Build a 1987/2204 or get a 1987x??

[Marcus Johns]

I have used both the 8025AH (784-139 Drake clone) and 8025H (Dagnall clone) and like them both. I lean towards the 8025AH and the color code is correct for those amps. I have no experience with the MM choke and avoid MM when possible because I don't think the extra cost is justified. I don't think the 8058M is available currently, at least through APD. Might be sacrilege but given the current parts supply I would consider the 8003M. It's a 3hy 200ma choke that has the same footprint.

Thanks, I ended up getting the mm choke and heyboer OT yesterday, the mm choke was their last one.

I’m just not sure if the mm choke is a C1999 equivalent?

Also, with the heyboer OT, how the apd heyboer compares to Merryn and Metro Heyboers. I always planned to get the Metro C1999, OT and PT but they have been unavailable now for about six months and just don’t know when they will be available again,

 

[neikeel]

Supply is an issue. I’m still waiting on a couple of 1202-118PTs. One for a resto of a forum member here and one for a build of mine. It is frustrating but at least we are not being bombed or invaded!
Btw stock choke (both Drake 354-114 and C1999) are 3H, 100ohm DCR and 250mA rating.

 

[Chrome]

I have owned and performed with both the 1987 and the 2204(current). to me both are fantastic amps, but the 2204 is much more versatile. you get the best of both worlds with a cascaded pre-amp. you can pull either traditional plexi tones or more aggressive JCM 800 tones. IMHO I don't think there is a better amp than the 2204. for a 50W amp

 

[Marcus Johns]

Only options I have that I can find for a 50w PT are:
- MM (upright mount - my chassis has the large opening for a lay down PT so not sure how this would work?), expensive, can’t find voltage specs on this only B+ of 440v.
- Hammond 290GX (lay down), cheaper, black wouldn't suit aesthetically, 345-0-345 sec - is this period correct voltage for a 1987/jmp/2204?

 

[Dblgun]

Only options I have that I can find for a 50w PT are:
- MM (upright mount - my chassis has the large opening for a lay down PT so not sure how this would work?), expensive, can’t find voltage specs on this only B+ of 440v.
- Hammond 290GX (lay down), cheaper, black wouldn't suit aesthetically, 345-0-345 sec - is this period correct voltage for a 1987/jmp/2204?

Yeah, as @neikeel said there are a bunch of folks waiting for iron. I'm waiting for a choke and P/T from Marstran and it's going to be while. I would caution you to wait and get what it is you want rather than buying something because it's currently available. This especially true for PT and OT's.

 

[Marcus Johns]

Yeah, as @neikeel said there are a bunch of folks waiting for iron. I'm waiting for a choke and P/T from Marstran and it's going to be while. I would caution you to wait and get what it is want rather than buying something because it's currently available. This especially true for PT and OT's.

I agree. I got little impatient - I’m just hoping I the MM choke and Heyboer OT I purchased from Apd will be as good as the Metro spec ones???

 

[Chris-in-LA]

Sorry to resurrect this thread, but have been still sourcing parts. Just want to check if the MM choke (3hy APD-8058M) and Heyboer OT (Drake 794-139) from amp parts direct would be good choices for my 50w 1987/2204 build?

Still need to source a PT.

I’m using 2 x F&T dual 50uF and dual 33uF axial filter caps.

If you mean this 784-139 OT:

Marshall Style 50W Output 4/8/16 APD-8025A-H by Heyboer Transformers (Alternative of APD-8025H))

Heyboer TransformersPremium guitar amplifier power transformers, output transformers and chokes.Proudly manufactured in the U.S.A. Our Part# OEM Part# Type Rating APD-8025A-H Drake 784-139 Output 50W 4/8/16 Alternates: APD-8025H Reference#: 50W OT, Drake wind, more interleaved #784-139 3.4K...

shop.amppartsdirect.com

Then, yes. I just put one in a 2204 clone. It sounds great, just like my Marshall 2204. For the PT in another 2204 clone, I went with a lay down Hammond. It’s a little hotter than the Heyboer PT but was easier to find.

 

[Chris-in-LA]

Thanks, I ended up getting the mm choke and heyboer OT yesterday, the mm choke was their last one.

I’m just not sure if the mm choke is a C1999 equivalent?

Also, with the heyboer OT, how the apd heyboer compares to Merryn and Metro Heyboers. I always planned to get the Metro C1999, OT and PT but they have been unavailable now for about six months and just don’t know when they will be available again,

I have recently used both the Marstran and Merren OT’s as well. The Heyboer is as good IMO.

 

[Marcus Johns]

@Chris-in-LA Thanks, I feel better now - yes, I got the above apd-8025A-H OT.

 

[Marcus Johns]

I got my tubes too before they are unavailable…

 

[Pete Farrington]

If you’ve got a suitable amp, it’s best to check valves soon after receiving them, whilst they’re still in warranty.
Or borrow a friend’s amp to do it.
To protect the amp from valves that short, arc etc, I think it’s good practice to power up new / unknown valves via a light bulb limiter.

 

[Marcus Johns]

If you’ve got a suitable amp, it’s best to check valves soon after receiving them, whilst they’re still in warranty.
Or borrow a friend’s amp to do it.
To protect the amp from valves that short, arc etc, I think it’s good practice to power up new / unknown valves via a light bulb limiter.

That’s a good plan except I don’t have an el34 amp, might need to ask around. I have a light bulb limiter.

 

[Marcus Johns]

Just planning out what I can do with the build while I wait for the PT. I’ll populate the board with the wire lengths as per the v’storm 50w instructions, drill extra earth holes in chassis, mount other components, just some quick questions:

-when populating/installing the board components do you place a bend in the component legs to allow for heating expansion and contractions, most of the gut shots I see this doesn’t seem to be a done thing, it seems to be a trade-off between neatness/asthethics and component life?

- I’ve ordered the perf board, should I place each outgoing wire through the hole adjacent to the turret post and solder each wire to the top of the board turret post? I’m thinking this would be good for future trouble-shooting or mods.

- do I place component legs into the top of the turret post hole and the wires go around the turret post?

 

[Marcus Johns]

I read that cc resistors at v4 and v5 grid work well, I have a stash of cc 5k6 resistors I’m looking find a good pair to use:

 

[Marcus Johns]

Sorry all, another quick question - all of parts have arrived, the only thing I still need to source is a PT. With the ValveStorm 50w chassis it has a laydown PT cutout, so I was hoping to get a Metro or APD Heyboer laydown PT. My question is - do I need the laydown transformer mounting plate for lay down power transformers? There is no mention of using one of these in the Metro 50w instructions.
Also, what is the ideal B+ to be looking for with regards to a PT? The build will be the 2204/1987 2 in 1. If I can’t get a Metro or APD Heyboer PT, I may need to look at either Mercury who has various models with different B+ voltages, I have no idea which is best.

 

[playloud]

Sorry all, another quick question - all of parts have arrived, the only thing I still need to source is a PT. With the ValveStorm 50w chassis it has a laydown PT cutout, so I was hoping to get a Metro or APD Heyboer laydown PT. My question is - do I need the laydown transformer mounting plate for lay down power transformers? There is no mention of using one of these in the Metro 50w instructions.
Also, what is the ideal B+ to be looking for with regards to a PT? The build will be the 2204/1987 2 in 1. If I can’t get a Metro or APD Heyboer PT, I may need to look at either Mercury who has various models with different B+ voltages, I have no idea which is best.

Don't count out Hammond and Modulus (Dagnall) either.

I have no opinions/personal experience on B+, but I've read that 1202-55 should run around 450V, whereas the specs of that APD PT suggest 400V.

 

[Marcus Johns]

@neikeel , just want to confirm the type of 470pf capacitor that goes in parallel with the 470k resistor that comes off the 1000pf off the 2204 gain pot? The SDM layout looks like it is a silver mica, is this correct? Cheers

 

[neikeel]

You can use either as the differences are subtle and a matter of taste but usually either the red Lemco dogbone which is tubular ceramic or simple ceramic disc. On the last couple of 100w I’ve done I used 2200pF RS silver micas and a much smaller bright cap on the pot (120-180pF) but you can tune the values with a cap box and/or croc clips to see what works for you.

 

[Marcus Johns]

You can use either as the differences are subtle and a matter of taste but usually either the red Lemco dogbone which is tubular ceramic or simple ceramic disc. On the last couple of 100w I’ve done I used 2200pF RS silver micas and a much smaller bright cap on the pot (120-180pF) but you can tune the values with a cap box and/or croc clips to see what works for you.

Thanks mate, now I just need to work out the best way to route these couple of components around the push-pull pot and input jack (want to make sure they are mounted stable so they don’t vibrate and break a joint or lead over time), I don’t suppose you have any picks of your input section that shows the 2204 channel low input resistor and cap and 2204 push-pull gain pot?

 

[neikeel]

Best pics I've got at the moment.
If you are stuck I can take some more. I tucked the cap/resistor down the side of the chassis to minimise extraneous noise: