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Looking for advise regarding Rogue M180’s

  Last week a friend gifted me a pair of Rogue M180’s. They were sold as 180’s and I received them from the original owner. Im guessing them to be 10-12 years old. They were used when first purchased for about 5 years sparingly. Since then they have resided on a flat dolly in a spare bedroom. The amps still have the original Phillips ECG 5751 and 5814A’s installed. The original EH KT 90’s are loose in a box with an octet of low hour Gold Lion KT-77’s . Years back when in use the owner contacted Rogue and stated they were too powerful for his room size and speaker selection. Rogue responded by recommending the GL KT77’s and suggesting that he could also lower the bias from 40ma to 30ma. I was provided the supporting emails dated September 2019. Here is my situation followed by my questions. I currently have a low power single ended system with Zu speakers. Second,  the owner stated one might have a hum, but was not sure. He’s on his second complete system since and has a room full of gear he’s lost interest in and his memory is vague. Also back then he had power issues with his provider and stated they installed a new transformer on the street. So my questions are first, checking for any hum. My intent is to take a single amp and connect one JBL 4312 to it. Install the KT77’s, plug it in and listen for a hum and bias the tubes. Do I need the input open or shorted ? Or something else ? Second, the 12AX7’s being replaced by the 5751. I see there’s a mu of 70 Vs 100 with the 12AX7. Does that effect the overall output power of the amp or just change tone and distortion? FWIT I have 6-7 pairs of NOS Telefunken 12AU7’s but zero 12AX7’s. My intent is to check for hum without causing any damage. If a hum exists, I’ll ship to Rogue. In the short term if I’m successful, I’ll test drive with my existing Rogue RP-1, the JBL 4312A’s that are mint and the 26” Sound Anchor stands I have with them. And I’d like to get some Telefunkens to put in the 12AX7 positions. After that, there’s a pristine Rogue Hera that’s been inspected and re tubed  by Rogue that I’ll ask to purchase before I start looking for speakers worthy of the pairing. Also I emailed Rogue for support a week ago and have not received a response. Thanks in advance for any feedback and my apologies for grammatical spaghetti, but I’m limited to an IPhone. Cheers , Mike B. 

buellrider97
mulveling's avatar
mulveling
2,232 posts
 

Nice, factory packing for $60 each is well worth it! Many audio companies charge HUNDREDS for the same quality of packing. Example: boxes for my Clearaudio Master Innovation table cost almost $900, ugh. This is a key advantage of Rogue - they won’t try to rip you off.

I previously neglected to weigh in on speakers. Well, I’ve been a Tannoy DC (dual-concentric drivers) fan for 20 years and that’s what I’ve used, across several models. I haven’t tried the new Chinese-made stuff, but amazing sounding Scottish Tannoys can be had for good deals on the used market, if shipping can be figured out. Even some of those late 90s - 2000s models (including pro models) are bangers. There are a few models I’d avoid like the oddball DC10A, which were voiced wrong imo (bright). You can also look at Fyne but the deals on older Tannoy are great. The DC drivers come in "tulip" (ceramic) and "pepperpot" (alnico) variants, with the latter being much more expensive, but the tulips are great in their own right. Tulips are usually better behaved in treble and well-balanced overall; pepperpot/alnicos have a super vibrant midrange. There are lots of popular vintage Tannoys too (all pepperpots), which I never waded into. Fyne has made a new version of the DC they call "iso-flare" and I haven’t heard it. The few Tannoy-Fyne comparisons out there usually prefer Fyne (possibly upgrade bias) but also attribute them as being "more detailed", which honestly sends me running in the other direction lol. As usual, we just need to hear for ourselves to make sense of it.

Sonically the pairing of Tannoys with any Rogue tube amp, and Hera preamp, is excellent. The newer RP-9 preamp's treble was not a good mix with pepperpot tweeters imo (too much, ouch, etc). Tannoys are moderately efficient so the high gain of Rogue tubes does come into play, but I’ve always tolerated it.

I also hear the pairing of Vandersteen with Rogues is superb!

hiend2's avatar
hiend2
482 posts
 

Been following your thread. Good luck to you and rogue service is great.

As you found out on the phone call they take ll this stuff very seriously.

I have an issue with the  old 120 put a output tube in incorrectly due to a broken off center pin. So I smoked the one amp

I called rogue they directed me what to look for and I actually fixed the amp with a couple of resistors, I sent the amp to them for a checkout of course

Ivve been thru the line 120, 150, Zeus, now appllos,

I upgraded the Caps to the Dark level here and Am very Happy with them,

Rogue will gey you there whatever you choose, Great crew there Really.

Interesting of what they find and you decisions are, cant wait to hear.

buellrider97's avatar
buellrider97 OP
646 posts
 

@hiend2 , Thanks for you’re input. I started to pull the cover on the one that’s having issues just to have a look. Unfortunately the screw didn’t want to budge and started to loose the head, so I stopped. I didn’t want to start whacking them with a mallet and you certainly can’t heat them like we do on motorcycles, so I just left it alone. Last month I received my Yiggy back from Schiit due to a failed USB card. And it was in a new chassis as the tech broke off the screws holding the board to the chassis. Considering I want the boards updated and brought up to spec they’re best just shipped. I would like your input on power tubes and speakers. I have a relatively fresh set of GL KT-77’s and in my mind they’re glorified EL-34’s. Down the road I’ll be considering KT-120’s and GL KT-88’s. So any input especially speakers is appreciated. Regards , Mike B. 

buellrider97's avatar
buellrider97 OP
646 posts
 

@mulveling    Hi all, here are todays updates. I received my boxes from Rogue and will pack and ship to Rogue for the repair and the Dark upgrades. Also I’d like to mention that I obtained the Hera II from the owner of the amps. Back when the amp had a problem the owner shipped the Hera to Rogue for a checkup and it received a clean bill of health. A fresh set of Sovtek tubes were installed that are graded by Upscale Audio. I’m not sure if Rogue or the owner replaced them. Also included with the Hera are the original set of tubes and the metal remote along with factory packaging. The Hera looks like new and hasn’t been used since the trip to the factory. I paid $2K for it, which seemed pretty fair. Another interesting fact is the Dark upgrade no longer includes NOS small tubes. They are using better grade new production which I’ll still replace. I’m planning on all 6 small tubes being NOS Telefunkens. Regards , Mike B. 

hiend2's avatar
hiend2
482 posts
 

Hey, cool your doing the dark upgrades! I listen to the  Apollos regularly have them in a Bi-amp setup them on top and am amazed on the added resolution I get over the krell monos That I can swap in.

So Factory no longer send NOS input tubes thats okay, think they had Clear top rca and teles. I have over here Nice sweet 5751's sound quite good in there have them all as well  kt88 Gold Lion  kt90 Electro and kt120 Electro all have a certain signature the Gold lion are smoothest.

Please keep us informed on your factory upgrades!

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