A new Peavey classic VT to HRM conversion

[erwin_ve]

Inspired by BobI's conversion of an old Peavey Classic VT to HRM I decided to do the same thing. Mine is with build in dumblelator
I'm in the middle of the build right now, here are some pics:

[stelligan]

Nice looking work. Man, there's a lot of room in that chassis!

[Bob-I]

Looking good. I used mine at the gig last night, sounded superb with a Hwy 1 Tele

[erwin_ve]

Nice looking work. Man, there's a lot of room in that chassis!

Thanks! I have some room for rent Serious; there is much room, but somehow a bit limited by the position of the OT.

Looking good. I used mine at the gig last night, sounded superb with a Hwy 1 Tele

I'm looking forward to use mine, thanks for all the inspiration I got from your build.

[erwin_ve]

The innards are almost done, only heater wires are left.

[bluesfendermanblues]

Do you really want Both as Clean master, OD master and (master) master?

The HRM 101 uses only a Clean master and OD master, but not the third master.

[erwin_ve]

Do you really want Both as Clean master, OD master and (master) master?

The HRM 101 uses only a Clean master and OD master, but not the third master.

Yes, because the last knob of the built-in dlator becomes the master. And I want that pot on the front! Besides that, I had 1 hole left

[bluesfendermanblues]

Ok, thats a good thinking

Remember to use shielded leads to/from the dumbleator. It can be a slightly noisy bucker.

[erwin_ve]

Ok, thats a good thinking

Remember to use shielded leads to/from the dumbleator. It can be a slightly noisy bucker.

I use shielded leads; Rg178 is thin shielded wire.

[erwin_ve]

And the innards done!

[Bob-I]

Looking good. Very cool having all that room isn't it

[erwin_ve]

Looking good. Very cool having all that room isn't it

Hi Bob,

Thnx!
That's cool indeed, but I am still touching other wires with my solder iron

[erwin_ve]

I fired her up today!
It squeeled like a pig at first, after disconnecting the GNFB the squeel was gone. So 2 wires at the PI has to be inverted.

Od and also Od with PAB are good sounding, no hum issues.
However the clean channel is humming like a bee(100Hz), so I suspect something is wrong at the Od/clean channel switching relays.


Also the voltages are high;
B1= 530v
B2= 529v
B3: 485v
B4: 401v
B5: 397v
F.e the plate voltage at v1a is 244V, v1b is 249v
Way too high.
My dropping string is 4,7k-22k- 2,2k
The Ps filtering at B1 is 2x100uF in series.
At B2 2x 68uF in series.
after that they are followed by the usual 1 cap(22uF) per node.

Anyone suggestions for my voltages and hum issue?

[bluesfendermanblues]

I fired her up today!
It squeeled like a pig at first, after disconnecting the GNFB the squeel was gone. So 2 wires at the PI has to be inverted.

Od and also Od with PAB are good sounding, no hum issues.
However the clean channel is humming like a bee(100Hz), so I suspect something is wrong at the Od/clean channel switching relays.


Also the voltages are high;
B1= 530v
B3: 483v
F.e the plate voltage at v1 is 240V.
Way too high.
My dropping string is 4,7k-22k- 2,2k
The Ps filtering at B1 is 2x100uF in series.
At B2 2x 68uF in series.
after that they are followed by the usual 1 cap(22uF) per node.

Anyone suggestions for my voltages and hum issue?

Regarding voltage issue:

a) Do you have the 150K at the end of the PSU?

b) If you do, then increase the 4.7K to around 10K in order to lower the voltages in the preamp(s).

c) The higher voltage should not be a problem in the power amp. However, the 483v on B3 (PI) could be a little on the high side, depending on the voltage on the PI pin 3. A 12AX7 do not like more than 300V between pin 1 and 3 respectively pin 6 and 8.

(My new build EL34 with ODS and HRM OD's has 580V on its EL34 plates, which is not a problem....on the contrary, its great and pushed around 75watts out of a pair of EL34s. FWIW my dropping string is 12k- 22k- 2.2k)

[erwin_ve]

Hi Claus,

Thanks for your response.
I don't have 150k at the end of the PS. Will try that.

The PI voltage is 331/327v which is too high as you mentioned.
I will try a 10k in instead of 4,7k.

Thanks!