| gypsielectro |
I: have a *workable* schematic; the tubes, transformers, and $$
You: have the time and experience to breadboard together a working prototype Monoblock Single-Ended Class A Amp
I'm looking for a quote; more details will be provided by request
Suggest: 50% payment on acceptance of your quote with balance of 50% paid on completion of the project
*Humor me; I have $$ to spend but v. little time + zero experience
Post here to followup, or email me: gware@eudoramail.com
I'll reply to all emails and followup postings here
Graham Ware |
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| Audio_idiot |
Hi,
A show of your "workable circuit" will be helpful.
Cheers |
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| gypsielectro |
These are *similar* to 6384 Bendix tubes, which in turn are part of the 6AR6/6L6 family
Jean-Paul has archived a link to a basic circuit here: ( which does not include a power supply )
http://www.diyaudio.com/forums/atta...tamp=1047252197
and there is an archived post for an Amp using the 6384 Bendix tubes here
http://www.the-planet.org/audio.html
courtesy: Gary Kaufman
I would stress; I am *NOT* attempting this as a commercial undertaking; this is strictly an Amp for my own use and enjoyment
*If Gary us unhappy with me posting the link; I will request a moderator remove it*
The specifications of the 6889 are here: ( warning, it's a PDF file )
http://datasheets.electron-tube.net.../131/6/6889.pdf
The 6384 is a very similar tube; but does not use a cap on top of the tube which the 6889 does; specification of the 6384 is here: ( warning, its a PDF file )
http://datasheets.electron-tube.net.../131/6/6384.pdf
I've been recommended to use 5K transformers for single ended Class A type Amp: and already have a Pair of Transcendars ( www.transcendar.com ) their Part number
TT-016-OT
I have 16 ohm Speakers which are v. efficient and the Amp only needs to make 1-2 Watts, I would prefer 2 x Monoblocks as opposed to 1 x stereo chassis
I have another 6384 schematic from a Japanese magazine I would have to scan and upload
I'm hoping that I can find someone to breadboard together a single working Monoblock; I will then construct a chassis based on that
Kind of like this:
http://wavebourn.com/images/4101/4101-maket.jpg
but I'm keeping an open mind and I'm open to suggestions
Best!
Graham
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| Bandersnatch |
Hey-Hey!!!,
Seems a waste to run the 6889 as a triode. Any special reason not to pick a triode instead?
If you must go ahead, what you propose is a week's work. It is going to take an undetermined amount of time *more* than a week depending on how complete your parts shopping has been, and what you want that isn't there already.
How complete should this breadboard project be? Here you have left a lot to assume( as I did above ). If you want it working, on a board, that's one thing. If you want a it attached to a plate you can drop into a base, that goes a bit farther than breadboarding( and the 1 week estimate ).
cheers,
Douglas |
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| gypsielectro |
OK, a week narrows the parameters down; let's argue that a Tech with the Right Stuff, working at a reasonably unpressured pace ( maybe in their own time ) is worth US$25.00 an hour, with a week ( 40 hours ) achieving results
Say; US$1,000 worth of labor
*Plus parts*
My expectation would be to be delivered the basis of a running, reliable, stable Amp; but not Rocket Science or miracles
Say we spread that 40 hours over 8-10 weeks to allow for accumulation of Parts, assembly and testing, you can set your own pace
*Price of parts is not included
*US$1,000 is the budget for labor ( max. )
* 10 weeks is the turnaround ( max. )
Could a single, simple, working Monoblock with a temporary base of say: *1/16th inch plywood/plastic/scrap * be assembled + tested within that timeframe?
And within that budget?
IE, not a completed, plug and play showpiece exhibit; but *definitely* a prototype that had been assembled and tested
Suggest: I could use the 1st chassis as the basis for assembling a second Monoblock myself
+@I could make a chassis out of something other than scrap at my own pace thereafter
Again; nothing is "carved in stone"
In the last 12 months I've had a Phono stage built for me using a DACT board ( Singapore ) and a turntable power supply built from scratch, ( Australia ) both successful one-off projects
What I am proposing *May* be realistic or unrealistic; feel free to comment!
And OK, maybe this goes *beyond* breadboarding....
GW |
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| garbage |
how abt monos that look like these:
:) |
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| audiovista |
"...What I am proposing *May* be realistic or unrealistic; feel free to comment!..."
Graham,
I'd say that your budget for labor and time seems reasonable. Same for the expectations as to what you should get in the end.
Boris |
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| gypsielectro |
| quote: | Originally posted by audiovista
"...What I am proposing *May* be realistic or unrealistic; feel free to comment!..."
Graham,
I'd say that your budget for labor and time seems reasonable. Same for the expectations as to what you should get in the end.
Boris |
Boris,
OK, then it looks like I'm on track, anyone want to out their hand up and take the job?
GW |
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| Bandersnatch |
Hey-Hey!!!,
I would consider it, but I have to finish this one first!
http://www.audiokarma.org/forums/sh...ad.php?t=105378
This one is a cross between presentable and breadboard. It will eventually get another output TX and 813 finals....:)
cheers,
Douglas |
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| gypsielectro |
| quote: | Originally posted by Bandersnatch
Hey-Hey!!!,
I would consider it, but I have to finish this one first!
http://www.audiokarma.org/forums/sh...ad.php?t=105378
This one is a cross between presentable and breadboard. It will eventually get another output TX and 813 finals....:)
cheers,
Douglas |
That's a great looking Amp and many thanks for your feedback and input;
I've accepted an Offer today from a DIYAudio guy in the Netherlands who is just starting his own tube Amp business
I'll post the results up here in a few weeks when we're done
Thanks to all who have contributed ideas!
Graham Ware |
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| d2134 |
| Yes, I want the job and I like this kind of jobs. I have send you a mail. |
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| Alastair E |
| quote: | Originally posted by gypsielectro
Boris,
OK, then it looks like I'm on track, anyone want to out their hand up and take the job?
GW |
I would be quite happy to undertake the job, Ill send you an email... |
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| gypsielectro |
| quote: | Originally posted by Alastair E
I would be quite happy to undertake the job, Ill send you an email... |
Many thanks for your interest; I now have a guy in Holland that's accepted the commission; if this deal doesn't happen I'll let you know!
GW |
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| gypsielectro |
OK, we went a little bit beyond "breadboarding" as you can see (! )
Henk at Tubeworks in the Netherlands has been :cool: Super-Good :cool: to work with; the 6889's I originally supplied him were *shot* ( I had no way of testing these ) so another Set were found that were NOS, that held things up for a couple weeks but he kept us his level of enthusiasm despite my throwing that spanner in the works
Henk has offered me options to improve the Amp as it's progressed; it has self biasing and a "soft start" Option which should extend the life of the tubes as well as reducing power up/down thumps through the speakers, and saves me poking multimeters under the thing and frying myself....
The setup looks nice, but is temporary as I will transfer the "guts" to other more permanent chassis when these Monoblocks arrive
*Aluminum chassis have already arrived, ex-Thailand*
Will be pushing along a Pair of 12" Tannoy Reds; my PreAmp is an English Woodham, balanced and Tube
Will post more as it happens; I'm very pleased with progress and can't wait to hear these ;)
The Amp: Bendix 6889 is the power tube with Raytheon 5842 ( WE 417A equivalents ) x 2
Picture is one of two Monoblocks, I'll post pictures of the finished product and a review of the *Sound* as it happens....
El Gippo , Tokyos Electric Gypsy |
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| audiovista |
Graham,
It looks really good for the first proto. Thanks for sharing the picture and please keep us updated with listening impressions and finalized chassis.
Good luck,
Boris |
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| gypsielectro |
Hey Boris;
apparently my builder/designer was unhappy with the WE417a's and has talked me into EC86's; no hardship as these are quite readilly available
Apparently the EC86's can handle the voltage swing better and the input to these Amps is balanced/XLR's
About a week away from the 2nd Monoblock being completed and another week or to freight to Japan, I'll post here and let you know the results :wave2:
Gypsies go Electric |
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| audiovista |
Graham,
Looks like you're in for a treat!
Enjoy,
Boris |
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