Thinking about re-doing the original Southwest Tech Tigersaurus with a new board that will accommodate a more up to date transistor array by eliminating the hard to find and costly 40410 and 40409 transistors that are mounted on their own heat sink. Does anyone have any ideas for a replacement transistor? I have located some 40409's and 40410's but at $10 a piece its a little more than I want to spend on my retirement income.
For those not familiar there was an article in the 1973 March-April issue of Radio Electronics. Designer was Daniel Meyer. This was the design that he discussed with Bongiorno and shortly after the discussion Bongiorno came out with the Ampzilla which copied Meyers quad diff front end.
For those not familiar there was an article in the 1973 March-April issue of Radio Electronics. Designer was Daniel Meyer. This was the design that he discussed with Bongiorno and shortly after the discussion Bongiorno came out with the Ampzilla which copied Meyers quad diff front end.
Back in the day, I replaced unobtanium (here) 40409/10 with cheap and plentiful BD139/140, with small heatsinks added, just a pinky sized strip of aluminum, one end touching and glued to PCB; otherwise in the long run (I am into musical instrument amplifiers which get bounced around) added weight would crack transistor legs.
Worked flawlessly.
You can search for stronger and better SOT39 case transistors, of course, but as starters, those will do.
Worked flawlessly.
You can search for stronger and better SOT39 case transistors, of course, but as starters, those will do.
The OP's asked the same question over a year ago and was given plenty of TLC.
The only thing I can add is to use small perf boards to fit the current transistors with the BCE pinout to the original CBE pad.
With that being said, The SWTP Tigesaurus is a dated design and is notoriously unreliable; you're better off picking something more contemporary like Nelson's New Stasis front end.
The only thing I can add is to use small perf boards to fit the current transistors with the BCE pinout to the original CBE pad.
With that being said, The SWTP Tigesaurus is a dated design and is notoriously unreliable; you're better off picking something more contemporary like Nelson's New Stasis front end.
Thanks for bringing that up along with the thread that I couldn't find. Now that you have linked the thread I am able to re-read it and possibly work on it.
I realize its a dated design but unless you've listened to a Tigersaurus you cannot fully appreciate it. I happened to have purchased several from the late DJK many years ago and rebuilt them and never had a problem with them. I guess it might depend on a persons ability to construct the kit correctly which in my humble opinion keeps them from going up in a puff of magic smoke. I enjoyed them for many years and unfortunately they got destroyed in the move back home from AZ.
I realize its a dated design but unless you've listened to a Tigersaurus you cannot fully appreciate it. I happened to have purchased several from the late DJK many years ago and rebuilt them and never had a problem with them. I guess it might depend on a persons ability to construct the kit correctly which in my humble opinion keeps them from going up in a puff of magic smoke. I enjoyed them for many years and unfortunately they got destroyed in the move back home from AZ.
Mark posted the original 70W Tiger.
Tigersaurus, 200+W, is similar but 2-high 2-wide output stage.
This has the error at point G.
https://worldradiohistory.com/Archive-Radio-Electronics/70s/1973/Radio-Electronics-1973-12.pdf
pg 43, 11MB PDF
If you wonder how a 2N5087 can live on 70V rails, note D1 D5 and R18/19. This works because the output stage has gain.
Thanks.
If available, can you please upload part 2 of that article?
The one with the parts list?
Schematic in post #4 has no component values.
Thanks.
Good morning all,
I've been interested in the Tigersaurus amplifier since I became aware of Avondale Audio's SE range of amplifier boards which are using the same output set-up i.e. common emitter (Sziklai) complementary pair. Schematics aren't available.
I'd like to make one of these Tigersaurus devices and would be interested in any new PCB design or a simple copy of the original - how is @vargasmongo3435 getting on with this? I know the 40409/ 40410 aren't cheap nowadays but I'd rather build this true to original if possible incorporating the "known fixes".
Looking through other threads I see in one, a good many years ago, that @Diogenes advised he had copies of the Benjamin Poehland articles from issues 1 & 2 of the 1990 Audio Amateur entitled "Taming the Flaming Tiger - A Restoration Odyssey" along with Walt Jung's review of this amplifier.
@Diogenes - if you're reading this please contact me as I don't have sufficient rights to contact you at this point.
Equally if anybody else reading this has access to these articles I'd love to have a copy please.
Although the transformer in the original is quite large I do wonder if it was actually fully up to the job of supplying the power required and, equally, the PSU smoothing capacity doesn't seem overly generous and with 75V rated capacitors there doesn't seem to be a great deal of headroom and 100V rated devices would seem a better long term investment???
Regards
Richard
I've been interested in the Tigersaurus amplifier since I became aware of Avondale Audio's SE range of amplifier boards which are using the same output set-up i.e. common emitter (Sziklai) complementary pair. Schematics aren't available.
I'd like to make one of these Tigersaurus devices and would be interested in any new PCB design or a simple copy of the original - how is @vargasmongo3435 getting on with this? I know the 40409/ 40410 aren't cheap nowadays but I'd rather build this true to original if possible incorporating the "known fixes".
Looking through other threads I see in one, a good many years ago, that @Diogenes advised he had copies of the Benjamin Poehland articles from issues 1 & 2 of the 1990 Audio Amateur entitled "Taming the Flaming Tiger - A Restoration Odyssey" along with Walt Jung's review of this amplifier.
@Diogenes - if you're reading this please contact me as I don't have sufficient rights to contact you at this point.
Equally if anybody else reading this has access to these articles I'd love to have a copy please.
Although the transformer in the original is quite large I do wonder if it was actually fully up to the job of supplying the power required and, equally, the PSU smoothing capacity doesn't seem overly generous and with 75V rated capacitors there doesn't seem to be a great deal of headroom and 100V rated devices would seem a better long term investment???
Regards
Richard
I've been looking on eBay for a while now and copies of Audio Amateur don't crop up very often, let alone the ones I'm looking for. I have no problem with buying.
Regards
Richard
Issues of TAA do show up here in swap from time to time.
I sold some here myself.
And TAA issued the first decade of their mags on a CD. Well worth it.
https://cc-webshop.com/collections/audio-amateur-magazine
I sold some here myself.
And TAA issued the first decade of their mags on a CD. Well worth it.
https://cc-webshop.com/collections/audio-amateur-magazine
Good afternoon all,
I recently bought a Tigersuarus from a seller in the U.S. which, unfortunately, wasn't as well packed as I would have wished for. 😡
The package was clearly dropped at some point. The plastic PCB mounts didn't survive as you can see and the meter plastic face cover got cracked.
I intend to firstly put it back together and then power it up via a variac and see whether or not it works before carrying out upgrades as per Poehland's two TAA articles.
Does anybody have any idea where a replacement plastic face cover for the meter might be sourced?
Regards
Richard
I recently bought a Tigersuarus from a seller in the U.S. which, unfortunately, wasn't as well packed as I would have wished for. 😡
The package was clearly dropped at some point. The plastic PCB mounts didn't survive as you can see and the meter plastic face cover got cracked.
I intend to firstly put it back together and then power it up via a variac and see whether or not it works before carrying out upgrades as per Poehland's two TAA articles.
Does anybody have any idea where a replacement plastic face cover for the meter might be sourced?
Regards
Richard