Fancy Parts

[SteveS]

Hi folks,

I'm looking over the parts list and I am wondering which parts would be good candidates for ordering "boutique" alternatives. Since I am in Canada and like to avoid border charges on mail order items, I have done business with Parts Connexion. They will likely be my source for the Hammond trannys, but their resistors and capacitor offerings are mostly targetted at the "audiophile" customer. You can read this as _expensive_ a bit like ordering from Michael Percy.

Anyway, they have good service, and I don't mind a few $5.00 Caps or $1.20 resistors if they are in critical locations for sonic payoff. They don't have everything so I'll be ordering from mouser anyway, but you know if auricaps or vishay resistors might be worthwhile , it would be useful to know which ones. If you can refer to the parts list numbers that would make like easier. (one of these days I'll figure out how to put an emoticon on my message)

thanks

[Thermion]

Everyone has a opinion when it comes to parts selection, and it really comes down to what kind of sound you are into. :boxing:

But since you are asking here are my two-cents.

As a rule of thumb, if you want to know where to put extra $ into high-end parts, follow the signal path. However, I believe that your get more of change in sonics with the capacitors than with the resitors. In any case, I would definately upgrade all of the components (resistors and capacitors) in lieu of using any of the Xicons. Call it personal bias. :protest:


Resitors: I like to use precision metal film resitors. I know some like the carbon resistors better, but I like the low noise and small tolerences of the metal film types. I have used the Holco H2 and H4 in several projects with good success. I also like the Dale/Vishay resistors sold by mouser. The IRC resitors sold by Handmade electronics http://www.hndme.com/ , both the 3 and 5 watt wirewound and the 3 watt metal film look like good choices for plate load resistors on the 12AU7 (R9 and R10), and also for R11 and R12. . There is no reason to use $6+ dollar resistors in this amp.

Capacitors: Instead of the Xicon polypropylene capcitors, there are several good choices. But I wouldn't use anything less than a Film and Foil capacitor. The solen or angela Film and foil caps are a great value for the money. I have used the angela caps and like them alot. If you feel like splurging use the Multicap RTX or Jensen paper in oil caps for the coupling caps C1&2 and C5&6. :zombiesmile:

Spend a little more for your passive components, and you will thank yourself later.

JT

[EWBrown]

I've used Hovland Musicaps in some of my SE amps, might try them in the next DIY-35. They have teflon-insulated stranded wire leads.instead of the usual tinned copper. Auricaps also have teflon/stranded, and are physically smaller.

This is their brochure: http://www.hovlandcompany.com/pdf/brochures/MusiCap.pdf

These are available at Antique Electronic Supply around $8 each.
www.tubesandmore.com

Note: the 0.1 uF 600V caps are 1.75" long, the .1 uF 400V are 1.25", these will fit on the board easily, the 600Vs are too long.
Inner foil is the red lead on MusiCaps


/ed B in NH

[Shannon Parks]

I would upgrade the interconnects. A nice set of rca connectors and terminal posts would be the biggest upgrade per buck over Mouser stock as I see it.

Shannon

[SteveS]

thanks guys - I really appreciate it.
Ofcourse as I've discussed briefly offline with Senor Parks, the real dither I am in is as regards the transformers. Most of the SCA-35's I've seen on ebay are going for slightly more than the cost of new Hammonds, and I don't make it out to enough estate sales or used shops find one locally.
My temptation ofcourse is the Dynaco replacements offered by Uncle Ned, especially the output trannys by Magnequest because I heard lots of good things about the quality of his iron.

The devil in one ear is saying - if your going to enjoy this amp project for several years you should buy the best parts, and the devil in the other ear is saying (with a distinct scottish accent) save the $100 on the trannys and spend it elsewhere.

[Thermion]

If you can get an SCA-35 on Ebay for slightly more than the Hammond transformers, then my advice would be go this route. The Dyna transformers are certainly better then the Hammonds, and equal or better than the Magnequest. Plus, if the SCA-35 is in good condition, you have an attractive heavy-duty chassis. Just perfect for a DIY tube linestage project.

The drawback for the Dyna output transformers is that they don’t have a 4 ohm tap. I built a ST35 clone amp several years ago using SCA35 transformers. Unfortunately, my speakers present a 3 ohm nominal load. I really don’t think I get the best sound out of the amp because of this.

The hobby of audio is the art of compromise. Every decision is a compromise between conflicting priorities. I like the build it and upgrade it later philosophy. Get the amp running using good quality reasonably inexpensive parts. Then treat yourself to an upgrade every now and then. Replace the coupling caps, change to triode mode, get better quality transformers, etc. Every time you make a change, it’s like getting a new amplifier. :headbang:

JT

[MLVA123]

Good conversation here. I too have been wondering which components would produce the highest ROI. I am worried about getting the old stuff off of Ebay or yard sales for fear of it being 'worn out'. Most of what my research has told me is to stick to the signal path. My list:
1) Interconnects, as Shannon says is a good place to start, with good quality shielded wiring back to J1
2) Coupling caps (C1, C2, C5, C6) maybe go with a lower tolerance, "fancy" cap like a paper-in-oil type: http://www.angela.com/catalog/capacitor ... a_PIO.html
3) 6BQ5s - I don't know much about the 'coloration' of different tubes yet, so I'm going to be rolling some to experiment and find out for my own ears. This seems to be kinda like wine tasting. Someone will say "the '98 cabernet has a more fruity finish", but until you try it yourself you won't really know what that means! :drinking:

Question for you guys that REALLY know what you're doing though: How do trannies "wear out"? Can a 30-year old Z-565 really perform like a new one?

[Thermion]

A 30 year old transformer can certainly perform as well as a new one, provided it is in good physical and electrical condition. In general, transformers are made from very stable materials. Iron, copper wire, paper, wax, etc. And they don't have any moving parts. So from a materials science standpoint, there is no reason why a transformer couldn't last 50 to 100 years without problems. :clock:

However they can be easily damaged in a number of ways. Heat is a big problem espcially in power tranformers. Heat accelerates the breakdown of the components holding the windings around the transformer core allowing shorts between the wires. Here in Fisher, the line voltage runs hot around 127 VAC. To keep the tranny's cool, I always run my tube gear through a variac. I find that most of the amps operate best at around 113.5 to 115 VAC. I normally adjust the voltage until the filaments read 6.3 volts. The good news is that output transformers operate much cooler than the powers.

Prolonged contact with water is also very detrimental. Corrosion of the iron core will cause the laminations to split apart. It may cause shorts in the windings.

I have also damaged a prized output transformer that fell from a shelf onto a concrete floor.

Ironically, the best way to make sure your tansformers last as long as possible to use them often and operate them conservatively.

JT

[EWBrown]

I used "stock" RCAs from Mouser in this go-round, probably will later change them to better quality gold plated RCAs, and will isolate them from the chassis so that the grounding occurs at the PCB, and this should avoid potential ground loops. All my othergrounding goes through the PCB and its mounting posts, even the AC plug safety ground, and none directly to the chassis.

In my small SE amps, I used "single point" grounding, all grounds radiated from one terminal located near the center of the chassis. The RCAs were gold plated and isolated with nylon shoulder washers (I don't recall where they came from originally), and the OPT seondaries were left "floating" so I could experiment with series or parallel connect for mono-blocking tests. These RCAs were not really "fancy" just as step up from the standard radio snack stuff. I'll leave the "botique jewelry" parts for the 211 or 300B SE designs, far in the future.

/ed Brown in NH

[EWBrown]

If one wants to be the ultimate cheapskate, try using 8BQ5s or 10BQ5s,
these are the same except for filament voltage and current requirements, and are available for a LOT cheaper than 6BQ5/EL84s. These would require some hacking (eeek!) of the blue board to use, so maybe not...
Howsomever,,,,,
They might be good for handwired prototypes, experiments, etc. They all reauire about 4.5 watts of filament power, 600 mA for the 8 and 450 mA for the 10, versus 760 mA for the 6BQ6/EL84. Good use for that otherwise unused 5VAC winding.

These are not much cheaper on AES, Ibut looked them up on other tubesites and found some for $2-4 each. YMMV, etc.

/ed B in NH

[EWBrown]

If you really want to go for the pancy farts, er, fancy parts, check out the
Audio Note site here:
http://www.hificollective.co.uk/

Click on "components", they have all sorts of deluxe caps and resistors, OPTs, etc. I can only dream, and drool... :silly: :shock:
Hovlands and Auricaps are my upper limit for the time being, I'll add the gold plated diamond encrusted rubidium and palladium jewels after I strike it rich :rofl:

/ed B in NH :drinking: :morning: :scrambleup:

[EWBrown]

I wonder how these Russian made teflon-dielectric caps might stack up against the Auricaps and Hovland Musicaps? :scratch:

http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... egory=4662

These appear to be military (or space) grade components, and if they were US made would probably cost their weight in gold...

I have bought a few other items from "Anthony Lake" and have had good results, some items ship fromthe UK, the Russian made componentry ships from Ukraine, takes 2-3 weeks to arrive (registered mail) after Pay Pal is sent.

BTW, this is also a good source for Russian made 6BQ5 / EL84 / 7189 tubes, but check each item, as the price does vary for identical items.

/ed B in NH

[EWBrown]

I got some of the aforementioned Russian made teflon-aluminum caps,
these are MONSTERS! :animalelephant: about the size of a D cell battery. A quick check with my DVM showed these to have a 2% or better tolerance (typically .098 -.102 uF capacitance. These are really serious-looking caps, probably intended for military or space usage. Glass seals on the ends, silver plated terminals. :nukemeltdown:

Too large for PCB mounting, these will have to be mounted on standoffs and hand wired between tube sockets. I also got some much smaller "military grade" .1 uF 400V caps from the same seller, these are a tad smaller than the "orange drop" caps. These are also glass-sealed on teh ends, have wire leads, look similar to mil-spec caps I have bought back in the 70s and 80s.

/ed B in NH

[Shannon Parks]

I got some of the aforementioned Russian made teflon-aluminum caps,
these are MONSTERS! :animalelephant: about the size of a D cell battery. A quick check with my DVM showed these to have a 2% or better tolerance (typically .098 -.102 uF capacitance. These are really serious-looking caps, probably intended for military or space usage. Glass seals on the ends, silver plated terminals. :nukemeltdown:

Yeah, Ed - once you posted that link I emailed Mr Welsh about the dimensions. The size is 2" x .75", from contacts 2.5". Monsters, indeed. I'm not huge into fancy coupling caps, mainly because I balk at prices, but those silver teflon caps certainly have a 'wow' factor. Let us know how they sound.

Shannon

[EWBrown]

These are a bit more "fat" than .75" , closer to a full inch or a tad more.
I figured these were about half the price of .1 uf 400-600V Hovland Musicaps or Auricaps, so it was worth a shot. The first use will be in a
SE I will be working on shortly (12AX7 or 6SL7 and EL34, into One Electron UBT-3s). THis will have point too point hand wiring, as it will be a developmental prototype, subject to design tweaking, so I'll just allow for the larger caps in the physical layout.

UPDATE: I measured one of the caps: 2 5/16" long, 1 3/16" Dia, overall length including terminals 3 1/16". Silver-painted metal body, glass sealed ends. Terminals appear to be silver plated.

Anthony Lake also has some .1 uF 600V teflon caps that are even larger,
as well as other (larger still) paper and PIO caps. but these are getting into the industrial grade giant category.

I'll bring a couple into the lab here and test for dissipation factor, leakage, ESR, etc. ANd compare them against the Musicaps and Auricaps.

/ed B in NH