Teac Reference Series

[niccav]

Hi

I have a ah-500i but it has two issues that prevents me from using it.

1. A slight channeled imbalance
2. Volume increases to fast, i.e. it goes from 0 almost immediately. During the evening (using headphone) I can’t even use on “1”.

I have had the volume pot replaced by Teac authorised personal in Sweden (Gothenburg) but there is no change, neither to the imbalance or how th volume increases.

I have heard of a similar case where a new quality pot (ALP) helped although that wasn’t on a Teac. He had first tried some cheap pot and it didn’t help.

Could this help me?
Could the pot they installed been bad?
Has anyone else experienced these issues?

I’m grateful for any help as I really would like to start enjoying the amp.

/Nico

 

[Victor rODRIGUEZ]

I am trying to buy two Teac A-L700P to use them as power amp mono and to use preamplifier my a1-d, would I gain in performance with these tripath? Has anyone done an experiment like that?

 

[Victor rODRIGUEZ]

Hi

I have a ah-500i but it has two issues that prevents me from using it.

1. A slight channeled imbalance
2. Volume increases to fast, i.e. it goes from 0 almost immediately. During the evening (using headphone) I can’t even use on “1”.

I have had the volume pot replaced by Teac authorised personal in Sweden (Gothenburg) but there is no change, neither to the imbalance or how th volume increases.

I have heard of a similar case where a new quality pot (ALP) helped although that wasn’t on a Teac. He had first tried some cheap pot and it didn’t help.

Could this help me?
Could the pot they installed been bad?
Has anyone else experienced these issues?

I’m grateful for any help as I really would like to start enjoying the amp.

/Nico

The technical service of teac was not able to solve your problem? How much did they charge you for leaving the amplifier as it was?

 

[niccav]

It wasn’t the technical service of Teac but rather their approved service shop.

Didn’t charge me “much” ( 90 usd) but they had it twice without solving the issue. That’s why I haven’t gone back. Also I let them have it for months as I told them I would rather get it done right than rushed. Seems I got neither.

Any suggestions on how I can fix it?

 

[Victor rODRIGUEZ]

Start with the basic methods for which we do not know about electronics. clean the pots and potentiometers with a spray of residue 0, sometimes they usually solve the problems of lack of sensitivity of the volumne controls

 

[Victor rODRIGUEZ]

After getting rid of some Reference Series components this is my new current configuration

 

[Victor rODRIGUEZ]

Hi

I have a ah-500i but it has two issues that prevents me from using it.

1. A slight channeled imbalance
2. Volume increases to fast, i.e. it goes from 0 almost immediately. During the evening (using headphone) I can’t even use on “1”.

I have had the volume pot replaced by Teac authorised personal in Sweden (Gothenburg) but there is no change, neither to the imbalance or how th volume increases.

I have heard of a similar case where a new quality pot (ALP) helped although that wasn’t on a Teac. He had first tried some cheap pot and it didn’t help.

Could this help me?
Could the pot they installed been bad?
Has anyone else experienced these issues?

I’m grateful for any help as I really would like to start enjoying the amp.

/Nico

currently in the United Kingdom (Ebay) they are selling for about 150 euros, I think it's a bit expensive the 90 that have been charged

 

[Victor rODRIGUEZ]

Hola a todos, otra vez, aquí hay una foto de mi modificada Teac A-H300 amp, he agregado un conjunto de preamplificadores para agregar un amplificador de potencia Teac AL700P ( usado como 2 canales solamente),
Lo siento, la foto es de mala calidad, agregará algunas mejores una vez que pueda agarrar el teléfono cam para socios, también agregó una toma de entrada de red 8 para que pueda hacer algunos cables de buena calidad, la razón principal fue por conveniencia ya que no me gusta el cableado separado, aquí la foto del cableado previo a la salida ...

por favor, ¿pueden enviarme las fotos de cómo hizo ese pre ot para el teac ah-300? Gracias

 

[Victor rODRIGUEZ]

Hola
Acabo de comprar un AG-H300 MK3 y me preguntaba si puedo usar el DSH01 Ipod dock / dac de la línea de referencia actual con esta unidad. ¿Lo conectaría a auxiliar en la parte posterior?

Sí y funcionará perfecto, lo tengo de esa manera?

 

[BigEars]

Hi

I have a ah-500i but it has two issues that prevents me from using it.

1. A slight channeled imbalance
2. Volume increases to fast, i.e. it goes from 0 almost immediately. During the evening (using headphone) I can’t even use on “1”.

I have had the volume pot replaced by Teac authorised personal in Sweden (Gothenburg) but there is no change, neither to the imbalance or how th volume increases.

I have heard of a similar case where a new quality pot (ALP) helped although that wasn’t on a Teac. He had first tried some cheap pot and it didn’t help.

Could this help me?
Could the pot they installed been bad?
Has anyone else experienced these issues?

I’m grateful for any help as I really would like to start enjoying the amp.

/Nico

Hi Nick
I bought an AH-500i with a dead right channel and successfully replaced the volume potentiometer (see post #320). The hardest part was finding the right pot. The pot in #320 is otherwise identical - the knob stays on fine and works great.

It's just possible that the workshop couldn't find the right part and substituted one with a different pinout. You might want to open the case and compare the pot you have with the picture in post #320.

Does the volume behave the same way on all inputs and outputs? Does it behave like a volume control at all, or more like an on/off switch?

It's not such a hard job to change the pot yourself if you can solder and have hand tools and some patience. (Take photos before disassembly! And remember to disconnect the power!!)

If it's not the pot there's an off chance it might be a loose connector. So if you're in there gently disconnect and reconnect the board to board connectors. Bad ground or signal return paths can sometimes cause bizarre symptoms!

If you want someone other than the dealer to fix it next time - get in touch. ;-)
Cheers
Big Ears

 

[niccav]

Thank you big ears

Is saw your post and it gave me hope.

Is that pot of good quality? I have reached a point where I rather pay for a good piece once rather than. Try several alternatives.

If you live in gothenburg or at least close by I'm very happy to accept your help.

They said they got an original part from teaching...

I will open it and see what I find. Can take some photos as well.

Thank you,
Nico

 

[niccav]

Does the volume behave the same way on all inputs and outputs? Does it behave like a volume control at all, or more like an on/off switch?

Well, something in between. It goes from 0 to "loud" quickly but then it keeps increasing the volume. For me it's already to loud at "1" at night time when I want background music. It's like there is no fine tuning at low volume

Yes it behaves the same on all inputs.

This is pot used after service, i.e. it’s the pot service installed.

 

[BigEars]

Well, something in between. It goes from 0 to "loud" quickly but then it keeps increasing the volume. For me it's already to loud at "1" at night time when I want background music. It's like there is no fine tuning at low volume

Yes it behaves the same on all inputs.

This is pot the inserted.
View attachment 24588

Hi Nico
Nice picture! This looks right so far. The whole assembly looks a bit cheap and primitive, but mine was the same when I opened it up and had look. The replacement pot from AliExpress looks similar, but it seems to give good results - although I've never tried the motor control part since I don't have a remote for it! Anyone out there got a spare remote they will sell me?

50KAx2 is correct per the schematics - 50kOhms end to end resistance on the pot, A for the type of audio taper (volume controls are non linear) and x2 for stereo, ie two channels.

Going a bit deeper... The round part at the top left is the motor - with a magnetic shield slipped over it. The rectangular part with the lettering is a gearbox and slipping clutch. To the right of this is the bit we care about most - the potentiometer. Interestingly your picture looks different from mine, and the AliExpress part in the picture I posted previously! If you refer to the Ali picture you'll see there's a small round silver part with 50KAx2 in blurry writing. Do you have one like this? Could be something, could be nothing...
I'd pop over and have a look, but I'm in northern England so its a bit far.
Big Ears

 

[BigEars]

...hmm maybe its not visible cos its buried in the front panel.

 

[BigEars]

is the volume problem the same on speakers and headphones?

 

[niccav]

Hm!

I would almost have to remove the front panel. Is it easily done?

I think so but I will connect some speakers and confirm. Until tomorrow when I have some more answers.

Thank you for taking the time to help me.

/nico

 

[Victor rODRIGUEZ]

https://www.vintageshifi.com/repertoire-pdf/pdf/telecharge.php?pdf=Teac-A-H500-Service-Manual.pdf
here is the service manual

 

[niccav]

is the volume problem the same on speakers and headphones?

So, I have confirmed that the issue remains when using speakers. Depending on music I would leave it between -60 and almost -45 for listening during the evening depending on music and recording. Almost always closer to -60 than -45.

I would leave it between -45 and -37 for some listening during day hours if I would want it quite a bit louder. It’s true that I rarely play loud; to give some point of reference, at, -26 it was really really loud.

Now to interesting discovery. It was much less pronounced when playing via a cheap DVD player rather than playing via phone-smsl m6-500i. I only tried one dvd (actually a movie. Only audio) since I couldn’t find any cd’s

I know I have some cd in the basement so I will try to find them tomorrow and try a few via the DVD player to see if my finding holds true.

If the issue lies with the smsl m6, is there a solution other than buying another dac?

I want a dac with several inputs as then I can use it for computer audio when gaming but also to stream music from the phone which is my primary source of music. I can’t just buy several dacs to see if one works as that would quickly become way to expensive and my wife would end me.

If there is a lighting -to- rca then I could confirm the issue is with the dac but it would create a new problem with lack of several inputs. Although I rather suffer from this issue than a faulty amp.

Ps, the imbalance remains also when using speakers. But less pronounced as 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.

I think that’s everything for now.

 

[niccav]

https://www.vintageshifi.com/repertoire-pdf/pdf/telecharge.php?pdf=Teac-A-H500-Service-Manual.pdf
here is the service manual

Thank you! I appreciate it

 

[niccav]

So, maybe my questions should be...

1. What dacs do you suggest. Preferable not more than 150 Euro. My prerequisite is that’s better than the one in the computer.

2. Since the imbalance is most audible at -60, can I presume a another dac will hide this issue once I can turn the volume pot further?

3. Do you have another alternative, suggestions?

Thank you