What are your favorite tube amp upgrades?

Niteshade · « **on:** 17 Oct 2008, 10:51 am »

What are your favorite tube amp upgrades?

Examples:
Variable Negative feedback?
Type of capacitor?
EL34/KT88 option?
Power supply upgrades?
***NEW*** Longevity upgrades: This is a unique upgrade! After some comments about amps breaking down, I thought it was a good idea to include this. My current offerings are built to weather time very well- but these options take it over the top. Nobody else carries this upgrade package, guaranteed.

In fact, the largest model stereo amplifier I have, the Lamphear 120-2 has this as standard equipment.

Make up your own upgrades/standard features list if you like.

Berndt · « **Reply #1 on:** 17 Oct 2008, 01:42 pm »

nos OIP caps
rectifier tube delay switch
stillpoints

macrojack · « **Reply #2 on:** 17 Oct 2008, 01:50 pm »

So far my best tube amp upgrade was a move to solid state. This technique is very simple and can actually save you a little money. It is quite easy to do and is well within the reach of anyone even a novice, for whom it may well be the best choice.

The only downsides to this transition are the risk of peer admonition and the loss of tube glow. My wife solved the latter for me with the purchase of a salt lamp and I've yet to encounter any peers in my region as I'm the only one in the vicinity who actually cares about audio.

Niteshade · « **Reply #3 on:** 17 Oct 2008, 02:25 pm »

I do own a Denon 3805 receiver that I believe is fairly decent. If you have heard this receiver or one like it, would you believe it's a good example of what SS technology has to offer? (A question for everybody)

Quote from: macrojack on 17 Oct 2008, 01:50 pm

So far my best tube amp upgrade was a move to solid state. This technique is very simple and can actually save you a little money. It is quite easy to do and is well within the reach of anyone even a novice, for whom it may well be the best choice.

The only downsides to this transition are the risk of peer admonition and the loss of tube glow. My wife solved the latter for me with the purchase of a salt lamp and I've yet to encounter any peers in my region as I'm the only one in the vicinity who actually cares about audio.

mcullinan · « **Reply #4 on:** 17 Oct 2008, 02:31 pm »

Denon is a warm pleasant sounding receiver.
Mike

miklorsmith · « **Reply #5 on:** 17 Oct 2008, 02:40 pm »

Tom - is your shoulder sore from the giant chip you carry around on it?

Question - Is "a receiver" a good example of what solid state is capable of? My audiophile prejudices scoff. However I've never heard that receiver, it could be The Greatest Thing Ever.

macrojack · « **Reply #6 on:** 17 Oct 2008, 02:43 pm »

I haven't heard your Denon so I can't say that it is or isn't representative of what solid state can do. Presently I'm using JRDG separates which, in all likelihood, provide a more refined example of solid state potential.

What are doing, or trying to do, with your saturation posting about tubes and their merits? It appears to be a pretty transparent, left-handed, self-promotion campaign.

Tubes are an option, not a gospel.

Niteshade · « **Reply #7 on:** 17 Oct 2008, 03:05 pm »

Tube equipment is a great option and I do promote the use of tubes for the DIY'er, enjoy answering questins about them or adding input. Naturally I promote my business and products in the proper forums.

I agree- tube equipment is not gospel and have acknowledged that in the past and recently. It's well known that the higher quality models of either technolgy are considered equals.

Constructive criticism and suggestions are always welcome.

Quote from: macrojack on 17 Oct 2008, 02:43 pm

What are doing, or trying to do, with your saturation posting about tubes and their merits? It appears to be a pretty transparent, left-handed, self-promotion campaign.

Tubes are an option, not a gospel.

macrojack · « **Reply #8 on:** 17 Oct 2008, 03:18 pm »

O'K' Blair, fair enough.

Mike - Don't make fun of my hump.

richidoo · « **Reply #9 on:** 17 Oct 2008, 04:56 pm »

The best tweak to my tube pre and power amps was from an Equitech Q balanced power conditioner. The difference was very noticable and very positive.

Other filters I have tried have been a negative effect on tube gear.

Blair I enjoy your posts. Keep em coming, at least one new per day. Keep us tubers awake.

DTB300 · « **Reply #10 on:** 17 Oct 2008, 05:15 pm »

Quote from: Niteshade on 17 Oct 2008, 02:25 pm

If you have heard this receiver or one like it, would you believe it's a good example of what SS technology has to offer? (A question for everybody)

A very subjective question which will garner a host of subjective answers.

IMO, which means nothing other than what I like and prefer, no it is not a good example, no receivers are.

JimJ · « **Reply #11 on:** 17 Oct 2008, 05:26 pm »

I think if I had to have a receiver, it'd be a Sansui G-33000, I was thoroughly impressed by it with the sheer coolness factor alone

Ultimate in SQ and flexibility in upgrading? No. Basis for one heck of a party system, yes

kbuzz3 · « **Reply #12 on:** 17 Oct 2008, 06:14 pm »

I also enjoy these posts. Of course blair is an amp maker, but his posts have been general thoughtful and not pushy. Keep em coming...

EDS_ · « **Reply #13 on:** 17 Oct 2008, 06:46 pm »

Audio is a funny hobby.

To me, most often, well executed tube gear trumps well executed SS gear.

Blair please keep your tube posts coming.

kenreau · « **Reply #14 on:** 17 Oct 2008, 07:30 pm »

Quote from: Niteshade on 17 Oct 2008, 10:51 am

What are your favorite tube amp upgrades?

Make up your own upgrades/standard features list if you like.

At risk of stating the obvious, it's relative to what you are starting with, both amps and speakers. I have a pair of Cayin 860 monoblocks that, imho, have great 'bones' (ie big hq trannys, point to point wiring, hd chassis) but corners were obviously cut on some key component parts (mo resistors, knock off caps, ufo wire). It appears to me the Cayin and more popular advertised Prima Luna gear may either be designed by the same firm, or, possible made in the same place, or both? It kind of reminds me of the GM auto line where an analogy might be the Cayin is a Cadillac and the PLuna the Chevy. They are similar but with definite upgrade differences in tranny sizes, chassis weight, p-to-p wiring, etc.

I got the schematic and consulted with Jeff at SonicCraft for a cost effective shopping list. In general, the high points were Hexfred rectifiers, Black Gates, Cardas film caps, Sonic Craft caps (of course...), PRP & Kiwame resistors and Cardas rca + signal path wires at critcal points.

I heard a significant improvement across the board with these upgrades after ~200 hours of break in. I continued to use the stock oem Cayin/EH tubes through break in and then upgraded all the tubes with sweet NOS Mullard Blackburns, Mullard reissues, etc. They really put the icing on the cake imho. I would guesstimate the parts upgrade made ~75% improvements and the upgraded tubes ~25% of the total improvements.

I really love the EL 34 based amps and they mated very well with Merlin VSMs. The Merlins are very revealing monitors and made it easy to hear the upgrades. I would imagine with less revealing speakers (and system), not all upgrades will provide significant, or cost effective, audible improvements. In my experience they did.

Note: Full disclosure / shameless plug time.... I recently made a trade for different, significantly less efficient speakers which warranted an amp change as well. I have put my Cayins up for sale here on AC and replaced them with some solid state 200 watt monoblock beasts.

Kenreau

rpf · « **Reply #15 on:** 17 Oct 2008, 08:13 pm »

Standby switch(es).

I recently changed the SonicCraft Platinums in my tube mono-blocks to Audiocap PCUs. Better, and the same price.

underdog64 · « **Reply #16 on:** 17 Oct 2008, 08:30 pm »

I have a VTL ST150 and the best upgrades were:

1.Upgrading the coupling caps to MTX multicaps.Cost me about $230 including parts and labor-person who did it was an local audioclub member.VTL would have wanted $900+ for the same upgrade

2.Upgraded the imput tubes only to Mullards (about $28 for both).If someone could recommend a 6550 tube that betters the new Svetlanas I have currently I'd love to hear the suggestion.

3.Upgraded two fuses to Hi-Fi tuning silver ones.Could'nt find a fuse the same size as the main one to upgrade but treated it with quicksilver gold along with all tube pins and rca jacks

4.Added Herbies tube dampers for all tubes

5.Added Marigo dots (resonance control) on all coupling caps

Niteshade · « **Reply #17 on:** 18 Oct 2008, 02:14 pm »

Sweet!

What a fantastic list so far!
It would seem the most inexpensive upgrade would be a standby switch. Tube cathodes don't wear out fast at all when they're not having electrons sucked out of them. Standby switches have been a long time boon to the HAM radio community and to commercial tube equipment (Peavey, Marshall, etc..) but have seen little use in the HiFi market.

I would place this circuit behind the rectifier so that the entire HV circuit could power down. I am concerned about a possible "POP" or "BOOM" when the HV is switched on from the inrush current. This will have to be addressed.

woodsyi · « **Reply #18 on:** 18 Oct 2008, 03:34 pm »

Bill Baker at Response Audio did the following extreme mod on my pair of ASL Hurricanes and the mod absolutely took the amps to a higher level. I have had them going on 3 years and I have no plan to replace them. In fact, I am going to send them back to Bill to get them spruced up with new paint and and a few "updates" that have been added to the line up.

Quote

** Reference Grade V-Cap Teflon capacitors installed in the signal path coupling stages. x16 pieces
The capacitors are mounted using a high quality double sided adhesive tape as well as being secured with zip-ties to eliminated vibration.

** Reference V-Cap Teflon capacitors installed in the innerstage coupling positions. x4 pieces

** Mills non-inductive resistors replace the input tube cathode resistors. x6 pieces

** Mills non-inductive resistors are used for the grid stop applications. x16 pieces
All grid stop resistors are mounted directly to the grid pin of each power tube eliminating all unnecessary wiring. It is a common practice to mount the body of grid stopper resistors as close to the tube grid as possible. Many tube amp manufacturers do not utilize this practice. All grid stop resistors are then mounted directly to the leads of the coupling capacitors and all leads are cut to minimum length.

** Mills non-inductive resistors are used for the screen grid applications. x16 pieces

** High quality 5 watt Mills non-inductive resistors used in cathode ground locations of all power tubes x16 pieces

** Dale/Vishay 1 watt 1% non-magnetic resistors used throughout the signal path. 40-60+ pieces. The signal leads of these resistors are shortened to the shortest lengths possible and all exposed leads are covered with heat shrink to help eliminate vibration and protect against shorts.

** Dale/Vishay 1 watt, 1% resistors are used in the bias stage in series with the coupling capacitors. These resistors are mounted in series with the coupling capacitors and then into the bias stage circuit boards. Again, we keep all signal wiring as short as possible.

** Dale/Vishay 3 watt 1%, non-magnetic resistors utilized throughout various power supply locations.

** All exposed resistor leads throughout these amplifiers have heatshrink applied to help reduce mechanical vibration as well as preventing circuit shorts.

** The grounding layout is reworked to provide a the best possible results with a dead quite background and lower noise floor.

** All power supply capacitors are bypassed with SoniCap Platinum Teflon units. Each power supply filter capacitor receives its own bypass unit. Total of 8 Teflon bypass capacitors depending on model

** Bybee Quantum Purifiers are installed in the B+ voltage of the power supply directly at the rectifying stage. 4 pieces total.

** Bybee Quantum Purifiers are installed in the input signal path of the signal ended input.

** Fairchild "Ultra Fast - Soft Recovery" diodes are utilized in the rectifying stage of the power supply. The diodes are mounted directly to the capacitors of the power supply.

** High quality silver plated solid core copper internal signal wire. x8 feet (Solid core 22 awg. OFC copper also available)
We also apply a full shield to this wire to also further reduce any possible noise.

** RCA input jacks are high quality gold plated "RA Jack" RCA jacks.

** WBT Silver solder used throughout (on US models only)

** Bench tested for 2 hours

** Minimum 12 hour burn in

** Labor : 17+ hours per pair

Audiovista · « **Reply #19 on:** 18 Oct 2008, 10:56 pm »

My favorite - NOS input (signal) tubes. IMHO - biggest bang for the buck. Philips Miniwatt is my favorite brand.

On a different note - yes, this is the right forum for manufacturers to market themselves, and anybody who posts here is assumed to have commercial interest in audio regardless of what's in his signature. So, Blair (and others), keep it coming!