Difficulty levels for amp building

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VictoriaGuy

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Joined 2008
grimberg said:
The heat sinks were purchased, but all the added metal work was done in my garage using remnants from aviation grade aluminum (T-6061)
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Grimberg:
Still, it's very impressive.
Thanks for sharing the pics and details in that thread, and giving me the link.
Getting large enough heatsinks for these amps is a major problem - I'm cheap!:D
I like to diy chassis or 'repurpose' something from the scrap pile here, but the usual run of heatsinks won't do the job.
Laying out $500+ CAD just for the chassis (4U Deluxe from DIYAudio to Canada?) is serious!:D
Where did you buy your heatsinks and how much did they cost?
 
grimberg

grimberg

Member
Joined 2002
The heat sinks were purchased from Conrad Engineering in Australia. My last purchase was back in 2009 when I bought 8 pairs (16 pieces) of model MF35-151.5. Thanks to a favorable exchange rate the final cost of each piece, including shipping, was $46.

Conrad Heatsinks - Products

Last year I used my last 4 pieces in two identical cases. One houses the M2 clone and the other an F6 clone. At that time, because the exchange rate was around AUD 1.46 to USD 1.00, I contacted them to purchase more, but was unable to get a reply. Member 2picoDumbs offered to help and called them. They claimed to be very busy and said they would answer my email, but I never heard back from them. Maybe you will have better luck.
You should also take a look at HeatsinkUSA.
 
grimberg

grimberg

Member
Joined 2002
The DIYAudio store offers matched pairs. They are currently sold out but they will be back in stock. Contact their customer service for an estimated availability date. There seems to be a couple other trustworthy sources. Search for the word "alweit", he is a member who sold the Toshiba jfets, maybe he still does. Another seller is "spencer", who may still have some available.
 
2 picoDumbs

2 picoDumbs

Member
Joined 2013
grimberg said:
Member 2picoDumbs offered to help and called them. They claimed to be very busy and said they would answer my email, but I never heard back from them. Maybe you will have better luck.
You should also take a look at HeatsinkUSA.
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Gday Mate
I just recently purchased 8 x MF25-151.5 to make 2 x 500mm deep cases.

The guy was very busy for a while, but seems to be a little more responsive with orders now.

Always call by phone where ever possible, if you still have trouble I will chase him up for you.
 
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brianco

brianco

Member
Joined 2005
I am building a stereo Pass M2 clone as two mono-blocs - using external power supplies - with DIYaudio 5unit heatsinks [210x250x40] and off-cut 7mm sheet alloy for top and bottom plates with 3mm alloy sheet opposite the heatsink. I will be using the stores bars on the heatsinks and 10mm sq. bars to give a bearing/fixing for panels. If this works nicely for me I will then strip out the electronics and have the alloy anodised and dyed...perhaps in an electric blue colour!!! :)

(my PS will initially be a single Tx as I have a really nice 600Va 18-0-18V, iron belted transformer. IF this gives a really good performance I will probably just leave it at that.;))
 
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Russellc

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Joined 2003
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ta240 said:
I guess if it were easy (and inexpensive) then everyone would do it but several times I've poured through threads on builds thinking 'this will be my next project' only to get derailed trying to figure out which parts are still available and which can be replaced with what. Or the 'I used old, not available power supply PCBs but you can make do with something else' parts to the build thread. Um, no I can't, not yet at least. I need to copy what you did and then maybe understand what it is doing and be able to tweak it later if necessary.

The other problem I run into is I know just enough to get myself in trouble but not enough to understand many of the posts on how to get back out of trouble with the build.
As a stranger in Electronicsville I'm only slightly familiar with the language and as helpful as many of the residents try to be the language is often way above my head. Sometimes they might as well be shouting "oogly boogly! oogly boogly!" for all of my understanding ability.
As I go through the threads I keep muttering to myself "give me a parts list, give me a parts list for exactly what you are building (and have it be currently available parts)" only to find partial lists with some parts as 'optional' or 'figure out the value based off your other components' and have seen people chastised for asking for a BOM because "Just make a list off the schematic".
As expensive as some of the components are I really want to know up front that I've sourced every part needed before ordering anything.

Having built a point to point single ended tube amp from nothing more than a schematic that sounds really good and then the Amp Camp Amp with the PCBs and sourcing all the parts for it my confidence shot up. Probably higher than it should have been.
I spent a long time shopping for heatsinks for the ACA only to find recently that if I'd drilled down deeper in the menus at the store here they were available separate from the kit (undrilled but still available).

What makes these projects so much fun is everyone innovates, tweaks and changes their build a bit from the prior one; often using some old parts they already had.. But that makes it really difficult for the non-engineer to 'copy'.

Maybe it isn't true DIY then, but I would love a next step up from the ACA that would have PCBs and a tested and proven BOM (with good heatsink specs) that would go together and function well with minimal adjustments like the ACA.
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I have no electronics background whatsoever, it hasn't stopped me. However, one must read these pages and ask questions. I probably would not have been successful had it not been for DIYaudio. All the parts are available if you know where to look. Start with the store and go from there. Ask questions, keep reading...there are plenty of folks out here to help. 6L6's build guides are a great place to begin learning, even if a particular amp isn't the one for you...they mostly have the same or similar power supplies, and each guide covers things differently so there is lots to learn there! The more effort you put in, the more people here will respond.

All this stuff is available, power supply? pretty straight forward and mostly the same for all he FirstWatt amps. Jfets? The store or Spencer. Unsure about a part? ask. Most everything else is available at Digikey or Mouser. Start your BOM and go!

Russellc
 
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V

VictoriaGuy

Member
Joined 2008
Russellc said:
Jfets? The store or Spencer. Unsure about a part? ask.
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You make it sound easy!
Thanks for that info.
From fetaudio.com
(Spencer)
Toshiba J74BL – 6.4 to 10mA (HK$110 each pc); >10 to 11.2mA (HKD$75 each pc)
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HK110 is about $14USD, HK75 is about $9.50 USD
Four J74s are required for a stereo amp, so that's either $56 or $38 plus shipping.
For an Aleph J, which 'grade' of J74 would be better? (The BOM doesn't have details that I could see, the 'Linear Systems' thread has a reference to BL or Grade B 6-12mA?.) It looks like Spencer's 'cheaper' ones are better matched??
The DIYAudio store ones are sold in batches of 8 pcs @ ~$65 but are 'unobtanium' right now and don't appear to be matched very closely - though like much about these amps, it's not clear how important that is...
 
6L6

6L6

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Joined 2010
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VictoriaGuy said:
For an Aleph J, which 'grade' of J74 would be better? (The BOM doesn't have details that I could see, the 'Linear Systems' thread has a reference to BL or Grade B 6-12mA?.)
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Toshiba BL or Linear B (Those are the same Idss range)


VictoriaGuy said:
The DIYAudio store ones are sold in batches of 8 pcs @ ~$65 but are 'unobtanium' right now and don't appear to be matched very closely - though like much about these amps, it's not clear how important that is...
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The bulk LS from the store are not matched.

The matched Jfet from the store will be restocked, we are waiting on our allotment from Linear.

Spencer's Jfets are really good, buy from him in the time being. :D
 
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