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Could anyone shed any light on this amp for me?
Could anyone shed any light on this amp for me?
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Old 18th August 2014, 09:41 PM   #1
dwjames is offline dwjames  United Kingdom
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Default Could anyone shed any light on this amp for me?

Hi all,
I've been offered an amp, but the seller knows very little about it other than that it has 2 x el34, 1 x 6sl7 and 1 x Westinghouse 5u4 and some big transformers.
Would anyone be able to check out the pictures and let me know what you think?
Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.Click the image to open in full size.
It looks reasonable well put together to me, and is reported to sound great, but I wouldn't have a chance to hear it before buying.
Are there any obvious good points or dodgy / dangerous things to look out for?
Is it a popular kit/design or something more homebrew?
Thanks in advance,
James
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Old 18th August 2014, 09:59 PM   #2
djn is offline djn  United States
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Looks like a low powered EL34 SET amp home brew. It should sound good and looks like there is a lot to work with if you wanted to mess with it.
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Old 18th August 2014, 10:09 PM   #3
ballpencil is offline ballpencil  Indonesia
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Looks like your typical run-o-the-mill Single Ended amplifier.
Wiring could be neater so there MIGHT be some hum but the regular suspects like heater wires are twisted so at least the builder is aware of such issue.
The volume pot looks of good quality ALPS.
The output transformers are properly sized.
Do you have the speaker for them? Single Ended amp needs to be coupled to sensitive speakers.
If it were me, i would buy it.
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Old 18th August 2014, 10:35 PM   #4
JonSnell Electronic is offline JonSnell Electronic  United Kingdom
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An amplifier that needs a lot of tidying up.
If it is cheap, buy it. If not let it go. I would use a tag board and put the components where they should go ... next to where they are going and not lots of wires everywhere.
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Old 19th August 2014, 07:35 PM   #5
Adolf Corkscrew is offline Adolf Corkscrew  Finland
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Looks a lot like Hammond iron. I agree with JonSnell, if it's cheap, go for it. Hammond iron is usually quite good. But I also agree that the build is not the cleanest possible work, though not outright shoddy either. I've seen builds that make me only want to rip everything out of the chassis and build the thing again from scratch.

A schematic would help a lot...
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Old 19th August 2014, 07:52 PM   #6
dwjames is offline dwjames  United Kingdom
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Thanks guys, really appreciate it.
I found out a bit more today.
Transformers are all Hammond classic with 1627 output transformers.
It's been originally built to the JE labs schematic.
I agree, it could do with a tidy up and moving components closer to where they're being used, but it'll sound nice and give me a good idea of whether I get on with a SET amp, so I'll give it a go.
I'm replacing a kel84 in triode mode running approx 5w into some heybrook sextets, so I'm good with the low power output.

Thanks again,
James
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Old 19th August 2014, 07:59 PM   #7
Adolf Corkscrew is offline Adolf Corkscrew  Finland
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One thing though. If the EL34's are run in triode, the 6SL7 is a little weak driver alone for them. I designed a basic EL34 single ended a couple of years ago with Hammond 125FSE's run at 5k primary. I used a 6SL7 input stage DC-coupled to a 6J5 cathode follower to achieve some kind of slew rate driving the EL34 grids. Does sound nice, though.

At least you'll get some quite decent OPT's for your money.
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Old 19th August 2014, 08:49 PM   #8
azazello is offline azazello  Bulgaria
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Cheap ampl. with cheap parts inside. Power in triod mode about 3 wt, if it enough for Your speakers. In penthode mode - about 6-7 wt, but with sharp sound from EL34, that will press You after one or two hour. IMO, I don't like EL34 in penthode mode with it "guitar" sound. I don't know what kind of OT, but they looks maybe good with big iron. All irons look good.
In Your place I will buy it and change EL34 to 6AS7, maybe in single or parallel mod , if OTs allow, acc. new schematic with really better sounding.
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Old 19th August 2014, 10:31 PM   #9
JMFahey is offline JMFahey  Argentina
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Donīt know why would anybody call it a "Cheap ampl. with cheap parts inside" ... except maybe those who ride an oil burning 70's VW Beetle with a sticker stating "My other car is a Mercedes"
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Old 20th August 2014, 01:48 AM   #10
Junm is offline Junm  Philippines
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why not audition it first then when its good sounding , buy it. Why bother to modify it.

Neat and tidy wiring, beautiful look, expensive parts doesn't mean a very nice sounding amp..

Look at ones in the net for sale...very good looking, good specs but some sound never mine...those needs a real modifications...
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