@fsonicsmith - sorry if I blinked and missed something, .... but what happened to your Ref 150SE? Did you get the Ref 80S yet? If so, did you get a chance to compare the 150SE to the 80S?
I took the same journey. My Ref 150SE needed an expensive repair (start-up circuit needed a thermister and solenoid switch). I decided to go the Ref 80S route as noted above. My 80S is pretty much broken in now and sounds terrific. I don't have a good sonic memory, but I think it sounds incrementally better than the 150SE. As noted by me and others, I like the circuit enhancements, especially the fuses on the KT-150s. I suffered through blown bias resisters in the past and it is no fun to soldier in new ones.
I look forward to hearing your reactions.
BIF
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@fsonicsmith - can you share some updated impressions on the Ref 80S. How does it compare to the Ref 150SE?
Thanks
BIF
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@fsonicsmith - I agree that phase angle is important. If the speaker's phase angle is highly capacitive at low frequencies and the impedance is also low, most techs would say that the amp should be able to produce a lot of current to get the speakers to hum. I am not sure I agree with your comment that speaker sensitivity means little. I surmise that my Ref 80S can drive my S8s with little trouble because the S8s are very sensitive (92db).
Let me challenge point you about finding an authorized ARC service center. Greg made a few suggestions to me last year. I have no reason to believe that the situation has changed. Best to call Greg.
Last, .... if you don't mind, what specifically is ailing your amp? Do you know? What is the problem?
Most of the passives (resisters, caps, etc) are low tech items. If something in the power supply regulation circuit went bad, ... that could be a different story because the Ref 150SE has a solid state power supply. It may be that a qualified tech could do the fix if the problem is not that technical. Again, ... best to call Greg.
BIF
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@fsonicsmith - is there an epilogue to the 150SE situation? Did ARC suggest next steps? How about a local ARC authorized service tech.
Even if the repair is properly done, I would expect that the tech would thoroughly bench test the 150SE to make sure it was operating at factory spec.
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dhite71 .... I just picked up a Ref 80S about 2 months ago. My old amp was an early build Ref 150SE, which was getting long-in-the-tooth. The 80S is basically one-half of a Ref 160S, but has all the other bells and whistles. I have racked up about 200 hours on the 80S so far. Although ARC says the amp requires up to 500 or 600 hours to fully break-in, I surmise that any incremental improvements in SQ will be more nuanced.
I bet your Ref 75SE sounds almost the same as the 150SE, ... just half the power. If you run highly sensitive speakers, the 75SE likely drives them with little effort. My speakers are rated at 92db sensitivity and the 80S does a fine job of driving them.
And incidentally, my 150SE was originally an early build 150. ARC did the SE upgrade about 6 years ago. The SE upgrade made a huge difference. So it would not surprise me if your 75SE sounds even better than your old 150.
By way of comparison, IMO, my 80S has a somewhat more refined presentation than the 150SE, but we're talking about maybe 10% to 15% or so better. The mids and highs are slightly more detailed, ... sharper. Maybe even sweeter, but not rounded or "tubey" by any means.
The bass is surprisingly tight for an amp that has one-half the power of the 150SE and a lower damping factor (8 versus 14). Not sure I understand why that is so.
Oh, ... and I really like the 80S' auto-bias and the push-button tube check features. The KT-150s drift and I didn't love manually checking and adjusting bias on the 150SE. The 80S does bias adjustment automatically. The 80S can play in triode mode too, but I kinda' like the old-fashioned ultra-linear mode.
One other nice feature is that the amp has a restart delay protect feature. The feature delays restarts for 2 mins after shut-down, which protects the circuits from an overload until the PS caps discharge.
In summary, IMO, based on my experience with the 150SE, I bet the 75SE is no slacker by any stretch. So I get you point about waiting for the 80S SE to come out. ;) That said, I think for those who are in the market for a tube amp, the ARC Ref 80S and 160S are amps to really check out. They are truly wonderful amps.
BIF |
dhite71 ... If your >1000 spec relates to the Parasound HCA 2200ii's damping factor, I surmise that the Parasound was a transistor amp, possibly with lots of negative feedback, thereby resulting in a near zero output impedance.
The output impedance of the Ref 75SE and Ref 80S is about 1 ohm in the low frequency space off the 8ohm tap, thereby resulting in a damping factor (DF) of 8 if the corresponding speaker input impedance is 8 ohms in the same low frequency space. By contrast, the Ref 150 had a DF of 14 off the 8 ohm tap.
My layperson understanding is that a "high'ish" DF helps to control the woofer and is a factor in yielding tight bass. I recall reading posts from some of our A'gon tech members that a DF over 20 does not incrementally add all that much by way of woofer control.
That said, I am sure that DF is not the only spec that drives quality bass. If Ralph Karsten (Atmasphere) catches this post, maybe he will explain (again) the various tech factors that contribute to quality bass. Such factor include, for example, in large the quality and input impedance of the speaker itself. For example, if a speaker has an input impedance of 16 ohms in the low frequency space, the DF would be approximately 12 if, for example, the amp's 16 ohm tap's output impedance is say 1.3 ohms.
In any case, enjoy your 75SE. It is a great amp!! |
@fsonicsmith
See my responses below:
- Although every loudspeaker is (duh) different, what is the nominal impedance of your Paradigm Sig S8 V3’s and what tap did you find best?
Response: The S8 (v3) nominal impedance is 8 ohms, but that is misleading. The impedance and phase angle curves are all over the place, ... like most modern speakers that are voiced to be driven by a solid state/low output impedance amp. More important I think, .... the S8s are rated at 92db sensitivity. The 8 ohm taps seem to work best, ... on both the 150SE and the 80S. The high sensitivity makes the S8s a good fit for the 80S.
- Did you play around at all with power cords? And related to that, are you going to through a power conditioner or straight to the wall?
Response: No playing around with power cords. I use stock cords. No power conditioner.
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@fsonicsmith .... did you consider using an ARC authorized service center? Greg should be able to give you some names. I am still not clear about what ails your amp, but the 150SE circuitry is not rocket science and there are probably only a few key parts that go bad. The real cost is labor.
My main problem was that the 150SE amp is heavy and bulky. The ARC tech guy I wanted to use would not lift the amp, so I had to schlepp it to his location. That was a nonstarter for me, ... but maybe not an issue for you. Also, if you need fresh KT-150s, consider Upscale Audio and be sure to let them know you are matching pairs for a 150SE. The matches should be pretty tight.
Let me know how you make out.
BIF
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@fsonicsmith - unless I am mistaken, which may be the case since I am not a tech, you have the same problem I had. The plastic cover of the slow start circuit fuse is burned. If so, the solenoid start switch and thermister need to be replaced.
This is not a cheap repair. An ARC service center tech quoted me $1K.
Did Evan or Greg share their impressions of the pics you posted? If my guess is correct, I was told that the whole circuit board needs to be lifted and the underside inspected. For a couple of parts costing less than $50, that could be a lot of labor.
Please advise. |
@fsonicsmith - agree with ghdprentice re change in sound refinement. The 80S will open up. In my experience, ... just like ghdprentice said. I look forward to your comments on the 80S in general after 200+ hours and also how the 80S compares to the 150SE.
Enjoy the amp. I think you will be pleased.
BIF
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@fsonicsmith - thanks for the update. My 80S has several hundred hours on it. The sound will get even more refined. I think the lower bass registers even tightened up too.
ARC made numerous circuit changes in the 80S. Perhaps a very important one is the auto-biasing function. Maybe the KT-150s operate in closer sync because the bias of each push-pull tube is more tightly aligned. That is just a guess.
Please report back after you rack up more hours.
BIF
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