Opinions on vintage cj amps and Teflon cap mods

I'm seeking opinions on having a vintage amp modified/updated. While I'm enjoying my conrad johnson Premier V as is, I can hear some significant differences when compared to some of the more modern amps I've heard. In my opinion, the sound I'm getting from my system is too soft, particularly the leading edge of notes and the upper base/lower mids. Decay, air, ambiance and overall musicality are great IMO. conrad johnson is offering modifications to the Premier 4&5 amplifiers which would include a new power supply and Teflon capacitors. What's crucial to me, is that I'm looking to improve the amplifiers performance, not just change it. The cj person I talked with said they've modified a couple of the Premier 4s with "smashing success". Thanks in advance for your experiences and opinions.
If CJ is doing the mods themselves they should be able to give you more specific details on the change in sound you can expect.

Power supply caps are often deteriorated in vintage amps. I've refurbished a pair of Fisher 80AZ's, and a pair of Dynaco Mk III both with new power supply caps, and teflon coupling caps.

I've been very pleased wherever I've been able to afford to use teflon caps. The DO take seriuos amounts of break in time to sound right, and may even sound worse initially.

John C.
I'm planning on capacitor upgrades to my CJ MV-55. I will use Jantzen Z-Superior Copper at the lower end of price scale, VH Audio V-Caps at higher end.

Based on my experience, either of these caps should provide the improvements you're looking for, while retaining the essential CJ sound. I wonder what caps CJ uses in their upgrade?
Hi Phaelon,

A "new" power supply in a 1984 vintage amp would make one heck of a difference, detail would probably improve along with more bass definition and solidity, along with better control over all. The new coupling caps will help too, but you've got a ton of output tubes (8 EL34's) so trying some other tubes might be another avenue, but I would go for the power supply and cap upgrade and see where you stand.

This can't be cheap though, and you really have to like the amps in their present state to spend more $$ on them.

Improved performance is a sticky issue, since the amps performance (output power, bandwith, stability) are a function of the circut to a great extent. The fact that CJ is doing the work is a big plus. Good luck.

cj are using their expensive proprietary teflon caps for these offered upgrades, which they use in all their new way more expensive amps.

I am sure cj would not offer the upgrades if they did not feel they gave a noticible improvement over there old caps ( closer to how their current amp line up sounds one would guess).
Why would they bother ruining their 2nd to none great customer service reputation ?.

Would be nice to hear someone who has actually done the upgrade thou.

I have owned the 5's and the 8's (about 2 years on each and about 8/10 years ago.)While they were hot stuff back then it's not hard to trounce them with today's amps.---Whatever you do you will have a very old amp that you could throw lots of money into; which you'll never re coupe.
If you got a hold of the CJ350,a SS amp;hooked it up to your speakers,if they are revealing enough---you wouldn't believe your ears.(or miss the tubes)---BTW I had Bill Thallman redo my 5's. My 8's were the triode/only version.---Compared to the SS amp these tubes amps are the poster picture of "soft-mushy" in tube amp design.
I'm with avguygeorge regarding the recoup of money spent on upgrades. Unless the guy doing the work knows his stuff, you could wind up with a result that is worth a lot less than the original. That being said, both C-J and Bill Thallman do GREAT work, and know the products inside and out.
I had Bill T. work on a pair of amps and a preamp (all of which are a lot older than your 5's)and I thought the sound was similar to pre-update, but had much more "clarity". My update was before Teflon caps were generally available.
Just like an vintage car; if you really love them, then have C-J do an upgrade, if you think they're lacking compared to the newer models, then don't.
Thank you, every post makes excellent points. I wouldn't be considering a modification of this expense if I wasn't considering these amps as long term keepers; long...long term. This modification is very expensive ($1800+ per chassis) and would be lunacy as an investment. However, and to my musical soul, there is an ineffable quality to these amplifiers that enables me to look past their audiophile shortcomings and enjoy music as I rarely do outside of a live event. I know that there are modifiers with excellent reputations, that would not restrict me to Teflon caps - Bill Thallman is certainly one; but the folks at cj believe that Teflon caps are the only worthwhile upgrade. It's a difficult decision to make without knowing the results. I don't want to lose the magic.

Pardon my naivete, but what kind of problems are endemic of older amplifiers. I know that caps eventually leak, but shouldn't a well maintained amplifier last indefinitely.
I'm with you on keeping the amps. I find my CJ amp a keeper in it's own right, I like it just because it offers a sound unlike the more modern tube amps I've owned or own.

I don't agree that Teflon caps are the only way to go, Jantzen Superior Z is a top choice, Duelund VSF copper the absolute best! Teflon has a sound, very clear and clean, too many can sometimes mess things up, synergy is paramount.

I don't know about amps lasting indefintely, but they should last a good long while. Nearly all parts have a definite lifespan, ask CJ about this.
Hi Phaelon,

Good point about not wanting to "loose the magic" -- just because CJ feels the teflon caps are an improvement, doesn't mean you'll like the sound of the so called upgrade. It might be better to go with an independent like Bill Thallman and do the changes one at a time. Upgrade the power supply, check it out. Then do the capacitors this might be the way to go. Regards...Paul
Thanks again everyone,
With your help, I've decided that the least I should do is try to hear some components that use teflon caps to try and identify their sonic signature in comparison with other capacitors and proceed from there.

Paul, I know that your right about taking baby steps and updating the power supply first, but if I'm going to go through the hassle, expense and risk of shipping these 90 lb. mono-blocks across country, I want to maximize my return.
if you own a vinatge amp for a reason, why modify it so that it sounds like a modern amp that another manufacturer produces ?
Mrtennis, I enjoy much of what this amp has to offer. I'm hoping I can improve it without altering its virtues. Think of it like buying a vintage house that you love for its woodwork and craftsmanship of a bygone era. Would it be inconsistent to tear out the coal burning furnace and replace it with a modern heating plant?
The power supply is responsible for much of your amps sonic signature. If you send it back to CJ for these updates, I can assure you that it will sound nothing like it did. My advice is to have it restored to spec. Buy a new amp if you want the modern "teflon cap" sound.
I had a chance to compare CJ's proprietary teflon Caps to VH Audio and Relcap teflon caps as coupling caps in a tube preamp.
CJ's caps do not sound at all like VH caps. Both are excellent, the CJ caps retain the CJ "magic" while increasing resolution, however they do not go over the edge.
VH caps are excellent choices if your aim is maximum transparency.
The Relcap TFT cap would be my third choice.
In summary, if you want to bring your amp to modern CJ specs, I believe you can not go wrong with the factory mod.

Phaelon, most vintage tube amplifiers (not CJ) were designed to a price point and to make the tubes last long (to the detriment of sound quality). Tubes were under-biased (or to put it technically, an "easy-on-the-tubes", low current operating point was chosen), transformers had limited bandwidth, oil caps were used for coupling and the power supplies used a minimum of capacitance, mostly electrolytic caps have a specified shelf life of 10 years.

With rare exceptions (Harman Kardon, Fisher, Marantz, Quad), the output transformers did not pass a wide frequency response. This was partly compensated through heavy use of negative feedback, which wreaks havoc with soundstaging and dynamics.
In summary, vintage tube amplifiers in mint condition sound mellow, limited in the frequency extremes and undynamic as compared to modern tube amps. Soundstaging is also affected.
If one factors in dry power supply caps, out-of-spec resistors due to 30+ years of aging and leaky coupling caps, we have the usual mellow/bloated, lo-definition sound quality of vintage amps.
I am not saying that all vintage amps sound bad, I have tried to explain in general the "vintage sound"

SNS, about parts life expectation: Parts with a limited life span are tubes, potentiometers, carbon resistors and electrolytic caps.
Nowadays, CJ uses mostly film caps in their power supplies.

Transformers, hook-up wire, modern resistors, modern film capacitors, connectors and well-engineered tube sockets have an indefinite life span. 100 years in a non-salty/corrosive environment is not unheard of.
I own a 1938 tube radio that works perfecly after the electrolytic caps were replaced.
So, a properly cared-for CJ amp should last the owner's lifetime, if he/she replaces the output tubes when the bias indicator sez so.
Input tubes last aproximately 10,000 hours or 5-8 years of normal usage.

I hope this helps
Casouza, I hear you on the V-Caps, can be too much of a good thing, the reason I would hesitate to recommend them in this case. I wonder who manufacturers CJ's film caps?

Granting that what you say about transformers being band limited is true (I hear it), it would seem somewhat pointless to upgrade most vintage amps. These amps will never be able to reproduce those things I most like about the modern amp sound (I don't know about Phaelon), ie. the dynamics, immediacy and soundstaging. These things my Art Audio does magnificently, my CJ likely doesn't have a hope in these areas.
Hi Casouza, Your post helps tremendously. You addressed all of the issues in question. Ultimately, I have to make a decision and it would seem to come down to this: 1) Would I be better off trying to restore these amps to as close to original spec as possible, 2)sell them, combining the revenue with the cost of the upgrade and buy a different amp or 3)taking a chance on the upgrade and hope that lightening strikes. Regardless of which I choose, your post is most appreciated. They all are.
Hi Phaelon, thanks for your kind words.
I really can not answer your doubts, having no experience with your particular model CJ amp, however, if you like and enjoy your system as it is today, the upgrade will certainly be an incremental improvement across-the-board, because power supplies and coupling caps DO matter. Capacitor technology has evolved a lot in the past 10 years.
Reminder: give teflon caps 200-300 hours of play to sound their best. Initially, things may sound a bit weird.

If you are not happy with your system, then by all means "open the can of worms" AKA amplifier/speaker sinergy.

In the past five years, I went though several amplifiers: 50W SS, 200W SS, 400W SS, 500W SS (notice the power-race trend?), then 90 W McIntosh tube amp ...to end up with a measly 20 Watts Hyperion SET tube amp...now I am as happy as a kid in a candy store.

Sns, CJ capacitors are custom-made by CEC in the USA.
I recently bought a pair of cj prem 8a's and had conrad johnson do the teflon cap upgrade.

The upgrade consisted of replacing the eight coupling capacitors (inverter to output tubes) with .15 uF Teflon capacitors and replacing 6 more capacitors (four in the regulated supplies, two in the unregulated main supply) with .15 uF Teflon. Filament diodes were replaced with "beefier" diodes

No downside whatsoever. Maintains the strengths of original prem 8a while adding transparancy, seperation and overall ease of delivery.

Highly recommended for any owner of older cj amplifiers.
Interesting that cj now have the upgrade detail on their web site

Luving the premier 8a's with the teflon cap upgrade now that I have over 400 hours on them

Does CJ offer these proprietary caps separately as parts for DIY in other makes or is this strictly for their own use in CJ model upgrades?
I would say no, as they probably believe this is part of their musical edge over other audio peers with their" own voiced" teflon caps.

Send them an email and ask - they are a very nice company.

They told me who made them (made in the USA) , however I forgot but I think it may be V caps - but as I said made expecially with cj's 12 proprietary herbs and spices so sound different.