miniHRM evolution

azatplayer · Post by **azatplayer** » Sun Mar 27, 2011 12:53 am

yeah i was surprised to see 325 volts from 190-0-190 secondaries. I had to check my rectifier knowledge see if there was a doubler!

mat · Post by **mat** » Sun Mar 27, 2011 4:38 am

Hello Jeff,
I'll measure the voltages as soon as I can. I'm out of town at my wifes parents. We are celebrating our childrens birthday. I'll get back asap.

bepone · Post by **bepone** » Sun Mar 27, 2011 9:35 am

mat wrote:Josip, thanks for the clips. Great potential there. I think the speaker plays big part on getting the amp to sound good. Let us know if You will try different speakers/cabinets on the amp.
To me the old Zoom H4 recorder sounded quite bad comparing to our other recording setup(SM57-Firepod-PC).

Would be nice to hear a clip of volume and gain cranked and guitar volume backed to 6 or something.

hello mat, unfortunately i have only h2 recorder, not any mic at home.... yesterday i tried again. amp was connected to other speaker (mesa boogie caliber 50, some celestion custom model) and sound was better, not so nervous, also i tamed some bass. sound was very very veery good. but when i came home i saw that h2 was in clipping all the time.

i must invest more time theese days..regards, josip

bepone · Post by **bepone** » Sun Mar 27, 2011 10:06 am

my prototype, i develop pcb-s for it to work easier
(it is anything to be proud of

chassis is prototype chassis for every other small amp which i build from scratch ) but i'm very happy with it, no noise, no humm, no hiss (i have carbon comp resistors everywhere)..amp dimensions are 30x17 cm, also left pcb have 2 little relay places on it, so i can upgrade to footswitch with ch/mid boost switches which will make this little amp to 4 ch amp. good maybe for studio use.

[IMG:160:120]http://i284.photobucket.com/albums/ll34/bepone/th_270320113354.jpg[/img] [IMG:160:120]http://i284.photobucket.com/albums/ll34/bepone/th_270320113355.jpg[/img] [IMG:160:120]http://i284.photobucket.com/albums/ll34/bepone/th_270320113357.jpg[/img] [IMG:160:120]http://i284.photobucket.com/albums/ll34/bepone/th_270320113358.jpg[/img]

rogb · Post by **rogb** » Sun Mar 27, 2011 10:15 am

double

rogb · Post by **rogb** » Sun Mar 27, 2011 10:17 am

azatplayer wrote:Ahhh be great to compare notes!
Ive ordered trannies from Heyboer, using a 3k/5k OT. Im going parallel EL84's on mine.
Plan is to wire in separate cathodes for each EL84, and use a dpdt switch to throw in the second cathode and change primary from 5k(single) to 3k for both tubes. Give me 5 watts which i think is great for a lot of gigs i do, but also a little more grunt/headroom from the extra tube when needed.

Im still undecided on whether to go tagstrips or make a board. Theres not a lot in there but i also wanna simplify things. Mat has only 5 knobs on his amp. Where this layout thats been suggested runs 7. I like the idea of using more trimpots and internal switching, so you can mess with it, but keep the front simple. Like the bright switch, im not putting one in, will determine what is needed when its built, one less thing. Might even decide that leaving the 86' on all the tme is what I like.

Be great anyways to see the two amps come out.
What are you planning on using for speakers?

My front panel runs (LtoR) input jack, mid boost (sw1), bright1&2(sw2), PAB(sw3), clean/od(sw4), treble(pot1), bass(pot2), clean master(pot3) drive(pot4), led.

Speaker will be a 10" Emmi Delta Lite

mat · Post by **mat** » Sun Mar 27, 2011 8:27 pm

10thTx wrote:Mat,

I know you're busy, but when you can, it would be important to know the accurate voltages on the EF86 tube at node C?

If 325v is accurate then another PT such as a 270FX may be needed instead of a 269EX for the single ended version 86 Special?

With respect, 10thtx

Hi Jeff,

Finally got time to check the voltages on the 86-Special. The picture shows how the EF86 is connected on my build but the voltages are from my TOS/dumble build. Very sorry for not pointing that out earlier. I have been really busy for too long time not to check them out.

Here are the measured voltages:

full bridge rectifier - 268V
node A - 262,5V
node B - 256,6V
node C - 260,5V
node D - 259V

V1(12AX7)
pin1 - 154,5V
pin2 - 1,555V
pin6 - 157,2V
pin8 - 1,484V

V2(EF86)
pin1 - 51,2
pin3 - 0,811V
pin6 - 104,7V

V3(EL84)
pin3 - 6,3V
pin7 - 256V
pin9 - 251,5V

Again, the power transformer is no name one without any numberings on it.

10thTx · Post by **10thTx** » Sun Mar 27, 2011 8:48 pm

EXCELLENT !!!! Thanks, Mat ! That is a tremendous help.

The Hammond 269EX is 190-0-190 (65ma)

190 X 1.4 (solid state rectification) = 266v

So that is pretty reasonably close to what you'd have on node A. Given that I think the 269EX would be a reasonable choice.

With respect, 10thtx

rogb · Post by **rogb** » Mon Mar 28, 2011 11:51 am

10thTx wrote:EXCELLENT !!!! Thanks, Mat ! That is a tremendous help.

The Hammond 269EX is 190-0-190 (65ma)

190 X 1.4 (solid state rectification) = 266v

So that is pretty reasonably close to what you'd have on node A. Given that I think the 269EX would be a reasonable choice.

With respect, 10thtx

Thanks mate, for clarifying that
got the 269EX staring forlornly at me from the desk

Saved from the scrap heap, little fella...

azatplayer · Post by **azatplayer** » Mon Mar 28, 2011 11:57 am

Mat, is the far right knob on your amp the drive tone? Is that something that can have a trimpot instead? Or is it pretty usable?

bepone · Post by **bepone** » Mon Mar 28, 2011 3:40 pm

one more (for the record

)
ECC83->EF80->PCL's86 , Gibson LP, Celestion 1x G12-100, zoom h2

http://www.soundclick.com/player/single ... i&newref=1

mat · Post by **mat** » Tue Mar 29, 2011 4:54 am

azatplayer wrote:Mat, is the far right knob on your amp the drive tone? Is that something that can have a trimpot instead? Or is it pretty usable?

The drive tone pot (a small one) is next to the drive pot. I would say it is very usable.

mat · Post by **mat** » Tue Mar 29, 2011 4:57 am

bepone wrote:one more (for the record )
ECC83->EF80->PCL's86 , Gibson LP, Celestion 1x G12-100, zoom h2

http://www.soundclick.com/player/single ... i&newref=1

Sounding good. Is this with the Mesas speaker ? I think I can hear the speaker or the power section adding a bit too much lower mid section frequencies to my taste to not make the sound clear or balanced. What is Your settings of the potentiometers on the amp/guitar?

azatplayer · Post by **azatplayer** » Tue Mar 29, 2011 6:32 am

Thanks Mat.
hey the pics of your amp show only 5 pots but the schemo has 7.
I know the pre volume is a trimmer, what is the other one that you have as a trimmer? The OD level?
Im keen to keep the front simple as possible, as i like on any build.
Thanks buddy.

rogb · Post by **rogb** » Tue Mar 29, 2011 9:22 am

azatplayer wrote:Thanks Mat.
hey the pics of your amp show only 5 pots but the schemo has 7.
I know the pre volume is a trimmer, what is the other one that you have as a trimmer? The OD level?
Im keen to keep the front simple as possible, as i like on any build.
Thanks buddy.

Whoops, forgot the 1M OD Master pot off the front panel

Thanks for making me recount the pots

Lucky I left a space on the back panel for that kind of thing

Fitting that in would mean moving a switch to the back and rejigging the whole thing, but it's too late as the panels are being cut today.

I think the best plan with this build is to tweak it to your own needs and space requirements. With a 12x2 panel there is a limit to how many controls you can fit in

Tube Amp Archive

miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution

Re: miniHRM evolution