Bringing Up My First Amp

[donvan]

Hello, high plate classic with I believe Peavey iron.
CW

Thanks Charlie. I’m guessing 6l6’s based on the fact that the fuse was labeled 3 amps and it’s a 100 watt amp. Is that a good assumption?

[norburybrook]

I would say so.

Also those peavey transformers give you around 500v DC for your B+

I've made two amps with those transformers, both very sweet sounding amps.



M

[martin manning]

I now have the FET circuit biased (Martin was right - Rs was too big) so my amp is officially fully functional.

I don't know how the battery bias method didn't get this right the first time. The cause was clear from your description, though.

https://www.youtube.com/watch?v=sKunm4Z1IXA

This vid is a great tour of the D sound and ODS operation. Some of the technical explanations are a little off, but overall well above average. Nice guitars and great playing. Comments are entertaining as usual ;^) I agree with the presenter, it takes a good player to fully appreciate what's there and take full advantage of it.

[norburybrook]

https://www.youtube.com/watch?v=sKunm4Z1IXA

I love the sound of this amp

Interesting that Charlie says it's a high plate Classic EQ with peavey iron.


M

[donvan]

I don't know how the battery bias method didn't get this right the first time. The cause was clear from your description, though.

I was confused by that as well. With the battery method and a pot for Rs, I had it dialed right in to get 9V at the FET drain. I even used 2 resisters in series to get really close to the value of the pot and I measured the correct legs of the pot to determine the resistance. I must have made a mistake somewhere but they way I remember it, I took it really slow and made all of my measurements twice. I don't see any reason the battery method wouldn't work for a 2N5486 FET right?

[Charlie Wilson]

https://www.youtube.com/watch?v=sKunm4Z1IXA

I love the sound of this amp

Interesting that Charlie says it's a high plate Classic EQ with peavey iron.


M

A forum member (not me) knows this amp very well. When the original owner wanted to sell it a replica of it was built. He told me he got very close to the sound of the original. I asked him about the circuit and was told high plate classic. I really like that circuit and from my experience the YouTube amp sounds like that circuit. As far as Peavey iron, I think he told me that is what was used but I am not sure. Said forum member may see this and chime in.

[talbany]

Here is one for ya. I think it's 185? (don't quote me) Yes it's an HRM Peavy Iron /w Resistor choke. Yes I know where are the pots for the HRM stack? He used fixed resistors under the board instead

Tony

[donvan]

Wow! Thanks Tony!

[talbany]

Wow! Thanks Tony!

Your Welcome!. I don't know what happened to the Amp Garage? It used to be people were interested (some excited)in gut shots of Overdrive Specials. Now it just gets a giant Yawn!!
Seen one you've seen them all I guess.

Tony

[M Fowler]

Tony,

Thanks for the photos and info.

I saw the HRM board and said what is going on there!

Mark

[talbany]

Tony,

Thanks for the photos and info.

I saw the HRM board and said what is going on there!

Mark

Your welcome Mark thanks for the shout out!. Yeah, it's hard to say what's going on there? given that each amp will have it's own timbre one would figure pots would need to be a necessity to set the amp up!. Well apparently not. Somewhere I think I have the value of those resistors written down. It does, however, make sense each HRM pad were set fairly close for him to be able to forgo the pots and set them via a fixed resistor value. Could also be he didn't have any trimmer pots on hand. From what I know 185 is a very good sounding amp!!

Tony

[Aaron]

Cool pics Tony. Thanks.
Looks like the OD trimmer network has been modded to Bluesmaster style. Notice the small cap, there's probably a parallel resistor under it.

The youtube amp is #128, High Plate but I'm pretty sure Fender Transformers.

Thanks,
Aaron

[Aaron]

Also, #185 has the snubbers on V2, other HRM amps don't usually have these, AFAIK.

Aaron

[Charlie Wilson]

Cool pics Tony. Thanks.
Looks like the OD trimmer network has been modded to Bluesmaster style. Notice the small cap, there's probably a parallel resistor under it.

The youtube amp is #128, High Plate but I'm pretty sure Fender Transformers.

Thanks,
Aaron

Ok I’ll split the difference. Fender power and Peavey OT(confirmed ).
CW

[donvan]

Wow! Thanks Tony!

Your Welcome!. I don't know what happened to the Amp Garage? It used to be people were interested (some excited)in gut shots of Overdrive Specials. Now it just gets a giant Yawn!!
Seen one you've seen them all I guess.

Tony

Tony,
Gut shots are exciting to me. Please don't stop. And while we are on the subject, I have really learned a lot from your several years of posting photos, layouts, and great comments. Thanks for all of that!

Don