (this requires rewiring some headphone cables which often do this). This is not an issue with regards to the input grounds, the RCAs, though different modders follow their own Muse.

BFitz · « **Reply #13 on:** 11 Jun 2005, 07:14 pm »

One issue to be aware of with the TEAC is the output filter

Basicly, you need to know what your tweeter impedance is above 5kHz.
The Teac really wants to see a flat 6 ohm impedance, otherwise, it will roll off early (for say 4 ohms) or having a rising response (for 8 ohms or greater)
This means a tweeter zobel (cap and resistor across +/- leads) can tailor the amp response rolloff, and significantly change the measured response. I point this out as I was looking at using using these with a 4 ohm load, but would not recommend that now, at least above 5 kHz. With a 4 ohm load, it starts rolling off at 8kHz, and is down about 3.5-4 dB at 20 kHz.

The output filter, BTW, is not the one recommended in the Tripath 2050 data sheet. I have new inductor toroids inbound for experiments to replace the stock ones.
-bob

CSMR · « **Reply #14 on:** 11 Jun 2005, 08:25 pm »

Quote from: Occam

CMSR- For the tripath chips used in the TEAC and the Sonic Inpact, etc... the ouputs are bridge tied load, BTL, and therefore do not have one of the output terminals at ground. Hence, the loudspeaker outputs should never tie any leads together. (this requires rewiring some headphone cables which often do this). This is not an issue with regards to the input grounds, the RCAs, though different modders follow their own Muse.

Oh yes he was talking about inputs. My mistake.

lcrim · « **Reply #15 on:** 12 Jun 2005, 01:35 am »

I was the one who used the copper flashing to shield the power supply board from the amp board. The single most effective tweak that virtually anybody can accomlish is to remove the center amp board. All this is detailed in the 19 page thread that Mark started aound a year ago re: TEAC.
The second most effective tweak is to give the thing time to burn in. It improves noticeably with time.
I eventually sent a TEAC to Vinnie Rossi long before Redwine and he did power supply board mods that basically added better and larger capacitors but kept the switch mode power supply in place. I eventually added a Transcendent Sound balanced power supply kit and an isolation filter from Wayne at Bolder Cable to get more utility from the balanced power unit. The switching power supply sends its EMI & RFI back up the power chord and it messes with other devices connected. Since balanced power is the only power conditioning I've ever known to work I wanted to connect everything to it.
My modded TEAC also uses a hard wired Volex power chord but retains the toroidal body. Better quality RCA jacks and Auricaps were installed on the inputs. The balanced power transformer made a night and day improvement but the filter was a good thing too. Occam's Felicia might just do it but if you can't DIY, the Equitech Son of Q Jr. can be had new from Bolder for around $650 which seems like a lot compared to a $100 amp until you hear the difference, it also emloys filtering.
Vinnie nowadays solves the issue by discarding the switch mode power supply for a battery. Since I already had the power conditioning in place I didn't spring for it. I think that Vinnie is a wonderful guy to deal with and does excellent work. The cult of battery power does get on my nerves at times.
The speakers I have used with the TEAC are the 88dB Sonus Faber Concertino Homes which are rated as a 6 ohm load. I have an AES AE-3 preamp whch employs the 6SN7 tube and has roughly 20 dB gain. I think that the Tripath based amps sound best with lots of gain. I love the neutral, transparent, tonal quality and the extreme detail and speaker control that the amp provides.

BFitz · « **Reply #16 on:** 12 Jun 2005, 10:19 pm »

Has anyone tried air core or type 2 low mu cores (recommended by tripath) on the outputs?

Before I went all gung ho elsewhere, I would make sure the components that sit between the amp chip and the loudpeakers are the best they can be. Those stock inductors are not impresing me too much, nor are the stock output caps. I would go to single crystal copper or silver wire wound on type 2 cores there, and all polypro caps, before I spent big bucks elsewhere. Just watch, next week some modder will be offering it, after reading this.

-bob

samplesj · « **Reply #17 on:** 15 Jun 2005, 01:26 am »

Thanks for the clarification on output grounds vs input grounds. I'm using the junky passive to break it in before I try it out for real.

Has anyone pulled the extra board out into another case? That way I could leave the normal Teac box (minus center channel) in the game room and really tweak the extra board for the modded amp. If you were feeding by battery and were going to bypass the built-in volume control I'm not sure why you would really need their mother board.

If you can scavange 2 amps out of this $100 box then its a awesome bargin.

Jeremy