Tmannion87
31 posts
Oct 07, 2014
7:41 PM
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Hi all,
I just picked up a Silvertone 5XL and was wondering if they are any good for harp? Looks like it's a hand-wired, point-to-point, single-ended Class A amp with 12AU6 for pre-amp, 5OC5 output, and a 35W4 tube rectifier. Any input would be greatly appreciated, thanks!
http://www.tonegems.com/amps/sears-5xl/
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bluzmn
84 posts
Oct 08, 2014
4:32 AM
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Amps with that tube complement and that design are called "widowmakers" because they can KILL you. I'll leave it to someone like Greg Heumann to explain it to you technically, but do NOT even plug it in until you have a qualified amp tech install an isolation transformer.
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bluzmn
85 posts
Oct 08, 2014
4:54 AM
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OK, after looking at the pictures and a schematic, it looks as though this amp might have a power transformer, which may isolate you from the deadly voltage. I'd still have a tech look at it, though.
Last Edited by bluzmn on Oct 08, 2014 4:57 AM
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Bilzharp
28 posts
Oct 08, 2014
6:45 AM
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In the schematic referenced, there's just a small filament transformer for the 12au6 so I guess this would still be a "widowmaker" circuit.
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Barley Nectar
549 posts
Oct 08, 2014
7:53 AM
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This type of amp that does not have a PT to supply the circuit with AC, are unsafe. The use of an isolation transformer is not a particularly good fix either. Isolation transformers are NOT intended to be a safety device. This was verified to me buy a Hammond design engeneer. Also verified by my brother who is an EE and works substation division for a major electricial utility. An isolation transformers intended use is to eliminate the passage of noise and/or electricial spikes from it's primary, to it's secondary. Isolation transformers will eliminate the circuits reference to ground. This means that your body will become the reference to ground when you touch a grounded object. Do you want to be the "reference to ground"? I don't!
IMO, you 5XL will be a nice display piece but can not be made safe by using an isolation transformer. To make this type of amp safe you would have to do an extensive rewire to update the circuit to a modern accepted circuit arrangement.
No doubt I will get argument on this to which I will not respond.
Just to repeat: Isolation Transformers are NOT intended to be safety devices. Take care...Goose
Last Edited by Barley Nectar on Oct 08, 2014 8:00 AM
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HawkeyeKane
2650 posts
Oct 08, 2014
9:49 AM
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Kind of amazes me....these didn't come out until '68 or so. Who the hell else in their right minds were making Widowmakers at that point? Furthermore, who else was making amps with those old outdated radio tubes?
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Hawkeye Kane - Hipbone Sam
Last Edited by HawkeyeKane on Oct 08, 2014 9:50 AM
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NiteCrawler .
313 posts
Oct 08, 2014
11:53 AM
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Harmony H303,s have the same tube lineup as these Silvertones.I,m sure that Danelectros probrably also have similar amps from this time period.Dano made amps for Sears in Neptune City,N.J. back in the day.I have a 303 that i got cheap yrs back and its a very low powered 5 watter.Fortunately it did,nt kill me the last time I used it.I was wondering why my wife always wanted me to play through it.(she knew more about it than I did)
Last Edited by NiteCrawler . on Oct 08, 2014 12:32 PM
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NiteCrawler .
314 posts
Oct 08, 2014
2:02 PM
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I would,nt say that its useless.How does it sound to you?I,ll plug into my 303 in the next couple of days(its been a while)and give you an update,.I,m sure theres thousands(many) of folks, who have played through this type of amp with no harm done.I also have a Harmony 400 model that I made the mistake of jumping,piggybacking into another amp and lets just say it has,nt worked since.I believe it had something to do with the single tranformer if I,m not mistaken.Have faith,if it sounds good to you I would,nt sweat it.
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HawkeyeKane
2652 posts
Oct 09, 2014
9:44 AM
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Tmannion...here's a good little article about Widowmakers...
Lectrolab Guitar Amplifiers - Widowmaker?
I'd say crack her open and see if there is indeed a transformer inside and how it is wired up. Does yours have the ouput transformer mounted to the speaker basket like the one in the review?
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Hawkeye Kane - Hipbone Sam
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NiteCrawler .
315 posts
Oct 09, 2014
1:05 PM
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@HK thanks for the article.I have the same Lectrolab R 200 but its badged Sound Projects/Chicago.It was given to me from a friend who was clearing out some of his 90 yr old grandmothers belongings when she passed.He also gave me her late 60,s Hammond with a Leslie.It wasn,t a very popular model, hence I sold it for about $300.Now the R 200 was the prize in the deal and is an awesome sounding little harp amp,especially for as cheaply made as it is,it has a real bark to it especially for five watts.I never knew about the widow maker curse although I,ve always wanted to add at least a three prong cord,but just havn,t gotten around to it.I have piggybacked it though through my Princeton and Kalamazoo without any issues which makes me think again about what happened to the H 400, which is pretty ironic that its mentioned in the same article.Thanks again for the article,I will heed the warning and add it to my to do list.
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Silvertone
164 posts
Oct 10, 2014
6:45 AM
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Heres a 5xl that my buddy got for Xmas a long time ago. There are definitely 2 transformers on the chassis and none on the speaker. I imagine there are multiple circuits for this amp. This one hums like a mofo and definitely need new caps. Im not sure how those transformers are wired in the chassis.
Thanks Hawkeye!!
Last Edited by Silvertone on Oct 10, 2014 8:16 AM
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HawkeyeKane
2655 posts
Oct 10, 2014
8:06 AM
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Silvertone...you need to use the HTML link to embed photos so that they're viewable here.
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Hawkeye Kane - Hipbone Sam
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Greg Heumann
2857 posts
Oct 10, 2014
8:20 AM
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I agree with Barley - the existence of lack thereof of a power transformer doesn't have much to do with the lethality of an amp. Either way - old ungrounded amps used the chassis itself for ground - to which your mic cable is connected. If that ground is not tied to "earth ground" - the potential can "float" at voltages other than zero. And if a component (such as the "death cap" often referred to) fails - you can have high voltage on the chassis. Even a little Kalamazoo has 500 VAC running around, and about 350VDC, which is probably even more dangerous.
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***************************************************
/Greg
BlowsMeAway Productions
See my Customer Mics album on Facebook
Bluestate on iTunes
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Bilzharp
29 posts
Oct 10, 2014
9:18 AM
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Silvertone,
The transformer on the right in your photo is too small to be a power transformer. That would be the filament transformer (T1) that is shown in the schematic linked in the first post and provides no isolation. Even just as a living room amp, I wouldn't play it barefooted or use it with any other grounded electronic equipment that you might inadvertently touch (like a pa microphone).
Nitecrawler,
The article that Hawkeye referenced concluded that the author's Lectrolab 200 was NOT a widowmaker circuit but would definitely benefit from a properly installed three prong cord and a FUSE. I had a 12 watt Lectrolab years ago and I know first hand that they made some great sounding amps - if a bit homely.
Last Edited by Bilzharp on Oct 10, 2014 9:21 AM
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HawkeyeKane
2656 posts
Oct 10, 2014
10:02 AM
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"I had a 12 watt Lectrolab years ago and I know first hand that they made some great sounding amps - if a bit homely."
That's no lie. My band leader has an R500, and it sound killer for harp.
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Hawkeye Kane - Hipbone Sam
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Tmannion87
33 posts
Oct 12, 2014
4:19 PM
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The amp should arrive tomorrow, I'll post a pic when it does.
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