Harmony B3500 update: Cab and Cord

Finally posting about updating the Harmony B3500 amp: fitting a 15 in. speaker to the cab, and upgrading the AC to a three-prong cord.

Upgrading the AC Power Cord

Most pre-mid 1970's amps don't have earth-grounded chassis. It can be a MAJOR safety problem when playing guitar. Guitars generally tie the strings to the ground wire on the amp, effectively "grounding" the player, too...if the chassis really is at earth ground, that is. Believe me, sometimes it's not (Zzzaaappp).

A correctly wired three-prong cord helps to assure that it really is earth grounded (it's not foolproof--there's no guarantee the wall receptacle has a ground connected).

For my own reasons, I chose to wire the Harmony B3500 "modern style"--rather than run a cord through a stress relief and hardwire, I used an appliance-style power cord receptacle. The type for a removable power cord--most modern amps use these. I had some on hand, I wasn't worried that I'd ruin the "vintage" value of the amp (doesn't really have much), and it's a little more flexible, length-wise. So sue me. The wire nut was already there, I just reused it.

Here's the mod from the backside. Suppose I should rivet this instead...

Also added a fuse holder to the AC input. There is a fuse soldered directly to the circuit board, but this is a better setup.The fuse holder also perfectly filled the hole from the old cord (the previous entry to this blog shows the original AC wiring for comparison, btw).

Fitting a New Speaker to the Cab

Since I had an old Utah 15 in. speaker that was unused, the cab seemed perfect. And it worked great.

I used a sheet of 5/8 ply for the baffle board. Sorry, I lost the pics of the 1x2 cleats I installed. But I do have "before and after." Painted flat black, of course...

I used four T-nuts for the screws to attach the speaker. Always seemed like the best solution here. Used a Sharpie to blacken the T-nuts, which worked so-so.

Here's the finished install (again, sorry, lost a bunch of photos).

Yeah, I'll clean up the grill once the weather is decent again in the spring. But everything works well. It's relatively light and portable for gigging.

The speaker itself...not exactly great for guitar, though it sounds OK for bass. There's a reason it wasn't pressed into use before...

The Harmony B3500 Bass Amp

Here's a little bass amplifier I picked up for pocket change: A late 70's solid state bass amp, the Harmony B3500, with a matching cabinet. For reasons unclear to even me, I'm inordinately pleased with this little thing. It's apparently somewhat rare--at least in working order. I haven't unearthed any web photos or documentation.

So the specs are rather unclear, but I can make some educated guesses:

-- B3500 is the retail model number.
-- 7044B-90PB is the factory model number.
-- 35 watt output (EDIT: maybe not. Sucker is loud for a SS amp, could be 50w).
-- Came with optional matching cabinet, 4 or 8 ohm load (Speaker complement? I'm thinking 1x15).

The wattage guess should be accurate--the back label lists the total power consumption at 50 watts (of course output must be lower), while the name itself--B3500--strongly suggests the likelihood of 35 as the magic number. (EDIT: again, rethinking this...might have to hack test the wattage...)

And the speaker load? Harmony sold a sister amp--the L3500--for guitars ("L" for Lead, no doubt). The L3500 had tremolo and reverb, and likely an identical output stage. References to that amp can be found online. Unfortunately they differ as to the cab impedance; sources list both 4 and 8 ohms. One source lists the cab as 2x12, but it's dimensions make that a very tight fit...

The cabinet is missing the original speaker and baffle board, but it's likely from it's size that the original complement was one 15'' speaker. It came with a poorly fitted homemade baffle and a Quam 12C16MI guitar speaker. "MI" for Musical Instrument speaker; apparently Ampeg used them in guitar amps in the late 70's, early 80's. It's painted gold and I have two. I'm fairly curious as to their sound in a good guitar cab. I have a 1950s Quam speaker in my Lectrolab R600 which has a very cool sound, but it has only fair efficiency--not surprising really, for the era.

The cabinet certainly belongs to the head--the width and tolex are identical. For now an old 100 watt Utah 15'' speaker will be fitted to the cab.

It's clearly dated to sometime in 1979. Here's the back of the head. I've redacted the actual serial number, but it's in the 05xxxx range.

As a Harmony product produced in 1979, this amp originates in a "shadow period" of company history. Harmony ceased operations in 1975. Originally founded in by Wilhelm Schultz in 1892, Harmony functioned continuously as a business until that year. Post 1975, Harmony seems to have undergone several incarnations--reportedly as a brand name for Asian-made musical instruments and accoutrements. However, there were a variety of owners and management over a 25 year period until 2000. At that time the name was acquired by M.B.T. International. The Harmony brand was purchased by the Westheimer Corporation in 2009, it's currently owner / operator.

Any additional information about the company during the era of these amplifiers (1979-1982) would be appreciated...

The internals are compact, as early solid state amps often are. The output stage is an NPN / PNP push-pull pair.

Note the fancy script "T" on the PCB. My old 70's Thomas Organ wah pedal has the identical manufacturers mark. I need to track that down...

Despite my dearth of experience with bass amps (I haven't really played bass since the early 70's), I find myself really liking the amp. I acquired an old Peavey Forum bass a couple years ago and it sounds very nice through the B3500--much better than running it through any of my guitar amps. It's punchy but not distorted (up to 9, anyway--and maybe that's 'cause I'm using a guitar cab until I fix up the Harmony cabinet). Sure, it's not loud enough for a rock setting, but it's not too quiet either. 

Anyone else have a Harmony B3500? Or use one back in the day? Drop me a line...

Farmers Insurance is...not so bad (was "worthless crap")

 Two weeks after the accident, I gotta say that "Farmers Insurance" dealt with us fairly honorably, although the claims representative was--not so great through the experience. If I hadn't found a service center and secured a rental myself, who knows how long it would have taken?

In the end, Farmers fixed my car, and they paid for the full rental. I suspect the complaints account on Facebook was a big help.

We were able to visit my ailing Uncle Don in MA pretty much as planned (delayed by one day), and that was the primary reason for the trip. So that was good. Given my uncle's health, I doubt we'd have been able to schedule a trip until late this year, and who knows?

The original post is below:

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Yesterday (Weds, 11:30AM) while at a dead stop in a road construction zone, I was rear-ended by a driver who carried Farmers Insurance. Today we were leaving for a trip to Massachusetts, to visit family and see my uncle, who's in hospice.

2:30PM, Thurs:

27 hours and seven phone calls later, I finally spoke to the claims representative. They tried to contact me once with wrong number yesterday, although I had left them two separate phone numbers, on three occasions... Yet when I called the claim center at 12:30 PM today, their automated system already knew who I was (I'd called yesterday). But when I called back two hours later at 2:30PM, the system no longer knew--the rep had apparently reset the number, rather than use a number that that the automated system had shown to be correct. That second call to the center (today; third total) finally connected me to the representative.

So get this--they accept the responsibility for the accident. But because I was able to drive my vehicle away, we're not eligible to receive a rental. So we're delayed possibly for days while we resolve this issue.

My vehicle is in better shape than the other driver, but the bumper is trashed and the exhaust system looks sketchy. We certainly don't want to drive it 1400 miles.

The moral: DON'T DEAL with FARMERS INSURANCE--if you possibly can avoid it.

Update 1, 3PM Thurs.--I'll keep posting as the farce continues. Now I'm waiting for a response regarding repair options...which they said would be included in an email, but were not... 

Update 2, 4:21PM Thurs.--the Farmers Insurance website sent me a document telling me that my claim was "inactive" until I get an estimate...but the web document could only be accessed by giving the incorrect phone number. And of course neither the representative or the supervisor has responded to my request to clarify a repair location--maybe because they're using the wrong number, even though I've given them each the correct number via phone, and email.

Update 3, 4:40PM, Thurs.--The staff at Farmers has been unresponsive, but their website at least has authorized service locations. I found a helpful person at a local shop, and can take my vehicle in without an appointment. Too bad it's too late for an estimate today...

Update 4, 6:10 PM, Thurs--Receive an email from the claims rep, saying they cannot contact me via phone. The phone number they quote is the same incorrect number they've been calling for a whole day. Even though I'd verbally given the same rep the correct number @ 2:30PM this afternoon, and emailed the correct number at 4:15PM.

So day two ends without resolution.

But my wife contacted Farmers via Facebook, where they have a complaints account. 

Friday Update

Took the vehicle early this morning to the authorized repair center. They were very helpful. They sent us on to the rental agency.

At the car rental we were informed that Farmers would only pay for the days while the car was being repaired. We expected this. But at this point we were a day behind schedule, so we didn't care. We got the rental vehicle and went home to continue packing for the trip.

At 10:15AM I called the claims rep, who had indicated the night before her intent to contact me. But she didn't even try Friday morning. By some miracle I got through. She was pleased the car was at an authorized center (sure--I did all the work), and seemed more sorry for the person who's number she kept calling, rather than my own correct number. I don't have a clue why she didn't try to call me Friday morning, as she'd indicated.

We left town and stopped my mother-in-law's house for a couple hours before leaving OH. Sometime during the drive I received a couple phone calls from their complaints people--probably prompted the Facebook msgs--but we didn't hear the phone in the car.

At this point, I didn't care. By 2:00PM we were on the road, next stop New England, via PA. 

If we had to pay for part of the rental, so be it. I was freaking sick of dealing with them.

Electro-Harmonix Holy Grail Rev A photos

As promised, here are photos of the Electro-Harmonix Holy Grail PCB board (Rev A), from the populated side...otherwise known as "the top." Yes, "Rev A" means the first release of the Holy Grail Reverb pedal.

In time I might even document the wire connections, which are labeled with individual letter codes.

They do make cool stuff...

The first Holy Grail post on Redplate City, with more photos etc., can be found here.

Teisco Checkmate 60--A First Look

Busy times--too many distractions prevented me from posting about the vintage Teisco Checkmate 60 amplifier. But here it is, in all it's worn glory. I'll keep this post mostly a preview, and not include too much detail...

First off, two of the front-panel knobs are missing. It's easy to spot the "stunt knobs" in the photo. The front panel itself is very clean. The tolex is decent.

Here's the back. Sorry, these aren't glamor shots--not enough free time currently. But decent enough resolution, compared to any other web photos.

It's not perfect. Plenty of imperfections. A coating of mouse piss (or is it?) inside to clean up. Some rust, too. The handle is missing.

Let's be straight, right off. The one significant disappointment is the output transformer, which is non-original. More--MUCH more on this later.

But it works, as-is. EVERYTHING works--reverb, tremolo, both channels, all the switches. Even the replacement OT works. Again--more later. And it sounds GOOD.

Whaaa.... That's pretty nasty. Note that some of the crud has already been scraped off the chassis. Luckily, the underside "guts" of the chassis are pretty clean. The chassis itself has an unusual in-cut or inset corner (on right of the photo). On the inset are jacks for the reverb and tremolo footswitchs. The high corner steel panel in the inset is unusual, too--maybe the footswitch and cable tucked into the inset for storage. For some reason, the steel panel has been bent and will need attention.

No way! That's NOT an output transformer for a 60 watt pair of EL34s in push-pull configuration. Nope, it's only attached with one screw--it's too small to reach the second hole in the chassis. The original was definitely larger. But it does provide proof-of-functionality (again, more later). 

The residue around the OT is wax, probably from the current or the previous transformer, which was likely potted. Since the original is gone, it's the primary suspect.

By the time I'm writing this, I've made progress. This amp is COOL.

Specifications

Here's a chart of the chassis, top side. The tubes and major components are labeled. There are four 12AX7, two 12AU7, and a 5AR4 rectifier. There are three multicaps, a reverb tank and the reverb driver transformer.

Power tubes? The Checkmate 60 uses a pair of 6CA7 tubes (EL34). I suspect this IS the original power tube complement. Other sources reference a pair of 6L6 tubes, but I offer as evidence a blurry enlargement from the '68 catalog:

While it incorrectly lists only one (two are required for 60 watts), it clearly does reference the 6CA7, which wouldn't be used in a guitar amp for anything but a power tube (there's also something X 2, but it's nearly illegible--might be a measurement, almost looks like "30cm"). The two power tubes are mounted on a small "daughter board" set into a rectangular hole in the chassis.

The back panel image is below. "Tremolo" and "Reverb" are footswitch jacks. The rest is self-evident. There's some weirdness with the speaker jack wiring, but I'll detail that in a later entry.

Incidentally, a historical Yen-to-USD online calculator indicates that 90,000 yen in 1968 equals $889.90 USD (or 687.98 EUR). Adjusted for inflation, that converts to a value in 2013 dollars of $5,946.25. For both the amplifier and the cabinet, of course. If purchased separately, the cabinet was 32,000 Y, about 35% of the total. You do the math...

Teisco Checkmate 60 amp arrived

A vintage Teisco Checkmate 60 amplifier landed on my doorstep yesterday. It's a flea-bay purchase from a seller in Kentucky. No photos yet; here's one from the seller:

It's circa 1968 or 1969--the Checkmate 60 is listed in the 1968-69 Teisco catalog, along with the May Queen. The catalog page has been floating around the web for years--my thanks to whomever scanned it originally.

More photos and documentation to come.

It's pronounced TAY-sco, BTW...

Cleveland Romper Room organ for sale

A piece of Cleveland baby-boomer history is up for sale: the organ used on the Cleveland production of Romper Room (allegedly) is currently on Craigslist. The seller is based in Euclid, a suburb of Cleveland (for any non-NE Ohio folks).

Here's the link:
http://cleveland.craigslist.org/msg/3702311343.html

The listing itself is rather matter-of-fact:

baldwin organ $49 (euclid) pic

This organ was originally used for Romper Room. Needs repair and some tlc. It powers on but the actual organ pitches need tuned. Will take trades also. Call 216 406 1699 

(A screen capture is below; all CL ads are transitory..)

Romper Room was a long-running children's television program shown mostly in the USA, but also internationally. It was notable because cities could host individual franchises instead of the national broadcast. Cleveland hosted a local production, starring "Miss Barbara" Plummer. While not the first Cleveland hostess, "Miss Barbara" will always remembered locally as the face of Romper Room; the highlight of the production which ran on WEWS from 1958 until 1971.

Tell me, tell me, tell me, do. Magic mirror, tell me today.
Have all my friends had fun at play?

As crude as TV F/X were in the early 60's, the Magic Mirror closing sequence of RR is probably the first TV special effect I remember from my childhood...

So any Do Bee out there with enough living-room space can purchase a bit of local broadcast history...