miniHRM evolution

[rogb]

Rog, Once you get this complete and running can you post some pics and gut shots?

I will for sure, please see my build update and why it may be a little longer

[dreric]

Messing with the boards based on 10thtx's layout and schematic:

[ampbldr2]

I've been trying to follow the Mini HRM. Are you building exactly to the 86-special schem and layout? And did you use the revG BOM?

[dreric]

I've been trying to follow the Mini HRM. Are you building exactly to the 86-special schem and layout? And did you use the revG BOM?

BTW, sorry about the poor quality in the photos.

I am following the layout and schematic 10thtx posted a page or so back. It's not complete as it doesn't show the power supply on the layout but it was easy to lay it out on graph paper.

I wasn't aware of a BOM, I've been using parts on hand. I found the lack of photo's on this thread, the multiple versions on two web pages (here and Hoffman's) frustrating and I had an old AX84 laying around so I decided to feel my way through the build. Hopefully this will inspire others!

Eric

[azatplayer]

Hey dreric, the schem shows the screen cap and the ef86 cap, branching from the choke output. Yours appears to have them in series. Dunno if it will make a lot of difference, but the voltages thru the nodes are pretty high, it could sag below spec if following from the screen supply in series.
Nice to see some pics!

[dreric]

Faceplate for a 16 x 2 chassis

[ampbldr2]

I've been trying to follow the Mini HRM. Are you building exactly to the 86-special schem and layout? And did you use the revG BOM?

BTW, sorry about the poor quality in the photos.

I am following the layout and schematic 10thtx posted a page or so back. It's not complete as it doesn't show the power supply on the layout but it was easy to lay it out on graph paper.

I wasn't aware of a BOM, I've been using parts on hand. I found the lack of photo's on this thread, the multiple versions on two web pages (here and Hoffman's) frustrating and I had an old AX84 laying around so I decided to feel my way through the build. Hopefully this will inspire others!

Eric

In the files section is a RevG BOM and faceplace files for the 86 special.
http://ampgarage.com/forum/viewtopic.php?t=14254

It would be helpful to have two posts in the files section (1) for "MT's MINI HRM" and (2) for "86-special HRM.

I found the schematic for the "MT's MINI HRM" that Colossal drew but now I can not find the link/post where i found it anymore. I was thinking I was going to build that one as starter and mod it to the ef86 in V2 later if I wanted or just build another amp.

If you can post more pics as you progress in the build would help us out.

[layupe]

Hi all! Im waiting for some parts (mostly caps and pots) i just ordered online and i will start buiding the 86 preamp as soon as i get them...Its not gonna be beauty, i will use an old hifi amp chassis i have around for testing purposses, power and output transformers come from there as well and at least for now i will just use these, probably the OT will be upgraded in the future if everythings goes fine and i decide to build the "final version" we will see...By the way the output section will be that in the AX84 November project with minor changes, 2x EL84 + EZ81 Rectifier switchable to diodes, etc... just for convenience as it is already there!

I will be glad to share my "adventures" in this post if it is the correct place to do so and maybe im gonna need some help from you guys so dont go too far hehehehe

[Ruslan]

HI MAT , I at all have got confused what actual diagram , This small amplifier.

[mat]

HI MAT , I at all have got confused what actual diagram , This small amplifier.

Hi Ruslan, what do You mean ?

[Colossal]

I found the schematic for the "MT's MINI HRM" that Colossal drew but now I can not find the link/post where i found it anymore.

Ampbldr,

Here is the link to the schematic: http://ampgarage.com/forum/files/mts_mini_hrm_190.pdf

And here is the link to the original discussion of Mat's Mini HRM:
http://ampgarage.com/forum/viewtopic.ph ... sc&start=0

[Ruslan]

It is checked up schematic el 84 ef 86 12ax7 [IMG:640:482]http://i073.radikal.ru/1105/17/f4cafc072ab1.jpg[/img] It is real actual schematic????

[10thTx]

Per Mat, who developed the amp ............ this is a copy of the schematic which he reviewed and stated represented his amp along with the voltages that he gave me regarding his amp.

I don't know if he has tweaked it any more beyond the original, you'd need to ask him?

There is an ExpressSCH editable version of it here:
http://www.el34world.com/Forum/index.php?topic=9149.0

With respect, 10thtx

[mat]

Hi Ruslan,

Sorry for the late responce. Check the 10thTx's schem. That is how my amp is wired. No mods after that. No build/tweak time at all for me

[talbany]

Sorry late to this party..Looks like a cool amp although I am not a big fan of the SE amps..I have messed around with this EF86 circuit and will add by changing the value on the 820k is a good way of playing around with the gain structure on that 86.. Mat...Did you play around with this and arrive at the 820..Just wondering..

Tony