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Introducing the Gillespie W-5M

@tekuhn, Great thread, man! I found it the other day. Now a month later, are you back? Working on the amplifier?

I know it sounds kind of ridiculous, but the Heathkit W-5M caught my eye because of the tube cage design, haha. But then I started reading things online about how this amp can be modded to become something superb. Then I came across your project, so my interest is definitely whetted. I hope you keep posting.

Cheers,

Kim G
Boston, MA
Where I recently did some upgrades on my Dynaco ST-70, and now it sings!
 
@tekuhn, Great thread, man! I found it the other day. Now a month later, are you back? Working on the amplifier?

I know it sounds kind of ridiculous, but the Heathkit W-5M caught my eye because of the tube cage design, haha. But then I started reading things online about how this amp can be modded to become something superb. Then I came across your project, so my interest is definitely whetted. I hope you keep posting.
Hey! Yes, I am back home at the moment, and thank you for reminding me that I need to provide some periodic updates.

I basically consider the first amp finished, but I do still need to complete some basic performance testing. It sounds very good to my ears, and I think testing is going to support that. I was waiting to get an oscilloscope working, and I have now accomplished that, so there's really no excuse for me not getting back on this. Last trip away I spotted a 1959 Pilot console and speakers listed on FB Marketplace and ended up buying them at a really great price. Since bringing that home, I got sidetracked inspecting the speakers, which led me to examining my eWaved Norman Lab Model 10's and I'm currently optimizing the crossovers in them. I do tend to jump around a lot on projects - especially when I hit a roadblock on one and it's easier to look at something else while I mull over a solution to the other issue. :rolleyes:.

Bottom line is this: The amp sounds great; I want to get my primary speakers fully optimized and sounding perfect in order to really assess the amps performance; and, most of my tools are still at my daughters house, so I don't have my drill press to start machining the second chassis.

Thanks for your interest, and I promise I will get back on this and bring some closure to the thread as soon as possible.

Tom
 
Cool. You inspired me to buy an oscilloscope. I almost tried to buy the Hewlett Packard HP 54501A that you mentioned. But a Textronix 465M AN/USM-425 with cart came up on my local Craigslist for $99, so I went to see the guy and just bought it. Though I'm mildly knowledgeable about electronics (I can read schematics and solder), I don't know squat about oscilloscopes. This one seems to have one channel that's not working. The other one (as far as I can tell) does work. But I figured it was a low-risk purchase as the cart is worth what I paid for it AND the scope, plus I got a couple of HP probes (10040A & 10041A) as part of the deal. And since only 1 channel was working, I got the whole shebang for $80, which seems like a decent deal. Now I have to decide whether I can live with one channel, or should try to take this baby apart and see if there's anything obviously wrong (burned resistors, etc.) with the 2nd channel.

Anyway, thanks for the reply. I'm definitely interested in what you do with your second amp.

Cheers,

Kim G
Boston, MA
Where I now need to learn how to use the 'scope.
 
Hopefully some of the more experienced can speak up, but I think one channel will do most of what you might need it for. I want to use mine mostly for viewing square-wave signals to look for distortions to the waveform indicating low and high frequency roll-off. It's also invaluable for tracing an input signal as it makes it's way through an amp for troubleshooting purposes.

The HP 54501A that I bought had the typical NVRAM calibration errors due to the lithium battery dying in the Dallas clock module. I replaced that and those errors went away, but it still seemed to have a fair amount of voltage "jitter" for lack of a better description. I was able to return it. I then found an HP54512B which is a few years newer with better specs for $75. It also had calibration errors due to a dead lithium battery, but this model uses an actual CR2354 lithium battery. It was still soldered to the mainboard, but still a whole lot easier and cheaper to change than a 28 pin DIP module. I replaced it with a remotely mounted socket for a CR123A cell which will last longer and be simple to change for the next owner. As for the jitter, it seems that is a common trait with digitizing scopes as they go through a continuous analog to digital to analog conversion of the input signal. I believe newer generation scopes have improved on that significantly though. This scope has many features that I will never use, but the price was right for an item that originally sold for several thousand dollars.

Do you already have a W-5M that you are planning to mod?
 
P.S. I grew up listening to Heathkit gear. When I was small, my dad built a full Heathkit system, with a tuner, a "multiplex adapter" (which would create a stereo signal from the tuner), a preamp (Maybe an SA-2?), and a big, heavy stereo amp, which I think was the AA-40. Later, he built a transistorized, integrated receiver and gave me all the old tube stuff. Sadly, I sold off the tube stuff in the late 70's as I had by then built an AA-1214 transistor amplifier, and that was the era when tubes were considered obsolete. Oh, how I wish I had that gear now.

Cheers,

Kim
 
Do you already have a W-5M that you are planning to mod?

No, I've just started looking at them. I do have a Dynaco ST-70, which I recently upgraded with the VTA/Tubes4Hifi input board, which uses 3 12AU7 tubes, and I also installed the Triode Electronics capacitor board. The latter improved the sound notably, but the former was astonishing when I powered up the amp and listened. Wow! I should have done it years ago.

But I'm still keeping my eyes out for a pair of W-5Ms. I also found another web page which referred to a dead link for a modification that the original poster said made the amp superlative. So I'm still digging around to see if I can figure out what that's about. I'd ideally like to find a pair of W-5Ms that are in unrestored condition and go from there.

As for the scope, yeah you're right. I can probably do just fine with only one channel. But if I can easily figure out what's wrong with the second I'll definitely fix it.

Cheers,

Kim
 
No, I've just started looking at them. I do have a Dynaco ST-70, which I recently upgraded with the VTA/Tubes4Hifi input board, which uses 3 12AU7 tubes, and I also installed the Triode Electronics capacitor board. The latter improved the sound notably, but the former was astonishing when I powered up the amp and listened. Wow! I should have done it years ago.

But I'm still keeping my eyes out for a pair of W-5Ms. I also found another web page which referred to a dead link for a modification that the original poster said made the amp superlative. So I'm still digging around to see if I can figure out what that's about. I'd ideally like to find a pair of W-5Ms that are in unrestored condition and go from there.

As for the scope, yeah you're right. I can probably do just fine with only one channel. But if I can easily figure out what's wrong with the second I'll definitely fix it.

Cheers,

Kim

There's a bunch of them on eBay as we speak.
 
There's a bunch of them on eBay as we speak.

Indeed, I've seen them. There's even a pair in Rhode Island, which is about an hour's drive from me. I'm tempted, but don't feel any urgency either. I'm still enjoying the warm afterglow of my recent Dynaco upgrades.

Thanks,

Kim
 
@tekuhn

Hi Tom!

Did you finish your second amp? Iron out all the wrinkles?

In about a week, I'll be the proud new owner of a pair of W-5Ms that I got from eBay. They look to be in very nice original condition, save for the fact that the RCA input was converted to a TRS, and there are two other non-standard TRS jacks that may be for speakers. Someone might have been using them for guitar amps. That said, they certainly don't look like someone was hauling them around for gigs. And they've got the 16458 output transformers.

I found a set of instructions purportedly written by Dennis Boyle of the now-defunct Chimera Labs explaining some fairly simple mods to the amplifier that supposedly make it sound much better. The basic gist is that Boyle said that the input tubes aren't being run at their best voltages, so he suggests a number of resistor changes to bring those tubes into a better operating range. Might you know anything about this?

I'm also looking at buying a capacitor board to replace the can caps and also to clean up the underside of the amp. Sheldon Stocks of quadesl.com has a design which he has graciously put up on OSH Park, a circuit board manufacturer which specializes in prototypes and small runs. And I'm likely to replace most of the old carbon composite resistors with precision metal film units. And I'll also replace the coupling caps. Anyway, I guess I should start my own thread.

Cheers,

Kim G
Boston, MA
Where an amplifier restoration project seems like a good way to while away the long quarantine hours.
 
Congratulations on the W-5s! Those Chimera Labs mods have been discussed here several times, especially in the Heathkit W4 thread. They are based on Talbot Wright's 1961 article about "improving" the Williamson. I would not recommend them from a sonic point of view, and Dave G and Tim Robbins cast considerable doubt on their effectiveness in reducing distortion as claimed. The Stokes capacitor board seems like a good idea, though I haven't tried them. Be sure you rate all PS and coupling caps for at least 630VDC! ;-)
 
@zackthedog
Thanks for the reply! Yes, I'm eager to get going on the W-5Ms. I've done quite a bit of reading on them, here as well as at other sites. From what I can see, the power transformers are vulnerable, but can be protected with either a surgistor (Heathkit old-school remedy) or a thermistor, which I'd be more inclined to install. Apparently they are also prone to failure due to leaky rectifier tube sockets, e.g., bad sockets create shorts which then burn out the PT. The third route of failure I've found folks talking about is burned out coupling caps between the first stage and the output tubes. Original spec calls for 400 V, but apparently they can see more than that and then go leaky. And yes, I've been emailing with Dr. Stokes about his board. The design is now up on OSH Park for anyone to order.

Thanks for the reply!

Kim G
Boston, MA
Where I'm wondering how much different the W-5Ms will be from my Dynaco ST-70, which has the VTA input board and an upgraded cap board.
 
@zackthedog
Thanks for the reply! Yes, I'm eager to get going on the W-5Ms. I've done quite a bit of reading on them, here as well as at other sites. From what I can see, the power transformers are vulnerable, but can be protected with either a surgistor (Heathkit old-school remedy) or a thermistor, which I'd be more inclined to install. Apparently they are also prone to failure due to leaky rectifier tube sockets, e.g., bad sockets create shorts which then burn out the PT. The third route of failure I've found folks talking about is burned out coupling caps between the first stage and the output tubes. Original spec calls for 400 V, but apparently they can see more than that and then go leaky. And yes, I've been emailing with Dr. Stokes about his board. The design is now up on OSH Park for anyone to order.

Thanks for the reply!

Kim G
Boston, MA
Where I'm wondering how much different the W-5Ms will be from my Dynaco ST-70, which has the VTA input board and an upgraded cap board.

Oh, I think you'll find the W-5s vastly different. First of all, you can't beat Peerless transformers. And second--it's a Williamson! Expect to hear a tonal purity you may not have heard before. ;-)
 
@zackthedog
Well, I'm quite excited, really. While I've always had audiophile tendencies, after a nearly 3 year absence from my home (sick elderly mother on other side of country), I am back home in Boston and started tweaking my stereo, which I had missed quite a bit. I moved the speakers away from the walls, bought an SACD player (it's sad that format never really caught on; it's superb), and then made some mods to my ST-70, including the VTA input board, and a Triode Electronics capacitor board. The combination of those two things, but especially the input board, has transformed the amplifier. If the W-5M is as much a step up as those mods to my ST-70, I'll be ecstatic.

Cheers!

Kim G
 
At my age, I need to stop obsessing and just use the time I have left enjoying listening, but the chase was a big part of my interest.
The Williamson is an older evolved topology originally designed to drive triode output tubes, the VTA is basically a conversion to a (simpler) Mullard 5/20 topology of a Dyna ST-70, which in its original form with its superb OEM output transformers, is simpler still with perfectly adequate drive to the recommended output tubes. My personal preference generally runs to the simpler signal path esthetic, also appreciating design "elegance".
Living with both for a while will no doubt be enjoyable for you, and you may like both equally. Not a bad outcome.
 
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@tekuhn

Hi Tom!

Did you finish your second amp? Iron out all the wrinkles?
Hey Kim! I have spent a little more time listening to the amp and still think it sounds fantastic. I wish I could say I will be posting meaningful testing anytime soon, but realistically I know that I can't. I still have too much going on in another city that keeps me away a lot, and when I'm home I still like to bounce around with whichever project sounds fun at the time. I'm procrastinating on the machining of the second chassis. I already have it marked and center punched to be identical to the first amp, but after someone asked whether I planned to make them mirror-imaged, I really like that idea, but hate the thought of having to layout and remark everything and probably fill several punch divots too. I also really want to have a pair of speakers that I feel will do justice in reproducing what these amps are capable of, and I am second guessing my choice of a high efficiency pro-audio woofer in my eWave'd Normans. The low extension is just not there and integrating a single sub is not a good solution. If money were no object, I would buy a couple of other woofers to try. I have a feeling that 25watts will drive a lower efficiency 90dB(ish) driver to levels that are plenty sufficient.

Good luck with your W-5M's. I'm a lot like Pio1980, at least half the fun is the building, creating, restoring, improving something, but the listening is important too.

I hate to admit this, but I still derive the most pleasure from listening to my PC sound system. It wows me more than anything else I own. I have a feeling that a lot of it is because it is nearfield listening, and I am dealing with tinnitus and 60+ old ears and poor room accoustics. As with much of my equipment, I typically piece together used items from eBay and homemade. I have a pair of KRK Rokit 5 studio monitors (eBay) on my desktop. The sound card is an Asus Xonar Essence STX (eBay) which offers 124dB signal to noise and 24bit, 192KHz sampling. I send that to a dbx 223xs crossover (eBay) set at 80Hz highpass to the monitors and 80Hz lowpass to a homemade sub using a 10" Dayton UltiMax driver powered by a Peavey CS200 (dumpster dive item I repaired bad solder joint) amplifier bridged mono. It is capable of astonishing volume levels that are absolutely clean and dynamic.

My favorite source at the moment is Amazon Music HD. There is some stuff at 24/192. What surprised me the most about the higher resolution flac files was not just the clearer highs, but the increase in DYNAMICS. The midrange and highs really comes alive - even when comparing 96KHz to 192Khz. I find so much contemporary music is so heavily processed and compressed. There are some really good pre-digital rock recordings that are done really well, and much less compressed - much more realistic sounding to me.

Have fun with your project!
 
Hey Tom,

Thanks for the reply. On the one hand, yeah, having mirror image monoblocks does have a certain coolness factor. But your amps are more or less symmetric already, and as you point out, you'd have to undo some work you've already done. And then there's the question of do you really want to have to figure out how to do the wiring symmetrically too? That could open the door to wiring errors, and at the very least, prevent you from doing the second amp faster than you did the first one. But I guess it depends on how visible your amps are. Mine is currently not all that visible, and when I get the W-5Ms, at least one will be mostly out of sight, so I'm certainly not going to worry about symmetry. And from the front, with the tube cage on, they are perfectly symmetrical anyway.

As for piecing together used stuff, haha, welcome to my life! I have more or less stopped buying new consumer durables. I don't know about your area, but here in Boston there's a surfeit of rich people who wake up and say to themselves, "I just need to get 'X' out of the house," and then they put it on Craigslist for a song. I recently bought a weight bench with 2 barbells, 2 dumbbells, and about 500 lbs of weight discs for $30 from some guy who was just tired of having them in the basement. And I recently scored a sit-up bench for $15. And while my W-5Ms weren't a steal, they weren't all that expensive either, and with some work and a couple hundred dollars in parts, I hope to have something truly excellent. So yeah, frugality is the way to go. Not to mention it's WAY more environmentally friendly, since you don't end up with a cubic yard of Styrofoam every time you buy something.

It's interesting what you have to say about Amazon music. I'm kind of old-school (58 y/o), so I like to own CDs, and to a lesser degree, records. But I also have a bunch of SACDs and I can really hear the difference compared to CDs. So I have wondered about doing the whole FLAC/DAC streaming thing, but have yet to take the plunge. I have a good friend who doesn't care about audio, but she likes music and has Pandora and/or Spotify. But the problem, IMHO, with those services is that they're sort of like a top 40 station in that they play music that you're supposed to like based on your first selection (which they mostly get right). But then they play the same thing over and over and over to the point it gets tired. I can't tell you how many times I've heard The Four Seasons in her house.

Anyway, thanks for the nice reply. I am eager to get the amplifiers, and wondering if it's too soon to start a thread on them.

Cheers,

Kim G
Boston, MA
Where grocery stores will no longer let you bring your own bags.
 
Hey Tom,

It's interesting what you have to say about Amazon music. I'm kind of old-school (58 y/o), so I like to own CDs, and to a lesser degree, records. But I also have a bunch of SACDs and I can really hear the difference compared to CDs. So I have wondered about doing the whole FLAC/DAC streaming thing, but have yet to take the plunge. I have a good friend who doesn't care about audio, but she likes music and has Pandora and/or Spotify. But the problem, IMHO, with those services is that they're sort of like a top 40 station in that they play music that you're supposed to like based on your first selection (which they mostly get right). But then they play the same thing over and over and over to the point it gets tired. I can't tell you how many times I've heard The Four Seasons in her house.
Amazon Music can work like that - there are stations and playlists you can use, but you also have access to a huge library of albums and artists that play exactly like the record or CD. I agree - I'd rather own the CD or vinyl, but they don't sell high resolution albums, so streaming is the only way to get it. I tried CD-Audio many years ago and it was very good also. I can definitely hear the difference in 16/44.1 audio - the good and the bad. The low frequencies are superior and the dynamic range is fantastic. The high frequencies suck - grainy and unrealistic. 24/192 fixes that, assuming it was recorded well to begin with and the resolution preserved throughout the mixing, mastering, etc. Unfortunately, the vast majority of people find it fine so there's little motivation to improve it for a relatively small customer base.
 
Indeed. "Good enough" has taken over audio in a rather vicious way. I have no objection in principle to iPods, ear buds, and "docks" of various stripes. But I think there's an entire generation of folks who literally have no idea of how good HiFi can sound if you have the right setup. I myself have a fairly modest or at least mid-range rig, assembled over time, but it sounds very nice, and certainly WAY better than any iPhone/Pod dock.

Kim G
 
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