Audio Research Ref150 SE

[opm]

Hello, I recently bought a used Audio Research Ref150 SE with a usage of 2100h. I must say that I am delighted with this amp, it has explosive dynamics, incredible punch, and first-class vibrancy and realism.

As I am new to the world of tubes and AR, I have some doubts.

When I bought the amp I asked the previous owner if he had checked for bias and he told me that he had never done it in 5 years and he didn't know how to do it. When I got the amp the first thing I did was check for bias and miraculously it was pretty cool. Since 1 month and about 100 hours of use have already passed, I have rechecked the bias and adjusted it with the following values:
Channel L: V5 = 65, V7 = 63, V9 = 65, V11 = 62
Channel R: V6 = 65, V8 = 50, V10 = 65, V12 = 64

1. Should I be concerned about the value of the V8?
2. When valves wear out, what indication is there in the sound?
3. I have read that it is recommended to change the valves by an official AR service but they are very expensive. Worth it? Or can you buy combination valves on the Internet?
4. Can the life of the valves be extended to 3,000h without worry?

Regards,

 

[Argonaut]

Congratulation...The Ref150 SE is a fine amplifier.
Hmmm, yes, that V8 KT is a tad on the low side, V6 is master to V8 and you have it biased spot on however the slave in that pair V8 should be reading 57- 73mVDC, It may indicate a problem with the valve however it may indicate a drift in its associated bias resister.
I cannot remember whether V6 and V8 share a common bias resister but I think not As you can bias V6.

I would advise emailing ARC tech support, they are pretty helpful

 

[microstrip]

Hello, I recently bought a used Audio Research Ref150 SE with a usage of 2100h. I must say that I am delighted with this amp, it has explosive dynamics, incredible punch, and first-class vibrancy and realism.

As I am new to the world of tubes and AR, I have some doubts.

When I bought the amp I asked the previous owner if he had checked for bias and he told me that he had never done it in 5 years and he didn't know how to do it. When I got the amp the first thing I did was check for bias and miraculously it was pretty cool. Since 1 month and about 100 hours of use have already passed, I have rechecked the bias and adjusted it with the following values:
Channel L: V5 = 65, V7 = 63, V9 = 65, V11 = 62
Channel R: V6 = 65, V8 = 50, V10 = 65, V12 = 64

1. Should I be concerned about the value of the V8?
2. When valves wear out, what indication is there in the sound?
3. I have read that it is recommended to change the valves by an official AR service but they are very expensive. Worth it? Or can you buy combination valves on the Internet?
4. Can the life of the valves be extended to 3,000h without worry?

Regards,

Yes, the V8 is too low - probably you need a new valve. Swap V5 with V6 and V7 with V8 - if the problem persists with the same tube you need a matched replacement.

You need matched quads for IP at 65 mA - several sellers can do it. Do not risk going over the recommended time - you risk burning the cathode resistors, the amplifier has no HV fuse.

 

[opm]

Yes, the V8 is too low - probably you need a new valve. Swap V5 with V6 and V7 with V8 - if the problem persists with the same tube you need a matched replacement.

You need matched quads for IP at 65 mA - several sellers can do it. Do not risk going over the recommended time - you risk burning the cathode resistors, the amplifier has no HV fuse.

I will try to change the valves as recommended and I will report the result.

If only the V8 valve fails, do I have to change all 4 of the same channel?

Can you recommend a reliable internet shop in Europe that serve paired valves? it is not necessary to go through the official technical service?

 

[opm]

I have made the changes you have suggested and the problem persists. The reading is 50mV.

 

[Argonaut]

“I Refer the Honourable Gentleman to the Reply I Gave Some Moments Ago in this house”

 

[opm]

Congratulation...The Ref150 SE is a fine amplifier.
Hmmm, yes, that V8 KT is a tad on the low side, V6 is master to V8 and you have it biased spot on however the slave in that pair V8 should be reading 57- 73mVDC, It may indicate a problem with the valve however it may indicate a drift in its associated bias resister.
I cannot remember whether V6 and V8 share a common bias resister but I think not As you can bias V6.

I would advise emailing ARC tech support, they are pretty helpful

thanks for your reply.
I just spoke with AR and he told me that I can replace only that tube, as long as it matches the grade, which is written on the base. in this case 363 130.

 

[Argonaut]

Thats just grand, hopefully the V8 bias circuit will run the new valve at spec , If not you are likely looking at the bias resister, lets hope not.

I have found ARC‘s tech support guys to be incredibly helpful whether one is the original purchaser or not.

 

[microstrip]

The reading is 50mV.

But with the same tube, that is now at position V7?

 

[opm]

But with the same tube, that is now at position V7?

Yes

 

[Addicted to hifi]

Hello, I recently bought a used Audio Research Ref150 SE with a usage of 2100h. I must say that I am delighted with this amp, it has explosive dynamics, incredible punch, and first-class vibrancy and realism.

As I am new to the world of tubes and AR, I have some doubts.

When I bought the amp I asked the previous owner if he had checked for bias and he told me that he had never done it in 5 years and he didn't know how to do it. When I got the amp the first thing I did was check for bias and miraculously it was pretty cool. Since 1 month and about 100 hours of use have already passed, I have rechecked the bias and adjusted it with the following values:
Channel L: V5 = 65, V7 = 63, V9 = 65, V11 = 62
Channel R: V6 = 65, V8 = 50, V10 = 65, V12 = 64

1. Should I be concerned about the value of the V8?
2. When valves wear out, what indication is there in the sound?
3. I have read that it is recommended to change the valves by an official AR service but they are very expensive. Worth it? Or can you buy combination valves on the Internet?
4. Can the life of the valves be extended to 3,000h without worry?

Regards,

welcome to wbf . when valves wear out you will loose in clarity, resolution and detail.the sound will be dull.its easy to tell when they need replacement.

 

[Addicted to hifi]

What I don’t like about valves is they continue to work even if they are worn and need replacement.I owned a audible illusion 3a preamp and the sound quality had deteriorated very quickly and needed new tubes every 3 months.I found out later that this preamp chewed tubes up quickly.

 

[Another Johnson]

Yes, that’s a strong argument in favor of replacement by the clock rather than at acute need. But because valves are expensive, many people are reluctant to toss one if it hasn’t red plated.