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Post by Deleted on Dec 29, 2020 1:11:54 GMT -5
As a beginner <--- that's even less experienced than a Novice tube amp guy I'm wondering how often tubes need be replaced? I'm seriously "inquiring" on McIntosh's MC275 stereo tube amp and wondering how many hours before I should expect replacing tubes? I listen to music/cinema for avg 3 hours a day at normal listening levels. I'm also debating whether to sell my Parasound Halo A31 at this time if decide to set my sights on the McIntosh tube amp. Question again, if I were to keep my Parasound and purchase the McIntosh are there such things as a switcher that I could go A to B without having to manually rewire the system? My thinking is it be nice to enjoy tube amplification for hifi audio and then switch to the Parasound for cinema..... Appreciate any advice, Shim Reference: www.mcintoshlabs.com/products/amplifiers/MC275B |
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Post by Deleted on Dec 29, 2020 1:19:10 GMT -5
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Post by garbulky on Dec 29, 2020 2:27:01 GMT -5
Those amps aren't gonna cut it for ya volume wise.
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Post by Deleted on Dec 29, 2020 2:36:40 GMT -5
Those amps aren't gonna cut it for ya volume wise. I'm thinking I'd be more than satisfied with the mains being powered by a McIntosh MC275. Just one Ulfberht in decibels: 99 db = 2 watts [2.83 volts into 4 ohms] 102 db = 4 watts 105 db = 8 watts 108 db = 16 watts 111 db = 24 watts 115 db = 48 watts That's pretty decent listening levels well within McIntosh's power ratings. Mind ya both 4-10 subwoofers have their own amplifiers. |
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Post by garbulky on Dec 29, 2020 5:01:36 GMT -5
Those amps aren't gonna cut it for ya volume wise. I'm thinking I'd be more than satisfied with the mains being powered by a McIntosh MC275. Just one Ulfberht in decibels: 99 db = 2 watts [2.83 volts into 4 ohms] 102 db = 4 watts 105 db = 8 watts 108 db = 16 watts 111 db = 24 watts 115 db = 48 watts That's pretty decent listening levels well within McIntosh's power ratings. Mind ya both 4-10 subwoofers have their own amplifiers. Every tube amp I've heard inlcuding one that had about 7 watts of power had enough power for me. But you went big for a reason. You want that slam and sense of speed. The tubes aren't gonna do that for you. I suggest trialing them before throwing serious cash at them. |
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Post by tropicallutefisk on Dec 29, 2020 6:42:51 GMT -5
I've only heard the MC275 on some large McIntosh speakers. I was pretty underwhelmed, but I feel its mostly because the MC275 was just not enough horsepower for the large Mc speakers. The imaging was awesome, the mids were pleasing and the highs were nice. What I didn't like was the bass and volume. The bass was very weak and it just never felt like it had the power to open up the speakers. However, it sounds like your Tektons are probably more efficient and results may be entirely different. Now that I am writing I remember another McIntosh setup with dual 75 Watt monoblocks. They were driving a pair of Wilson Sabrina's very nicely. Ample bass and it filled the room with sweet mids and highs as well. I should note it was a rather small, closed listening area which probably helped.
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Post by AudioHTIT on Dec 29, 2020 9:10:23 GMT -5
To answer your original question, it somewhat depends on how the tubes are biased, whether it is an aggressive or conservative design. I had an MC275 (many) years ago and even took it to the fabled “Mac Clinic” where they measured and repaired any defects (for free, including tubes). As I remember they replaced one tube after many years of use, which is to say Macs are well built and have stable circuitry (a generalization). With my VTL MB450s I replace the power tubes every 4 to 6 years, they’re also on a dedicated 2-channel system and don’t get near as much use as you’re indicating,
It should also have plenty of power for most listening with your very sensitive Ulfberht. I think it will all come down to how you like the sound compared to the Parasound, certainly worth a try. I’m leery of switching amp outputs (with its autoformers the 275 shouldn’t mind), but I know many have done it successfully, so no real advice there. (I think the difference in sound will be great enough that you won’t need a direct A/B)
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Post by audiobill on Dec 29, 2020 9:26:02 GMT -5
The issue with speaker switching is even a small amount of resistance or capacitance may affect frequency response. Like changing crossover component values...
Also, tubes absolutely don't like an open load.
I've been exploring using sealed, gold plated high current relay switching for this very purpose....
Why not ask the Tekton designer his thoughts?
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bootman
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Post by bootman on Dec 29, 2020 9:39:47 GMT -5
Why not ask the Tekton designer his thoughts? +1 Tekton makes speakers specifically designed for tube loading (Perfect SET) and they are similar in sensitivity but are 8 vs 4 ohm designs. It may be that the MC1502 might be a better match for your speakers. But I would trust the designer first.  |
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Post by audiobill on Dec 29, 2020 9:56:05 GMT -5
I think the MC1502 may be way overkill for the very efficient Tektons (and $$$$$)!
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Post by audiobill on Dec 29, 2020 9:58:22 GMT -5
Those amps aren't gonna cut it for ya volume wise. Not at all the case. |
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Post by garbulky on Dec 29, 2020 10:20:32 GMT -5
Those amps aren't gonna cut it for ya volume wise. Not at all the case. Did you watch his spl video at listening distance? Going in the upper 90s at listening distance (cleanly with guts) even is going to be a tough sell. Now try 120 db listening distance ...which he likes to do. Those tubes will bust! |
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Post by audiobill on Dec 29, 2020 10:32:51 GMT -5
Gar, perhaps you missed this in his post, or do you have additional information to share with the group?
"Just one Ulfberht in decibels:
99 db = 2 watts [2.83 volts into 4 ohms]
102 db = 4 watts
105 db = 8 watts
108 db = 16 watts
111 db = 24 watts
115 db = 48 watts
That's pretty decent listening levels well within McIntosh's power ratings. "
And, from Stereophile:
"With each tap's nominal value matched to the load, the McIntosh amplifier more than meets its specified output power of 75Wpc (18.8dBW), with 90Wpc available from the 4 ohm tap at clipping into 4 ohms (16.5dBW), 85Wpc available from the 8 ohm tap into 8 ohms (19.3dBW), and 92Wpc from the 16 ohm tap into 16 ohms (22.65dBW). (Clipping is defined as 1% THD+N.) These graphs show that the distortion remains well below 0.1% as long as the nominal tap value is equal to or less than the load impedance."
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Post by lhracing on Dec 29, 2020 12:02:07 GMT -5
I have a poor man’s tube amp, the Jolida Integrated JD 502CRC which is rated at 60 watts, I typically use it with my JBL L300 speakers which are 93db rated. This combination can play very loud and sound great so the MC275 should be fantastic. I also use a switch to change from my tube amp to my XPA-1L’s which may not be the best idea but I have not had any issues.
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Post by brutiarti on Dec 29, 2020 12:27:30 GMT -5
Did you consider adding a tube preamp and keep the Parasound??
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Post by ttocs on Dec 29, 2020 13:59:26 GMT -5
@shimei I'd be leery of using a switcher for the the reasoning audiobill pointed out, plus, push-buttons like that switcher has don't lock out possible double switches from being engaged. You can push two buttons and engage both. About the simplest and possibly the best I can think of is the ancient knife switch. You still gotta make certain each tube amp has no way of turning on when it's not married to the speaker. |
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Post by Deleted on Dec 29, 2020 14:34:46 GMT -5
Did you watch his spl video at listening distance? Going in the upper 90s at listening distance (cleanly with guts) even is going to be a tough sell. Now try 120 db listening distance ...which he likes to do. Those tubes will bust! With mains receiving 48 watts: One Ulf plays at 115 db. Add a second Ulf and that's now 118 db only for the mains. The subs play 10 db louder than the mains. Altogether 48 watts to mains w/ both 4-10s should be: 118/128 db. That's about the maximum I play the system in rare occasions when having the house to myself. Sharing videos I have makes it seem I'm always listening at those high volumes but that's not the case. Realistically I listen far less in volume as my wife works from home during the day. Power wise I'm pretty confident that 2x75 watts are more than enough. I noticed one reviewer stated McIntosh delivers its power into 8, 4, and 2 ohm loads. 2 ohms was my concern because Ulfberhts do dip down to 2.3 ohms in the mid bass region. Good advice, next week I'll visit the local McIntosh dealer. I'm losing too much money by buying equipment while trying to save money. After depreciation etc I end up paying more than if I purchased top tier equipment to begin with. McIntosh appeals to me for not only its reputation but also resale value. I really haven't heard anyone saying I can't live with McIntosh equipment after already an owner. Looking at the pricing from McIntosh's MC275 to MC1502 w/ doubling wattage for 3db increases comes w/ doubling the price. |
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Post by audiobill on Dec 29, 2020 14:46:11 GMT -5
Be sure to wear ear protection at those levels!!!
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bootman
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Post by bootman on Dec 29, 2020 15:08:33 GMT -5
One note about sensitivity ratings. Its measured at only one frequency (usually 1k) and does vary greatly between 20-20k. So when you hear "tubes sound thin with bass" what they usually mean is my speakers are about 10-15dB less sensitive at 100 Hz vs 1kHz without even realizing it. So that 1 watt at 1k would need 100 watts at 100Hz for the same level in a 10dB difference example.  |
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Post by bluemeanies on Mar 22, 2022 18:50:17 GMT -5
I have a poor man’s tube amp, the Jolida Integrated JD 502CRC which is rated at 60 watts, I typically use it with my JBL L300 speakers which are 93db rated. This combination can play very loud and sound great so the MC275 should be fantastic. I also use a switch to change from my tube amp to my XPA-1L’s which may not be the best idea but I have not had any issues. I used a homemade switch boxes between my 2channel and HT…NO ISSUES for years. Making that point I am in the process of purchasing an integrated amplifier…i intend to NOT use the switch boxes and manually use both sets of cables. PS…if you are thinking of upgrading from poor man to rich man 😂 I am selling two High End pieces…CONRAD JOHNSON…check out the Emporium. |
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