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Messages - ilyaa

Tubes and Hybrids / Mesa Triple Rec Woes
March 16, 2020, 07:13:54 PM
hey team!

trying to stay busy and keep working as the world burns....

and this stupid mesa triple rectifier is not helping my mood!

it has a weird hum (ground-esque) -

mostly on channels 2 and 3 but sliiight hum on channel 1, as well.

it stays, but quiet, if i pull V1 and goes away completely if i pull V2 -

its def in the preamp (half-split the amp, etc.) -

if i scope i see weird noise on pins 1, 7, 8, 6 of V3 that is totally not knob dependent - still there with knobs all the way down, and only the gain knob affects it. but if i cut out the previous part of the circuit, around V2, it goes away.

SO its clearly something around V2. i suspect some of the jfet/darlington muting stuff, but its gotten kind of hard to troubleshoot because i only have a dual rec schematic and it doesnt seem to match 100%.....

does anyone have a good triple rec schematic?

PS its not the preamp tubes i swapped em all and ive already replaced most of the Jfets and Darlingtons and smaller filter supply change!

Tubes and Hybrids / Laney VC30 Output Transformer
December 12, 2019, 01:06:25 AM
if you were replacing a blown OT in this 30 Watt, 4xEl84 amp, which one would you get?


(not sure if they have that one - i e-mailed em)



any other suggestions?

part of my issue is the stock transformer thats in the amp is very small - its snuggled between the second preamp 12ax7 and the PI - would like to find something small so i dont have to destroy the chassis putting the new one in.....

thank you!
Amplifier Discussion / Re: Gallien Krueger 800RB
August 19, 2019, 03:42:15 PM
Finally got my hands on the speaker -

Autopsy results point to DC condition -


If the Amp is testing fine on the bench - any thoughts as to how I'd go about tracking this DC failure down??
Amplifier Discussion / Re: Gallien Krueger 800RB
July 23, 2019, 01:58:45 PM
let me see if i can get my hands on the blown speaks -

how would overpowering vs. a DC fault look differently on a blown voice coil?
Amplifier Discussion / Re: Gallien Krueger 800RB
July 23, 2019, 03:03:24 AM
i am - thats how ive been testing it -

Amplifier Discussion / Gallien Krueger 800RB
July 22, 2019, 03:22:39 PM
frustrating issues -

this amp has blown a few woofers - a pair of 10s in a 4x10 and a beefy EV 15 - it blew the 10s after about an hour and a half or so and blew the 15 in under a minute -

problem is, on the bench, it has no measurable issues. no DC on the output - shows me a perfect sine wave at full power on the scope - runs for as long as youd like with no visible problems.

im hesitant to plug it into an actual speaker because i dont wanna blow anything - any ideas what could be happening?

i asked the client about cabs and speaker wiring - the cabs and speaker cables were being used with other amps with no problems.


Looking for a schematic for this amp

Particularly interested in the power amp - Zobel resistor blown, no way to tell what it was.

Thanks guys

recently came across a crazy old gem -

a Gun (United Sound Company) Lead 200

it looks just like this:

with some researched i figured out its a later model Stramp - apparently, after he sold Stramp to Dynacord - because mine is a solid state preamp and tube power amp (with a tube PI). 100W 4xEl34 power section

has anyone ever seen a schematic for this hybrid?? its in rough shape and id love to get it going....
Amplifier Discussion / Re: Polytone 102 Tremolo
February 01, 2019, 01:29:09 PM
thanks, guys!

lamp was on, but no oscillation -

replaced C45 and C46 - the phase shifting caps - and were back in business!

those were weird old black boxy caps - prob dried out just enough to not do their job in this application -

vibrato sounding great!

had to reduce the gain on the reverb a bit - it was feeding back - but amps put together and back in action!

thanks again!
Amplifier Discussion / Polytone 102 Tremolo
January 24, 2019, 02:02:30 PM
finally got this amp almost back to life -

the power amp was busted and, because i could not find a schematic that seemed to match the amp i was looking at, i figured id just replace it with a simple class D thing. got a kit online and wired it up - it even fit the heatsink with no modifications necessary! - and the amp is working fine.

last step: the effects. the reverb is a bit weak (i think i can handle that), but the tremolo is not working at all. the good news is i found the right schematic! the bad news is, i really cant understand how the tremolo circuit is supposed to work - which obviously makes it hard to troubleshoot.

the right schematic is attached - can anyone with a bigger brain than mine explain how this tremolo is supposed to work? and whats that symbol by the LDR?

hey guys!

been a minute -

trying to clean out the crap pile while things are a bit slow at work -

i have this Polytone amp thats been taken apart for quite a bit now - the preamp is perfectly fine but somebody tried to "repair" the power amp and its just a total disaster.

the PT is fine and I decided I am just going to gut it and build a simple power amp from scratch so I can get this thing back to life -

I've got +/- 40V and heatsinks for two output transistors -

Also have a second, lower voltage tap (about +/- 20V) -

can you guys recommend a simple power amp build I can retrofit to this thing? its got a nice cab and a nice preamp with reverb and tremolo and everything - shame for it to die on this bench!
Amplifier Discussion / Re: polytone 102 schematic
March 08, 2018, 01:04:31 PM
gotta be honest - i think id be better off just rebuilding the power amp for this thing - the can does not seem to be matching up with any of the schematics - and even if it did who knows if that can is still good...

any recommendations for a simple single PNP/NPN pair output design? would rather make something that doesnt involve a dual can! +/- 30V rails...right now i have an MJ15023/2N3055 situation (what i had laying around) but id be willing to work with whatever - would like to get this thing working!
Amplifier Discussion / Re: polytone 102 schematic
March 07, 2018, 02:33:59 PM
anyone have any thoughts on this?

here's the thread from ampage - got into it a bit deeper but still no dice...