Teac Reference Series

B

BigEars

Audiophyte
Hi Nico
Any luck with the volume control? Does the part against the inside of the front panel it look like the one in the AliExpress picture? You might be able to shine a strong light in behind the front panel and verify it without dismantling any further. Otherwise it might be fairly easy to pull off the volume knob, unscrew the small nut around the potentiometer shaft (an 11mm (?) deep socket is best, but long nose pliers can work if you're careful) and remove the small volume control PCB. Cross-head screwdrivers and the exploded view diagram on pages 21/22 from the manual are your friends here. :)

If the volume control looks correct then the problem may be weirder and harder to find without some test equipment. The left and right channels follow separate pathways through the amplifier, and are only varied together at the volume control - so this is a good place to start. But both channels share various power supplies, so it would be a fairly easy to check these with a multimeter to rule them out.

The block diagram on pages 7/8 is a great place to see the flow of the signals. The phono input has an RIAA preamp on it, but the other inputs are identical. You can eliminate the tone controls by switching on CD mode, which bypasses them.

Hey - maybe your input signal is just way too big!! :p Any luck with other audio sources? If you use a weaker inpout signal you might be able to get further up the pot where the channels are better balanced...
Big Ears
 
B

BigEars

Audiophyte
@Nico Well - this is the value of not emptying the bin for several years! Here's the dud that I took out of the amp:

pot compressed.jpg


For the record I tend to leave the amp set to about 16dB (which as you describe would be really really loud, but also clean and beautiful) and do all the volume control from RuneAudio, which is running on a Raspberry Pi Zero and an IQAudio Dac - seen in the background - and driving a pair of Rega Juras.

pot with DAC compressed.jpg

B. E.
 
N

niccav

Enthusiast
Don
@Nico Well - this is the value of not emptying the bin for several years! Here's the dud that I took out of the amp:

View attachment 24639

For the record I tend to leave the amp set to about 16dB (which as you describe would be really really loud, but also clean and beautiful) and do all the volume control from RuneAudio, which is running on a Raspberry Pi Zero and an IQAudio Dac - seen in the background - and driving a pair of Rega Juras.

View attachment 24640
B. E.
Don’t I feel silly; I have checked the thread everyday looking for an update but missed your reply was on the next page. That's what you get for not sleeping properly.

I haven't had time to remove the board of check further into my theory regarding the input as I have been travelling. Will try get some time during the weekend...hopefully without the kids help....

At "16"! I couldn't even imagine how loud that would be.

Below you can see the package of the pot they inserted. At least that's what they said it was.
 

Attachments

J

Jorandy

Audiophyte
Hi - brand new member here.
I have a TEAC A-H300 amplifier. Is there any way I can connect a signal processor into one of the tape loops and hear the effect on the signal? The actual item is a Kef Kube for the Reference 102 speakers and normally this goes in a recorder loop and you would just press the tape monitor switch, or alternatively, place it between a pre and power amp. I just can’t see how to set it up on the TEAC and the manual is no help. Looking at the Input selector, I can select a source OR one of the recorders but not source AND one of the recorders as if I were monitoring a recording. Is this a design flaw or am I missing something?
Thanks for any help.
 
B

BigEars

Audiophyte
Don


Don’t I feel silly; I have checked the thread everyday looking for an update but missed your reply was on the next page. That's what you get for not sleeping properly.

I haven't had time to remove the board of check further into my theory regarding the input as I have been travelling. Will try get some time during the weekend...hopefully without the kids help....

At "16"! I couldn't even imagine how loud that would be.

Below you can see the package of the pot they inserted. At least that's what they said it was.
Hi Nico
I checked the part number with the manual - it's correct.
 
N

niccav

Enthusiast
Hi Nico
I checked the part number with the manual - it's correct.
Thank you. That's some good news.

Finally had time to do some testing.

Dvd player (using a music cd) connected to the 500i got me the following results (average) according to a decibel meter for my iPhone.
-60: 41 dB(A)
-45: 54 dB(A)

This might be slightly lower than via the dac but not much lower.

The imbalance isn't as obvious using speakers rather than headphones. Not sure if this is due background noise hiding any imbalance or if the imbalance is restricted to the headphone pathway.

My main concern is the volume output and this must be a problem in the common pathway? The imbalance isn't obvious using speakers rather than headphones. I'm not sure if this due to background noise hiding any imbalance or if the imbalance is restricted to the headphone pathway. Do you think this fixable BigEars or is it just the way it's supposed to be?

I won't be able to dismantle anything until my wife his to visit her parents with the kids on Saturday.
 
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N

niccav

Enthusiast
After having a closer look inside. The pot looks like your so I guess it’s the correct one. Not sure how to proceed from here.

A little recap:
the imbalance remains also when using speakers. But a little less pronounced compared to when using headphones (I turn the volume a litte more compared to when using headphones),ie the issue is mostly predominant around -60 but you can still hear it but further up. Also I think it’s more obvious with headphones as the block a little ambient background noice.

Measurements: I did some measurements using speakers (cd->amp->speakers) and got the following. The measurements were done with my iPhone roughly 1 m, diagonally from both speakers. Windows were closed and I was alone at home.

Pot at 60: 44.2 dB
Pot at 45: 53.8 dB

The pot at 45 produced a nice for volume background music during day hours. I would have found it to loud at night for background.

Any further suggestion are welcome.
 
afterlife2

afterlife2

Audioholic Spartan
Ratings
2,440 14 3
Anyone hear these LS-301?





  • Teac LS-301 Specs
Type 2-way coaxial single speaker, bass reflex typeLoudspeakerLow-Frequency: 3.9" (10 cm) cone
High-Frequency: 0.8" (2 cm) soft domeInputRated Input: 20 W
Maximum Input: 50 W
Input Impedance: 6 ΩOutputOutput SPL: 85 dB/W/m
Playback Frequency Range: 65 Hz to 40 kHz
Crossover Frequency: 3.8 kHzCabinet Volume4.5 l / 275 cubic inchesDimensions (WxHxD)6.4 x 9.1 x 8.1" (161 x 230 x 207 mm),excluding protruding portion, per speakerWeight6 lb (2.7 kg),per speaker
Packaging Info Package Weight15.25 lbBox Dimensions (LxWxH)
 
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P

pablotaxi69

Audiophyte
Hello TEAC users. I have some TEAC reference stuff like : AH-500i, PD-H500i, AG-H550. System plays with Q Acoustics 3050 Stereo Speakers and Tannoy EFX 5.1 Set. True is that im so happy with this Set. AH 500i play better then 3 times expensive sets. I just have only 1 problem with Volume potentiometer in AG-H550. Volume is incerasing with all speaker good but in ceneter speaker voice ocasionally disappears and scratching but if i punch into potentiometer or incarase volume the sound does become the norm. Greetings

"I just have only 1 problem with Volume potentiometer in AG-H550. Volume is incerasing with all speaker good but in ceneter speaker voice ocasionally disappears and scratching but if i punch into potentiometer or incarase volume the sound does become the norm. "
Did you solve the problem? How?
 
D

davidscott

Audioholic
Ratings
74
Off topic here but I owned a mid level Teac cassette deck back in the 80s and it was very good. Probably would have had to upgrade to a NAK to improve the sound.
Dave
 

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