LP140M

[penbeck]

I am based in the UK, and have recently acquired a pair of CJ LP140Ms.
Are there any cost effective improvements that can be made to these amplifiers ?
I have full sets of :
Svetlana 6550C winged
Psvane KT88
Golden Dragon KT88
Tung Sol KT120 and KT150

At present the KT120s are installed.

[admin]

Welcome to CJO, great to have you with us.

Congrats on the LP140Ms, very nice indeed. Not sure what improvements you are looking for? Those are pretty nice amps and not that old that they would require a recap. I probably wouldn't do to much to them other than enjoy the sweet sound.

Again, welcome.

[AnotherJohnson]

I think they could be improved with the full Teflon cap upgrade. RJ probably can give you extensive advice on the LP140Ms.

[penbeck]

There has been a suggestion made, that changing the internal fuses to audiophile quality would make a huge difference. However, I am rather sceptical about changing fuses and the like, possibly through naivety.

[admin]

There has been a suggestion made, that changing the internal fuses to audiophile quality would make a huge difference. However, I am rather sceptical about changing fuses and the like, possibly through naivety.

I would be pretty skeptical myself. I've never found fuses making a "huge" difference. You can cryo them, soak them in unicorn tears, and have the pope bless them, but I would temper your expectations. YMMV.

Certainly doesn't hurt to try them but I would buy somewhere with a return policy if you plan to drop big $$$ on fuses.

[AnotherJohnson]

Joe Apierto has positive experience with audiophile fuses and might offer advice.

The PS Audio Forum has a lot of committed fuse aficionados. Paul McGowan himself seems to be a believer.

I went within a foot of the edge of that canyon last year, but decided not to step off the edge. I’m too conservative, and would be uncomfortable using a protective device that had not been recommended by the manufacturer.

Lots of people do report wonderful things.

Power cords are another playground, and I’ve been impressed by the AQ Hurricanes for my ARC amps.

[Joe Appierto]

The topic of fuses may be a bit contentious.

That having been said I have had positive results changing the external (plate and/or mains) fuses on CJ equipment. Should you decide to go down that path only use fuses of like type (slow or fast) and amperage. Do not use a fuse with a higher rating than what the manufacturer recommends. I believe that most vendors will not offer a refund if you're unimpressed although I believe Synergistic Research does offer a 30-day trial period. Check before you purchase.

Power cords are another avenue as AJ suggests that will yield beneficial results.

[penbeck]

Thank you for all your replies.
Any thoughts on tubes ?

[Joe Appierto]

You already have a nice assortment. One type I enjoyed when I owned the Premier 140 (a different design from the LP140M, I believe) was the New Sensor Genalex Gold Lion KT-88. That's assuming you can find them at a cost less than a king's ransom. Some members may suggest sticking with 6550 types as they were OEM.

[Big Dog RJ]

The LP series amplifiers are designed very well, with rock solid power supplies and high quality parts, they can be modded towards extraordinary performance. However, this takes a lot of skill, experience and knowledge to do so, so unless you have access to such a techie, I wouldn't recommend it. Other than the usual owner upgrades: KT120's and higher grade power cords. Just go for the best you can afford. I use exclusively Nordost and they're bloody expensive but they're superb!

A few years ago, JF offered the full SE upgrade kit for the LP series amplifiers. This included:
KT120's, Teflon caps and Vishay resistors.
This was around 2018... so nearly 5yrs ago. This particular full SE upgrade kit is no longer offered. Mainly due to the Vishays being very costly that were reserved for the ART series amplifiers. Teflons were available but again it depended on which LP series amplifiers you had. The larger the LP series amps, the more Teflons were required, hence the cost goes right up there!

Just for those upgrades on the full SE version that I did, cost me a pretty penny. All up, it was close to 8grand. About 4grand per monoblock, so this is quite a serious spend and something you need to consider when you're going to sell these amplifiers. Simply because that cost in SE upgrades cannot be recovered. It's a lost cost, and whoever the new buyer is, simply doesn't care about SE upgrades... as a used item, all he/she cares about is the used price.

Therefore, I'll never sell my LP series amplifiers, and I've modded them further towards a higher Class A bias, which did cost another damn pretty penny. Hence, I can never recover those costs... might as well just keep them and that was my sole intention towards these upgrades.

You really need to give it some thought, other than just dumping hard earned money and going ahead with upgrades. Also, depends heavily on what type of speakers you're using. Since I'm using ML CLX's, they absolutely love Class A bias output from fine tube gear. They can sound pretty good with most other types, Class AB, Class D or SET but they just shift gears onto another dimension when driven in Class A. So that's something you need to consider.

The assortment of tubes you have are fine, and will give you different flavours/ options, not necessarily improve on performance of the amplifiers. Overall, the KT120's operating in ultra-leaner power pentodes, will give you the best drive and control factor both in terms of detailed dynamics and and full control of impedence swings, if your speakers are difficult to drive.

I wouldn't use KT150's in there, they require a slightly larger version of power supplies. The KT150 tube requires more of everything, plate voltage, currect dissipation etc , the trannies on the LP series amplifiers are wired in such a way to accommodate most of the KT series tubes, plus 6550's. Not the KT150, this is a much larger tube and requires a few mods on the main circuit to accommodate their parameters without damaging the amplifiers.

The only CJ amplifiers that can handle or are meant to accommodate the KT150 topology, are the ART150 and ART300's, nothing else!

Just check with JF and ask him if he still offers the full SE upgrade kit for your amplifiers and see what he says. If so then who does the upgrade? Can he send you the kit/s? Or do you have to send your amps to the UK importer (Branko) and have him do the upgrade...!!! Good luck with Branko! After what he did to Matty (an absolute disaster) I wouldn't touch Branko/ Audio Freaks, with a 10ft pole! No thanks.
OTOH, JF may say yes, and ask for the amps to be sent all the way to VA USA... that will also cost a pretty penny!

See how you go... I think the best advice so far, like a few valuable members have already said, just enjoy the amplifiers the way they are.
All the best, RJ

[SolderSlinger]

PENBEK -

The LP140M is loaded with Teflon capacitors and Vishay resistors. There is not a "SE" upgrade because they already have the same parts. Just like there is no ART SE. The ART has Teflon and Vishay, and so does the LP140M. It was designed and manufactured before CJ started to cost thrift products. The later series LP125M, LP66S, LP260M are offered in two versions, the SE is the second version. The dual model approach is still used in the current Classic amplifiers.

Have fun and roll some tubes. V1 has the most effect. I'm not a fan of the KT120 tube in the LP140M. It was voiced with 6550 tubes. In my home with Quad ESL2905 speakers, I like the Russian Tung Sol 6550.

[Joe Appierto]

You are one of the few, actually only one besides me on this forum I think with a preference for the New Sensor Tung-Sol 6550 over their KT-120. I used to own the earlier stereo version, the Premier 140, and as nice as the KT-120 sounded, I thought the NS Tung-Sol 6550 were more to my taste. The original Premier 140 came OEM with SED =C= 6550C but the later Tung-Sol 6550 were a good substitution in my opinion.

Nothing, and I mean nothing, were as good as the original Tung-Sol 6550 (any of the three varieties) but then they invented the tube.

EDIT: My speakers at the time were QUAD 989.

[AnotherJohnson]

Although there were never any formal SE models in the first round of LP amps from CJ, JF implied to me that there were upgrades beyond the KT120s that he’d done on mine (aka solderslinger’s ).

I never thought much about it, but RJ has said more than once that his LP140 had been treated to the last upgrades that CJ had been willing to send to his technician in OZ.

I know that there are Teflon caps and Vishay resistors already in the first LP series, but there are polystyrene and polypropylene too. It can be confusing because the other plastic caps CJ uses look like they’re Teflon… JF told me the only way to tell the difference would be to weigh them.

There’s quite a bit of myth and magic behind all of these internal components. For me, the biggest issue was that infernal ground loop that came when everything wasn’t on the same power strip.

In the McIntosh history book they talk about this single power strip issue in several separate interviews as a serious negative that guided their designs to “balanced.” I’ve never run into this issue, or the single power strip recommendation, from any other manufacturer… but the others have all moved on to balanced. McIntosh, with their large government, radio station, and industrial amplifier customer base just states clearly that single ended would never be accepted in the professional use world. Of course, they are right.

[Big Dog RJ]

Yes, that's correct AJ mate, good point.

Also just to add on Joe and Solder-S preferences with the 6550's, I can certainly relate to that. When we first took delivery of the entire Premier series top of the line, starting with the Prem11A, Prem12's and finally onto the Prem8A's, they were all fitted with the 6550C version Output tubes.
They drove several types of speakers from Infinity's IRS 1B's, Epsilon, Renaissance 90's, to Maggie's 3.5, 3.6, and MG20 then finally onto the Apogee Diva's, which were the best we had at the time. Partnered with the ART preamp, it was absolutely tops!

We also put together several systems comprising of the Prem11A and Prem12's with Quad ESL's, and matched with either the PV12 or PFR preamps at the time. All those customers were happy as! Some of them still have those very first CJ and Quad systems we offered them, and this is going back to 95-98... great memories.

At that time the KT120 had not been developed as yet... although there was the KT90, which sounded fabulous on the VTL Wotans and Manley Labs amplifiers. It was only after 2004/05 that we got news about a new KT series tube. Then I closed the business and migrated to Oz. Only around 2006/07 thereabouts I tried out the KT120's for the first time on a MV60SE, which was recommended by LJ. Said that I should experience a "fuller sound."

So, naturally my previous dealership mates were all very eager to try out this new KT120 on their CJ Premier amplifiers. None of them liked it! Regardless on what they tried; Prem11, Prem12, Prem8, Prem140 and MV60SE, none of them liked it. So they all went back to the 6550's and most stayed with the SED 6550C type. I would agree, they were just about perfect in those particular Premier series amplifiers. CJ had perfected that design.

Only after the new LP series was introduced, plus the new Classic series, the KT120 topology was fully optimised in these amplifier circuits. They took the full advantage of the attributes of the KT120's higher power handling and the ability to hold a much higher Class A bias compared to the 6550 type. And that's another reason why I was given the certification to proceed with higher Class A bias operation on my monoblocks, merely because the KT120's are capable without breaking up, even at very high volumes. If this was not the case, I would have never done those mods and just stuck with 6550C's.

So yes, I wouldn't recommend modifying or upgrading the LP140M's and I think that's what we've all advised the OP on. Only thing is, we never heard from the OP after my last post... most probably enjoying those fine tunes!

Cheers, RJ

[Joe Appierto]

Thank you for filling in the back story, RJ. Never having progressed beyond the Pr. 11A and then the Pr 140 that helps explain my preference for the 6550 type. I don't feel like so much of a contrarian any longer.

[Big Dog RJ]

Ha ha! Good point Joe mate.
Woof! RJ

[penbeck]

Thank you for all your very informed replies. Clearly the LP140s are already very accomplished amps, and it would make sense to leave them unmolested until something fails. I am tempted to move to 6550 with them being the original tube suited to the amp. I just need to complete my "octet", being a few tubes short.

[Big Dog RJ]

If you're already having great sound quality and performance from the speakers are in top sync, just leave it! Obviously the tubes in there are performing well, so why change...
Only if YOU feel that something is lacking or you're after something different in terms of tonality or something more in certain frequencies like bass or different midrange then perhaps a different output tube type may help.

However, judging from your last post, it certainly seems like you're enjoying them. So there's only one thing to do,
Just sit back and enjoy those fine tunes!
Look after them well, and make sure they're in top spec. The LP series amplifiers are truly tops! They deserve top end gear.
Woof! RJ

[Lucky One]

Congratulations on the purchase.

If I may give some advice, you've only had the CJ LP140Ms for a short time. Get to know the system first, get used to the sound until you know it thoroughly. You have actually reached Valhalla, improvement will cost money, which in my opinion is not in proportion to the marginal improvement. Good is good, right?
It is of course up to you whether you have extra money to stop there, who are we to stop you from doing so.

Yours sincerely,